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Sample records for 2u-globulin hyaline droplet

  1. Effect of gonadotropins and alpha 2u-globulin on testicular steroidogenesis and spermatogenesis in melatonin-treated rats

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    R Biswas

    2012-09-01

    Full Text Available Administration of melatonin (400?g/100g bd.wt. for 14 days caused a fall in weights of the testes and accessory sex organs and testicular 17?-hydroxysteroid dehydrogenase (17?-HSD but rise in 3?-hydroxysteroid dehydrogenase (3?-HSD activity, decreased spermatogenesis, serum level of gonadotropins, testosterone and alpha 2u-globulin, The animals treated with melatonin when received gonadotropins or alpha 2u-globulin for the last seven days reversed the weight of testis and accessory sex organs, 3?-HSD, 17?-HSD activities, serum level of gonadotropins, testosterone and alpha 2u-globulin when compared with melatonin-treated rats. It is concluded that alpha 2u-globulin prevents testicular degeneration in melatonin-treated rats by stimulating the synthesis of gonadotropins. Journal of College of Medical Sciences-Nepal,2012,Vol-8,No-1, 7-12 DOI: http://dx.doi.org/10.3126/jcmsn.v8i1.6819

  2. Detection of α2u-globulin in rat pup preputial gland by Maldi-tof mass spectrometry

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    Ponnirul PONMANICKAM,Gnanasekaran JEBAMERCY, Govindaraju ARCHUNAN, Soundrapandian KANNAN

    2009-08-01

    Full Text Available The α2u-globulin, a soluble protein identified in the urine and preputial gland of adult male rat is reported to be pheromone carrier. The pup preputial gland plays a significant role in chemical communication for mother-young interaction; however, the presence of a pheromone-carrying protein in the pup preputial gland has not been confirmed. Therefore, the present study was carried out to identify the α2u-globulin in the pup preputial gland by Matrix Assisted laser Desorption Ionization Time of Flight mass spectrometry (MALDI-TOF. The preputial glands of prepubertal rats were subjected to one-dimensional SDS-PAGE. In-gel trypsin digestion of a 18 kDa band was carried out and analyzed by MALDI-TOF. The results of a MASCOT search showed the presence of α2u-globulin in the18 kDa band. In contrast to the report of the synthesis of this protein only in adult rats, the identification of this protein in pup preputial gland is significant. The results suggest that synthesis of α2u-globulin in the rat preputial gland starts in the prepubertal stage itself. In prepubertal rats, the preputial gland is a source of pheromone for performing anogenital licking behaviour by the mother rat. Since α2u-globulin belongs to the lipocalin (ligand carrier family, it might carry the volatile for processing pheromonal communication in mother-pup bonding in rat [Current Zoology 55(4: 296–300, 2009].

  3. EFFECTS OF FOUR TRIHALOMETHANES ON DNA STRAND BREAKS, RENAL HYALINE DROPLET FORMATION AND SERUM TESTOSTERONE IN MALE F-344 RATS

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    All four possible trihalomethanes (THMs) containing bromine and chlorine, as well as perchloroethylene (PCE), were evaluated for their ability to produce DNA strand breaks, a2u-globulin rich renal deposits, and testosterone changes in male F-344 rats. Rats received daily equimola...

  4. Effects of a major androgen-dependent urinary protein,. alpha. 2u-globulin on the pituitary-gonadal axis and hypothalamic monoamines in adult male mice

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    Ghosh, P.K.; Chandrashekar, V.; Steger, R. Bartke, A. (Southern Illinois Univ., Carbondale (USA))

    1990-01-01

    The purpose of the present study was to evaluate the effects of alpha-2u-globulin, a sex-dependent male rat urinary protein on pituitary-gonadal functions and hypothalamic monamine contents in male mice. Adult male mice, maintained under standardized laboratory conditions were injected subcutaneously with alpha-2u-globulin or with vehicle daily for 14 days and killed 16 h after the last injection. Plasma levels of luteinizing hormone (LH), follicle-stimulating hormone (FSH), testosterone (T) and testicular levels of T were measured by radioimmunoassays. The concentrations of norepinephrine (NE), dopamine (DA) and serotonin (5-HT) in medial basal hypothalamus (MBH) and anterior hypothalamus (AH) were measured by high performance liquid chromatography. Administration of alpha-2u-globulin led to a significant increase in plasma FSH and LH levels. In the MBH of alpha-2u-globulin treated mice, there were significant elevations of NE, DA and 5-HT contents. In the AH, both DA and 5-HT contents were decreased while NE content remained unaltered.

  5. Cytoplasmic androgen binding protein of rat liver: molecular characterization after photoaffinity labeling and functional correlation with the age-dependent synthesis of alpha 2u-globulin

    International Nuclear Information System (INIS)

    The liver of the mature male rat contains a moderate affinity (Kd = 10(-8)M), low-capacity, cytoplasmic androgen binding protein (CAB) whose appearance during puberty and disappearance during senescence correlate with the androgen-dependent synthesis of alpha 2u-globulin. Molecular properties of CAB were examined by photoaffinity labeling with tritiated methyltrienolone (R-1881), a synthetic androgen, and by its localization within the hepatocytes which are competent to produce alpha 2u-globulin. Photoaffinity labeling of the liver cytosol derived from postpubertal male rats, followed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and fluorography, showed a predominant androgen binding band corresponding to Mr 31,000. This 31-kilodalton (kDa) binding component was conspicuously absent in the liver of androgen-insensitive prepubertal and senescent male rats and in adult male rats treated with estradiol-17 beta. In addition, unlike the cytoplasmic extract, the nuclear lysate of the male rat hepatocytes did not contain the 31-kDa androgen binder. Disappearance of the 31-kDa androgen binding band from the cytosolic fraction of androgen-insensitive animals was associated with a concomitant appearance of a minor androgen binding component of apparent Mr 29,000. The livers of postpubertal male rats normally contain two subpopulations of hepatocytes, only one of which is highly active (competent) in alpha 2u-globulin synthesis. Separation of these two subpopulations through a fluorescence-activated cell sorter followed by whole cell labeling showed more than a 2-fold higher uptake of R-1881 by the competent cells

  6. Complex histopathologic response in rat kidney to oral β-myrcene: an unusual dose-related nephrosis and low-dose alpha2u-globulin nephropathy.

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    Cesta, Mark F; Hard, Gordon C; Boyce, John T; Ryan, Michael J; Chan, Po C; Sills, Robert C

    2013-01-01

    Oral gavage studies with β-myrcene in male F344 rats showed a complex renal pathology comprising both alpha2u-globulin (α2u-g) nephropathy, an unusual nephrosis involving the outer stripe of outer medulla (OSOM), and an increased incidence of renal tubule tumors by 2 years. In the 90-day and 2-year studies, respectively, α2u-g nephropathy and linear papillary mineralization were observed in males at the two lower doses but were absent from the high dose. Nephrosis was characterized by dilation of the S3 tubules, nuclear enlargement (including karyomegaly), and luminal pyknotic cells, all in the outermost OSOM. Nephrosis was minimal at the higher doses in the 90-day study, but progressed to a severe grade in males dosed with 1,000 mg/kg for 2 years. Renal tubule tumors developed in treated groups with incidences up to 30% in the 250 and 500 mg/kg male dose groups. Tumors at the lower doses in males may have been associated with α2u-g nephropathy, while those at higher doses in both sexes may have been due to the nephrosis. Because β-myrcene induced a complex spectrum of renal pathology, the α2u-g nephropathy mechanism cannot be the sole mechanism of carcinogenesis in these rats.

  7. Pulmonary hyalinizing granulomas.

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    Macedo, E V; Adolph, J

    1985-03-01

    Little has been written about pulmonary hyalinizing granuloma as a cause of nodules in the lungs. In a patient with a past history of carcinoma of the breast, the diagnosis made a significant difference in the prognosis. PMID:2984210

  8. [Pulmonary hyalinizing granuloma].

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    Westhoff, M; Litterst, P; Albert, M; Welim, B

    2015-01-01

    Benign lesions as pulmonary hyalinizing granuloma may mimic a malign disease. A 63-year old patient complained dyspnea and a weight loss of 30 kg. CT-thorax scans showed a destructive and infiltrative pulmonary process with pleural thickening. Histologic examination of transbronchial and transthoracic biopsies as well as of biopsies taken by minithoracotomy was not conclusive. Due to further progression the patient underwent a left-sided pleuropneumonectomy despite a VO2 peak of 9 ml/kg/min. Histology revealed DIP-like infiltrations, a histiocytic reaction and hyaline granulomas. Among less than 100 published cases of pulmonary hyaline granuloma a comparable rapid progression with a total functional loss of the affected lung is not reported. Mostly hyalinizing granuloma presents with infiltrations, which may mimic lung cancer, or nodular lesions, partly with cavitations or calcifications. The etiology is unknown, a persistent immunologic response to an antigenic stimulus is discussed. Associations with infections, lymphomas, amyloidosis or IgG4-related disease are reported. Some cases have features of multifocal fibrosis. In the case reported none of these associations could be found. The prognosis of pulmonary hyaline granuloma is regarded as benign. There is no effective treatment yet. Once the diagnosis has been established a conservative approach as well as a resection of nodules and a therapeutic attempt with steroids are an option. Extensive resections as pleuropneumonectomy are an exception. PMID:25599140

  9. Symptomatic pulmonary hyalinizing granuloma.

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    Ramirez, J; Mehta, J B; Taylor, R A; Byrd, R P; Roy, T M

    1998-09-01

    An otherwise healthy 37-year-old man came to the emergency room with left-sided dull chest pain of 4 weeks' duration. Physical examination, laboratory studies, and electrocardiogram were all unremarkable. A chest x-ray film revealed calcified pulmonary nodules. Computed tomography of the chest confirmed bilateral parenchymal cavitary lesions. Via limited thoracotomy, a tan nodule measuring 2.5 to 3.0 cm in diameter was excised from the left upper lobe. Histopathologic examination revealed a well circumscribed lesion and extensive lamellar hyalinization. A few foci of finely granular calcification were present within the hyalinizing areas. After surgery and short-term use of nonnarcotic analgesics, the chest pain resolved. Although pulmonary hyalinizing granuloma (PHG) is known to produce cavitating lesions, calcification at multiple sites is also consistent with this diagnosis. Clinicians should remember to include PHG in the differential diagnosis of multiple pulmonary nodules. PMID:9743062

  10. [Multiple pulmonary hyalinizing granuloma].

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    Haro, M; Ruiz, J; Vila, X; Avellanet, M; Izquierdo, J

    1994-01-01

    The causes of multiple pulmonary nodules are many, with metastasis being the most feared. A rare but possible etiology, however, is hyalinizing multiple granuloma. We present a case that allows us to review this condition and its course, as well as a variety of associated immunological changes and possible complications. PMID:8087395

  11. Juvenile hyaline fibromatosis.

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    Larralde, M; Santos-Muñoz, A; Calb, I; Magariños, C

    2001-01-01

    Juvenile hyaline fibromatosis (JHF) is a rare autosomal recessive disease with onset in infancy or early childhood. It is characterized by papulonodular skin lesions, soft tissue masses, gingival hypertrophy, and flexion contractures of the large joints. The light and electron microscopic features are very distinctive. Here we report an 8-month-old boy with characteristic stiffness of the knees and elbows and pink confluent papules on the paranasal folds, and periauricular and perianal regions. He also had hard nodules all over the scalp and around the mouth, and severe gingival hypertrophy. Histologic and ultrastructural features were typical of JHF. Clinical features, pathology, and physiology are discussed.

  12. Hyaline fibromatosis syndrome: cutaneous manifestations*

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    Marques, Silvio Alencar; Stolf, Hamilton Ometto; Polizel, Juliana Ocanha; Munhoz, Tânia; Brandão, Marcela Calixto; Marques, Mariangela Esther Alencar

    2016-01-01

    Hyaline fibromatosis syndrome is the current name for clinical manifestations of diseases previously known as “infantile systemic hyalinosis” and “juvenile hyaline fibromatosis”. The authors report representative clinical cases of each one of the above subtypes with emphasis on cutaneous manifestations and difficulties for early diagnosis in this syndrome, essentially of multidisciplinary approach. PMID:27192526

  13. Recurrent pulmonary hyalinizing granuloma.

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    Arruda, Guilherme D'Andréa Saba; Carvalho, Paulo César Ribeiro de; Andrade, Mara Patrícia Guilhermino de; Cusmanich, Maurício Campos; Bandeira, Gustavo; Tozaki, Felipe Shigueo Passos

    2010-01-01

    We report the case of a 61-year-old male patient who underwent surgical excision of a lung mass for anatomopathological study. The patient had previously presented with fever, dry cough, and chest pain, together with lung masses detected by chest X-ray, and had undergone thoracotomy for diagnostic investigation on two occasions (1976 and 1981), although a conclusive diagnosis had not been made. A CT scan of the chest revealed large masses with areas of calcification in both lung fields. The anatomopathological study was consistent with pulmonary hyalinizing granuloma. In the postoperative period, the patient experienced several episodes of bronchospasm, which was reversible with the use of symptomatic medication. At this writing, the patient was receiving maintenance therapy with prednisone (40 mg/day) and had shown clinical improvement. PMID:21085833

  14. Juvenile hyaline fibromatosis

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    Jayashree Krishnamurthy

    2011-01-01

    Full Text Available Juvenile hyaline fibromatosis is a rare, autosomal-recessive disease characterized by papular and nodular skin lesions, gingival hyperplasia, joint contractures and bone involvement in variable degrees. It is a connective tissue disorder with aberrant synthesis of glycosaminoglycans by fibroblasts. We report a 5-year-old female born of first-degree consanguineous marriage who presented with multiple, recurrent, painless, variable-sized nodules. Fine needle aspiration cytology smears and the subsequent histopathological examination from the nodules showed benign spindle cells in a Periodic acid Schiff-positive myxoid background. The disease has a relentlessly progressive course, with most patients surviving only up to the 4 th decade. As of now, there is no specific treatment for this disorder. Genetic counseling is essential to explain to parents about a 25% chance of having a diseased baby in any pregnancy. With the gene being mapped recently, techniques for antenatal diagnosis are likely to be established.

  15. The pathogenesis of hyaline arteriolosclerosis.

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    Gamble, C. N.

    1986-01-01

    Although hyaline arteriolosclerosis is very common and has been of interest to pathologists for well over 100 years, its pathogenesis has never been determined. This study demonstrates that iC3b bound via an ester linkage to hydroxyl groups on the repeating disaccharide units of hyaluronic acid is a major component of arteriolar hyaline. The deposition of iC3b within the walls of arterioles appears to be due to slow spontaneous activation of the alternative complement pathway and random bindi...

  16. Pulmonary hyalinizing granuloma with hydronephrosis.

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    Hashimoto, Seiji; Fujii, Wataru; Takahashi, Tatsurou; Shiroshita, Koichi; Sakurai, Tetsuo; Ueda, Takahiro; Kawata, Tetsuya

    2002-06-01

    A 49-year-old man was admitted for the evaluation of a bilateral mass shadow in his chest X-ray film. No definitive diagnosis was established either by brushing cytology or biopsy through bronchoscopy. No malignancies were suggested by general work-up. Both masses were surgically removed, and were diagnosed as pulmonary hyalinizing granuloma (PHG). Fifteen months later, low grade fever continued and the renal function decreased. Laboratory examinations revealed bilateral hydronephrosis with polyclonal hypergammaglobulinemia. The findings of abdominal CT and urography were compatible with retroperitoneal fibrosis. Steroid treatment completely reversed the initial abnormality in laboratory data and the symptoms disappeared. PMID:12135180

  17. Pulmonary Hyalinizing Granuloma in HIV/AIDS

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    Theresa Liu

    2007-01-01

    Full Text Available A 55-year-old man who was recently diagnosed with HIV/AIDS developed multiple bilateral pulmonary nodules after starting highly active antiretroviral therapy. Workup confirmed the diagnosis of pulmonary hyalinizing granuloma. This is the first described case of pulmonary hyalinizing granuloma in HIV/AIDS, and may represent a rare form of immune reconstitution inflammatory syndrome.

  18. Pulmonary hyalinizing granuloma in HIV/AIDS.

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    Liu, Theresa; Kyrollos, Maggy; Kravcik, Stephen

    2007-09-01

    A 55-year-old man who was recently diagnosed with HIV/AIDS developed multiple bilateral pulmonary nodules after starting highly active antiretroviral therapy. Workup confirmed the diagnosis of pulmonary hyalinizing granuloma. This is the first described case of pulmonary hyalinizing granuloma in HIV/AIDS, and may represent a rare form of immune reconstitution inflammatory syndrome. PMID:18923729

  19. Pulmonary Hyalinizing Granuloma in HIV/AIDS

    OpenAIRE

    Theresa Liu; Maggy Kyrollos; Stephen Kravcik

    2007-01-01

    A 55-year-old man who was recently diagnosed with HIV/AIDS developed multiple bilateral pulmonary nodules after starting highly active antiretroviral therapy. Workup confirmed the diagnosis of pulmonary hyalinizing granuloma. This is the first described case of pulmonary hyalinizing granuloma in HIV/AIDS, and may represent a rare form of immune reconstitution inflammatory syndrome.

  20. Pulmonary hyalinizing granuloma mimicking lung carcinoma.

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    Basoglu, A; Findik, S; Celik, B; Yildiz, L

    2006-06-01

    Pulmonary hyalinizing granuloma has rarely been reported and is a benign entity of unknown origin. The chest radiograph reveals multiple and frequently bilateral pulmonary nodules. We describe a patient with pulmonary hyalinizing granuloma who presented with a central mass in the left lung mimicking lung carcinoma. PMID:16755455

  1. Pulmonary hyalinizing granuloma in HIV/AIDS

    Science.gov (United States)

    Liu, Theresa; Kyrollos, Maggy; Kravcik, Stephen

    2007-01-01

    A 55-year-old man who was recently diagnosed with HIV/AIDS developed multiple bilateral pulmonary nodules after starting highly active antiretroviral therapy. Workup confirmed the diagnosis of pulmonary hyalinizing granuloma. This is the first described case of pulmonary hyalinizing granuloma in HIV/AIDS, and may represent a rare form of immune reconstitution inflammatory syndrome. PMID:18923729

  2. Pulmonary Hyalinizing Granuloma Mimicking Metastatic Lung Cancer

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    Nuri Düzgün

    2015-01-01

    Full Text Available Pulmonary hyalinizing granuloma is a very rare benign condition, which usually manifests as solitary and sometimes as multiple pulmonary nodules. Deposition of immune complexes in the lung parenchyma due to hypersensitivity reactions is implicated in the etiology of pulmonary hyalinizing granuloma. A 59-year-old female patient who presented to our clinic with complaints of chest pain and cough had bilateral, multiple, and rounded lesions with regular margins suggesting metastatic lung disease. A transthoracic needle biopsy of the nodule was performed in the left pulmonary anterior segment. Biopsy showed no malignancy. Since no diagnosis was made by the biopsy, the patient underwent a video-assisted thoracic surgery. The wedge biopsy reported pulmonary hyalinizing granuloma. We aimed to present the diagnosis and treatment stages of our patient who was diagnosed with pulmonary hyalinizing granuloma in the light of literature review.

  3. Pulmonary Hyalinizing Granuloma Mimicking Metastatic Lung Cancer.

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    Düzgün, Nuri; Kurtipek, Ercan; Esme, Hıdır; Eren Karanis, Meryem İlkay; Tolu, İsmet

    2015-01-01

    Pulmonary hyalinizing granuloma is a very rare benign condition, which usually manifests as solitary and sometimes as multiple pulmonary nodules. Deposition of immune complexes in the lung parenchyma due to hypersensitivity reactions is implicated in the etiology of pulmonary hyalinizing granuloma. A 59-year-old female patient who presented to our clinic with complaints of chest pain and cough had bilateral, multiple, and rounded lesions with regular margins suggesting metastatic lung disease. A transthoracic needle biopsy of the nodule was performed in the left pulmonary anterior segment. Biopsy showed no malignancy. Since no diagnosis was made by the biopsy, the patient underwent a video-assisted thoracic surgery. The wedge biopsy reported pulmonary hyalinizing granuloma. We aimed to present the diagnosis and treatment stages of our patient who was diagnosed with pulmonary hyalinizing granuloma in the light of literature review. PMID:26347384

  4. Pulmonary Hyalinizing Granuloma Mimicking Metastatic Lung Cancer

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    Düzgün, Nuri; Kurtipek, Ercan; Esme, Hıdır; Eren Karanis, Meryem İlkay; Tolu, İsmet

    2015-01-01

    Pulmonary hyalinizing granuloma is a very rare benign condition, which usually manifests as solitary and sometimes as multiple pulmonary nodules. Deposition of immune complexes in the lung parenchyma due to hypersensitivity reactions is implicated in the etiology of pulmonary hyalinizing granuloma. A 59-year-old female patient who presented to our clinic with complaints of chest pain and cough had bilateral, multiple, and rounded lesions with regular margins suggesting metastatic lung disease. A transthoracic needle biopsy of the nodule was performed in the left pulmonary anterior segment. Biopsy showed no malignancy. Since no diagnosis was made by the biopsy, the patient underwent a video-assisted thoracic surgery. The wedge biopsy reported pulmonary hyalinizing granuloma. We aimed to present the diagnosis and treatment stages of our patient who was diagnosed with pulmonary hyalinizing granuloma in the light of literature review. PMID:26347384

  5. Genetics Home Reference: juvenile hyaline fibromatosis

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    ... Antaya RJ, Cajaiba MM, Madri J, Lopez MA, Ramirez MC, Martignetti JA, Reyes-Múgica M. Juvenile hyaline ... 103. Citation on PubMed Dowling O, Difeo A, Ramirez MC, Tukel T, Narla G, Bonafe L, Kayserili ...

  6. Pulmonary Hyalinizing Granuloma Mimicking Metastatic Lung Cancer

    OpenAIRE

    Nuri Düzgün; Ercan Kurtipek; Hıdır Esme; Meryem İlkay Eren Karanis; İsmet Tolu

    2015-01-01

    Pulmonary hyalinizing granuloma is a very rare benign condition, which usually manifests as solitary and sometimes as multiple pulmonary nodules. Deposition of immune complexes in the lung parenchyma due to hypersensitivity reactions is implicated in the etiology of pulmonary hyalinizing granuloma. A 59-year-old female patient who presented to our clinic with complaints of chest pain and cough had bilateral, multiple, and rounded lesions with regular margins suggesting metastatic lung disease...

  7. [Pulmonary hyalinizing granuloma mimicking pulmonary carcinoma].

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    Uçvet, Ahmet; Tözüm, Halil; Gürsoy, Soner; Gülle, Ali Alper; Yaldiz, Sadik; Aydoğdu Dinç, Zekiye

    2006-01-01

    Pulmonary hyalinizing granuloma is a rare fibrosing nodular disease of the lung characterized by solitary or multiple pulmonary nodules. They can occur after inflammatory or post-inflammatory changes. A 60 years old asymptomatic patient admitted to our clinic because of a solid mass of 6 cm in his routine chest radiography. A lobectomy was performed and the histological diagnosis was reported as pulmonary hyalinizing granuloma. This case, mimicking pulmonary carcinoma, is rarely found in the literature. PMID:16615022

  8. P-Nitrobenzoic acid alpha2u nephropathy in 13-week studies is not associated with renal carcinogenesis in 2-year feed studies.

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    Williams, K D; Dunnick, J; Horton, J; Greenwell, A; Eldridge, S R; Elwell, M; Sills, R C

    2001-01-01

    The objective of this study was to characterize the renal toxicity and carcinogenicity of p-nitrobenzoic acid in F344 rats. Dose levels in 13-week and 2-year studies ranged from 630-10,000 ppm and 1,250-5,000 ppm, respectively. At 13 weeks, renal lesions included minimal to mild hyaline droplet accumulation in male rats and karyomegaly in male and female rats. At 2 years, renal lesions included proximal tubule epithelial cell hyperplasia in male rats and oncocytic hyperplasia in high-dose male and female rats, and a decreased severity of nephropathy in males and females. The hvaline droplets in renal tubular epithelial cells of male rats at 13 weeks were morphologically similar to those described in alpha2u-globulin nephropathy. Using immunohistochemical methods, alpha2u-globulin accumulation was associated with the hyaline droplets. In addition, at 13 weeks, cell proliferation as detected by PCNA immunohistochemistry was significantly increased in males exposed to 5,000 and 10,000 ppm when compared to controls. Cytotoxicity associated with alpha2U-globulin nephropathy such as single-cell necrosis of the P2 segment epithelium or accumulation of granular casts in the outer medulla did not occur in the 13-week study. In addition, chronic treatment related nephrotoxic lesions attributed to accumulation of alpha2u-globulin such as linear foci of mineralization within the renal papilla, hyperplasia of the renal pelvis urothelium and kidney tumors were not observed. Although there was histologic evidence of alpha2u-globulin accumulation in male rats at 13 weeks, the minimal severity of nephropathy suggests that the degree of cytotoxicity was below the threshold, which would contribute to the development of renal tumors at 2 years.

  9. A case of pulmonary hyalinizing granuloma.

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    Anazawa, Y; Nagai, H; Motomiya, M; Isawa, T; Saito, Y; Takahashi, T; Kawabata, Y

    1992-05-01

    A case of pulmonary hyalinizing granuloma was presented. The patient was a 37-year-old male who was found to have abnormal chest roentgenograms showing multiple pulmonary nodules taken at the annual chest mass survey in October 1989. The largest nodule measured 35 mm in diameter. He was asymptomatic. No definite diagnosis was established either by brushing cytology, biopsy through bronchoscopy or percutaneous needle biopsy. No abnormalities were found in the GI tract, the urogenital system or the bone. Brain CT indicated an iso-density area surrounded by low density in the left fronto-parietal region. Two nodules of the lingula removed by open lung biopsy revealed a homogeneous cut surface. Histological diagnosis was pulmonary hyalinizing granuloma, consisting of hyalinized collagen fibers and bundles infiltrated with chronic inflammatory cells. No therapeutic effect was recognized with prednisolone. Craniotomy was performed and the brain lesion was removed. Anaplastic astrocytoma was the diagnosis. The brain lesion had no etiological correlation with pulmonary hyalinizing granuloma. Pulmonary hyalinizing granuloma itself is a rare benign disease with no specific therapy and is important in the differential diagnosis of lung diseases showing multiple pulmonary nodules. PMID:1280866

  10. Hyaline Fibromatosis Syndrome: A Rare Inherited Disorder

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    Mantri, Meeta Dipak; Pradeep, Mahajan M; Kalpesh, Patil O; Pranavsinh, Raj J

    2016-01-01

    Hyaline fibromatosis syndrome (HFS) is rare autosomal recessive disease characterized by the deposition of amorphous hyaline material in skin and visceral organs. It represents a disease spectrum with infantile systemic hyalinosis (ISH) being the severe form and juvenile hyaline fibromatosis (JHF) being the mild form. Dermatologic manifestations include thickened skin, perianal nodules, and facial papules, gingival hyperplasia, large subcutaneous tumors on the scalp, hyperpigmented plaques over the metacarpophalangeal joints and malleoli, and joint contractures. ISH shows a severe visceral involvement, recurrent infections, and early death. We report a case of 2.5-year-old female patient who presented with HFS who had overlapping features of both ISH and JHF. To the best of our knowledge, very few cases of HFS have been reported in Indian literature till date. PMID:27688461

  11. Hyaline fibromatosis syndrome: A rare inherited disorder

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    Meeta Dipak Mantri

    2016-01-01

    Full Text Available Hyaline fibromatosis syndrome (HFS is rare autosomal recessive disease characterized by the deposition of amorphous hyaline material in skin and visceral organs. It represents a disease spectrum with infantile systemic hyalinosis (ISH being the severe form and juvenile hyaline fibromatosis (JHF being the mild form. Dermatologic manifestations include thickened skin, perianal nodules, and facial papules, gingival hyperplasia, large subcutaneous tumors on the scalp, hyperpigmented plaques over the metacarpophalangeal joints and malleoli, and joint contractures. ISH shows a severe visceral involvement, recurrent infections, and early death. We report a case of 2.5-year-old female patient who presented with HFS who had overlapping features of both ISH and JHF. To the best of our knowledge, very few cases of HFS have been reported in Indian literature till date.

  12. A case of juvenile hyaline fibromatosis.

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    Yayli, Savaş; Uncu, Sibel; Alpay, Köksal; Yildiz, Kadriye; Cimşit, Gülseren; Bahadir, Sevgi

    2006-04-01

    Juvenile hyaline fibromatosis (JHF) is a rare, autosomally-recessive disease characterized by papulonodular skin lesions, soft tissue masses, joint contractures, gingival hypertrophy and osteolytic bone lesions. Its onset is in infancy or early childhood. The most commonly affected sites are the nose, chin, ears, scalp, back and knees. The accumulation of an amorphous, hyaline material is typical in the skin and the other organs. Herein, we report a 14-month-old boy who presented with confluent pink papules on the paranasal folds and the chin, and nodular lesions on the periauricular and perianal regions. He had gingival hypertrophy and contractures of the shoulders, knees and elbows. He also had third-degree consanguineous parents. Histopathological studies confirmed the diagnosis of JHF with the presence of increased numbers of fibroblasts embedded in a hyalinized connective tissue stroma.

  13. [A case of multiple pulmonary hyalinizing granuloma].

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    Wierzbicka, Martyna; Kuś, Jan; Langfort, Renata

    2002-01-01

    Pulmonary hyalinizing granulomata are unusual, noninfectious lesions of the lung of uncertain etiology. The pathologic entity may represent a peculiar form of pulmonary immune reaction. We report the history of a 23-year-old woman who had nodular lesions in the right lung without any other abnormalities. Non-invasive procedures didn't yield diagnosis. Thoracotomy was performed. During intraoperative microscopic examination of one of 4 nodules, neoplastic disease was excluded. Remaining 3 nodules were also resected. The pulmonary hyalinizing granuloma was recognised in the histological examination. Follow-up after 12 months didn't reveal recurrence. PMID:12148183

  14. AB 73. Pulmonary hyalinizing granuloma: case report

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    Papaemmanouil, Stiliani; Cheva, Aggeliki; Dimitriadis, John; Sakkas, Leonidas

    2012-01-01

    Background Pulmonary hyalinizing granuloma is an unusual condition, characterized by fibrosing nodules, consisting of the either unilateral or bilateral central whorled deposits of lamellar collagen hyaline. Although the etiology is uncertain there are evidences that suggest an autoimmune origin. Clinically and with imaging techniques it may be minic primary or metastatic carcinoma or nodular amyloidosis. Patients and methods We report case of 74 years old woman who admitted in our hospital with cough, dyspnea and chest pain. A CT scan of the chest revealed a mass located in the middle lobe of the right lung. The patient underwent thoracotomy for surgical excision of the mass macroscopic examination of the excised lobe revealed a well-circumscribed firm, grayish-white mass, measuring 3.1 cm × 2 cm × 1.3 cm. The sections were examined with H+E, PAS, and Congo-Red and followed by immunohistochemical study for Amyloid A and P, CD138, κ and λ light chains. Results The microscopic examination with H+E showed that the lung parenchyma presented extensive hyaline fibrosis PAS positive, areas of calcification and foci of bone metaplasia, accompanied by an inflammatory reaction. Congo-Red stain was positive but screening for birefringent material under polarized light was negative. Amyloid A and P were negative. The plasma calls were positive for CD138, κ and λ light chains. These histological findings were consistent with diagnosis of pulmonary hyalinizing granuloma. Conclusions The pulmonary hyalinizing granuloma should be considered in the differential diagnosis of pulmonary nodules or masses, even when they are cavitary or contain calcifications.

  15. Pulmonary hyalinizing granuloma. Electron microscopic and immunologic studies.

    Science.gov (United States)

    Guccion, J G; Rohatgi, P K; Saini, N

    1984-04-01

    We present a case of pulmonary hyalinizing granuloma (PHG). On light microscopy, the pulmonary nodular lesions consisted of extracellular, eosinophilic hyaline lamellae. Histochemical stains of the hyaline lamellae for amyloid were focally positive and the diagnosis of amyloidosis was seriously considered; however, on electron microscopic examination, the hyaline lamellae consisted of electrondense, compact, amorphous material quite unlike fibrillar amyloid. Although circulating immune complexes containing IgA were detected in our patient, immunoperoxidase stains did not reveal immunoglobulins in the hyaline lamellae. This case illustrates the value of electron microscopy in differentiating PHG from amyloidosis and supports the hypothesis that PHG represents an exaggerated immune response. PMID:6200274

  16. Pulmonary hyalinizing granuloma associated with Aspergillus infection.

    Science.gov (United States)

    Pinckard, J Keith; Rosenbluth, Daniel B; Patel, Kishor; Dehner, Louis P; Pfeifer, John D

    2003-01-01

    A 38-year-old immunocompetent man with occupational exposure to Aspergillus presented with dyspnea, pleuritic chest pain, and hemoptysis. Chest roentgenograms and computed tomography scans demonstrated multiple pulmonary nodules bilaterally. An initial set of bronchial washing cultures grew Aspergillus fumigatus, serologic testing showed an elevated anti-Aspergillus titer, and immunodiffusion testing was positive for antibody against A. fumigatus and A. niger. There was no microbiologic or serologic evidence of infection by other pathogens, and no clinical or laboratory evidence of autoimmune disease. An open lung biopsy was diagnostic of pulmonary hyalinizing granuloma. This novel association with Aspergillus infection not only expands the spectrum of pathogens linked to pulmonary hyalinizing granuloma but also documents a new pattern of lung disease that can be caused by Aspergillus. PMID:12598920

  17. [Pulmonary hyalinizing granuloma diagnosed by thoracoscopy].

    Science.gov (United States)

    Kadoyama, C; Yokosuka, T; Otsuji, M; Suzuki, M

    1999-06-01

    A 36-year-old woman was examined by our hospital for pulmonary coin shadows in both lungs, as disclosed on chest X-ray films. She had no subjective complaints other than allergic rhinitis, but exhibited hypergam-maglobulinemia, particularly in IgE. Inhalative allergen tests were positive for three types of allergens, but no autoimmune disease was detected. Although transbronchial and percutaneous fine needle biopsies failed to obtain enough specimens because of the wandering shadow a thoracoscopic biopsy was effective because of the subpleural location of the target lesions. The histologic findings were consistent with pulmonary hyalinizing granuloma, with extensive, hyalinized lamellar collagen bundles arranged haphazardly in the central area. Infiltration by lymphocytes and plasma cells, together with the destruction of bronchiolar and vessel walls, were observed in the marginal areas. No amyloid deposits or lymphocytic monoclonality were observed in the lesion. Twenty-five months after the biopsy, the patient's clinical and radiographic data had not changed. PMID:10434548

  18. Pulmonary hyalinizing granuloma with Castleman's disease.

    Science.gov (United States)

    Atagi, S; Sakatani, M; Akira, M; Yamamoto, S; Ueda, E

    1994-11-01

    A case of pulmonary hyalinizing granuloma (PHG) with Castleman's disease in a 43-year-old man is presented. He was asymptomatic, but the disease was recognized due to a routine chest roentgenographic study. Anemia, multiple lymphadenopathy, hypoalbuminemia and polyclonal hypergamma-globulinemia were observed. Histological examination of cervical lymph nodes revealed the plasma cell type of Castleman's disease. The diagnosis of PHG was confirmed by video-assisted thoracoscopical lung biopsy, and the immuno-histochemical staining of lamellar fibrosis for types I and III collagen was positive. PMID:7849383

  19. [Pulmonary hyalinizing granuloma: review of two cases].

    Science.gov (United States)

    Hantous-Zannad, S; Zidi, A; Boussema, F; Mestiri, I; Ben Hassine, R; Cherif, O; Kammoun, N; Ben Miled-M'rad, K

    2004-01-01

    Pulmonary hyalinizing granuloma is a rare fibrosing nodular disease of the lung characterized by solitary or multiples pulmonary nodules. This report describes two cases of this rare disorder. MRI was available in one case. For the first case, the stability of the lesions and past history of retroperitoneal fibrosis suggested the diagnosis. For the second case, open lung biopsy was required for diagnosis. When multiple nodules are present, metastatic disease cannot be excluded and biopsy may be required. Evolution is usually benign but follow up is necessary. PMID:15332013

  20. Pulmonary hyalinizing granuloma presenting with dysphagia.

    Science.gov (United States)

    Khilnani, G C; Kumar, A; Gupta, S Datta; Surendranath, A; Sharma, S

    2003-05-01

    We describe a middle aged, non-smoking female who presented with dysphagia and underwent repeated endoscopies and oesophageal dilatation for a period of six months without any response. On imaging she was found to be having a lobulated mass with a radiological differential diagnosis of malignancy, lymphoma or a rare inflammatory lesion. After an inconclusive CT guided biopsy the patient underwent thoracoscopy on which an unresectable mass was found. The biopsy from the mass revealed pulmonary hyalinizing granuloma (PHG). To best of our knowledge this is the first case of PHG presenting as dysphagia reported in the English Literature. Literature on this rare entity is reviewed. PMID:12974440

  1. Juvenile hyaline fibromatosis: a case report.

    Science.gov (United States)

    Karaçal, Naci; Gülçelik, Nevzat; Yildiz, Kadriye; Mungan, Sevdegül; Kutlu, Necmettin

    2005-07-01

    Juvenile hyaline fibromatosis ( JHF ) is a rare autosomal recessive disease characterized by papulonodular skin lesions, gingival hyperplasia, joint contractures, and bone lesions. The skin lesions may consist of multiple large tumors, commonly on the scalp and around the neck, and small pearly, pink papules and plaques on the trunk, chin, ears, and around the nostrils. Here, we report a 2-year-old boy with characteristic stiffness of the knees and elbows and pink confluent papules on the paranasal folds, and periauricular and perianal regions. He also had hard nodules all over the scalp and around the mouth, and severe gingival hyperplasia. The lesions were totally excised and clinicopathological diagnosis was JHF.

  2. Swimming Droplets

    Science.gov (United States)

    Maass, Corinna C.; Krüger, Carsten; Herminghaus, Stephan; Bahr, Christian

    2016-03-01

    Swimming droplets are artificial microswimmers based on liquid droplets that show self-propelled motion when immersed in a second liquid. These systems are of tremendous interest as experimental models for the study of collective dynamics far from thermal equilibrium. For biological systems, such as bacterial colonies, plankton, or fish swarms, swimming droplets can provide a vital link between simulations and real life. We review the experimental systems and discuss the mechanisms of self-propulsion. Most systems are based on surfactant-stabilized droplets, the surfactant layer of which is modified in a way that leads to a steady Marangoni stress resulting in an autonomous motion of the droplet. The modification of the surfactant layer is caused either by the advection of a chemical reactant or by a solubilization process. Some types of swimming droplets possess a very simple design and long active periods, rendering them promising model systems for future studies of collective behavior.

  3. Dancing Droplets

    Science.gov (United States)

    Cira, Nate; Prakash, Manu

    2013-11-01

    Inspired by the observation of intricate and beautifully dynamic patterns generated by food coloring on corona treated glass slides, we have investigated the behavior of propylene glycol and water droplets on clean glass surfaces. These droplets exhibit a range of interesting behaviors including long distance attraction or repulsion, and chasing/fleeing upon contact. We present explanations for each of these behaviors, and propose a detailed model for the long distance interactions based on vapor facilitated coupling. Finally we use our understanding to create several novel devices which: passively sort droplets by surface tension, spontaneously align droplets, drive droplets in circles, and cause droplets to bounce on a vertical surface. The simplicity of this system lends it particularly well to application as a toy model for physical systems with force fields and biological systems such as chemotaxis and motility.

  4. Black Droplets

    CERN Document Server

    Santos, Jorge E

    2014-01-01

    Black droplets and black funnels are gravitational duals to states of a large N, strongly coupled CFT on a fixed black hole background. We numerically construct black droplets corresponding to a CFT on a Schwarzchild background with finite asymptotic temperature. We find two branches of such droplet solutions which meet at a turning point. Our results suggest that the equilibrium black droplet solution does not exist, which would imply that the Hartle-Hawking state in this system is dual to the black funnel constructed in \\cite{Santos:2012he}. We also compute the holographic stress energy tensor and match its asymptotic behaviour to perturbation theory.

  5. A case of pulmonary hyalinizing granuloma associated with posterior uveitis.

    Science.gov (United States)

    Esme, Hidir; Ermis, Sitki Samet; Fidan, Fatma; Unlu, Mehmet; Dilek, Fatma Husniye

    2004-09-01

    A 48-year-old male was admitted to our hospital because of abnormal pulmonary shadows and a decrease in visual acuity. He had a history of tuberculosis 20 years ago. The chest roentgenogram showed multiple pulmonary nodules throughout both lung fields. No definitive diagnosis was established either by brushing cytology or biopsy through bronchoscopy or percutaneous needle biopsy. Pathological examination of open lung biopsy specimen revealed that extensive, hyalinized lamellar collagen bundles arranged in whorls, parallel arrays. Plasma cells and lymphocytes were found between the collagen bands and germinal centers were seen at the periphery of the lesion. A definitive diagnosis of pulmonary hyalinizing granuloma was made on the basis of these histopathological findings. Although there is no established treatment for pulmonary hyalinizing granuloma, during 1 month of follow-up, posterior uveitis mildly resolved with glucocorticoid treatment and there had been a slight increase in visual acuity. PMID:15329468

  6. [Pulmonary hyalinizing granuloma with massive infiltration of lymphocytes].

    Science.gov (United States)

    Fujishima, N; Takada, T; Moriyama, H; Saito, Y; Suzuki, E; Yoshiya, K; Yamato, Y; Kourakata, H; Honma, T; Gejyo, F

    2001-12-01

    A 39-year-old man was admitted to our hospital for examination of multiple nodules and infiltrates on a chest radiograph. His chest HRCT revealed multiple nodules with or without thick- or thin-walled cavities. Specimens obtained by video-assisted thoracoscopic biopsy showed bundles of hyalinized collagen fibers, some of which contained accumulated plasma cells in the center. The nodules were surrounded by massive lymphoid cells which formed germinal centers. These findings are compatible with pulmonary hyalinizing granuloma. The lymphoid cells looked uniform in some areas and had infiltrated along the bronchioles and small vessels and into the intralobular septa in a manner resembling pulmonary lymphoma or pseudolymphoma. The findings suggested that pulmonary hyalinizing granuloma may overlap pulmonary lymphoma. The disease has shown no progression for four years although no treatment has been given. PMID:11875809

  7. Pulmonary hyalinizing granuloma: an unusual association with multiple sclerosis.

    Science.gov (United States)

    John, P G; Rahman, J; Payne, C B

    1995-10-01

    Pulmonary hyalinizing granuloma (PHG) is a rare entity included in the differential diagnosis of pulmonary nodules of unknown origin. The pathologic entity may represent a peculiar form of pulmonary immune reaction. We report the case of a 40-year-old white woman who had nodular lesions in both lung bases after a 10-year history of multiple sclerosis. An open lung biopsy was required to make the diagnosis. The association of pulmonary hyalinizing granuloma with multiple sclerosis could be coincidental, but since there is a possibility of immune reaction in the pathogenesis of both diseases, the association may be significant. PMID:7481968

  8. Subpleural pulmonary hyalinizing granuloma presenting as a solitary pulmonary nodule.

    Science.gov (United States)

    Na, Kook Joo; Song, Sang Yun; Kim, Jo Heon; Kim, Young Chul

    2007-08-01

    We introduce a case of pulmonary hyalinizing granuloma presented as a solitary pulmonary nodule located subpleurally. The patient was a 57-year-old man who had abnormal chest roentgenograms showing a solitary pulmonary nodule in the right lower lung field. The nodule was resected for definitive diagnosis and histopathologically proved to be pulmonary hyalinizing granuloma. In previously reported cases, most patients had ill-defined margins and usually bilateral, multiple lesions radiographically. In our case, the subpleural location is an uncommon location of this rare entity. PMID:17762348

  9. High-resolution CT findings in pulmonary hyalinizing granuloma.

    Science.gov (United States)

    Shibata, Yoshihiro; Kobayashi, Takeshi; Hattori, Yuki; Matsui, Osamu; Gabata, Toshifumi; Tamori, Shunichi; Minato, Hiroshi; Ohta, Yasuhiko

    2007-11-01

    A 47-year-old man with pulmonary hyalinizing granuloma is herein presented. The patient, whose chief complaint was a mild cough, was found by chest radiograph to have multiple bilateral nodules. Subsequent high-resolution computed tomography demonstrated multiple slightly irregular nodules, perinodular ground-glass opacity, peribronchovascular interstitial thickening, and cysts. A mild enlargement of systemic lymph nodes was also noted. Laboratory tests disclosed a slight elevation in the C-reactive protein, gamma-globulin, interleukin-6, and soluble interleukin-2 receptor levels. A histopathologic examination of the specimen yielded from a thoracoscopic lung biopsy resulted in a definite diagnosis of pulmonary hyalinizing granuloma. PMID:18043399

  10. Gastric hyalinization as a possible consequence of corrosive injury.

    Science.gov (United States)

    Kazsuba, A; Vitéz, A; Gáll, J; Máthé, L; Ludmány, E; Krasznai, G

    2000-04-01

    We report a case of gastric obstruction due to hyalinization of the antrum. The endoscopic appearance of the lesion was suggestive of Crohn's disease or gastric neoplasm. Biopsy showed pseudopolypous gastritis with ulceration and fibroid granulation. Surgery was carried out to relieve the obstruction. Examination of the resected specimen showed massive hyalinization of all layers of the antral wall with circular collagenous infiltration and a normal duodenal bulb. The question of hyaloid gastritis as a unique entity is raised. Subsequently, information from the patient revealed the cause: voluntary acid ingestion causing corrosive injury. PMID:10774977

  11. Dancing Droplets

    CERN Document Server

    Cira, Nate J

    2013-01-01

    Inspired by the observation of intricate and beautifully dynamic patterns generated by food coloring on clean glass slides, we have investigated the behavior of propylene glycol and water droplets on high energy surfaces. In this fluid dynamics video we show a range of interesting behaviors including long distance attraction, and chasing/fleeing upon contact. We present explanations for each of these behaviors including a mechanism for the long distance interactions based on vapor facilitated coupling. Finally we use our understanding to create several novel devices which: spontaneously align droplets, drive droplets in circles, cause droplets to bounce on a vertical surface, and passively sort droplets by surface tension. The simplicity of this system lends it particularly well to application as a toy model for physical systems with force fields and biological systems such as chemotaxis and motility.

  12. Hyaline fibromatosis of Hoffa's fat pad in a patient with a mild type of hyaline fibromatosis syndrome

    International Nuclear Information System (INIS)

    Hyaline fibromatosis syndrome (HFS) is a rare, homozygous, autosomal recessive disease, characterized by deposition of hyaline material in skin and other organs, resulting in esthetic problems, disability, and potential life-threatening complications. Most patients become clinically apparent in the first few years of life, and the disorder typically progresses with the appearance of new lesions. We describe a rare case of a 20-year-old patient with juvenile-onset mild HFS who presented with a history of progressive anterior knee pain. Detailed magnetic resonance (MR) imaging findings with histopathological correlation are presented of hyaline fibromatosis of Hoffa's fat pad, including differential diagnosis. The diagnosis of HFS is generally made on basis of clinical and histopathological findings. Imaging findings, however, may contribute to the correct diagnosis in patients who present with a less typical clinical course of HFS. (orig.)

  13. Hyaline fibromatosis of Hoffa's fat pad in a patient with a mild type of hyaline fibromatosis syndrome

    Energy Technology Data Exchange (ETDEWEB)

    Raak, Sjoerd M. van [Albert Schweitzer Hospital, Department of Radiology, Dordrecht (Netherlands); Meuffels, Duncan E. [Erasmus MC - University Medical Center, Department of Orthopaedic Surgery, Rotterdam (Netherlands); Leenders, Geert J.L.H. van [Erasmus MC - University Medical Center, Department of Pathology, Rotterdam (Netherlands); Oei, Edwin H.G. [Erasmus MC - University Medical Center, Department of Radiology, Rotterdam (Netherlands)

    2014-04-15

    Hyaline fibromatosis syndrome (HFS) is a rare, homozygous, autosomal recessive disease, characterized by deposition of hyaline material in skin and other organs, resulting in esthetic problems, disability, and potential life-threatening complications. Most patients become clinically apparent in the first few years of life, and the disorder typically progresses with the appearance of new lesions. We describe a rare case of a 20-year-old patient with juvenile-onset mild HFS who presented with a history of progressive anterior knee pain. Detailed magnetic resonance (MR) imaging findings with histopathological correlation are presented of hyaline fibromatosis of Hoffa's fat pad, including differential diagnosis. The diagnosis of HFS is generally made on basis of clinical and histopathological findings. Imaging findings, however, may contribute to the correct diagnosis in patients who present with a less typical clinical course of HFS. (orig.)

  14. Hydrogels as a Replacement Material for Damaged Articular Hyaline Cartilage

    Directory of Open Access Journals (Sweden)

    Charlotte M. Beddoes

    2016-06-01

    Full Text Available Hyaline cartilage is a strong durable material that lubricates joint movement. Due to its avascular structure, cartilage has a poor self-healing ability, thus, a challenge in joint recovery. When severely damaged, cartilage may need to be replaced. However, currently we are unable to replicate the hyaline cartilage, and as such, alternative materials with considerably different properties are used. This results in undesirable side effects, including inadequate lubrication, wear debris, wear of the opposing articular cartilage, and weakening of the surrounding tissue. With the number of surgeries for cartilage repair increasing, a need for materials that can better mimic cartilage, and support the surrounding material in its typical function, is becoming evident. Here, we present a brief overview of the structure and properties of the hyaline cartilage and the current methods for cartilage repair. We then highlight some of the alternative materials under development as potential methods of repair; this is followed by an overview of the development of tough hydrogels. In particular, double network (DN hydrogels are a promising replacement material, with continually improving physical properties. These hydrogels are coming closer to replicating the strength and toughness of the hyaline cartilage, while offering excellent lubrication. We conclude by highlighting several different methods of integrating replacement materials with the native joint to ensure stability and optimal behaviour.

  15. Pulmonary epithelial permeability in hyaline-membrane disease

    International Nuclear Information System (INIS)

    Neonatal hyaline-membrane disease is complicated by pulmonary edema, yet left atrial pressures are normal. Alveolar-capillary-membrane permeability may therefore be increased. To assess pulmonary epithelial permeability, we measured the pulmonary clearance and half-life of aerosolized /sup 99m/Tc-diethylenetriamine pentacetate (/sup 99m/Tc-DTPA) on 31 occasions in 15 intubated premature infants with hyaline-membrane disease. Three infants with respiratory failure due to other diseases were studied on four occasions. All studies of infants with hyaline-membrane disease that were performed in the first 72 hours of life demonstrated a biphasic clearance curve with a rapid-phase half-life of 1.6 +/- 0.6 minutes (mean +/- S.D.). As these infants recovered, the curve became monophasic with a half-life of 56.0 +/- 32.1 minutes. Two infants remained dependent on oxygen and ventilator support and had persistent biphasic curves with a rapid-phase half-life of 1.5 +/- 0.7 minutes. All infants without hyaline-membrane disease had monophasic curves with a half-life of 65.4 +/- 33.6 minutes. Using a similar technique, we observed that newborn lambs and piglets have a monophasic pulmonary clearance of /sup 99m/Tc-DTPA (114 +/- 59 minutes in lambs and 52.5 +/- 16.3 minutes in piglets). We conclude that the lungs of neonates with hyaline-membrane disease are abnormally permeable to small solutes and that this abnormality persists in infants with subsequent chronic lung disease

  16. Multiple pulmonary hyalinizing granulomas associated with systemic idiopathic fibrosis.

    Science.gov (United States)

    Kuramochi, S; Kawai, T; Yakumaru, K; Mikata, A; Torikata, C; Kasuga, Y; Fujiwara, T

    1991-05-01

    A 41-year-old man with progressive nodular infiltration of the lung of about 2 years' duration died of cardiac and respiratory failure. Autopsy revealed bilateral multiple pulmonary hyalinizing granulomas (PHGs) diagnosed on the basis of the characteristic dense hyaline collagen bundles with nonspecific inflammatory infiltration. Constrictive pericarditis, retroperitoneal fibrosis, mediastinal fibrosis, fibrous thickening of the peritoneal and pleural surfaces, and fibrosis of soft tissue of the neck, flank, and hepatic hilar region were present, therefore, a diagnosis of systemic idiopathic fibrosis was made. The patient had anti-thyroglobulin and anti-thyroid microsomal antibodies and lymphocytic thyroiditis. The inflammatory process of PHG of the present case was active and the clinical course was progressive. PHG seems to be a lesion belonging to the systemic idiopathic fibrosis complex. Immunologic abnormalities may be related to PHG and systemic idiopathic fibrosis. PMID:1714226

  17. Hyaline membrane disease (HMD): the role of the perinatal pathologist

    OpenAIRE

    Giorgia Locci; Vassilios Fanos; Clara Gerosa; Gavino Faa

    2014-01-01

    Hyaline membrane disease (HMD), the pathologic correlate of respiratory distress syndrome (RDS) of the newborn, is an acute lung disease of premature infant caused by inadequate amounts of surfactant. Decreased surfactant results in insufficient surface tension in the alveolus during expiration, leading to atelectasis, decreased gas exchange, severe hypoxia and acidosis. HMD predominantly occurs in infants younger than 32 weeks of gestation and weighing less than 1,200 g. In the interpretatio...

  18. Pulmonary hyalinizing granuloma and retroperitoneal fibrosis in an adolescent

    Energy Technology Data Exchange (ETDEWEB)

    Young, Adam S.; Binkovitz, Larry A.; Adler, Brent H. [Columbus Children' s Hospital, Children' s Radiological Institute, Columbus, OH (United States); Nicol, Kathleen K. [Columbus Children' s Hospital, Department of Pathology, Columbus, OH (United States); Rennebohm, Robert M. [Columbus Children' s Hospital, Department of Rheumatology, Columbus, OH (United States)

    2007-01-15

    We describe a 15-year-old boy who developed pulmonary hyalinizing granuloma (PHG) and retroperitoneal fibrosis (RPF). His PHG and RPF were not associated with histoplasmosis or tuberculosis and appeared to represent idiopathic autoimmune phenomena. This is the first reported case of PHG in a pediatric patient and the fourth reported co-occurrence of PHG and RPF. The use of F-18 fluorodeoxyglucose positron emission tomography in the diagnostic and follow-up evaluation of PHG is reported. (orig.)

  19. Hyalinizing Granuloma: An Unusual Case of a Pulmonary Mass

    Directory of Open Access Journals (Sweden)

    Viviane Brandão

    2010-01-01

    Full Text Available We describe the case of pulmonary hyalinizing granuloma in a 34-year-old asymptomatic man who presented with a pulmonary nodule apparent by chest radiography and computed tomography (CT. He had a history of previous treatment for tuberculosis. His laboratory data were normal. Bronchoscopy and CT-guided percutaneous transthoracic fine needle aspiration cytology were inconclusive. The diagnosis was revealed after the histopathological examination of an open lung biopsy.

  20. Hyalinizing Granuloma: An Unusual Case of a Pulmonary Mass

    OpenAIRE

    Viviane Brandão; Edson Marchiori; Gláucia Zanetti; Guilherme Abdalla; Nina Ventura; Carolina Lamas Constantino; Mariana Leite Pereira; Pedro Martins; Rodrigo Canellas; Antonio Muccillo; Romulo Varella de Oliveira

    2010-01-01

    We describe the case of pulmonary hyalinizing granuloma in a 34-year-old asymptomatic man who presented with a pulmonary nodule apparent by chest radiography and computed tomography (CT). He had a history of previous treatment for tuberculosis. His laboratory data were normal. Bronchoscopy and CT-guided percutaneous transthoracic fine needle aspiration cytology were inconclusive. The diagnosis was revealed after the histopathological examination of an open lung biopsy.

  1. Pulmonary hyalinizing granuloma and retroperitoneal fibrosis in an adolescent.

    Science.gov (United States)

    Young, Adam S; Binkovitz, Larry A; Adler, Brent H; Nicol, Kathleen K; Rennebohm, Robert M

    2007-01-01

    We describe a 15-year-old boy who developed pulmonary hyalinizing granuloma (PHG) and retroperitoneal fibrosis (RPF). His PHG and RPF were not associated with histoplasmosis or tuberculosis and appeared to represent idiopathic autoimmune phenomena. This is the first reported case of PHG in a pediatric patient and the fourth reported co-occurrence of PHG and RPF. The use of F-18 fluorodeoxyglucose positron emission tomography in the diagnostic and follow-up evaluation of PHG is reported. PMID:17061085

  2. Pulmonary Hyalinizing Granuloma Associated with Idiopathic Thrombocytopenic Purpura

    OpenAIRE

    Christopher Coleman; Aziza Nassar; Barbara McComb

    2014-01-01

    Pulmonary hyalinizing granuloma (PHG) is a rare, benign lung disease of unknown etiology. It manifests as discrete, rounded nodules within the lung parenchyma. A 39-year-old woman presented for investigation after pulmonary nodules were found incidentally. Chest computed tomography showed multiple, discrete, non-enhancing pulmonary nodules bilaterally. Positron emission tomography (PET) was negative. Biopsy demonstrated a non-specific lymphoplasmacytic infiltrate. Open resection yielded two n...

  3. Hyalinizing granuloma: an unusual case of a pulmonary mass.

    Science.gov (United States)

    Brandão, Viviane; Marchiori, Edson; Zanetti, Gláucia; Abdalla, Guilherme; Ventura, Nina; Constantino, Carolina Lamas; Pereira, Mariana Leite; Martins, Pedro; Canellas, Rodrigo; Muccillo, Antonio; Varella de Oliveira, Romulo

    2010-01-01

    We describe the case of pulmonary hyalinizing granuloma in a 34-year-old asymptomatic man who presented with a pulmonary nodule apparent by chest radiography and computed tomography (CT). He had a history of previous treatment for tuberculosis. His laboratory data were normal. Bronchoscopy and CT-guided percutaneous transthoracic fine needle aspiration cytology were inconclusive. The diagnosis was revealed after the histopathological examination of an open lung biopsy. PMID:20592998

  4. Hyalinizing Granuloma: An Unusual Case of a Pulmonary Mass

    Science.gov (United States)

    Brandão, Viviane; Marchiori, Edson; Zanetti, Gláucia; Abdalla, Guilherme; Ventura, Nina; Constantino, Carolina Lamas; Pereira, Mariana Leite; Martins, Pedro; Canellas, Rodrigo; Muccillo, Antonio; Varella de Oliveira, Romulo

    2010-01-01

    We describe the case of pulmonary hyalinizing granuloma in a 34-year-old asymptomatic man who presented with a pulmonary nodule apparent by chest radiography and computed tomography (CT). He had a history of previous treatment for tuberculosis. His laboratory data were normal. Bronchoscopy and CT-guided percutaneous transthoracic fine needle aspiration cytology were inconclusive. The diagnosis was revealed after the histopathological examination of an open lung biopsy. PMID:20592998

  5. Pulmonary hyalinizing granuloma and retroperitoneal fibrosis in an adolescent

    International Nuclear Information System (INIS)

    We describe a 15-year-old boy who developed pulmonary hyalinizing granuloma (PHG) and retroperitoneal fibrosis (RPF). His PHG and RPF were not associated with histoplasmosis or tuberculosis and appeared to represent idiopathic autoimmune phenomena. This is the first reported case of PHG in a pediatric patient and the fourth reported co-occurrence of PHG and RPF. The use of F-18 fluorodeoxyglucose positron emission tomography in the diagnostic and follow-up evaluation of PHG is reported. (orig.)

  6. Pulmonary Hyalinizing Granuloma Associated with Idiopathic Thrombocytopenic Purpura

    Directory of Open Access Journals (Sweden)

    Christopher Coleman

    2014-01-01

    Full Text Available Pulmonary hyalinizing granuloma (PHG is a rare, benign lung disease of unknown etiology. It manifests as discrete, rounded nodules within the lung parenchyma. A 39-year-old woman presented for investigation after pulmonary nodules were found incidentally. Chest computed tomography showed multiple, discrete, non-enhancing pulmonary nodules bilaterally. Positron emission tomography (PET was negative. Biopsy demonstrated a non-specific lymphoplasmacytic infiltrate. Open resection yielded two nodules consistent with hyalinizing granulomas. The differential for multiple pulmonary nodules is broad. PET scan can help rule out metastatic disease, although some cancers are not hypermetabolic on PET. Furthermore, some non-malignant conditions, including hyalinizing granuloma, can show increased activity on PET. PHG should be included in the differential of multiple pulmonary nodules, especially if nodule stability can be demonstrated and/or needle biopsies are non-diagnostic. Associated immune-mediated conditions, such as idiopathic thrombocytopenic purpura (ITP in our patient, may also favor HG. In this case report we find an association between PHG and ITP.

  7. Three new species of Trichoderma with hyaline ascospores from China.

    Science.gov (United States)

    Zhu, Z X; Zhuang, W Y

    2015-01-01

    Collections of Trichoderma having hyaline ascospores from different areas of China were examined. Using combined analyses of morphological data, culture characters and phylogenetic information based on rDNA sequences of partial nuc translation elongation factor 1-α encoding gene (TEF1-α) and the gene encoding the second largest nuc RNA polymerase subunit (RPB2), three new species, Trichoderma applanatum, T. oligosporum and T. sinoluteum, were discovered and are described. Trichoderma applanatum produces continuous flat to pulvinate, white to cream stromata with dense orange or pale brown ostioles, and simple acremonium-like to verticillium-like conidiophores, belongs to the Hypocreanum clade and is closely related to T. decipiens. Trichoderma oligosporum forms reddish brown stromata with a downy surface, hyaline conidia and gliocladium-like conidiophores, and is closely related to but distinct from T. crystalligenum in the Psychrophila clade. Trichoderma sinoluteum, as a member of the Polysporum clade, is characterized by pale yellow stromata, white pustulate conidiomata, pachybasium-like conidiophores, and hyaline conidia. Differences between the new species and their close relatives are discussed.

  8. Pulmonary hyalinizing granuloma. A limited form of Wegener's granulomatosis?

    Science.gov (United States)

    Gorini, M; Forloni, F; Pezzoli, A; Pezzica, E

    1998-01-01

    Pulmonary hyalinizing granuloma is an uncommon disease that consists of slowly enlarging nodules in the pulmonary parenchyma. It occurs rarely: in fact, fewer than 70 case reports have been published in the past 20 years. It is important however in the differential diagnosis of lung diseases manifesting multiple pulmonary nodules. The etiology and pathogenesis of this disorder are unknown. Evidence suggests that the nodules could be the result of a chronic exaggerated immune response to infectious agents or to any other process in which antigen-antibody complexes are involved. More than 50% of the patients reported have evidence of autoimmune phenomena, e.g. positive antinuclear antibodies, a positive rheumatoid factor, or circulating immune complexes. The present report describes, for the first time, a case of pulmonary hyalinizing granuloma in which the patient had antineutrophil cytoplasmic autoantibodies with a granular cytoplasmatic pattern with typical central accentuation of fluorescence intensity and negative nuclei. The presence of antineutrophil cytoplasmic autoantibodies suggests that pulmonary hyalinizing granuloma could be regarded as a localized, non-evolving, form of Wegener's granulomatosis or a purely granulomatous Wegener's granulomatosis. PMID:9859576

  9. Pulmonary hyalinizing granuloma associated with idiopathic thrombocytopenic purpura.

    Science.gov (United States)

    Coleman, Christopher; Nassar, Aziza; McComb, Barbara

    2014-01-01

    Pulmonary hyalinizing granuloma (PHG) is a rare, benign lung disease of unknown etiology. It manifests as discrete, rounded nodules within the lung parenchyma. A 39-year-old woman presented for investigation after pulmonary nodules were found incidentally. Chest computed tomography showed multiple, discrete, non-enhancing pulmonary nodules bilaterally. Positron emission tomography (PET) was negative. Biopsy demonstrated a non-specific lymphoplasmacytic infiltrate. Open resection yielded two nodules consistent with hyalinizing granulomas. The differential for multiple pulmonary nodules is broad. PET scan can help rule out metastatic disease, although some cancers are not hypermetabolic on PET. Furthermore, some non-malignant conditions, including hyalinizing granuloma, can show increased activity on PET. PHG should be included in the differential of multiple pulmonary nodules, especially if nodule stability can be demonstrated and/or needle biopsies are non-diagnostic. Associated immune-mediated conditions, such as idiopathic thrombocytopenic purpura (ITP) in our patient, may also favor HG. In this case report we find an association between PHG and ITP. PMID:24744965

  10. Pulmonary Hyalinizing Granuloma Associated with Idiopathic Thrombocytopenic Purpura

    Science.gov (United States)

    Coleman, Christopher; Nassar, Aziza; McComb, Barbara

    2014-01-01

    Pulmonary hyalinizing granuloma (PHG) is a rare, benign lung disease of unknown etiology. It manifests as discrete, rounded nodules within the lung parenchyma. A 39-year-old woman presented for investigation after pulmonary nodules were found incidentally. Chest computed tomography showed multiple, discrete, non-enhancing pulmonary nodules bilaterally. Positron emission tomography (PET) was negative. Biopsy demonstrated a non-specific lymphoplasmacytic infiltrate. Open resection yielded two nodules consistent with hyalinizing granulomas. The differential for multiple pulmonary nodules is broad. PET scan can help rule out metastatic disease, although some cancers are not hypermetabolic on PET. Furthermore, some non-malignant conditions, including hyalinizing granuloma, can show increased activity on PET. PHG should be included in the differential of multiple pulmonary nodules, especially if nodule stability can be demonstrated and/or needle biopsies are non-diagnostic. Associated immune-mediated conditions, such as idiopathic thrombocytopenic purpura (ITP) in our patient, may also favor HG. In this case report we find an association between PHG and ITP. PMID:24744965

  11. Surgical correction of joint deformities and hyaline cartilage regeneration

    Directory of Open Access Journals (Sweden)

    Vyacheslav Alexandrovich Vinokurov

    2015-12-01

    Full Text Available Aim. To determine a method of extra-articular osteochondral fragment formation for the improvement of surgical correction results of joint deformities and optimization of regenerative conditions for hyaline cartilage. Materials and Methods. The method of formation of an articular osteochondral fragment without penetration into the joint cavity was devised experimentally. More than 30 patients with joint deformities underwent the surgery. Results. During the experiments, we postulated that there may potentially be a complete recovery of joint defects because of hyaline cartilage regeneration. By destructing the osteochondral fragment and reforming it extra-articularally, joint defects were recovered in all patients. The results were evaluated as excellent and good in majority of the patients. Conclusion. These findings indicate a novel method in which the complete recovery of joint defects due to dysplastic genesis or osteochondral defects as a result of injuries can be obtained. The devised method can be used in future experiments for objectification and regenerative potential of hyaline cartilage (e.g., rate and volume of the reformed joints that regenerate, detection of cartilage elements, and the regeneration process.

  12. OUTCOME OF VENTILATION IN HYALINE MEMBRANE DISEASE: THE INDIAN EXPERIENCE

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    Nayana Prabha

    2016-06-01

    Full Text Available OBJECTIVE To study the short-term outcome of both preterm and term babies requiring assisted ventilation for hyaline membrane disease and report the complications contributing to morbidity and mortality of these patients from a regional medical college with limited resources. DESIGN Retrospective file review. SETTING Regional Medical College. PARTICIPANTS All babies ventilated for HMD over a 6-year period from June 2008 to June 2014. OUTCOME MEASURES Outcome of ventilation and factors contributing to mortality. RESULTS Out of 100 babies with hyaline membrane disease who were ventilated, 82% survived. Increasing gestational age and birth weight was associated with survival. The commonest complication was shock (77% and the commonest cause of mortality was septicaemia (77%. Septicaemia, Disseminated Intravascular Coagulation (DIC and pulmonary haemorrhage were significantly more common complications babies who died (p<0.05. Binary logistic regression analysis showed that DIC (Odds ratio 5.2 [Confidence intervals (C.I. 1.1-27.1] and pulmonary haemorrhage (OR 18 [1.72-45.2] to be predictors of mortality. The incidence of intraventricular haemorrhage was 1% and that of pneumothorax was 2%. The initial peak inspiratory pressure administered was significantly lower (p=0.033 and maximum peak end expiratory pressure was significantly higher in those who expired (p=0.027. CONCLUSION Outcome of ventilation for hyaline membrane disease improves with increasing gestational age and birth weight. The commonest cause of mortality and morbidity were septicaemia and shock respectively.

  13. Hyaline membrane disease or respiratory distress syndrome? A new approach for an old disease

    OpenAIRE

    Lidia Grappone; Francesco Messina

    2014-01-01

    The term “hyaline membrane disease” refers to the histological aspect of the most frequent pulmonary pathology in preterm newborn patients. The lung of the preterm baby is morphologically and functionally immature. Surfactant deficiency in the immature lungs causes alveolar instability and collapse, capillary edema and the formation of hyaline membrane. Thus, the hyaline membranes are epiphenomena and are not the cause of respiratory failure in infants with immature lungs. This definition is ...

  14. Droplet organelles?

    Science.gov (United States)

    Courchaine, Edward M; Lu, Alice; Neugebauer, Karla M

    2016-08-01

    Cells contain numerous, molecularly distinct cellular compartments that are not enclosed by lipid bilayers. These compartments are implicated in a wide range of cellular activities, and they have been variously described as bodies, granules, or organelles. Recent evidence suggests that a liquid-liquid phase separation (LLPS) process may drive their formation, possibly justifying the unifying term "droplet organelle". A veritable deluge of recent publications points to the importance of low-complexity proteins and RNA in determining the physical properties of phase-separated structures. Many of the proteins linked to such structures are implicated in human diseases, such as amyotrophic lateral sclerosis (ALS). We provide an overview of the organizational principles that characterize putative "droplet organelles" in healthy and diseased cells, connecting protein biochemistry with cell physiology.

  15. Juvenile hyaline fibromatosis. Radiological diagnosis. Fibromatosis hialina juvenil. Diagnostico radiologico

    Energy Technology Data Exchange (ETDEWEB)

    Fuentes, R.; Sar, V.; Cabrera, J.J.; Diaz, L.; Hernandez, B.; Valeron, P.; Baez, O.; Rodriguez, M.

    1993-10-01

    Juvenile hyaline fibromatosis (JHF) is a rare disorder of unknown etiology, very few cases of which have been reported in the literature. It presents similarities to other fibromatosys, but has its particular radiological features which differentiate it from them. The clinical findings consist of several, slow growing, subcutaneous nodules, flexion contractures of the joints which can lead to disability, gingival hypertrophy and muscular atrophy. The suspected radiological diagnosis is confirmed by electron microscopy study of the nodules, although light microscopy can also reveal suggestive images. Author (9 refs.)

  16. Hyalinizing trabecular tumor and papillary carcinoma of the thyroid

    Institute of Scientific and Technical Information of China (English)

    ZHU Hong; QI Ji-ping; WANG Ying-wei; SONG Yue-jia; ZHANG Zhi-yi

    2010-01-01

    Background Hyalinizing trabecular tumor (HTT) is a rare thyroid neoplasm, which shares some histologic features with thyroid papillary carcinoma (TPC). Clinically, it is frequently misdiagnosed as papillary carcinoma, even for some experienced pathologists. The aim of this study was to investigate whether HTT is variant of TPC or HTT is an independent entity of thyroid neoplasm.Methods The expression of CK19, galectin-3, HBME-1 and MIB-1 was detected by immunohistochemical staining in 12 cases of hyalinizing trabecular tumor and 20 cases of thyroid papillary carcinoma.Results Two of the 12 HTT samples were positive or focally positive for CK19. Four of the 12 samples of HTT presented positive to galectin-3; 3 were stained strongly and the other one was focally positive. None of the 12 samples of HTT was positive for HBME-1. Five in 12 HTT samples were stained in nucleus for MIB-1. Almost all the 20 cases of thyroid papillary carcinoma were intensely stained for CK19, galectin-3 and HBME-1. Fifteen in 20 cases of thyroid papillary carcinoma showed nuclear staining for MIB-1.Conclusions HTT is an independent thyroid neoplasm, not a variant of TPC. This study could help in the differential diagnosis of HTT from TPC. CK19, galectin-3 and HBME-1 are adequate to identify HTT and TPC, but MIB-1 does not play an important role in discrimination between HTT and TPC.

  17. Pulmonary hyalinizing granuloma: a cause of pulmonary nodules.

    Science.gov (United States)

    Chalaoui, J; Grégoire, P; Sylvestre, J; Lefebvre, R; Amyot, R

    1984-07-01

    The radiological and histological appearance of pulmonary hyalinizing granuloma (PHG) and its pathogenesis are described. The histological features bear a striking resemblance to fibrosing mediastinitis. Patients present clinically with nonspecific respiratory or general symptoms. Slowly growing solitary or, more often, multiple nodules are found on radiographs of the chest, suggesting neoplastic disease. Four patients with PHG are described. Four patients with PHG are described. One had lesions in the kidneys that were pathologically identical to those of PHG. There is no clear etiology for this disease, but from the cases reported here and those reported previously it is postulated that diverse etiologic factors might lead to a common immunological response. Inflammatory agents such as tubercle bacilli or fungal organisms (e.g., Histoplasma), or a collagen or autoimmune disease may act as trigger mechanisms for the induction of PHG. PMID:6203137

  18. Immunologic abnormalities in two patients with pulmonary hyalinizing granuloma.

    Science.gov (United States)

    Schlosnagle, D C; Check, I J; Sewell, C W; Plummer, A; York, R M; Hunter, R L

    1982-08-01

    Pulmonary hyalinizing granuloma (PHG) is a disease of slowly enlarging pulmonary nodules made up of dense bundles of collagen accompanied by an infiltrate of chronic inflammatory cells. The etiology is unknown. Although it has been suggested that the lesions represent an exaggerated immune response to unidentified agents, results of a detailed immunologic work-up of these patients have not been published. This report presents the laboratory findings of two patients with biopsy-proven PHG who have been followed four and eighteen years. Autoantibodies were detected (antinuclear antibody, rheumatoid factor, and positive antiglobulin tests), although clinically there was no evidence of a specific collagen-vascular disorder. Both patients had elevated levels of circulating immune complexes. These data suggest that immune complex mechanisms may be important in the pathogenesis of PHG. PMID:7102822

  19. Pulmonary hyalinizing granuloma with ureteric fibrosis: A case report and review of relevant literature.

    Science.gov (United States)

    Agrawal, D; Deshpande, R; Maheshwari, S; Patel, A; Udwadia, Z F

    2006-01-01

    A 52-year-old, asymptomatic patient presented with bilateral lung nodules on chest radiograph. She was diagnosed to have "pulmonary hyalinizing granuloma" on an open lung biopsy. We review the clinical features of this rare disease. PMID:16970297

  20. Hyaline membrane disease (HMD: the role of the perinatal pathologist

    Directory of Open Access Journals (Sweden)

    Giorgia Locci

    2014-06-01

    Full Text Available Hyaline membrane disease (HMD, the pathologic correlate of respiratory distress syndrome (RDS of the newborn, is an acute lung disease of premature infant caused by inadequate amounts of surfactant. Decreased surfactant results in insufficient surface tension in the alveolus during expiration, leading to atelectasis, decreased gas exchange, severe hypoxia and acidosis. HMD predominantly occurs in infants younger than 32 weeks of gestation and weighing less than 1,200 g. In the interpretation of perinatal lung pathology, it is necessary to consider the development of the immature lung, particulary in the third trimester. Microscopically HMD is characterized by the occurrence of dilated terminal and respiratory bronchioles and of alveolar ducts lined by acellular eosinophilic hyaline membranes. The membranes are composed of necrotic alveolar lining cells, amniotic fluid constituents and fibrin. Retinopathy of prematurity and bronchopulmonary dysplasia are late complications of RDS that usually occur in infants who weigh less than 1,500 g and were maintained on a mechanical respiration more than 6 days. Here a pratical approach to a microscopic analysis of the lung in newborns died with the clinical setting of RDS is presented. The most important pathological findings for a complete clinical pathological diagnosis are: the evaluation of the architectural lung development; the endothelial cell lesions; the interstitial edema; the occurrence of disseminated intravascular coagulation; the presence of associated inflammatory lesions. The usefulness of some immunohistochemical stains is also underlined, including anti-surfactant, anti-smooth muscle actin and anti-CD31 to better evaluate surfactant production, pulmonary artery maturation and endothelial cell damage, respectively. Finally, the prevalent role of endothelial dysfunction and endothelial barrier loss is underlined, representing a major pathological event in the deposition of HMD

  1. Hyaline articular cartilage dissected by papain: light and scanning electron microscopy and micromechanical studies.

    OpenAIRE

    O'Connor, P; Brereton, J D; Gardner, D.L.

    1984-01-01

    Papain was used to digest the hyaline femoral condylar cartilages of 30 adult Wistar rats. Matrix proteoglycan degradation was assessed by the light microscopy of paraffin sections stained with toluidine blue. The extent of surface structural change was estimated by scanning electron microscopy, and the structural integrity of the hyaline cartilage tested by the controlled impact of a sharp pin. The results demonstrated an early loss of cartilage metachromasia, increasing with time of papain ...

  2. Hyaline protoplasmic astrocytopathy in the setting of tuberous sclerosis.

    Science.gov (United States)

    Prayson, Richard A

    2016-09-01

    Hyaline protoplasmic astrocytopathy is a rare disorder marked by an accumulation of protein material in the cytoplasm of astrocytic cells, mostly in the cortex. The finding has been described in Aicardi syndrome (agenesis of the corpus callosum, chorioretinal lacunae and infantile spasms) as well as in patients with pharmacoresistant epilepsy and in association with focal cortical dysplasia, polymicrogyria and nodular heterotopia. This report describes the first case of this entity described in a patient with tuberous sclerosis. The patient was a 3-year-old boy who presented at age 2months with medically intractable seizures. Has mother has a tuberous sclerosis 2 (TSC 2) gene abnormality and a diagnosis of tuberous sclerosis. On imaging, he was noted to have multiple lesions in the left parietal and temporal lobes consistent with focal cortical dysplasia and a subependymal nodule. He additionally had two hypopigmented lesions on the skin. He underwent resection of the left parietal lobe 32months after seizure onset. Histopathologic examination showed eosinophilic cytoplasmic inclusions within astrocytes in the cortex and superficial white matter focally accompanied by a disordered cortical architecture with dysmorphic neurons and balloon cells, consistent with focal cortical dysplasia classified as type IIb according to International League Against Epilepsy classification criteria (ILAE type IIb). At the time of most recent follow-up, 93months postoperatively, he is still experiencing seizures with overall worthwhile improvement while on seizure medication. PMID:27174083

  3. Prevalence and factors associated with scleral hyaline plaque: clinical study of older adults in southeastern Brazil

    Directory of Open Access Journals (Sweden)

    Horowitz S

    2015-06-01

    Full Text Available Soraya Horowitz,1 Nadyr Damasceno,1 Eduardo Damasceno21Department of Ophthalmology, Hospital Naval Marcilio Dias, Rio de Janeiro, 2Department of Ophthalmology, Universidade Federal Fluminense, Niterói, BrazilPurpose: To investigate the prevalence of scleral hyaline plaque among older adults in the city of Niterói in southeastern Brazil. A second goal was to assess the correlation between scleral hyaline plaque and several age-related diseases, including eye diseases and systemic diseases.Methods: The study sample comprised 667 participants who were followed for 15 months. The study had a prospective, longitudinal, observational design that established inclusion and exclusion criteria. The following variables were selected for correlation with scleral hyaline plaque: sex, age, age range, iris color, ethnicity, presence of cataract, moderate to high myopia, age-related macular degeneration (AMD, diabetes mellitus, systemic arterial hypertension, degenerative arthritis, and osteoporosis. These correlations were assessed by means of the χ2 test and Student’s t-test. Multivariate analysis was performed to exclude factors that were potentially associated with aging exclusively but that did not have a direct relationship with hyaline plaque. Binary logistic regression was used to calculate odds ratios, significance, and confidence intervals.Results: Scleral hyaline plaques were found in 177 patients (17.54%. There was a statistically significant association between the presence of hyaline plaques and sex (female, age range (≥70 years old, ethnicity (Caucasian, cataract, moderate to high myopia, systemic arterial hypertension, degenerative arthritis, and osteoporosis (P<0.05. On multivariate binary logistic regression analysis, only female sex, age range (≥70 years, moderate to high myopia, and degenerative arthritis exhibited significant correlation.Conclusion: The prevalence of scleral hyaline plaque in the present study was higher than in

  4. HYALINIZING TRABECULAR ADENOMA FEIGNING PAPILLARY CARCINOMA THYROID: CASE REPORT WITH REVIEW OF LITERATURE

    Directory of Open Access Journals (Sweden)

    Kandukuri Mahesh

    2014-05-01

    Full Text Available Hyalinizing Trabecular Adenoma (HTA of the thyroid is a rare neoplasm that was first described by Carney in 1987. It is a tumor of follicular derivation with peculiar nuclear, architectural, histochemical, and immunohistochemical features. We report a case of Hyalinizing trabecular adenoma in a 36-year-old woman with enlarged thyroid lobe. Ultrasonographic features and fine needle aspiration cytology (FNAC of the enlarged thyroid was performed and the diagnosis given was Papillary carcinoma of the thyroid. The patient underwent total thyroidectomy, with a histopathological diagnosis of hyalinizing trabecular Adenoma (HTA. We present this case in view of its rarity and to discuss the clinical and diagnostic approach, including the role of FNAC, and the pathologic features of HTA with special reference to the possible differential diagnosis and also review of literature. Although rare cases of malignant Hyalinizing trabecular adenoma (HTA have been documented, this tumor should be considered a benign neoplasm or at most, a neoplasm of extremely low malignant potential, however invasion of the capsule should be considered on histopathology. An awareness of hyalinizing trabecular adenomas and their characteristic features is valuable for their recognition and management as well as for the possible prevention of over diagnosis and over treatment for benign disease

  5. The value of MDCT in diagnosis of hyaline-vascular Castleman's disease

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Xiaoli [Department of Radiology, Beijing Shijitan Hospital affiliated to Capital University of Medical Sciences, Yangfangdian Tieyiyuan, Road No. 10, Haidian District, Beijing, 100038 China (China); Liu, Cheng [CT Department, Shandong Medical Imaging Research Institute (China); Wang, Rengui, E-mail: 490150302@qq.com [Department of Radiology, Beijing Shijitan Hospital affiliated to Capital University of Medical Sciences, Yangfangdian Tieyiyuan, Road No. 10, Haidian District, Beijing, 100038 China (China); Zhu, Xuejun [Dermatology Department, Beijing University First Hospital (China); Gao, Li [Department of Radiology, Beijing University First Hospital (China); Chen, Jiuhong [Healthcare, Siemens Ltd. (China)

    2012-09-15

    Purpose: Castleman's disease (CD) is an uncommon entity characterized by a massive growth of lymphoid tissue. There are two types: the hyaline-vascular (HV) type and the plasma cell (PC) type. The purpose of this study was to evaluate the clinical value of multiple detector computed tomography (MDCT) in the diagnosis and planning of treatment for hyaline-vascular CD. Materials and methods: Fifty-two cases of confirmed hyaline-vascular CD were retrospectively reviewed. Unenhanced and contrast-enhanced MDCT scans had been performed in all patients, followed by surgery and pathological analysis of the lesion. Original MDCT transverse and reconstructed images were used for image interpretation. Features of the lesion and its adjacent structures were identified. Results: The lesion was present in the thorax of 24 patients and the abdomen in 28. Obvious features of hyaline-vascular CD (especially feeding vessels and draining veins) and its adjacent structures were demonstrated on 52 patients. Conclusion: On MDCT imaging, original MDCT transverse and reconstructed images provide an excellent tool for diagnosis of hyaline-vascular CD and have high value in the determination of a treatment plan.

  6. Hyalinizing trabecular tumor of the thyroid gland: characteristic features on ultrasonography.

    Science.gov (United States)

    Kobayashi, Kaoru; Hirokawa, Mitsuyoshi; Jikuzono, Tomoo; Fukata, Shuji; Amino, Nobuyuki; Miyauchi, Akira; Nakamura, Yasushi

    2007-03-01

    We report a case of hyalinizing trabecular tumor of the thyroid gland and describe the characteristic ultrasonographic features of this tumor. This was a rare tumor of follicular cell origin with a trabecular pattern of growth and marked intratrabecular hyalinization. The tumor had an irregular shape, a delicately jagged border, and hypoechoic and heterogeneous internal echoes on B-mode ultrasonography. Very rich intratumoral blood flow, the so-called "tumor inferno" was evident on power Doppler ultrasonography. In the clinical management of thyroid nodules, clinicians should be aware of this peculiar type of thyroid tumor and its characteristic ultrasonographic findings.

  7. Radiology-Pathology Conference: pulmonary hyalinizing granuloma associated with lupus-like anticoagulant and Morvan's Syndrome.

    Science.gov (United States)

    Winger, David I; Spiegler, Peter; Trow, Terence K; Goyal, Amit; Yu, Huiying; Yung, Elizabeth; Katz, Douglas S

    2007-01-01

    Pulmonary hyalinizing granulomata are rare, noninfectious, fibrosing lesions of the lung, which can mimic metastatic disease radiographically. Their etiology is unknown, but they may be caused by an exaggerated immune response. We report the radiology, long clinical course, and pathology of a patient with pulmonary hyalinizing granuloma who presented with initially asymptomatic pulmonary nodules. Over a 10-year period, the patient developed multiple insidious autoimmune phenomena, including lupus anticoagulant, neuromyotonia, demyelinating sensorimotor polyneuropathy, and eventually, Morvan's syndrome. Such an association has not been previously published to our knowledge. PMID:17599621

  8. Juvenile hyaline fibromatosis and infantile systemic hyalinosis: Divergent expressions of the same genetic defect?

    Directory of Open Access Journals (Sweden)

    Dhingra Mandeep

    2008-01-01

    Full Text Available We describe here a three year-old girl with classic clinical and histological features of juvenile hyaline fibromatosis. We found a history of similar skin findings in her eldest sister, in whom the disorder took a rapidly progressive and fatal course in the second year of life, suggesting either a very severe form of juvenile hyaline fibromatosis, or the possibility of infantile systemic hyalinosis. The similarities and differences between these two described types of hyalinoses have been reviewed in reference to the present report.

  9. Oral pulse or hyaline ring granuloma: A case report and a brief review

    Directory of Open Access Journals (Sweden)

    Swetha Acharya

    2015-01-01

    Full Text Available Pulse or hyaline ring granulomas are rare but are well-defined oral and extraoral lesions due to implantation of the cellulose moiety of plant foods in contrast starch components. A unique form as reactive gingival growth showing histologic features of oral pulse or hyaline ring granuloma (OPHRG which had resulted from implantation of food particles of plant or vegetable origin into the periodontium has been illustrated. Such a presentation is attributable to compromised periodontal health and poor oral hygiene favoring the implantation of food particles has been described here along with a literature update on OPHRG.

  10. Water droplets also swim!

    Science.gov (United States)

    van der Linden, Marjolein; Izri, Ziane; Michelin, Sébastien; Dauchot, Olivier

    2015-03-01

    Recently there has been a surge of interest in producing artificial swimmers. One possible path is to produce self-propelling droplets in a liquid phase. The self-propulsion often relies on complex mechanisms at the droplet interface, involving chemical reactions and the adsorption-desorption kinetics of the surfactant. Here, we report the spontaneous swimming of droplets in a very simple system: water droplets immersed in an oil-surfactant medium. The swimmers consist of pure water, with no additional chemical species inside: water droplets also swim! The swimming is very robust: the droplets are able to transport cargo such as large colloids, salt crystals, and even cells. In this talk we discuss the origin of the spontaneous motion. Water from the droplet is solubilized by the reverse micellar solution, creating a concentration gradient of swollen reverse micelles around each droplet. By generalizing a recently proposed instability mechanism, we explain how spontaneous motion emerges in this system at sufficiently large Péclet number. Our water droplets in an oil-surfactant medium constitute the first experimental realization of spontaneous motion of isotropic particles driven by this instability mechanism.

  11. Computed tomography findings in patients with pulmonary hyalinizing granulomas: a case report; Granulomas hialinizantes pulmonares: aspectos na tomografia computadorizada - relato de caso

    Energy Technology Data Exchange (ETDEWEB)

    Marchiori, Edson [Universidade Federal Fluminense, Niteroi, RJ (Brazil). Dept. de Radiologia]. E-mail: edmarchiori@zipmail.com.br; Valiante, Paulo Marcos [Universidade Federal, Rio de Janeiro, RJ (Brazil). Faculdade de Medicina. Dept. de Patologia; Correia, Ana Helena Pereira; Carneiro, Leonardo Hoehl; Caldas, Carolina Rodrigues [Hospital Universitario Clementino Fraga Filho, Rio de Janeiro, RJ (Brazil). Servico de Anatomia Patologica; Souza Junior, Arthur Soares [Faculdade de Medicina de Sao Jose do Rio Preto (FAMERP), SP (Brazil). Dept. de Radiologia

    2003-12-01

    Hyalinizing granulomas are benign fibrotic lesions that generally present multiple nodules seen on radiological examinations, which are frequently cavitary and/or calcified lesions. We report a case of a 28 year-old-woman with hyalinizing granulomas probably secondary to a previous tuberculosis infection. Hyalinizing granulomas should be included in the differential diagnosis of patients with multiple pulmonary nodules. (author)

  12. Pulmonary hyalinizing granuloma: a rare cause of a solitary pulmonary nodule.

    Science.gov (United States)

    Eschelman, D J; Blickman, J G; Lazar, H L; O'Keane, J C; Schechter, M

    1991-04-01

    Pulmonary hyalinizing granulomata are unusual, noninfectious lesions of the lung of uncertain etiology that probably represent an exaggerated immune response. They present radiographically as noncalcified solitary or multiple pulmonary nodules, thereby mimicking primary or metastatic malignancy. The article discusses a case of this rare entity that presented as a solitary pulmonary nodule. PMID:1713275

  13. Levitated droplet dye laser

    DEFF Research Database (Denmark)

    Azzouz, H.; Alkafadiji, L.; Balslev, Søren;

    2006-01-01

    a high quality optical resonator. Our 750 nL lasing droplets consist of Rhodamine 6G dissolved in ethylene glycol, at a concentration of 0.02 M. The droplets are optically pumped at 532 nm light from a pulsed, frequency doubled Nd:YAG laser, and the dye laser emission is analyzed by a fixed grating...

  14. Vaporization of Deforming Droplets

    Science.gov (United States)

    Wang, Yanxing; Chen, Xiaodong; Ma, Dongjun; Yang, Vigor

    2012-11-01

    Droplet deformation is one of the most important factors influencing the evaporation rate. In the present study, high-fidelity numerical simulations of single evaporating droplets with deformation are carried out over a wide range of the Reynolds and Weber numbers. The formulation is based on a complete set of conservation equations for both the liquid and surrounding gas phases. A modified volume-of-fluid (VOF) technique that takes into account heat and mass transfer is used to track the behavior of the liquid/gas interface. Special attention is given to the property conservation, which can be realized by using an iterative algorithm that enforces a divergence constraint in cells containing the interface. The effect of the ambient flow on droplet dynamics and evaporation are investigated systematically. Various underlying mechanisms dictating the droplet characteristics in different deformation regimes are identified. Correlations for the droplet evaporation rate are established in terms of the Reynolds and Weber numbers.

  15. Waveguides for walking droplets

    CERN Document Server

    Filoux, Boris; Schlagheck, Peter; Vandewalle, Nicolas

    2015-01-01

    When gently placing a droplet onto a vertically vibrated bath, a drop can bounce permanently. Upon increasing the forcing acceleration, the droplet is propelled by the wave it generates and becomes a walker with a well defined speed. We investigate the confinement of a walker in different rectangular cavities, used as waveguides for the Faraday waves emitted by successive droplet bounces. By studying the walker velocities, we discover that 1d confinement is optimal for narrow channels. We also propose an analogy with waveguide models based on the observation of the Faraday instability within the channels.

  16. Finite range Droplet Model

    International Nuclear Information System (INIS)

    A treatment of nuclear masses and deformations is described which combines the Droplet Model with the folding model surface and Coulomb energy integrals. An additional exponential term, inspired by the folding model, but treated here as an independent contribution with two adjustable parameters, is included. With this term incorporated, the accuracy of the predicted masses and fission barriers was improved significantly, the ability of the Droplet Model to account for isotope shifts in charge radii was retained, and the tendency of the Droplet Model to over-predict the surface-tension squeezing of light nuclei was rectified. 20 references, 4 figures

  17. Butschli Dynamic Droplet System

    DEFF Research Database (Denmark)

    Armstrong, R.; Hanczyc, M.

    2013-01-01

    of a technology with living properties. Otto Butschli first described the system in 1898, when he used alkaline water droplets in olive oil to initiate a saponification reaction. This simple recipe produced structures that moved and exhibited characteristics that resembled, at least superficially, the amoeba. We......Dynamical oil-water systems such as droplets display lifelike properties and may lend themselves to chemical programming to perform useful work, specifically with respect to the built environment. We present Butschli water-in-oil droplets as a model for further investigation into the development...... to the oil phase), qualify this system as an example of living technology. The analysis of the Butschli droplets suggests that a set of conditions may precede the emergence of lifelike characteristics and exemplifies the richness of this rudimentary chemical system, not only for artificial life...

  18. Functions of the Coacervate Droplets

    Science.gov (United States)

    Okihana, Hiroyuki; Ponnamperuma, Cyril

    1982-12-01

    Functions of coacervate droplets as protocells are studied by using synthetic polymers. The coacervate droplets were made from PVA-A and PVA-S. When glycine or diglycine were in the surrounding medium, the coacervate droplets concentrated them. The concentration of glycine in the coacervate droplets was higher than that of diglycine. When this mixture was irradiated by UV light, the coacervate droplets protected them from the photochemical decomposition.

  19. OCS in He droplets

    Energy Technology Data Exchange (ETDEWEB)

    Grebenev, V.

    2000-06-01

    Phenomenon of superfluidity of para-hydrogen (pH{sub 2}){sub 1-17} and helium {sup 4}He{sub 1-7000} systems doped with an OCS chromophore molecule was investigated in this work. The study of such systems became possible after the development of the depletion spectroscopy technique in helium droplets. The droplets can be easily created and doped with up to 100 particles such as OCS, para-hydrogen or ortho-hydrogen molecules and {sup 4}He atoms. The measured infrared depletion spectra give the information about the temperature of the droplets and their aggregate state. The depletion spectrum of OCS in pure {sup 4}He droplets was comprehensively studied. The rovibrational OCS spectrum shows well resolved narrow lines. The spectrum is shifted to the red relative to the corresponding gas phase spectrum and the rotational constant of OCS in {sup 4}He droplet is three times smaller than that for free molecule. Different models of OCS rotation in the helium environment were discussed. It was shown that the shapes of the rovibrational lines are defined mainly by inhomogeneous broadening due to the droplet size distribution. The sub-rotational structure of the OCS rovibrational lines was revealed in microwave-infrared double resonance experiments. This structure arises due to the interaction of the OCS with the He environment. However, the information obtained in the experiments was not enough to understand the nature of this interaction. (orig.)

  20. Prevention of hyaline membrane disease in premature lambs by apneic oxygenation and extracorporeal carbon dioxide removal.

    Science.gov (United States)

    Pesenti, A; Kolobow, T; Buckhold, D K; Pierce, J E; Huang, H; Chen, V

    1982-01-01

    Hyaline membrane disease is found only in lungs where pulmonary ventilation has been established, i.e. after birth. We delivered eleven fetal lambs of a gestational age of 128-130 days but instead kept their lungs in total apnea and inflated to constant pressure, while removing all metabolically produced carbon dioxide with an extracorporeal membrane lung. Oxygen was provided by the membrane lung, and by apneic oxygenation through the natural lungs. Hence, arterial blood gases remained always normal, without any pulmonary ventilation. After 6-66 h the lungs had sufficiently cleared to allow normal mechanical pulmonary ventilation in 10 our of 11 lambs so treated. In a control group treated with mechanical ventilation alone, five of seven lambs died within the first 24 h of severe hyaline membrane disease. PMID:6799556

  1. Pulmonary hyalinizing granuloma detected in a family member after confirmation of tuberculosis in his father.

    Science.gov (United States)

    Matsuoka, Katsunari; Imanishi, Naoko; Matsuoka, Takahisa; Nagai, Shinjiro; Ueda, Mitsuhiro; Miyamoto, Yoshihiro

    2014-01-01

    Pulmonary hyalinizing granuloma (PHG) is an uncommon lung disease that usually presents as bilateral multiple nodules, and more rarely as a solitary nodule. An exaggerated immune response to antigenic stimuli resulting from infection or an autoimmune process has been suggested as the cause of PHG. Here, we describe a rare case of solitary PHG that was detected in a family member after tuberculosis had been confirmed in his father, without any background of infectious disease or autoimmune abnormality. PMID:23903707

  2. [Differential diagnosis of multiple pulmonary coin lesions--pulmonary hyaline granuloma].

    Science.gov (United States)

    Banaschak, S; Müller, K M

    1996-02-01

    In addition to metastases, the differential diagnosis of pulmonary nodules also includes tuberculosis, sarcoidosis, and silicosis. Rarer diseases such as amyloid tumors, rheumatic nodules, and plasma-cell granulomas can, depending on the clinical situation, be the cause of this finding. For the example of the clinical picture of pulmonary hyalinizing granuloma, the differential diagnosis of multiple pulmonary nodules is illustrated under consideration of the pathognomonic, morphologic observations. PMID:8868595

  3. Diagnostic value of gastric shake test for hyaline membrane disease in preterm infant

    OpenAIRE

    Mahmood NooriShadkam; Mohammad Hossein Lookzadeh; Mahmood Taghizadeh; Azam Golzar; Zahra NooriShadkam

    2014-01-01

    Background: Hyaline membrane disease (HMD) has remained a common neonatal problem and is a cause of morbidity in infants. The shake test can be used to assess whether surfactant is present in the infant's lungs at birth. Objective: The goal of this study was to determine the usefulness and accuracy of gastric aspirate shake test for the diagnosis of two HMD. Materials and Methods: This was a diagnostic accuracy study carried out on 49 preterm infant born at Shahid Sadoughi hospital in 2...

  4. [Trabecular hyalinizing adenoma of the thyroid (HAT): A report of two cases].

    Science.gov (United States)

    Román-González, Alejandro; Simón-Duque, Carlos; Camilo-Pérez, Juan; Vélez-Hoyo, Alejandro

    2016-01-01

    The hyalinizing trabecular adenoma is a rare lesion of the thyroid. There is controversy in the literature about the correct name for this disease. Dr. Carney defended the benign nature of this condition and therefore continues calling it adenoma, the World Health Organization calls for the potential of tumor malignancy, and others qualify it as a variant of papillary carcinoma based on the presence of rearranged in transformation/papillary thyroid carcinoma (RET/PTC) rearrangements. In Latin America there are few reported cases. Two cases of hyalinizing trabecular adenoma are reported. The first is a 40-year-old woman with a thyroid nodule of 3x3 cm. The immunohistochemistry was positive for thyroglobulin and calcitonin and negative for cytokeratin 19 and chromogranin. The second case is a 36-year-old patient with a thyroid nodule of 4x4 cm with an immunohistochemical pattern identical to the first case. Trabecular hyalinizing adenoma is a benign disease, easily confused with papillary or medullary thyroid carcinoma. Awareness of this entity will allow a better classification and management of thyroid conditions. PMID:26927651

  5. Hyalinizing trabecular tumor of the thyroid gland: A puzzling entity on fine needle aspiration cytology

    Directory of Open Access Journals (Sweden)

    Jitendra Nasit

    2014-01-01

    Full Text Available Hyalinizing trabecular tumor (HTT is a rare unique but controversial thyroid neoplasm, characterized by prominent trabecular growth pattern and stromal hyalinization. Whether HTT is a benign tumor or a variant of papillary thyroid carcinoma (PTC is still unclear. Cytology findings of HTT have been described in few reports. Cytological features of HTT frequently overlap with those of PTC and medullary thyroid carcinoma, which can lead to frequent misdiagnosis. In order to avoid overtreatment like total thyroidectomy, pathologist should be aware of cytological features of HTT. We present a case of 35-year-old female with a right-side thyroid swelling for three years. Fine needle aspiration cytology was performed. According to The Bethesda System for Reporting Thyroid Cytopathology, cytological diagnosis of benign thyroid neoplasm was made. Histopathology of the right thyroidectomy specimen showed HTT. Accurate preoperative diagnosis of HTT requires a very meticulous and cautious approach in the evaluation of cytological features. Trabecular pattern of cells, vague curved nuclear palisading, radiating arrangement of cells around hyaline material, spindled to elongated cells, filamentous cytoplasmic processes with ill-defined cell border and yellow bodies are important diagnostic features of HTT. Nuclear features alone are insufficient for the diagnosis of HTT. Any suspicious cytology of thyroid lesion should follow hemithyroidectomy and histopathological evaluation.

  6. Uninduced adipose-derived stem cells repair the defect of full-thickness hyaline cartilage

    Institute of Scientific and Technical Information of China (English)

    ZHANG Hai-ning; LI Lei; LENG Ping; WANG Ying-zhen; Lü Cheng-yu

    2009-01-01

    Objective: To testify the effect of the stem cells derived from the widely distributed fat tissue on repairing full-thickness hyaline cartilage defects.Methods: Adipose-derived stem cells (ADSCs) were derived from adipose tissue and cultured in vitro.Twentyseven New Zealand white rabbits were divided into three groups randomly.The cultured ADSCs mixed with calcium alginate gel were used to fill the full-thickness hyaline cartilage defects created at the patellafemoral joint,and the defects repaired with gel or without treatment served as control groups.After 4,8 and 12 weeks,the reconstructed tissue was evaluated macroscopically and microscopically.Histological analysis and qualitative scoring were also performed to detect the outcome.Results: Full thickness hyaline cartilage defects were repaired completely with ADSCs-derived dssue.The result was better in ADSCs group than the control ones.The microstructure of reconstructed tissue with ADSCs was similar to that of hvaline cartilage and contained more cells and regular matrix fibers,being better than other groups.Plenty of collagen fibers around cells could be seen under transmission electron microscopy.Statistical analysis revealed a significant difference in comparison with other groups at each time point(t=4.360,P<0.01).Conclusion: Thcse results indicate that stem cells derived from mature adipose without induction possess the ability to repair cartilage defects

  7. Castleman Disease of Hyaline Vascular Type in the Infrathyroidal Region: A Masquerader of Parathyroid Adenoma

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sang Kwon; Kwon, Sun Young [Dongsan Medical Center, Keimyung University School of Medicine, Daegu (Korea, Republic of)

    2013-03-15

    Castleman disease of the infrathyroidal region is extremely rare. We report both CT and sonographic findings of a case of infrathyroidal paratracheal Castleman disease of hyaline vascular type, which masquerades parathyroid adenoma, in a 48-year-old woman. We further provide its histological findings at sonographically guided core-needle biopsy (US-CNB) and excisional biopsy. The lesion was ovoid with homogeneous intense enhancement on contrast-enhanced CT (CECT), and was homogeneous, markedly hypoechoic, and hypervascular on ultrasonography (US). Histological findings of the specimen obtained by US-CNB suggested lymphoproliferative lesion, and thus was inconclusive; those obtained by excisional biopsy were characteristics of Castleman disease of hyaline vascular type. Hyaline vascular type Castleman's disease should be included in the differential diagnosis of a mass of the infrathyroidal region with homogeneous intense enhancement on CECT, as well as with marked hypoechogenicity and hypervascularity on US. US-CNB may be of limited value in the histological diagnosis of this entity.

  8. Microfluidic devices for droplet injection

    Science.gov (United States)

    Aubrecht, Donald; Akartuna, Ilke; Weitz, David

    2012-02-01

    As picoliter-scale reaction vessels, microfluidic water-in-oil emulsions have found application for high-throughput, large-sample number analyses. Often, the biological or chemical system under investigation needs to be encapsulated into droplets to prevent cross contamination prior to the introduction of reaction reagents. Previous techniques of picoinjection or droplet synchronization and merging enable the addition of reagents to individual droplets, but present limitations on what can be added to each droplet. We present microfluidic devices that couple the strengths of picoinjection and droplet merging, allowing us to selectively add precise volume to our droplet reactions.

  9. Hydrodynamics of a quark droplet

    CERN Document Server

    Bjerrum-Bohr, Johan J; Døssing, Thomas

    2011-01-01

    We present a simple model of a multi-quark droplet evolution based on the hydrodynamical description. This model includes collective expansion of the droplet, effects of the vacuum pressure and surface tension. The hadron emission from the droplet is described following Weisskopf's statistical model. We have considered evolution of baryon-free droplets which have different initial temperatures and expansion rates. As a typical trend we observe an oscillating behavior of the droplet radius superimposed with a gradual shrinkage due to the hadron emission. The characteristic life time of droplets with radii 1.5-2 fm are about 9-16 fm/c.

  10. The Walking Droplet Instability

    Science.gov (United States)

    Bostwick, Joshua; Steen, Paul

    2013-11-01

    A droplet of liquid that partially wets a solid substrate assumes a spherical-cap equilibrium shape. We show that the spherical-cap with a mobile contact-line is unstable to a non-axisymmetric disturbance and we characterize the instability mechanism, as it depends upon the wetting properties of the substrate. We then solve the hydrodynamic problem for inviscid motions showing that the flow associated with the instability correlates with horizontal motion of the droplet's center-of-mass. We calculate the resulting ``walking speed.'' A novel feature is that the energy conversion mechanism is not unique, so long as the contact-line is mobilized. Hence, the walking droplet instability is potentially significant to a number of industrial applications, such as self-cleansing surfaces or energy harvesting devices.

  11. Chip-based droplet sorting

    Energy Technology Data Exchange (ETDEWEB)

    Beer, Neil Reginald; Lee, Abraham; Hatch, Andrew

    2014-07-01

    A non-contact system for sorting monodisperse water-in-oil emulsion droplets in a microfluidic device based on the droplet's contents and their interaction with an applied electromagnetic field or by identification and sorting.

  12. Chip-based droplet sorting

    Science.gov (United States)

    Beer, Neil Reginald; Lee, Abraham; Hatch, Andrew

    2014-07-01

    A non-contact system for sorting monodisperse water-in-oil emulsion droplets in a microfluidic device based on the droplet's contents and their interaction with an applied electromagnetic field or by identification and sorting.

  13. Hydrodynamics of a quark droplet

    DEFF Research Database (Denmark)

    Bjerrum-Bohr, Johan J.; Mishustin, Igor N.; Døssing, Thomas

    2012-01-01

    We present a simple model of a multi-quark droplet evolution based on the hydrodynamical description. This model includes collective expansion of the droplet, effects of the vacuum pressure and surface tension. The hadron emission from the droplet is described following Weisskopf's statistical...

  14. Sessile nanofluid droplet drying.

    Science.gov (United States)

    Zhong, Xin; Crivoi, Alexandru; Duan, Fei

    2015-03-01

    Nanofluid droplet evaporation has gained much audience nowadays due to its wide applications in painting, coating, surface patterning, particle deposition, etc. This paper reviews the drying progress and deposition formation from the evaporative sessile droplets with the suspended insoluble solutes, especially nanoparticles. The main content covers the evaporation fundamental, the particle self-assembly, and deposition patterns in sessile nanofluid droplet. Both experimental and theoretical studies are presented. The effects of the type, concentration and size of nanoparticles on the spreading and evaporative dynamics are elucidated at first, serving the basis for the understanding of particle motion and deposition process which are introduced afterward. Stressing on particle assembly and production of desirable residue patterns, we express abundant experimental interventions, various types of deposits, and the effects on nanoparticle deposition. The review ends with the introduction of theoretical investigations, including the Navier-Stokes equations in terms of solutions, the Diffusion Limited Aggregation approach, the Kinetic Monte Carlo method, and the Dynamical Density Functional Theory. Nanoparticles have shown great influences in spreading, evaporation rate, evaporation regime, fluid flow and pattern formation of sessile droplets. Under different experimental conditions, various deposition patterns can be formed. The existing theoretical approaches are able to predict fluid dynamics, particle motion and deposition patterns in the particular cases. On the basis of further understanding of the effects of fluid dynamics and particle motion, the desirable patterns can be obtained with appropriate experimental regulations. PMID:25578408

  15. Impact of blood droplets

    NARCIS (Netherlands)

    N. Laan

    2015-01-01

    Within Bloodstain Pattern Analysis, forensic experts commonly use the stringing method, based on a straight line approximation of the blood droplets trajectories to determine where the source of a bloodstain pattern was. However, by ignoring gravity, large errors may arise when inferring the 3D-loca

  16. Hyaline membrane disease or respiratory distress syndrome? A new approach for an old disease

    Directory of Open Access Journals (Sweden)

    Lidia Grappone

    2014-06-01

    Full Text Available The term “hyaline membrane disease” refers to the histological aspect of the most frequent pulmonary pathology in preterm newborn patients. The lung of the preterm baby is morphologically and functionally immature. Surfactant deficiency in the immature lungs causes alveolar instability and collapse, capillary edema and the formation of hyaline membrane. Thus, the hyaline membranes are epiphenomena and are not the cause of respiratory failure in infants with immature lungs. This definition is presently used to indicate surfactant deficit alone and should not be used for other causes of respiratory distress. Clinicians prefer to talk of “respiratory distress syndrome” (RDS. Improvement in neonatal treatment has changed the natural course of the illness, its clinical and radiological features and has enabled extremely low birth weight newborns (ELBW to survive. Alveoli paucity and pulmonary interstitial thickness in ELBW impair gas exchange and may necessitate prolonged ventilation treatment, increasing the risk of ventilator-induced lung injury (VILI and bronchopulmonary dysplasia (BPD. RDS, therefore, is a complex illness where pulmonary immaturity and surfactant deficit play a role together with other pathological conditions that determine the course of the illness and both short and long-term results. Proceedings of the International Course on Perinatal Pathology (part of the 10th International Workshop on Neonatology · October 22nd-25th, 2014 · Cagliari (Italy · October 25th, 2014 · The role of the clinical pathological dialogue in problem solving Guest Editors: Gavino Faa, Vassilios Fanos, Peter Van Eyken

  17. Pulmonary hyalinizing granuloma. Bilateral pulmonary nodules associated with chronic idiopathic thrombocytopenic purpura.

    Science.gov (United States)

    Satti, Mohamed B; Batouk, Abdelnasir A; Abdelaziz, Muntasir M; Ahmad, Mohamed F; Abdelaal, Mohamed A

    2005-09-01

    We report a case of a 30-year-old female who had been treated periodically with steroids for idiopathic thrombocytopenic purpura ITP over the last 10 years. Recently, during the course of investigation, she was found to have incidental asymptomatic multiple pulmonary nodules on chest CT. Following a needle biopsy to exclude malignancy, 2 nodules were excised and were histologically confirmed as pulmonary hyalinizing granuloma PHG. The remaining 2 nodules regressed on increasing her dose of steroids. The case is discussed with emphasis on the histological and radiological differential diagnosis, in addition to including ITP among the spectrum of immunologic conditions associated with PHG. PMID:16155671

  18. [A case of pulmonary hyalinizing granuloma with its occupational history of dust exposure].

    Science.gov (United States)

    Kido, M; Kajiki, A; Nagata, N; Manabe, H; Iwata, Y

    1995-03-01

    Multiple pulmonary nodules were found in a patient who had an occupational history of coal mining for eleven years and road construction for fifteen years. An open lung biopsy was performed, because nodules had increased in size compared to previous ones and a trasbronchial biopsy was not diagnostic. The nodules were composed of dense concentric lamellar collagenous structures with a serpentine pattern surrounded by an infiltration of histiocytes, lymphocytes and plasma cells with Russel bodies. These findings are compatible with pulmonary hyalinizing granuloma (PHG) named by Liebow A. A. The etiopathogenetic mechanism and the difference between PHG and silicotic nodule is discussed. PMID:7724907

  19. Non-diagnosed pulmonary hyalinizing granuloma (PHG) as a cause of sudden unexpected death.

    Science.gov (United States)

    Preuss, J; Woenckhaus, C; Thierauf, A; Strehler, M; Madea, B

    2008-08-01

    Pulmonary hyalinizing granuloma (PHG), a very rare benign tumour of the lungs, was first reported in 1977. We present a PHG of a 32-year-old woman from Yemen who collapsed 1 day after her arrival in Germany. Tuberculosis was suspected and the health authorities nearly closed part of one of the major international airports in Europe. However, this drastic measure was avoided by autopsy and a correct interpretation of the solid-elastic and well-circumscribed lung tumour as not characteristic for tuberculosis. Although the final diagnosis of PHG was only achieved after histology, this case strongly illustrates the necessity of a profound morphological training of forensic physicians. PMID:18621495

  20. Pulmonary hyalinizing granuloma with laryngeal and subcutaneous involvement: report of a case successfully treated with glucocorticoids.

    Science.gov (United States)

    Shinohara, Takeshi; Kaneko, Takeshi; Miyazawa, Naoki; Nakatani, Yukio; Nishiyama, Harumi; Shoji, Akira; Ishigatsubo, Yoshiaki

    2004-01-01

    We report a case of pulmonary hyalinizing granuloma (PHG) with laryngeal and subcutaneous involvement. A 43-year-old man was admitted to our hospital for assessment of hoarseness. Cervical and chest computed tomography, respectively, revealed a laryngeal tumor and two pulmonary masses. Specimens obtained from the pulmonary masses were compatible with PHG. The histopathology of biopsy specimens from both the laryngeal tumor and a subcutaneous tumor resembled that of the resected lung masses. Although there is no established treatment for PHG, the laryngeal tumor was diminished and all other lesions disappeared with glucocorticoid treatment. PMID:14964583

  1. Droplets and sprays

    CERN Document Server

    Sazhin, Sergei

    2014-01-01

    Providing a clear and systematic description of droplets and spray dynamic models, this book maximises reader insight into the underlying physics of the processes involved, outlines the development of new physical and mathematical models, and broadens understanding of interactions between the complex physical processes which take place in sprays. Complementing approaches based on the direct application of computational fluid dynamics (CFD), Droplets and Sprays treats both theoretical and practical aspects of internal combustion engine process such as the direct injection of liquid fuel, subcritical heating and evaporation. Includes case studies that illustrate the approaches relevance to automotive applications,  it is also anticipated that the described models can find use in other areas such as in medicine and environmental science.

  2. Hovering UFO Droplets

    CERN Document Server

    Anand, Sushant; Dhiman, Rajeev; Smith, J David; Varanasi, Kripa K

    2012-01-01

    This fluid dynamics video is an entry for the Gallery of Fluid Motion of the 65th Annual Meeting of the APS-DFD. This video shows behavior of condensing droplets on a lubricant impregnated surface and a comparison with a superhydrophobic surface. On impregnated surfaces, drops appear like UFOs hovering over a surface. The videos were recorded in an Environmental SEM and a specially built condensation rig.

  3. Two new hyaline-ascospored species of Trichoderma and their phylogenetic positions.

    Science.gov (United States)

    Qin, W T; Zhuang, W Y

    2016-01-01

    Collections of hypocrealean fungi found on decaying wood in subtropical regions of China were examined. Two new species, Trichoderma confluens and T. hubeiense, were discovered and are described. Trichoderma confluens is characterized by its widely effuse to rarely pulvinate, yellow stromata with densely disposed yellowish brown ostioles, simple acremonium- to verticillium-like conidiophores, hyaline conidia and multiform chlamydospores. Trichoderma hubeiense has pulvinate, grayish yellow stromata with brownish ostioles, trichoderma- to verticillium-like conidiophores and hyaline conidia. The phylogenetic positions of the two fungi were investigated based on sequence analyses of RNA polymerase II subunit b and translation elongation factor 1-α genes. The results indicate that T. confluens belongs to the Hypocreanum clade and is associated with but clearly separated from T. applanatum and T. decipiens. Trichoderma hubeiense belongs to the Polysporum clade and related to T. bavaricum but obviously differs from other members of the clade in sequence data. Morphological distinctions between the new species and their close relatives are noted and discussed.

  4. Pulmonary hyalinizing granuloma%肺玻璃样变肉芽肿病

    Institute of Scientific and Technical Information of China (English)

    Zhao-lin XU; Drew BETHUNE; Daria MANOS; Annette FOYLE; Harry HENTELEFF; Michael JOHNS-TON; Yannick CARTIER

    2009-01-01

    Objective:To present clinical and pathologic features of pulmonary hyalnizing granuloma through analyzing three cases found in our institution and reviewing cases reported in the English language literature. Methods and Results: Three eases of pulmonary hyalnizing granuloma identified at our institu-tion during the past ten years were reviewed. In the first case, the patient presented with concurrent pulmonary hyalinizing granuloma and histoplasmosis. In the second case, the patient presented with a 5.5 cm lung mass and a separate smaller lesion radiologically resembling bronchogenic carcinoma. There was very prominent polyclonal lymphocytic proliferation at the periphery especially of the smaller lesion likely representing an early stage of the disease process. In the third case, the patient presented with multiple subpleural plaque-like lesions in addition to nodular lesions of the lung. All cases also demonstrated various degrees of lymphocytic infiltration within the lesions. The English literature has been reviewed through searching the PubMed. Conclusion: Since patients with pulmonary hyalinizing granuloma demonstrated a spectrum of clinical presentations, radiologic changes and histologic features with a variety of associated clinical disorders, pulmonary hyalnizing granuloma is more in keeping with a clinicopathologic entity rather than a specific pathologic disease.

  5. Granular cell tumor of the cecum with extensive hyalinization and calcification: A case report

    Institute of Scientific and Technical Information of China (English)

    Ran Hong; Sung-Chul Lim

    2009-01-01

    A granular cell tumor (GCT) is a benign neoplasm of unclear histogenesis that is generally believed to be of nerve sheath origin. GCT is not common and most often affects the tongue, skin and soft tissue, although it may occur anywhere in the body. We experienced a case of GCT that arose in the cecum of a 55-yearold man. The GCT was removed by laparoscopic resection. In addition to the tumor, endoscopic examination revealed the presence of a 5-mm-polyp in the descending colon and multiple tiny polyps in the sigmoid colon and rectum. Histological examination with a hard consistency; in cut sections, mixed cells with yellowish and whitish portions were seen. The tumor was located between the mucosa and subserosa,and was composed of plump histiocyte-like tumor cells with abundant granular eosinophilic cytoplasm, which were immunoreactive for S-100 protein, vimentin,neuron-specific enolase, inhibin-a and calretinin.The tumor showed extensive hyalinization and focal dystrophic calcification. Immunohistochemical profiles did not confirm any particular cell type for the histogenetic origin of the GCT, including a nerve sheath origin. Extensive hyalinization and calcification showing involution of tumor cells suggest benign clinical behavior of GCT.

  6. Rapidly pulsed helium droplet source

    Energy Technology Data Exchange (ETDEWEB)

    Pentlehner, Dominik; Riechers, Ricarda; Dick, Bernhard; Slenczka, Alkwin [Institute for Physical and Theoretical Chemistry, University of Regensburg, 93053 Regensburg (Germany); Even, Uzi; Lavie, Nachum; Brown, Raviv; Luria, Kfir [Sackler Faculty of Exact Sciences, School of Chemistry, Tel Aviv University, Ramat Aviv, 69978 Tel Aviv (Israel)

    2009-04-15

    A pulsed valve connected to a closed-cycle cryostat was optimized for producing helium droplets. The pulsed droplet beam appeared with a bimodal size distribution. The leading part of the pulse consists of droplets suitable for doping with molecules. The average size of this part can be varied between 10{sup 4} and 10{sup 6} helium atoms, and the width of the distribution is smaller as compared to a continuous-flow droplet source. The system has been tested in a single pulse mode and at repetition rates of up to 500 Hz with almost constant intensity. The droplet density was found to be increased by more than an order of magnitude as compared to a continuous-flow droplet source.

  7. Deleted in Malignant Brain Tumors 1 (DMBT1) is present in hyaline membranes and modulates surface tension of surfactant

    DEFF Research Database (Denmark)

    Müller, Hanna; End, Caroline; Renner, Marcus;

    2007-01-01

    surfactant was measured by a capillary surfactometer. DMBT1-levels in tracheal aspirates of ventilated preterm and term infants were determined by ELISA. RESULTS: Pulmonary DMBT1 was localized in hyaline membranes during respiratory distress syndrome. In vitro addition of human recombinant DMBT1...

  8. Significance of droplet-droplet interactions in droplet streams: Atmospheric to supercritical conditions

    Science.gov (United States)

    Connon, Corinne Shirley

    In an effort to optimize liquid fuel combustion a considerable amount of research has been directed towards the atomization of large liquid masses into small droplets to increase the surface area available for vaporization. The current work uses a single linear array of moving droplets of uniform size and spacing to investigate the behavior of interacting droplets. A series of experiments, over a range of ambient conditions, demonstrate how a lead droplet alters the environment experienced by its trailing neighbor. This behavior is of particular interest for droplet groups under high pressure and temperature, where experimental data has been limited. Gas phase velocity and vapor concentration measurements show that as the space between adjacent droplets decreases entrainment of fluid towards the axis of motion is reduced. Trapped gases create a gaseous cylinder, composed of ambient gas and fuel vapor, which surrounds and moves with the droplet stream. As ambient pressure increase, the oscillatory behavior of the lead droplet wake begins to interfere with its trailing neighbor. Loss of stream stability and enhanced droplet stripping in part result from these oscillating wakes. However, acceleration of droplet stripping is mainly produced by liquid and gas density similarity, which increases the centrifugal stress and the growth rate of capillary waves. Further, injection of subcritical droplets into an ambient environment at temperatures and pressures above the liquid droplet critical point shows behavior not greatly different from the results obtained at high ambient pressures. The similarity results from thermal heatup times exceeding the breakup times generated from the severe aerodynamics encountered at high ambient density and high liquid-gas relative velocities.

  9. Change in the optical properties of hyaline cartilage heated by the near-IR laser radiation

    International Nuclear Information System (INIS)

    The in vitro dynamics of the change in optical properties of hyaline cartilage heated by fibre lasers at wavelengths 0.97 and 1.56 μm is studied. The laser-induced bleaching (at 1.56 μm) and darkening (at 0.97 μm) of the cartilage, caused by the heating and transport of water as well as by a change in the cartilage matrix, were observed and studied. These effects should be taken into account while estimating the depth of heating of the tissue. The investigated dynamics of light scattering in the cartilage allows one to choose the optimum radiation dose for laser plastic surgery of cartilage tissues. (laser applications and other topics in quantum electronics)

  10. Pulmonary small lymphocytic lymphoma (mucosa-associated lymphoid tissue type) associated with pulmonary hyalinizing granuloma.

    Science.gov (United States)

    Ren, Y; Raitz, E N; Lee, K R; Pingleton, S K; Tawfik, O

    2001-09-01

    A case of pulmonary hyalinizing granuloma (PHG) and concomitant low-grade, small lymphocytic lymphoma of the lung is presented. This is the first occurrence of pulmonary lymphoma in patients with PHG ever reported. The infiltrates around a left lower lobe nodule with left pleural effusion and thickening seen on chest CT were histologically proven to be lymphomatous infiltrates of the lung, pleura, and chest wall muscle. We believe that the lymphoma developed around the nodule and spread to the pleura and muscle in our patient. When infiltrates around the nodules, pleural effusion, or adenopathy are developed in a patient with proven PHG, close follow-up, biopsy, or careful cytology should be seriously considered to rule out a developing lymphoma. PMID:11555545

  11. Pulmonary hyalinizing granuloma mimicking multiple lung metastases: report of fluorodeoxyglucose positron emission findings.

    Science.gov (United States)

    Lien, Chi-Tun; Yang, Chih-Jen; Yang, Sheau-Fang; Chou, Shah-Hwa; Huang, Ming-Shyan

    2010-05-01

    Pulmonary hyalinizing granuloma (PHG) is a rare disease characterized by multiple bilateral pulmonary nodules of uncertain etiology. We describe a 71-year-old female patient with thyroid papillary carcinoma in whom bilateral pulmonary nodules were found during a routine chest radiography examination. Subsequent fluorodeoxyglucose positron emission tomography/computed tomography scan gave the impression of multiple pulmonary metastases based on high maximum standardized uptake value. She underwent video-assisted thoracoscopic surgery with wedge resection, and PHG was diagnosed on the basis of histopathologic findings. To our knowledge, this is the first report of PHG developing in a patient as a solid cancer, mimicking multiple pulmonary metastases. We also present the first description of positron emission tomography in PHG, according to a Medline search. PMID:20351580

  12. Hyaline Tintinnina (Protozoa-Ciliophora-Oligotrichida from northeast Brazilian coastal reefs

    Directory of Open Access Journals (Sweden)

    Roberto Sassi

    1989-01-01

    Full Text Available Seven species of hyaline Tintinnina were obtained from plankton samples collected near the coastal reefs of Ponta do Seixas (Lat. 7º09'16"S, Long. 34º4735"W, Northeastern Brazil, from April 1981 to May 1982 and from April 1983 to May 1984: Amphorellopsis acuta (Schmidt, 1901, Dadayiella ganymedes (Entz Sr., 1884, Epiplocyloides reticulata (Ostenfeld & Schmidt, 1901, Eutintinnus tubulosus (Ostenfeld, 1899, Favella ehrenbergi (Claparède & Lachmann, 1858, Metacylis mereschkowskyi Kofoid & Campbell, 1929 and M. perspicax (Hada, 1938. The most frequent and abundant species were M. mereschkowskyi and F. ehrenbergi. Except/.ganymedes, E. reticulata and F. ehrenbergi all species are new records from Brazil. Metacylis perspicax is also the seventh world register. For all species we provide description, drawings, measurements, seasonal occurrence, world distribution and some systematic comments.

  13. Post-radiotherapy locoregional recurrence of hyalinizing clear cell carcinoma of palate

    Directory of Open Access Journals (Sweden)

    Sonia Gon

    2013-01-01

    Full Text Available Clear cell carcinoma of the salivary glands is a rare tumor that represents less than 1% of all salivary tumors and is a new disease that is only recognized in recent years. It is rare and the standard treatment is still under investigation. This tumor often follows an indolent course and treatment includes wide surgical excision with or without adjuvant radiotherapy. Recurrence of the hyalinizing clear cell carcinoma (HCCC after complete surgical resection is uncommonly documented. We hereby report a case of post-radiotherapy locoregional recurrence of HCCC of the palate and recommend further clinicopathological study and long-term follow-up to document the biological behavior of this entity along with highlighting the role of special stains and immunohistochemistry in its diagnosis.

  14. Changes of cerebral hemodynamics following the administration of surfactant in the hyaline membrane disease of prematurity

    Energy Technology Data Exchange (ETDEWEB)

    Yoo, Jeong Hyun; Kim, Kyung Hee [Ewha Womans University College of Medicine, Seoul (Korea, Republic of)

    2000-09-15

    To evaluate the changes of cerebral blood flow velocity according to the time, before and after surfactant administration in hyaline membrane disease using Doppler ultrasonography. The patients were 15 premature babies who were clinically and radiologically diagnosed HMD. The ratio of male : female was 11:4, the mean gestational age was 30.1 {+-} 2.5 wks, mean body weight was 1.4 {+-} 0.6 kg,mean Apgar score at 5 min was 6.28, and type of delivery was C-section : vaginal delivery 9.6. Before and after, 10 mm, 30 min, 1 hr, 6 hr, 12 hr, 1 day, 3 day, 5 day and 7 day after surfactant administration, peak systolic and end-diastolic cerebral blood flow velocity (PSFV, EDFV) and resistive index (RI) were estimated by Doppler ultrasonography measuring MCA flow velocity using temporal window. The averages of all data according to the time were obtained and analyzed statistical significance. For the evaluation of the clinical status systemic BP, FiO2, pH, and respiratory rate were also checked according to the same time. The clinical status of FiO2, metabolic acidosis, and tachypnea was significantly improved after surfactant administration. There was no significant change of cerebral blood flow velocity (PSFV, EDFV) after the surfactant administration. The change of RI was nor statistically significant. The changes of the systemic BP had no significant changes. In spite of clinical improvement, there were no significant increases of cerebral blood flow velocity and changes of RI after surfactant administration in hyaline membrane disease.

  15. Asymmetric Wettability Directs Leidenfrost Droplets

    Science.gov (United States)

    Agapov, Rebecca; Boreyko, Jonathan; Briggs, Dayrl; Srijanto, Bernadeta; Retterer, Scott; Collier, C. Patrick; Lavrik, Nickolay

    2014-03-01

    Exploration of Leidenfrost droplets on nano- and microstructured surfaces are of great importance for increasing control over heat transfer in high power density systems using boiling phenomena. They also provide an elegant way to direct droplet motion in a variety of emerging fluidic systems. Here, we report the fabrication and characterization of tilted nanopillar arrays (TNPAs) that exhibit directional Leidenfrost water droplets under dynamic conditions. The batch fabrication of the TNPAs was achieved by glancing-angle anisotropic reactive ion etching of a thermally dewet platinum mask. In contrast to previously implemented macro- and microscopic Leidenfrost ratchets, our TNPAs induce no preferential directional movement of Leidenfrost droplets under conditions approaching steady-state film boiling. This suggests that the observed droplet directionality is not a result of asymmetric vapor flow. Phase diagrams were constructed for the boiling behavior upon droplet impact onto TNPAs, straight nanopillar arrays, and smooth silicon surfaces. Asymmetric wettability and directional trajectory of droplets was exclusive to the TNPAs for impacts corresponding to the transition boiling regime, revealing this to be the mechanism for the droplet directionality. This work was conducted at the Center for Nanophase Materials Sciences, which is sponsored at Oak Ridge National Lab by the Division of Scientific User Facilities, US Dept. of Energy.

  16. DROPLET COLLISION AND COALESCENCE MODEL

    Institute of Scientific and Technical Information of China (English)

    LI Qiang; CAI Ti-min; HE Guo-qiang; HU Chun-bo

    2006-01-01

    A new droplet collision and coalescence model was presented, a quick-sort method for locating collision partners was also devised and based on theoretical and experimental results, further advancement was made to the droplet collision outcome.The advantages of the two implementations of smoothed particle hydrodynamics (SPH)method were used to limit the collision of droplets to a given number of nearest droplets and define the probability of coalescence, numerical simulations were carried out for model validation. Results show that the model presented is mesh-independent and less time consuming, it can not only maintains the system momentum conservation perfectly, but not susceptible to initial droplet size distribution as well.

  17. Leidenfrost levitation: beyond droplets.

    Science.gov (United States)

    Hashmi, Ali; Xu, Yuhao; Coder, Benjamin; Osborne, Paul A; Spafford, Jonathon; Michael, Grant E; Yu, Gan; Xu, Jie

    2012-01-01

    Friction is a major inhibitor in almost every mechanical system. Enlightened by the Leidenfrost effect - a droplet can be levitated by its own vapor layer on a sufficiently hot surface - we demonstrate for the first time that a small cart can also be levitated by Leidenfrost vapor. The levitated cart can carry certain amount of load and move frictionlessly over the hot surface. The maximum load that the cart can carry is experimentally tested over a range of surface temperatures. We show that the levitated cart can be propelled not only by gravitational force over a slanted flat surface, but also self-propelled over a ratchet shaped horizontal surface. In the end, we experimentally tested water consumption rate for sustaining the levitated cart, and compared the results to theoretical calculations. If perfected, this frictionless Leidenfrost cart could be used in numerous engineering applications where relative motion exists between surfaces.

  18. Asymmetric Wettability Directs Leidenfrost Droplets

    Energy Technology Data Exchange (ETDEWEB)

    Agapov, Rebecca L [ORNL; Boreyko, Jonathan B [ORNL; Briggs, Dayrl P [ORNL; Srijanto, Bernadeta R [ORNL; Retterer, Scott T [ORNL; Collier, Pat [ORNL; Lavrik, Nickolay V [ORNL

    2014-01-01

    Leidenfrost phenomena on nano- and microstructured surfaces are of great importance for increasing control over heat transfer in high power density systems utilizing boiling phenomena. They also provide an elegant means to direct droplet motion in a variety of recently emerging fluidic systems. Here, we report the fabrication and characterization of tilted nanopillar arrays (TNPAs) that exhibit directional Leidenfrost water droplets under dynamic conditions, namely on impact with Weber numbers 40 at T 325 C. The batch fabrication of the TNPAs was achieved by glancing-angle anisotropic reactive ion etching of a thermally dewet platinum mask, with mean pillar diameters of 100 nm and heights of 200-500 nm. In contrast to previously implemented macro- and microscopic Leidenfrost ratchets, our TNPAs induce no preferential directional movement of Leidenfrost droplets under conditions approaching steady-state film boiling, suggesting that the observed droplet directionality is not a result of asymmetric vapor flow. Using high-speed imaging, phase diagrams were constructed for the boiling behavior upon impact for droplets falling onto TNPAs, straight nanopillar arrays, and smooth silicon surfaces. The asymmetric impact and directional trajectory of droplets was exclusive to the TNPAs for impacts corresponding to the transition boiling regime, revealing that asymmetric wettability upon impact is the mechanism for the droplet directionality.

  19. Droplets, Bubbles and Ultrasound Interactions.

    Science.gov (United States)

    Shpak, Oleksandr; Verweij, Martin; de Jong, Nico; Versluis, Michel

    2016-01-01

    The interaction of droplets and bubbles with ultrasound has been studied extensively in the last 25 years. Microbubbles are broadly used in diagnostic and therapeutic medical applications, for instance, as ultrasound contrast agents. They have a similar size as red blood cells, and thus are able to circulate within blood vessels. Perfluorocarbon liquid droplets can be a potential new generation of microbubble agents as ultrasound can trigger their conversion into gas bubbles. Prior to activation, they are at least five times smaller in diameter than the resulting bubbles. Together with the violent nature of the phase-transition, the droplets can be used for local drug delivery, embolotherapy, HIFU enhancement and tumor imaging. Here we explain the basics of bubble dynamics, described by the Rayleigh-Plesset equation, bubble resonance frequency, damping and quality factor. We show the elegant calculation of the above characteristics for the case of small amplitude oscillations by linearizing the equations. The effect and importance of a bubble coating and effective surface tension are also discussed. We give the main characteristics of the power spectrum of bubble oscillations. Preceding bubble dynamics, ultrasound propagation is introduced. We explain the speed of sound, nonlinearity and attenuation terms. We examine bubble ultrasound scattering and how it depends on the wave-shape of the incident wave. Finally, we introduce droplet interaction with ultrasound. We elucidate the ultrasound-focusing concept within a droplets sphere, droplet shaking due to media compressibility and droplet phase-conversion dynamics.

  20. Hyalinizing trabecular adenoma--a case report with FNAC histologic, MIB-1 proliferative index and immunohistochemical findings.

    Science.gov (United States)

    Karak, A K; Sahoo, M; Bhatnagar, D

    1998-10-01

    Hyalinizing trabecular adenoma is a recently described benign thyroid tumor, almost exclusively occurring in females. The morphological features of this entity overlap with both papillary and medullary carcinoma to varying extent. This, in turn, creates a situation of serious diagnostic pitfall particularly for a false positive diagnosis of papillary carcinoma in fine needle aspiration (FNA) cytology. False consideration of medullary carcinoma is also possible by the unwary especially if staining for Congo red and/or immunostaining for calcitonin is not resorted to. At histologic level, the distinctive architectural pattern is however of great help and thus poses a much lesser danger of misdiagnosis. We relate here our experience in a recently encountered case of hyalinizing trabecular adenoma and describe detailed FNA cytologic and histologic findings along with immunohistochemical profile using a panel of eight monoclonal antibodies. The tumor proliferative potential has also been assessed using MIB-1 (Ki-67) immunostaining. The various pros and cons of diagnostic pitfalls are discussed. PMID:9866913

  1. Strictly correlated uniform electron droplets

    OpenAIRE

    Rasanen, E.; Seidl, M.; Gori Giorgi, P.

    2011-01-01

    We study the energetic properties of finite but internally homogeneous D-dimensional electron droplets in the strict-correlation limit. The indirect Coulomb interaction is found to increase as a function of the electron number, approaching the tighter forms of the Lieb-Oxford bound recently proposed by Rasanen et al. [Phys. Rev. Lett. 102, 206406 (2009)]. The bound is satisfied in three-, two-, and one-dimensional droplets, and in the latter case it is reached exactly - regardless of the type...

  2. Deleted in Malignant Brain Tumors 1 (DMBT1 is present in hyaline membranes and modulates surface tension of surfactant

    Directory of Open Access Journals (Sweden)

    Griese Matthias

    2007-10-01

    Full Text Available Abstract Background Deleted in Malignant Brain Tumors 1 (DMBT1 is a secreted scavenger receptor cysteine-rich protein that binds various bacteria and is thought to participate in innate pulmonary host defense. We hypothesized that pulmonary DMBT1 could contribute to respiratory distress syndrome in neonates by modulating surfactant function. Methods DMBT1 expression was studied by immunohistochemistry and mRNA in situ hybridization in post-mortem lungs of preterm and full-term neonates with pulmonary hyaline membranes. The effect of human recombinant DMBT1 on the function of bovine and porcine surfactant was measured by a capillary surfactometer. DMBT1-levels in tracheal aspirates of ventilated preterm and term infants were determined by ELISA. Results Pulmonary DMBT1 was localized in hyaline membranes during respiratory distress syndrome. In vitro addition of human recombinant DMBT1 to the surfactants increased surface tension in a dose-dependent manner. The DMBT1-mediated effect was reverted by the addition of calcium depending on the surfactant preparation. Conclusion Our data showed pulmonary DMBT1 expression in hyaline membranes during respiratory distress syndrome and demonstrated that DMBT1 increases lung surface tension in vitro. This raises the possibility that DMBT1 could antagonize surfactant supplementation in respiratory distress syndrome and could represent a candidate target molecule for therapeutic intervention in neonatal lung disease.

  3. Dysplastic follicular dendritic cells in hyaline-vascular Castleman disease: a rare occurrence creating diagnostic difficulty.

    Science.gov (United States)

    Medina, Edward A; Fuehrer, Neil E; Miller, Frank R; Kinney, Marsha C; Higgins, Russell A

    2016-09-01

    Follicular dendritic cell (FDC) proliferations and dysplastic FDCs can be seen in Hyaline-vascular Castleman disease (HVCD). The association between HVCD and FDC sarcoma is well-documented; dysplastic FDCs may be precursors to FDC sarcoma. Herein, we describe a case of HVCD with strikingly large and dysplastic FDCs, which raised the differential of Hodgkin lymphoma and other neoplasms. Scattered dysplastic FDCs were predominantly in germinal centers and mantle zones, and rarely in interfollicular areas. Although occasional germinal centers contained increased FDCs, no mass forming proliferations were present to suggest FDC sarcoma. Immunostaining demonstrated that the atypical FDCs expressed CD21, clusterin and CXCL13, but not CD23, S100, pankeratin or CD30; they aberrantly expressed epidermal growth factor receptor (EGFR). The present case demonstrates that dysplastic FDCs may be present as isolated cells that require immunophenotyping to distinguish them from malignant entities with similar morphologic features. A variety of FDC markers is required to confirm their origin as the expression of any single marker is not assured, as occurred in this case. Pathologists need be aware of FDC proliferations in HVCD because of their association with FDC sarcoma. Aberrant EGFR expression by dysplastic FDCs may indicate that they are pre-neoplastic and necessitate long-term patient follow-up. PMID:27593552

  4. Uniform-droplet spray forming

    Energy Technology Data Exchange (ETDEWEB)

    Blue, C.A.; Sikka, V.K. [Oak Ridge National Lab., TN (United States); Chun, Jung-Hoon [Massachusetts Institute of Technology, Cambridge, MA (United States); Ando, T. [Tufts Univ., Medford, MA (United States)

    1997-04-01

    The uniform-droplet process is a new method of liquid-metal atomization that results in single droplets that can be used to produce mono-size powders or sprayed-on to substrates to produce near-net shapes with tailored microstructure. The mono-sized powder-production capability of the uniform-droplet process also has the potential of permitting engineered powder blends to produce components of controlled porosity. Metal and alloy powders are commercially produced by at least three different methods: gas atomization, water atomization, and rotating disk. All three methods produce powders of a broad range in size with a very small yield of fine powders with single-sized droplets that can be used to produce mono-size powders or sprayed-on substrates to produce near-net shapes with tailored microstructures. The economical analysis has shown the process to have the potential of reducing capital cost by 50% and operating cost by 37.5% when applied to powder making. For the spray-forming process, a 25% savings is expected in both the capital and operating costs. The project is jointly carried out at Massachusetts Institute of Technology (MIT), Tuffs University, and Oak Ridge National Laboratory (ORNL). Preliminary interactions with both finished parts and powder producers have shown a strong interest in the uniform-droplet process. Systematic studies are being conducted to optimize the process parameters, understand the solidification of droplets and spray deposits, and develop a uniform-droplet-system (UDS) apparatus appropriate for processing engineering alloys.

  5. Renal histopathology in toxicity and carcinogenicity studies with tert-butyl alcohol administered in drinking water to F344 rats: a pathology working group review and re-evaluation.

    Science.gov (United States)

    Hard, Gordon C; Bruner, Richard H; Cohen, Samuel M; Pletcher, John M; Regan, Karen S

    2011-04-01

    An independent Pathology Working Group (PWG) re-evaluated the kidney changes in National Toxicology Program (NTP) toxicology/carcinogenicity studies of tert-butyl alcohol (TBA) in F344/N rats to determine possible mode(s) of action underlying renal tubule tumors in male rats at 2-years. In the 13-week study, the PWG confirmed that the normal pattern of round hyaline droplets in proximal convoluted tubules was replaced by angular droplet accumulation, and identified precursors of granular casts in the outer medulla, changes typical of alpha(2u)-globulin (α(2u)-g) nephropathy. In the 2-year study, the PWG confirmed the NTP observation of increased renal tubule tumors in treated male groups. Linear papillary mineralization, another hallmark of the α(2u)-g pathway was present only in treated male rats. Chronic progressive nephropathy (CPN) was exacerbated in high-dose males and females, with a relationship between advanced grades of CPN and renal tumor occurrence. Hyperplasia of the papilla lining was a component of CPN in both sexes, but there was no pelvic urothelial hyperplasia. High-dose females showed no TBA-related nephrotoxicity. The PWG concluded that both α(2u)-g nephropathy and exacerbated CPN modes of action were operative in TBA renal tumorigenicity in male rats, neither of which has relevance for human cancer risk.

  6. Soft substrates suppress droplet splashing

    CERN Document Server

    Howland, Christopher J; Style, Robert W; Castrejón-Pita, A A

    2015-01-01

    Droplets splash when they impact dry, flat substrates above a critical velocity that depends on parameters such as droplet size, viscosity and air pressure. We show that substrate stiffness also impacts the splashing threshold by imaging ethanol drops impacting silicone gels of different stiffnesses. Splashing is significantly suppressed: droplets on the softest substrates need over 70% more kinetic energy to splash than they do on rigid substrates. We show that splash suppression is likely to be due to energy losses caused by deformations of soft substrates during the first few microseconds of impact. We find that solids with Youngs modulus $\\lesssim O(10^5)$Pa suppress splashing, in agreement with simple scaling arguments. Thus materials like soft gels and elastomers can be used as simple coatings for effective splash prevention.

  7. Droplet centrifugation, droplet DNA extraction, and rapid droplet thermocycling for simpler and faster PCR assay using wire-guided manipulations

    OpenAIRE

    You David J; Yoon Jeong-Yeol

    2012-01-01

    Abstract A computer numerical control (CNC) apparatus was used to perform droplet centrifugation, droplet DNA extraction, and rapid droplet thermocycling on a single superhydrophobic surface and a multi-chambered PCB heater. Droplets were manipulated using “wire-guided” method (a pipette tip was used in this study). This methodology can be easily adapted to existing commercial robotic pipetting system, while demonstrated added capabilities such as vibrational mixing, high-speed centrifuging o...

  8. Impinging Jets and Droplet Dynamics

    CERN Document Server

    Chen, Xiaodong; Ma, Dongjun; Yang, Vigor

    2011-01-01

    In this fluid dynamics video, results from high fidelity numerical simulations are presented, which have been carried out to study the flow and droplet dynamics of liquid sheets formed by two impinging jets. A three-dimensional Volume-of-Fluid (VOF) method with adaptive mesh refinement (AMR) based on octree meshes [1] is used to simulate the various flow patterns associated with impinging jets, secondary breakup and binary collision of droplets. In addition to AMR, a thickness based refinement algorithm is also developed and implemented to efficiently resolve the various scales of surface tension driven interfacial flows.

  9. Evaporation of elongated droplets on chemically stripe-patterned surfaces

    NARCIS (Netherlands)

    Jansen, H.P.; Zandvliet, H.J.W.; Kooij, E.S.

    2015-01-01

    We investigate the evaporation of elongated droplets on chemically striped patterned surfaces. Variation of elongation is achieved by depositing droplets on surfaces with varying ratios of hydrophobic and hydrophilic stripe widths. Elongated droplets evaporate faster than more spherical droplets. Bo

  10. Droplet migration characteristics in confined oscillatory microflows

    CERN Document Server

    Chaudhury, Kaustav; Chakraborty, Suman

    2015-01-01

    We analyze the migration characteristics of a droplet in an oscillatory flow field in a parallel plate micro-confinement. Using phase filed formalism, we capture the dynamical evolution of the droplet over a wide range of the frequency of the imposed oscillation in the flow field, drop size relative to the channel gap, and the capillary number. The latter two factors imply the contribution of droplet deformability, commonly considered in the study of droplet migration under steady shear flow conditions. We show that the imposed oscillation brings in additional time complexity in the droplet movement, realized through temporally varying drop-shape, flow direction and the inertial response of the droplet. As a consequence, we observe a spatially complicated pathway of the droplet along the transverse direction, in sharp contrast to the smooth migration under a similar yet steady shear flow condition. Intuitively, the longitudinal component of the droplet movement is in tandem with the flow continuity and evolve...

  11. Droplet centrifugation, droplet DNA extraction, and rapid droplet thermocycling for simpler and faster PCR assay using wire-guided manipulations

    Directory of Open Access Journals (Sweden)

    You David J

    2012-09-01

    Full Text Available Abstract A computer numerical control (CNC apparatus was used to perform droplet centrifugation, droplet DNA extraction, and rapid droplet thermocycling on a single superhydrophobic surface and a multi-chambered PCB heater. Droplets were manipulated using “wire-guided” method (a pipette tip was used in this study. This methodology can be easily adapted to existing commercial robotic pipetting system, while demonstrated added capabilities such as vibrational mixing, high-speed centrifuging of droplets, simple DNA extraction utilizing the hydrophobicity difference between the tip and the superhydrophobic surface, and rapid thermocycling with a moving droplet, all with wire-guided droplet manipulations on a superhydrophobic surface and a multi-chambered PCB heater (i.e., not on a 96-well plate. Serial dilutions were demonstrated for diluting sample matrix. Centrifuging was demonstrated by rotating a 10 μL droplet at 2300 round per minute, concentrating E. coli by more than 3-fold within 3 min. DNA extraction was demonstrated from E. coli sample utilizing the disposable pipette tip to cleverly attract the extracted DNA from the droplet residing on a superhydrophobic surface, which took less than 10 min. Following extraction, the 1500 bp sequence of Peptidase D from E. coli was amplified using rapid droplet thermocycling, which took 10 min for 30 cycles. The total assay time was 23 min, including droplet centrifugation, droplet DNA extraction and rapid droplet thermocycling. Evaporation from of 10 μL droplets was not significant during these procedures, since the longest time exposure to air and the vibrations was less than 5 min (during DNA extraction. The results of these sequentially executed processes were analyzed using gel electrophoresis. Thus, this work demonstrates the adaptability of the system to replace many common laboratory tasks on a single platform (through re-programmability, in rapid succession (using droplets

  12. Droplet centrifugation, droplet DNA extraction, and rapid droplet thermocycling for simpler and faster PCR assay using wire-guided manipulations.

    Science.gov (United States)

    You, David J; Yoon, Jeong-Yeol

    2012-01-01

    A computer numerical control (CNC) apparatus was used to perform droplet centrifugation, droplet DNA extraction, and rapid droplet thermocycling on a single superhydrophobic surface and a multi-chambered PCB heater. Droplets were manipulated using "wire-guided" method (a pipette tip was used in this study). This methodology can be easily adapted to existing commercial robotic pipetting system, while demonstrated added capabilities such as vibrational mixing, high-speed centrifuging of droplets, simple DNA extraction utilizing the hydrophobicity difference between the tip and the superhydrophobic surface, and rapid thermocycling with a moving droplet, all with wire-guided droplet manipulations on a superhydrophobic surface and a multi-chambered PCB heater (i.e., not on a 96-well plate). Serial dilutions were demonstrated for diluting sample matrix. Centrifuging was demonstrated by rotating a 10 μL droplet at 2300 round per minute, concentrating E. coli by more than 3-fold within 3 min. DNA extraction was demonstrated from E. coli sample utilizing the disposable pipette tip to cleverly attract the extracted DNA from the droplet residing on a superhydrophobic surface, which took less than 10 min. Following extraction, the 1500 bp sequence of Peptidase D from E. coli was amplified using rapid droplet thermocycling, which took 10 min for 30 cycles. The total assay time was 23 min, including droplet centrifugation, droplet DNA extraction and rapid droplet thermocycling. Evaporation from of 10 μL droplets was not significant during these procedures, since the longest time exposure to air and the vibrations was less than 5 min (during DNA extraction). The results of these sequentially executed processes were analyzed using gel electrophoresis. Thus, this work demonstrates the adaptability of the system to replace many common laboratory tasks on a single platform (through re-programmability), in rapid succession (using droplets), and with a high level of

  13. Sophisticated compound droplets on fiber networks

    Science.gov (United States)

    Weyer, Floriane; Lismont, Marjorie; Dreesen, Laurent; Vandewalle, Nicolas

    2015-11-01

    Droplets on fibers are part of our everyday lives. Indeed, many phenomena involve drops and fibers such as the formation of dew droplets on a spiderweb, the trapping of water droplets on cactus spines or the dyeing of cotton or wool fibers. Therefore, this topic has been widely studied in the recent years and it appears that droplets on fibers can be the starting point for an open digital microfluidics. We study the behavior of soapy water droplets on a fiber array. When a droplet slides along a vertical fiber and encounters a horizontal fiber, it can either stick there or continue its way. In the latter case, the droplet releases a tiny residue. We study the volume of these residues depending on the geometry of the node. By using this technique, a large number of small droplets can be trapped at the nodes of a fiber array. These residues can be encapsulated and collected by an oil droplet in order to create a multicompound droplet. Moreover, by using optical fibers, we can provoke and detect the fluorescence of the inner droplets. Fibers provide therefore an original way to study compound droplets and multiple reactions. F. Weyer is financially supported by an FNRS grant. This work is also supported by the FRFC 2.4504.12.

  14. Water droplet impact on elastic superhydrophobic surfaces.

    Science.gov (United States)

    Weisensee, Patricia B; Tian, Junjiao; Miljkovic, Nenad; King, William P

    2016-01-01

    Water droplet impact on surfaces is a ubiquitous phenomenon in nature and industry, where the time of contact between droplet and surface influences the transfer of mass, momentum and energy. To manipulate and reduce the contact time of impacting droplets, previous publications report tailoring of surface microstructures that influence the droplet - surface interface. Here we show that surface elasticity also affects droplet impact, where a droplet impacting an elastic superhydrophobic surface can lead to a two-fold reduction in contact time compared to equivalent rigid surfaces. Using high speed imaging, we investigated the impact dynamics on elastic nanostructured superhydrophobic substrates having membrane and cantilever designs with stiffness 0.5-7630 N/m. Upon impact, the droplet excites the substrate to oscillate, while during liquid retraction, the substrate imparts vertical momentum back to the droplet with a springboard effect, causing early droplet lift-off with reduced contact time. Through detailed experimental and theoretical analysis, we show that this novel springboarding phenomenon is achieved for a specific range of Weber numbers (We >40) and droplet Froude numbers during spreading (Fr >1). The observation of the substrate elasticity-mediated droplet springboard effect provides new insight into droplet impact physics. PMID:27461899

  15. Droplet based cavities and lasers

    DEFF Research Database (Denmark)

    Mølhave, Kristian; Kristensen, Anders; Mortensen, Asger

    2009-01-01

    The self-organized and molecularly smooth surface on liquid microdroplets makes them attractive as optical cavities with very high quality factors. This chapter describes the basic theory of optical modes in spherical droplets. The mechanical properties including vibrational excitation are also d...

  16. Salt stains from evaporating droplets

    NARCIS (Netherlands)

    N. Shahidzadeh; M.F.L. Schut; J. Desarnaud; M. Prat; D. Bonn

    2015-01-01

    The study of the behavior of sessile droplets on solid substrates is not only associated with common everyday phenomena, such as the coffee stain effect, limescale deposits on our bathroom walls, but also very important in many applications such as purification of pharmaceuticals, deicing of airplan

  17. Evaluating the capabilities and uncertainties of droplet measurements for the fog droplet spectrometer (FM-100)

    OpenAIRE

    J. K. Spiegel; Zieger, P.; Bukowiecki, N.; E. Hammer; Weingartner, E.; W. Eugster

    2012-01-01

    Droplet size spectra measurements are crucial to obtain a quantitative microphysical description of clouds and fog. However, cloud droplet size measurements are subject to various uncertainties. This work focuses on the evaluation of two key measurement uncertainties arising during cloud droplet size measurements with a conventional droplet size spectrometer (FM-100): first, we addressed the precision with which droplets can be sized with the FM-100 on the basis of Mie theory. We deduced erro...

  18. Evaluating the capabilities and uncertainties of droplet measurements for the fog droplet spectrometer (FM-100)

    OpenAIRE

    J. K. Spiegel; Zieger, P.; Bukowiecki, N.; E. Hammer; Weingartner, E.; W. Eugster

    2012-01-01

    Droplet size spectra measurements are crucial to obtain a quantitative microphysical description of clouds and fog. However, cloud droplet size measurements are subject to various uncertainties. This work focuses on the error analysis of two key measurement uncertainties arising during cloud droplet size measurements with a conventional droplet size spectrometer (FM-100): first, we addressed the precision with which droplets can be sized with the FM-100 on the basis of the Mie theory. We dedu...

  19. Single droplet experimentation on spray drying:evaporation of sessile droplets deposited on a flat surface

    OpenAIRE

    Perdana, J.A.; Fox, M.B.; Schutyser, M.A.I.; Boom, R.M.

    2010-01-01

    Abstract: Individually dispensed droplets were dried on a flat surface to mimic the drying of single droplets during spray drying. A robust dispensing process is presented that generates small droplets (dp>150 µm). A predictive model based on Bernoulli’s law accurately describes droplet size with varying liquids and dispensing parameters. Shrinkage of the droplets, monitored with a camera, was described using mass balance equations. Finally, a Sherwood correlation was derived to describe t...

  20. Granuloma hialinizante de pulmão recidivante Recurrent pulmonary hyalinizing granuloma

    Directory of Open Access Journals (Sweden)

    Guilherme D'Andréa Saba Arruda

    2010-10-01

    Full Text Available Relatamos o caso de um paciente de 61 anos, masculino, internado com objetivo de exérese de massa pulmonar para estudo anatomopatológico. O paciente apresentara anteriormente um quadro de febre, tosse seca e dor torácica, associado à presença de massas pulmonares detectadas por radiografia de tórax, tendo sido submetido em duas ocasiões (1976 e 1981 a toracotomia para a investigação diagnóstica, sem diagnóstico anatomopatológico conclusivo. A TC de tórax revelou volumosas massas com áreas de calcificação em ambos os campos pulmonares. O material do estudo anatomopatológico foi compatível com granuloma hialinizante de pulmão. No pós-operatório, o paciente apresentou vários episódios de broncoespasmo que foram revertidos com medicação sintomática. Foi mantido com prednisona na dose de 40 mg/dia com boa evolução clínica até o envio deste relato.We report the case of a 61-year-old male patient who underwent surgical excision of a lung mass for anatomopathological study. The patient had previously presented with fever, dry cough, and chest pain, together with lung masses detected by chest X-ray, and had undergone thoracotomy for diagnostic investigation on two occasions (1976 and 1981, although a conclusive diagnosis had not been made. A CT scan of the chest revealed large masses with areas of calcification in both lung fields. The anatomopathological study was consistent with pulmonary hyalinizing granuloma. In the postoperative period, the patient experienced several episodes of bronchospasm, which was reversible with the use of symptomatic medication. At this writing, the patient was receiving maintenance therapy with prednisone (40 mg/day and had shown clinical improvement.

  1. Polygonal excitations of spinning and levitating droplets

    CERN Document Server

    Hill, R J A

    2008-01-01

    The shape of a weightless spinning liquid droplet is governed by the balance between the surface tension and centrifugal forces. The axisymmetric shape for slow rotation becomes unstable to a non-axisymmetric distortion above a critical angular velocity, beyond which the droplet progresses through a series of 2-lobed shapes. Theory predicts the existence of a family of 3- and 4-lobed equilibrium shapes at higher angular velocity. We investigate the formation of a triangular-shaped magnetically levitated water droplet, driven to rotate by the Lorentz force on an ionic current within the droplet. We also study equatorial traveling waves which give the droplet 3, 4 and 5-fold symmetry.

  2. Strings of droplets propelled by coherent waves

    CERN Document Server

    Filoux, B; Vandewalle, N

    2015-01-01

    Bouncing walking droplets possess fascinating properties due to their peculiar wave/particule interaction. In order to study such walkers in a 1d system, we considered the case of one or more droplets in an annular cavity. We show that, in this geometry, walking droplets form a string of synchronized bouncing droplets that share a common coherent wave propelling the group at a speed faster than single walkers. The formation of this coherent wave and the collective behavior of droplets is captured by a model.

  3. Formation and Levitation of Unconfined Droplet Clusters

    Science.gov (United States)

    Liu, S.; Ruff, G. A.

    1999-01-01

    Combustion experiments using arrays of droplets seek to provide a link between single droplet combustion phenomena and the behavior of complex spray combustion systems. Both single droplet and droplet array studies have been conducted in microgravity to better isolate the droplet interaction phenomena and eliminate or reduce the confounding effects of buoyancy-induced convection. In most experiments involving droplet arrays, the droplets are supported on fibers to keep them stationary and close together before the combustion event. The presence of the fiber, however, disturbs the combustion process by introducing a source of heat transfer and asymmetry into the configuration. As the number of drops in a droplet array increases, supporting the drops on fibers becomes less practical because of the cumulative effect of the fibers on the combustion process. The overall objective of this research is to study the combustion of well-characterized drop clusters in a microgravity environment. Direct experimental observations and measurements of the combustion of droplet clusters would fill a large gap in our current understanding of droplet and spray combustion and provide unique experimental data for the verification and improvement of spray combustion models. This paper describes current work on the design and performance of an apparatus to generate and stabilize droplet clusters using acoustic and electrostatic forces.

  4. Dancing droplets: Contact angle, drag, and confinement

    Science.gov (United States)

    Benusiglio, Adrien; Cira, Nate; Prakash, Manu

    2015-11-01

    When deposited on a clean glass slide, a mixture of water and propylene glycol forms a droplet of given contact angle, when both pure liquids spread. (Cira, Benusiglio, Prakash: Nature, 2015). The droplet is stabilized by a gradient of surface tension due to evaporation that induces a Marangoni flow from the border to the apex of the droplets. The apparent contact angle of the droplets depends on both their composition and the external humidity as captured by simple models. These droplets present remarkable properties such as lack of a large pinning force. We discuss the drag on these droplets as a function of various parameters. We show theoretical and experimental results of how various confinement geometries change the vapor gradient and the dynamics of droplet attraction.

  5. [A case of pulmonary hyalinizing granuloma with high-grade uptake on FDG-PET mimicking metastatic lung cancer].

    Science.gov (United States)

    Kaneta, Toshikado; Saito, Atsushi; Akiyama, Takayoshi; Takahashi, Youko; Takahashi, Ryuji; Kudou, Kazuhiro

    2009-10-01

    A 28-year-old man was referred to Hakodate Municipal Hospital for examination of multiple pulmonary nodules detected on a medical check-up. His chest CT demonstrated well-defined multiple nodules with random distribution. 18-fluorodeoxyglucose positron emission tomography (FDG-PET) showed abnormal uptake in the pulmonary nodules and the hilar, mediastinal lymph node. No other accumulation was observed outside the thorax. Transbronchial lung biopsy did not yield a diagnosis. Based on the high accumulation on FDG-PET, we suspected a malignant tumor and performed right S4 wedge resection under video assisted thoracoscopy. Considering the histologocal and immunohistological findings, we diagnosed pulmonary hyalinizing granuloma. No treatment was given and subsequently stable disease was obtained on chest radiography. The follow-up FDG-PET showed standardized uptake value reduction. Pulmonary hyalinizing granuloma is infrequent and benign, but has been reported to possibly progress to lymphoproliferative disease. Consequently, FDG-PET is valuable to evaluate the activity of the disease itself and the possibility of transition. PMID:19882922

  6. Shape-Shifting Droplet Networks

    Science.gov (United States)

    Zhang, T.; Wan, Duanduan; Schwarz, J. M.; Bowick, M. J.

    2016-03-01

    We consider a three-dimensional network of aqueous droplets joined by single lipid bilayers to form a cohesive, tissuelike material. The droplets in these networks can be programed to have distinct osmolarities so that osmotic gradients generate internal stresses via local fluid flows to cause the network to change shape. We discover, using molecular dynamics simulations, a reversible folding-unfolding process by adding an osmotic interaction with the surrounding environment which necessarily evolves dynamically as the shape of the network changes. This discovery is the next important step towards osmotic robotics in this system. We also explore analytically and numerically how the networks become faceted via buckling and how quasi-one-dimensional networks become three dimensional.

  7. Modelling of slurry droplet drying

    Energy Technology Data Exchange (ETDEWEB)

    Kadja, M.; Bergeles, G. [National Technical University of Athens, Athens (Greece). Dept. of Mechanical Engineering

    2003-05-01

    Heat, mass and momentum transfer between a slurry droplet and a gas flow are investigated numerically. The developed model can be applied to assess drying and combustion properties of slurries inside spray dryers or combustors and to estimate the time needed to reach ignition of the solid component in slurry fuels. The model was applied to coal water droplet slurries the properties of which are available in the literature but can also be used for study of drying of any other slurry such as that encountered in flue gas desulfurization systems. The parametric study revealed that the most important factor in slurry drying is the ambient temperature and that the injection velocity, the ambient pressure of the flowing medium or the particle initial temperature affect very little the drying rate.

  8. Compound droplet manipulations on fiber arrays

    Science.gov (United States)

    Weyer, Floriane; Lismont, Marjorie; Dreesen, Laurent; Vandewalle, Nicolas

    2014-11-01

    Recent works demonstrated that fibers are the basis of an open digital microfluidics. Indeed, various processes such as droplet motion, fragmentation, trapping, releasing, mixing and encapsulation can be constructed on fiber arrays. However, addressing a large number of tiny droplets resulting from the mixing of several liquid components is still a challenge. Here we show that it is possible to manipulate tiny droplets reaching a high level of complexity. Wetting droplets are known to glide along vertical fibers. When a droplet reaches an horizontal fiber, it sticks at the crossing if capillary overcomes gravity. Otherwise, the droplet continues its way, crosses the node and leaves a tiny residue. Therefore, a vertical fiber decorated with a series of horizontal fibers will retain residual droplets at the successive nodes. An oil droplet, sliding on the vertical fiber, is able to collect the residues. Thus a multicompound droplet is created. The volume of the residual droplets has been studied and seems to be related to the diameters of both vertical and horizontal fibers. Moreover, the conditions under which the residues are released have been investigated in order to understand the formation of such a fluidic object. F. Weyer is financially supported by an FNRS grant. This work is also supported by the FRFC 2.4504.12.

  9. Droplet Deformation Prediction With the Droplet Deformation and Breakup Model (DDB)

    Science.gov (United States)

    Vargas, Mario

    2012-01-01

    The Droplet Deformation and Breakup Model was used to predict deformation of droplets approaching the leading edge stagnation line of an airfoil. The quasi-steady model was solved for each position along the droplet path. A program was developed to solve the non-linear, second order, ordinary differential equation that governs the model. A fourth order Runge-Kutta method was used to solve the equation. Experimental slip velocities from droplet breakup studies were used as input to the model which required slip velocity along the particle path. The center of mass displacement predictions were compared to the experimental measurements from the droplet breakup studies for droplets with radii in the range of 200 to 700 mm approaching the airfoil at 50 and 90 m/sec. The model predictions were good for the displacement of the center of mass for small and medium sized droplets. For larger droplets the model predictions did not agree with the experimental results.

  10. Integrated microfluidic device for droplet manipulation

    OpenAIRE

    Basova, E.

    2013-01-01

    Droplets based microfluidic systems have a big potential for the miniaturization of processes for bioanalysis. In the form of droplets, reagents are used in discrete volume, enabling high-throughput chemical reactions as well as single-cell encapsulation. Microreactors of this type can be manipulated and applied in bio-testing. In this work we present a platform for droplet generation and manipulation by using dielectrophoresis force. This platform is an integrated microfluidic device wit...

  11. INTEGRATED MICROFLUIDIC DEVICE FOR DROPLET MANIPULATION

    OpenAIRE

    Basova Evgenia; Drs Jakub; Zemanek Jiri; Hurak Zdenek; Foret František

    2013-01-01

    Droplets based microfluidic systems have a big potential for the miniaturization of processes for bioanalysis. In the form of droplets, reagents are used in discrete volume, enabling high-throughput chemical reactions as well as single-cell encapsulation. Microreactors of this type can be manipulated and applied in bio-testing. In this work we present a platform for droplet generation and manipulation by using dielectrophoresis force. This platform is an integrated microfluidic device wit...

  12. Fundamental Aspects of Droplet Combustion Modelling

    Directory of Open Access Journals (Sweden)

    Shah Shahood Alam

    2014-11-01

    Full Text Available The present paper deals with important aspects of liquid droplet evaporation and combustion. A detailed spherically symmetric, single component droplet combustion model is evolved first by solving time dependent energy and species conservation equations in the gas phase using finite difference technique. Results indicate that the flame diameter F first increases and then decreases and the square of droplet diameter decreases linearly with time. Also, the FD/ ratio increases throughout the droplet burning period unlike the quasi-steady model where it assumes a large constant value. The spherically symmetric model is then extended to include the effects of forced convection. Plots of 2 D and droplet mass burning rate mf versus time are obtained for steady state, droplet heating and heating with convection cases for a n-octane droplet of 1.3 mm diameter burning in standard atmosphere. It is observed that the mass burning rate is highest for forced convective case and lowest for droplet heating case. The corresponding values of droplet lifetime follow the inverse relationship with the mass burning rate as expected. Emission data for a spherically symmetric, 100 m n-heptane droplet burning in air are determined using the present gas phase model in conjunction with the Olikara and Borman code [1] with the aim of providing a qualitative trend rather than quantitative with a simplified approach. It is observed that the products of combustion maximise in the reaction zone and NO concentration is very sensitive to the flame temperature. This paper also discusses the general methodology and basic governing equations for analysing multicomponent and high pressure droplet vaporisation/combustion in a comprehensible manner. The results of the present study compare fairly well with the experimental/theoretical observations of other authors for the same conditions. The droplet sub models developed in the present work are accurate and yet simple for their

  13. Pyrolysis of Large Black Liquor Droplets

    Science.gov (United States)

    Bartkus, Tadas P.; Dietrich, Daniel L.; T'ien, James S.; Wessel, Richard A.

    2007-01-01

    This paper presents the results of experiments involving the pyrolysis of large black liquor droplets in the NASA KC-135 reduced gravity aircraft. The reduced gravity environment facilitated the study of droplets up to 9 mm in diameter extending the results of previous studies to droplet sizes that are similar to those encountered in recovery boilers. Single black liquor droplets were rapidly inserted into a 923 K oven. The primary independent variables were the initial droplet diameter (0.5 mm to 9 mm), the black liquor solids content (66.12% - 72.9% by mass), and the ambient oxygen mole fraction (0.0 - 0.21). Video records of the experiments provided size and shape of the droplets as a function of time. The results show that the particle diameter at the end of the drying stage (D(sub DRY)) increases linearly with the initial particle diameter (D(sub O)). The results further show that the ratio of the maximum swollen diameter (D(sub MAX)) to D(sub O) decreases with increasing D(sub O) for droplets with D(sub O) less than 4 mm. This ratio was independent of D(sub O) for droplets with D(sub O) greater than 4 mm. The particle is most spherical at the end of drying, and least spherical at maximum swollen size, regardless of initial sphericity and droplet size.

  14. Compound droplet manipulations on fiber arrays

    CERN Document Server

    Weyer, Floriane; Dreesen, Laurent; Vandewalle, Nicolas

    2015-01-01

    Recent works demonstrated that fiber arrays may constitue the basis of an open digital microfluidics. Various processes, such as droplet motion, fragmentation, trapping, release, mixing and encapsulation, may be achieved on fiber arrays. However, handling a large number of tiny droplets resulting from the mixing of several liquid components is still a challenge for developing microreactors, smart sensors or microemulsifying drugs. Here, we show that the manipulation of tiny droplets onto fiber networks allows for creating compound droplets with a high complexity level. Moreover, this cost-effective and flexible method may also be implemented with optical fibers in order to develop fluorescence-based biosensor.

  15. Droplet actuation in an electrified microfluidic network.

    Science.gov (United States)

    Wehking, Jonathan D; Kumar, Ranganathan

    2015-02-01

    This work demonstrates that liquid droplet emulsions in a microchannel can be deformed, decelerated and/or pinned by applying a suitable electrical potential. By concentrating a potential gradient at the corners, we show that different droplets can be passively binned by size and on demand in a branched microfluidic device. The deformation, deceleration, squeezing and release of droplets in a three-dimensional numerical simulation are qualitatively verified by experiments in a PDMS microfluidic device. The forces required for pinning or binning a droplet provide a delicate balance between hydrodynamics and the electric field, and are obtained using appropriate non-dimensional parameters. PMID:25435073

  16. Colliding droplets: a short film presentation

    International Nuclear Information System (INIS)

    A series of experiments were performed in which liquid droplets were caused to collide. Impact velocities to several meters per second and droplet diameters up to 600 micrometers were used. The impact parameters in the collisions vary from zero to greater than the sum of the droplet radii. Photographs of the collisions were taken with a high speed framing camera in order to study the impacts and subsequent behavior of the droplets. The experiments will be discussed and a short movie film presentation of some of the impacts will be shown

  17. Lineage plasticity and cell biology of fibrocartilage and hyaline cartilage: Its significance in cartilage repair and replacement

    Energy Technology Data Exchange (ETDEWEB)

    Freemont, Anthony J. [Regenerative Medicine Research Group, University of Manchester, England (United Kingdom)]. E-mail: Tony.freemont@man.ac.uk; Hoyland, Judith [Regenerative Medicine Research Group, University of Manchester, England (United Kingdom)

    2006-01-15

    Cartilage repair is a major goal of modern tissue engineering. To produce novel engineered implants requires a knowledge of the basic biology of the tissues that are to be replaced or reproduced. Hyaline articular cartilage and meniscal fibrocartilage are two tissues that have excited attention because of the frequency with which they are damaged. A basic strategy is to re-engineer these tissues ex vivo by stimulating stem cells to differentiate into the cells of the mature tissue capable of producing an intact functional matrix. In this brief review, the sources of cells for tissue engineering cartilage and the culture conditions that have promoted differentiation are discussed within the context of natural cartilage repair. In particular, the role of cell density, cytokines, load, matrices and oxygen tension are discussed.

  18. Pulmonary hyalinizing granulomas in a patient with malignant lymphoma, with development nine years later of multiple myeloma and systemic amyloidosis.

    Science.gov (United States)

    Drasin, H; Blume, M R; Rosenbaum, E H; Klein, H Z

    1979-07-01

    In our patient, multiple bilateral nodular pulmonary densities appeared on a chest x-ray at the time of diagnosis of stage IV diffuse lymphocytic lymphoma. After localized radiation therapy, the patient received no further systemic therapy. The pulmonary nodules slowly became larger and more numerous. Nine years later the patient developed proven multiple myeloma. Pulmonary hyalinizing granulomas have not heretofore been associated with proven lymphoreticular neoplasia, although this has long been suspected. The occurrence of two B-cell tumors at different points in time associated with systemic amyloidosis is an extremely rare event. The authors discuss the possibility that these conditions represent an abnormality in a common cell of origin with differing expression over time. Coincidence, however, remains a likely explanation for the different immunopathies that occurred in our patient. PMID:582294

  19. Droplet dynamics on patterned substrates

    Indian Academy of Sciences (India)

    A Dupuis; J M Yeomans

    2005-06-01

    We present a lattice Boltzmann algorithm which can be used to explore the spreading of droplets on chemically and topologically patterned substrates. As an example we use the method to show that the final configuration of a drop on a substrate comprising hydrophobic and hydrophilic stripes can depend sensitively on the dynamical pathway by which the state is reached. We also consider a substrate covered with micron-scale posts and investigate how this can lead to superhydrophobic behaviour. Finally we model how a Namibian desert beetle collects water from the wind.

  20. The epididymis, cytoplasmic droplets and male fertility

    Institute of Scientific and Technical Information of China (English)

    Trevor G Cooper

    2011-01-01

    The potential of spermatozoa to become motile during post-testicular maturation,and the relationship between the cytoplasmic droplet and fertilizing capacity are reviewed.Post-testicular maturation of spermatozoa involves the autonomous induction of motility,which can occur in vivo in testes with occluded excurrent ducts and in vitro in testicular explants,and artefactual changes in morphology that appear to occur in the testis in vitro.Both modifications may reflect time-dependent oxidation of disulphide bonds of head and tail proteins.Regulatory volume decrease(RVD),which counters sperm swelling at ejaculation,is discussed in relation to loss of cytoplasmic droplets and consequences for fertility.It is postulated that:(i)fertile males possess spermatozoa with sufficient osmolytes to drive RVD at ejaculation,permitting the droplet to round up and pinch off without membrane rupture; and(ⅱ)infertile males possess spermatozoa with insufficient osmolytes so that RVD is inadequate,the droplet swells and the resulting flagellar angulation prevents droplet loss.Droplet retention at ejaculation is a harbinger of infertility caused by failure of the spermatozoon to negotiate the uterotubal junction or mucous and reach the egg.In this hypothesis,the epididymis regulates fertility indirectly by the extent of osmolyte provision to spermatozoa,which influences RVD and therefore droplet loss.Man is an exception,because ejaculated human spermatozoa retain their droplets.This may reflect their short midpiece,approximating head length,permitting a swollen droplet to extend along the entire midpiece; this not only obviates droplet migration and flagellar angulation but also hampers droplet loss.

  1. Friction-formed liquid droplets

    Energy Technology Data Exchange (ETDEWEB)

    Lockwood, A J; Inkson, B J [NanoLAB Centre, Department of Materials Science and Engineering, University of Sheffield, Sheffield S1 3JD (United Kingdom); Anantheshwara, K; Bobji, M S, E-mail: a.lockwood@sheffield.ac.uk, E-mail: beverley.inkson@sheffield.ac.uk [Department of Mechanical Engineering, Indian Institute of Science (IISc), Bangalore 560012 (India)

    2011-03-11

    The formation of nanoscale liquid droplets by friction of a solid is observed in real-time. This is achieved using a newly developed in situ transmission electron microscope (TEM) triboprobe capable of applying multiple reciprocating wear cycles to a nanoscale surface. Dynamical imaging of the nanoscale cyclic rubbing of a focused-ion-beam (FIB) processed Al alloy by diamond shows that the generation of nanoscale wear particles is followed by a phase separation to form liquid Ga nanodroplets and liquid bridges. The transformation of a two-body system to a four-body solid-liquid system within the reciprocating wear track significantly alters the local dynamical friction and wear processes. Moving liquid bridges are observed in situ to play a key role at the sliding nanocontact, interacting strongly with the highly mobile nanoparticle debris. In situ imaging demonstrates that both static and moving liquid droplets exhibit asymmetric menisci due to nanoscale surface roughness. Nanodroplet kinetics are furthermore dependent on local frictional temperature, with solid-like surface nanofilaments forming on cooling. TEM nanotribology opens up new avenues for the real-time quantification of cyclic friction, wear and dynamic solid-liquid nanomechanics, which will have widespread applications in many areas of nanoscience and nanotechnology.

  2. Friction-formed liquid droplets

    Science.gov (United States)

    Lockwood, A. J.; Anantheshwara, K.; Bobji, M. S.; Inkson, B. J.

    2011-03-01

    The formation of nanoscale liquid droplets by friction of a solid is observed in real-time. This is achieved using a newly developed in situ transmission electron microscope (TEM) triboprobe capable of applying multiple reciprocating wear cycles to a nanoscale surface. Dynamical imaging of the nanoscale cyclic rubbing of a focused-ion-beam (FIB) processed Al alloy by diamond shows that the generation of nanoscale wear particles is followed by a phase separation to form liquid Ga nanodroplets and liquid bridges. The transformation of a two-body system to a four-body solid-liquid system within the reciprocating wear track significantly alters the local dynamical friction and wear processes. Moving liquid bridges are observed in situ to play a key role at the sliding nanocontact, interacting strongly with the highly mobile nanoparticle debris. In situ imaging demonstrates that both static and moving liquid droplets exhibit asymmetric menisci due to nanoscale surface roughness. Nanodroplet kinetics are furthermore dependent on local frictional temperature, with solid-like surface nanofilaments forming on cooling. TEM nanotribology opens up new avenues for the real-time quantification of cyclic friction, wear and dynamic solid-liquid nanomechanics, which will have widespread applications in many areas of nanoscience and nanotechnology.

  3. Vortices catapult droplets in atomization

    CERN Document Server

    Jerome, J John Soundar; Matas, Jean-Philippe; Zaleski, Stéphane; Hoepffner, Jérôme

    2016-01-01

    A droplet ejection mechanism in planar two-phase mixing layers is examined. Any disturbance on the gas-liquid interface grows into a Kelvin-Helmholtz wave, and the wave crest forms a thin liquid film that flaps as the wave grows downstream. Increasing the gas speed, it is observed that the film breaks up into droplets which are eventually thrown into the gas stream at large angles. In a flow where most of the momentum is in the horizontal direction, it is surprising to observe these large ejection angles. Our experiments and simulations show that a recirculation region grows downstream of the wave and leads to vortex shedding similar to the wake of a backward-facing step. The ejection mechanism results from the interaction between the liquid film and the vortex shedding sequence: a recirculation zone appears in the wake of the wave and a liquid film emerges from the wave crest; the recirculation region detaches into a vortex and the gas flow over the wave momentarily reattaches due to the departure of the vor...

  4. Droplet Microfluidics for Virus Discovery

    Science.gov (United States)

    Rotem, Assaf; Cockrell, Shelley; Guo, Mira; Pipas, James; Weitz, David

    2012-02-01

    The ability to detect, isolate, and characterize an infectious agent is important for diagnosing and curing infectious diseases. Detecting new viral diseases is a challenge because the number of virus particles is often low and/or localized to a small subset of cells. Even if a new virus is detected, it is difficult to isolate it from clinical or environmental samples where multiple viruses are present each with very different properties. Isolation is crucial for whole genome sequencing because reconstructing a genome from fragments of many different genomes is practically impossible. We present a Droplet Microfluidics platform that can detect, isolate and sequence single viral genomes from complex samples containing mixtures of many viruses. We use metagenomic information about the sample of mixed viruses to select a short genomic sequence whose genome we are interested in characterizing. We then encapsulate single virions from the same sample in picoliter volume droplets and screen for successful PCR amplification of the sequence of interest. The selected drops are pooled and their contents sequenced to reconstruct the genome of interest. This method provides a general tool for detecting, isolating and sequencing genetic elements in clinical and environmental samples.

  5. Slip of Spreading Viscoplastic Droplets.

    Science.gov (United States)

    Jalaal, Maziyar; Balmforth, Neil J; Stoeber, Boris

    2015-11-10

    The spreading of axisymmetric viscoplastic droplets extruded slowly on glass surfaces is studied experimentally using shadowgraphy and swept-field confocal microscopy. The microscopy furnishes vertical profiles of the radial velocity using particle image velocimetry (PIV) with neutrally buoyant tracers seeded in the fluid. Experiments were conducted for two complex fluids: aqueous solutions of Carbopol and xanthan gum. On untreated glass surfaces, PIV demonstrates that both fluids experience a significant amount of effective slip. The experiments were repeated on glass that had been treated to feature positive surface charges, thereby promoting adhesion between the negatively charged polymeric constituents of the fluids and the glass surface. The Carbopol and xanthan gum droplets spread more slowly on the treated surface and to a smaller radial distance. PIV demonstrated that this reduced spreading was associated with a substantial reduction in slip. For Carbopol, the effective slip could be eliminated entirely to within the precision of the PIV measurements; the reduction in slip was less effective for xanthan gum, with a weak slip velocity remaining noticeable. PMID:26418827

  6. Effect of droplet shape on ring stains from dried liquid

    Science.gov (United States)

    Santiago, Melvin; Brown, Katherine; Mathur, Harsh

    A landmark experimental paper on coffee stains by Deegan et al included a simple theoretical analysis of circular droplets. The analysis was based on a model informally called the Maxwell House equations. It describes the evolving height profile of the droplet, the evaporation of the solvent and the outflow of solute to the rim of the droplet. Since typical droplets are not circles, here we extend the analysis to more general shapes. We find that for thin droplets the height profile may be determined by solving Poisson's equation in a domain corresponding to the footprint of the droplet. Evaporation is treated in a simple approximation via an electrostatic analogy and is dominated by the sharp edges of the droplet. Assuming zero vorticity allows us to analyze the solvent flow in droplets of arbitrary shape. We compare circular droplets to other shapes including long linear droplets, ring shaped droplets and droplets with an elliptical footprint

  7. A falling droplet as it falls apart

    CERN Document Server

    Jalaal, M; Mehravaran, K

    2011-01-01

    Using direct numerical simulations, the fragmentation of falling liquid droplets in a quiescent media is studied. Three simulations with different Eotvos numbers were performed. An adaptive volume of fluid(VOF) method based on octree meshing is used, providing a notable reduction of computational cost. The current video includes 4 main parts describing the fragmentation of the falling droplet.

  8. Double droplets simultaneous impact on liquid film

    Science.gov (United States)

    Guo, Y.; Chen, G.; Shen, S.; Zhang, J.

    2015-09-01

    The evolution of double droplets simultaneously impinging on flat liquid film are obtained with CLSVOF method(Combined Level Set and VOF). the impinging velocity, liquid film thickness, and the horizontal distance between the two droplets were investigated to analyze the factors that affect the evolution.

  9. Exotic states of bouncing and walking droplets

    DEFF Research Database (Denmark)

    Wind-Willassen, Øistein; Moláček, Jan; Harris, Daniel M.;

    2013-01-01

    We present the results of an integrated experimental and theoretical investigation of droplets bouncing on a vibrating fluid bath. A comprehensive series of experiments provides the most detailed characterisation to date of the system's dependence on fluid properties, droplet size, and vibrationa...

  10. Fine droplet generation using tunable electrohydrodynamic pulsation

    International Nuclear Information System (INIS)

    High-efficiency generation of fine droplets is significant for many microfluidic chips and sensor applications. To produce fine droplets, nozzles with small diameters are needed, which results in a high cost for nozzles and low efficiency of droplet generation. In this paper, a tunable electrohydrodynamic pulsation method which can generate fine droplets with high frequency and controllable size is presented using low conductivity liquids. The effects of flow rates and voltage parameters with respect to deposition frequency and droplet size are investigated. The influence of these parameters on Taylor cone formation time are also discussed and simple scaling laws are proposed to reveal and guide the droplet generation process. Experimental results show that single cycle deposition frequency decreases with increasing voltage frequency, but is only slightly influenced by the flow rates. The droplet size also decreases with voltage frequency, while large flow rates can make this decline gradual allowing better control. Moreover, the Taylor cone formation time may greatly affect the stability of the deposition frequency when the voltage frequency is larger than 30 Hz. Due to the short cycle time of high voltage frequencies, the hydrodynamic behavior in the emission process may be considerably affected by the increase of volume, which is also related to the flow rates. Tunable micropatterns consisting of fine droplets can be achieved by using this method in combination with motion stages. (paper)

  11. Orientation Dependence of Jumping Droplet Condensation

    Science.gov (United States)

    Berrier, Austin; Boreyko, Jonathan; Nature-Inspired Fluids; Interfaces Team

    2015-11-01

    On nanostructured superhydrophobic surfaces, microscopic condensate exhibits out-of-plane jumping that minimizes the average droplet size for maximal phase-change heat transfer. This jumping-droplet phenomenon occurs independently of gravity and is due to surface energy being partially converted to kinetic energy upon coalescence events. Although the initial departure of the jumping droplets is independent of gravity, the subsequent trajectories exhibit a dependence upon the orientation of the substrate. The drop size distribution of jumping-droplet condensation growing on a superhydrophobic substrate was characterized for both horizontal and vertical surface orientations. With the horizontal orientation, jumping condensate returns to the substrate by gravity. While this can result in chain reactions with other droplets to trigger further jumping events, eventually the rebounding droplets become too large to jump and are stuck on the surface. In contrast, droplets jumping off a vertically oriented surface do not return to the substrate. For this reason, the maximum droplet diameters during condensation growth were found to be significantly larger on the horizontally oriented superhydrophobic surface than on the vertical orientation.

  12. Binary droplet collision at high Weber number

    Science.gov (United States)

    Pan, Kuo-Long; Chou, Ping-Chung; Tseng, Yu-Jen

    2009-09-01

    By using the techniques developed for generating high-speed droplets, we have systematically investigated binary droplet collision when the Weber number (We) was increased from the range usually tested in previous studies on the order of 10 to a much larger value of about 5100 for water (a droplet at 23 m/s with a diameter of 0.7 mm). Various liquids were also used to explore the effects of viscosity and surface tension. Specifically, beyond the well-known regimes at moderate We’s, which exhibited coalescence, separation, and separation followed by satellite droplets, we found different behaviors showing a fingering lamella, separation after fingering, breakup of outer fingers, and prompt splattering into multiple secondary droplets as We was increased. The critical Weber numbers that mark the boundaries between these impact regimes are identified. The specific impact behaviors, such as fingering and prompt splattering or splashing, share essential similarity with those also observed in droplet-surface impacts, whereas substantial variations in the transition boundaries may result from the disparity of the boundary conditions at impacts. To compare the outcomes of both types of collisions, a simple model based on energy conservation was carried out to predict the maximum diameter of an expanding liquid disk for a binary droplet collision. The results oppose the dominance of viscous drag, as proposed by previous studies, as the main deceleration force to effect a Rayleigh-Taylor instability and ensuing periphery fingers, which may further lead to the formations of satellite droplets.

  13. Droplet turbulence interactions under subcritical and supercritical conditions

    Science.gov (United States)

    Coy, E. B.; Greenfield, S. C.; Ondas, M. S.; Song, Y.-H.; Spegar, T. D.; Santavicca, D. A.

    1993-01-01

    The goal of this research is to experimentally characterize the behavior of droplets in vaporizing liquid sprays under conditions typical of those encountered in high pressure combustion systems such as liquid fueled rocket engines. Of particular interest are measurements of droplet drag, droplet heating, droplet vaporization, droplet distortion, and secondary droplet breakup, under both subcritical and supercritical conditions. The paper presents a brief description of the specific accomplishments which have been made over the past year.

  14. Statistical steady state in turbulent droplet condensation

    CERN Document Server

    Siewert, Christoph; Krstulovic, Giorgio

    2016-01-01

    Motivated by the early stages of clouds and other systems in which droplets grow and shrink in a turbulence-driven supersaturation field, we investigate the problem of turbulent condensation using direct numerical simulations. The turbulent fluctuations of the supersaturation field offer different conditions for the growth of droplets which evolve in time due to turbulent transport and mixing. Based on that, we propose a Lagrangian stochastic model for condensation and evaporation of small droplets in turbulent flows. It consists of a set of stochastic integro-differential equations for the joint evolution of the squared radius and the supersaturation along the droplet trajectories. The model has two parameters fixed by the total amount of water and the thermodynamic properties, as well as the Lagrangian integral timescale of the turbulent supersaturation. The model reproduces very well the droplet size distributions obtained from direct numerical simulations and their time evolution. A noticeable result is t...

  15. Preparation and nucleation of spherical metallic droplet

    Directory of Open Access Journals (Sweden)

    Bing-ge Zhao

    2015-03-01

    Full Text Available The preparation and solidification of metallic droplets attract more and more attention for their significance in both engineering and scientific fields. In this paper, the preparation and characterization of Sn-based alloy droplets using different methods such as atomization and consumable electrode direct current arc (CDCA technique are reviewed. The morphology and structure of these droplets were determined by optical microscopy, X-ray diffraction (XRD and scanning electron microscopy (SEM. The solidification behavior of single droplet was systematically studied by means of scanning calorimetry (DSC, and the nucleation kinetics was also calculated. In particular, the development of fast scanning calorimetry (FSC made it possible to investigate the evolution of undercooling under ultrafast but controllable heating and cooling conditions. The combination of CDCA technique and FSC measurements opens up a new door for quantitative studies on droplet solidification, which is accessible to demonstrate some theories by experiments.

  16. Droplet size in a rectangular Venturi scrubber

    Directory of Open Access Journals (Sweden)

    M. A. M. Costa

    2004-06-01

    Full Text Available The Venturi scrubber is a device which uses liquid in the form of droplets to efficiently remove fine particulate matter from gaseous streams. Droplet size is of fundamental importance for the scrubber performance. In the present experimental study, a laser diffraction technique was used in order to measure droplet size in situ in a Venturi scrubber with a rectangular cross section. Droplet size distribution was measured as a function of gas velocity (58.3 to 74.9 m/s, liquid-to-gas ratio (0.07 to 0.27 l/m³, and distance from liquid injection point (64 to 173 mm. It was found that all these variables significantly affect droplet size. The results were compared with the predictions from correlations found in the literature.

  17. New models for droplet heating and evaporation

    KAUST Repository

    Sazhin, Sergei S.

    2013-02-01

    A brief summary of new models for droplet heating and evaporation, developed mainly at the Sir Harry Ricardo Laboratory of the University of Brighton during 2011-2012, is presented. These are hydrodynamic models for mono-component droplet heating and evaporation, taking into account the effects of the moving boundary due to evaporation, hydrodynamic models of multi-component droplet heating and evaporation, taking and not taking into account the effects of the moving boundary, new kinetic models of mono-component droplet heating and evaporation, and a model for mono-component droplet evaporation, based on molecular dynamics simulation. The results, predicted by the new models are compared with experimental data and the prehctions of the previously developed models where possible. © 2013 Asian Network for Scientific Information.

  18. Acoustophoresis in Variously Shaped Liquid Droplets

    CERN Document Server

    Yu, Gan; Xu, Jie; 10.1039/c1sm05871a

    2012-01-01

    The ability to precisely trap, transport and manipulate micrometer-sized objects, including biological cells, DNA-coated microspheres and microorganisms, is very important in life science studies and biomedical applications. In this study, acoustic radiation force in an ultrasonic standing wave field is used for micro-objects manipulation, a technique termed as acoustophoresis. Free surfaces of liquid droplets are used as sound reflectors to confine sound waves inside the droplets. Two techniques were developed for precise control of droplet shapes: edge pinning and hydrophilic/hydrophobic interface pinning. For all tested droplet shapes, including circular, annular and rectangular, our experiments show that polymer micro particles can be manipulated by ultrasound and form into a variety of patterns, for example, concentric rings and radial lines in an annular droplet. The complexity of the pattern increases with increasing frequency, and the observations are in line with simulation results. The acoustic mani...

  19. Numerical simulations of pendant droplets

    Science.gov (United States)

    Pena, Carlos; Kahouadji, Lyes; Matar, Omar; Chergui, Jalel; Juric, Damir; Shin, Seungwon

    2015-11-01

    We simulate the evolution of a three-dimensional pendant droplet through pinch-off using a new parallel two-phase flow solver called BLUE. The parallelization of the code is based on the technique of algebraic domain decomposition where the velocity field is solved by a parallel GMRes method for the viscous terms and the pressure by a parallel multigrid/GMRes method. Communication is handled by MPI message passing procedures. The method for the treatment of the fluid interfaces uses a hybrid Front Tracking/Level Set technique which defines the interface both by a discontinuous density field as well as by a local triangular Lagrangian mesh. This structure allows the interface to undergo large deformations including the rupture and coalescence of fluid interfaces. EPSRC Programme Grant, MEMPHIS, EP/K0039761/1.

  20. Growth and Division of Active Droplets: A Model for Protocells

    CERN Document Server

    Zwicker, David; Weber, Christoph A; Hyman, Anthony A; Jülicher, Frank

    2016-01-01

    It has been proposed that during the early steps in the origin of life, small droplets could have formed via the segregation of molecules from complex mixtures by phase separation. These droplets could have provided chemical reaction centers. However, whether these droplets could divide and propagate is unclear. Here we examine the behavior of droplets in systems that are maintained away from thermodynamic equilibrium by an external supply of energy. In these systems, droplets grow by the addition of droplet material generated by chemical reactions. Surprisingly, we find that chemically driven droplet growth can lead to shape instabilities that trigger the division of droplets into two smaller daughters. Therefore, chemically active droplets can exhibit cycles of growth and division that resemble the proliferation of living cells. Dividing active droplets could serve as a model for prebiotic protocells, where chemical reactions in the droplet play the role of a prebiotic metabolism.

  1. Self-propelled droplet behavior during condensation on superhydrophobic surfaces

    Science.gov (United States)

    Chu, Fuqiang; Wu, Xiaomin; Zhu, Bei; Zhang, Xuan

    2016-05-01

    Self-propelled droplet motion has applications in various engineering fields such as self-cleaning surfaces, heat transfer enhancement, and anti-icing methods. A superhydrophobic surface was fabricated using two simultaneous chemical reactions with droplet condensation experiments performed on the horizontal superhydrophobic surface to characterize the droplet behavior. The droplet behavior is classified into three types based on their motion features and leftover marks as immobile droplet coalescence, self-propelled droplet jumping, and self-propelled droplet sweeping. This study focuses on the droplet sweeping that occurs due to the ultra-small rolling angle of the superhydrophobic surface, where the resulting droplet sweeps along the surface, merging with all the droplets it meets and leaving a long, narrow, clear track with a large droplet at the end of the track. An easy method is developed to predict the droplet sweeping direction based on the relative positions of the droplets just before coalescence. The droplet sweeping always absorbs dozens of droplets and is not limited by the surface structures; thus, this sweeping has many useful applications. In addition, the relationships between the droplet behavior and the number of participating droplets are also analyzed statistically.

  2. Self-arraying of charged levitating droplets.

    Science.gov (United States)

    Kauffmann, Paul; Nussbaumer, Jérémie; Masse, Alain; Jeandey, Christian; Grateau, Henri; Pham, Pascale; Reyne, Gilbert; Haguet, Vincent

    2011-06-01

    Diamagnetic levitation of water droplets in air is a promising phenomenon to achieve contactless manipulation of chemical or biochemical samples. This noncontact handling technique prevents contaminations of samples as well as provides measurements of interaction forces between levitating reactors. Under a nonuniform magnetic field, diamagnetic bodies such as water droplets experience a repulsive force which may lead to diamagnetic levitation of a single or few micro-objects. The levitation of several repulsively charged picoliter droplets was successfully performed in a ~1 mm(2) adjustable flat magnetic well provided by a centimeter-sized cylindrical permanent magnet structure. Each droplet position results from the balance between the centripetal diamagnetic force and the repulsive Coulombian forces. Levitating water droplets self-organize into satellite patterns or thin clouds, according to their charge and size. Small triangular lattices of identical droplets reproduce magneto-Wigner crystals. Repulsive forces and inner charges can be measured in the piconewton and the femtocoulomb ranges, respectively. Evolution of interaction forces is accurately followed up over time during droplet evaporation.

  3. Spontaneous droplet trampolining on rigid superhydrophobic surfaces.

    Science.gov (United States)

    Schutzius, Thomas M; Jung, Stefan; Maitra, Tanmoy; Graeber, Gustav; Köhme, Moritz; Poulikakos, Dimos

    2015-11-01

    Spontaneous removal of condensed matter from surfaces is exploited in nature and in a broad range of technologies to achieve self-cleaning, anti-icing and condensation control. But despite much progress, our understanding of the phenomena leading to such behaviour remains incomplete, which makes it challenging to rationally design surfaces that benefit from its manifestation. Here we show that water droplets resting on superhydrophobic textured surfaces in a low-pressure environment can self-remove through sudden spontaneous levitation and subsequent trampoline-like bouncing behaviour, in which sequential collisions with the surface accelerate the droplets. These collisions have restitution coefficients (ratios of relative speeds after and before collision) greater than unity despite complete rigidity of the surface, and thus seemingly violate the second law of thermodynamics. However, these restitution coefficients result from an overpressure beneath the droplet produced by fast droplet vaporization while substrate adhesion and surface texture restrict vapour flow. We also show that the high vaporization rates experienced by the droplets and the associated cooling can result in freezing from a supercooled state that triggers a sudden increase in vaporization, which in turn boosts the levitation process. This effect can spontaneously remove surface icing by lifting away icy drops the moment they freeze. Although these observations are relevant only to systems in a low-pressure environment, they show how surface texturing can produce droplet-surface interactions that prohibit liquid and freezing water-droplet retention on surfaces. PMID:26536959

  4. Mechanical vibration of viscoelastic liquid droplets

    Science.gov (United States)

    Sharp, James; Harrold, Victoria

    2014-03-01

    The resonant vibrations of viscoelastic sessile droplets supported on different substrates were monitored using a simple laser light scattering technique. In these experiments, laser light was reflected from the surfaces of droplets of high Mw poly acrylamide-co-acrylic acid (PAA) dissolved in water. The scattered light was allowed to fall on the surface of a photodiode detector and a mechanical impulse was applied to the drops using a vibration motor mounted beneath the substrates. The mechanical impulse caused the droplets to vibrate and the scattered light moved across the surface of the photodiode. The resulting time dependent photodiode signal was then Fourier transformed to obtain the mechanical vibrational spectra of the droplets. The frequencies and widths of the resonant peaks were extracted for droplets containing different concentrations of PAA and with a range of sizes. This was repeated for PAA loaded water drops on surfaces which displayed different values of the three phase contact angle. The results were compared to a simple model of droplet vibration which considers the formation of standing wave states on the surface of a viscoelastic droplet. We gratefully acknowledge the support of the Leverhulme trust under grant number RPG-2012-702.

  5. Mass spectrometry of acoustically levitated droplets.

    Science.gov (United States)

    Westphall, Michael S; Jorabchi, Kaveh; Smith, Lloyd M

    2008-08-01

    Containerless sample handling techniques such as acoustic levitation offer potential advantages for mass spectrometry, by eliminating surfaces where undesired adsorption/desorption processes can occur. In addition, they provide a unique opportunity to study fundamental aspects of the ionization process as well as phenomena occurring at the air-droplet interface. Realizing these advantages is contingent, however, upon being able to effectively interface levitated droplets with a mass spectrometer, a challenging task that is addressed in this report. We have employed a newly developed charge and matrix-assisted laser desorption/ionization (CALDI) technique to obtain mass spectra from a 5-microL acoustically levitated droplet containing peptides and an ionic matrix. A four-ring electrostatic lens is used in conjunction with a corona needle to produce bursts of corona ions and to direct those ions toward the droplet, resulting in droplet charging. Analyte ions are produced from the droplet by a 337-nm laser pulse and detected by an atmospheric sampling mass spectrometer. The ion generation and extraction cycle is repeated at 20 Hz, the maximum operating frequency of the laser employed. It is shown in delayed ion extraction experiments that both positive and negative ions are produced, behavior similar to that observed for atmospheric pressure matrix-assisted laser absorption/ionization. No ion signal is observed in the absence of droplet charging. It is likely, although not yet proven, that the role of the droplet charging is to increase the strength of the electric field at the surface of the droplet, reducing charge recombination after ion desorption. PMID:18582090

  6. Vibrations of a diamagnetically levitated water droplet

    CERN Document Server

    Hill, R J A

    2010-01-01

    We measure the frequencies of small-amplitude shape oscillations of a magnetically-levitated water droplet. The drop levitates in a magnetogravitational potential trap. The restoring forces of the trap, acting on the droplet's surface in addition to the surface tension, increase the frequency of the oscillations. We derive the eigenfrequencies of the normal mode vibrations of a spherical droplet in the trap and compare it with our experimental measurements. We also consider the effect of the shape of the potential trap on the eigenfrequencies.

  7. Laser induced surface stress on water droplets.

    Science.gov (United States)

    Wang, Neng; Lin, Zhifang; Ng, Jack

    2014-10-01

    Laser induced stress on spherical water droplets is studied. At mechanical equilibrium, the body stress vanishes therefore we consider only the surface stress. The surface stress on sub-wavelength droplets is slightly weaker along the light propagation direction. For larger droplets, due to their light focusing effect, the forward stress is significantly enhanced. For a particle roughly 3 micron in radius, when it is excited at whispering gallery mode with Q ∼ 10⁴ by a 1 Watt Gaussian beam, the stress can be enhanced by two orders of magnitude, and can be comparable with the Laplace pressure. PMID:25321955

  8. From Single Droplet to Column Design

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The technique state to design counter-current extraction columns is based on the performance of pilot plant experiments. The modelling is then either with the equilibrium or dispersion model, whereas in the latter the dispersion coefficient accounts for all hydrodynamic non-idealities. A new approach uses single droplet experiments to obtain the basic laws and functions governing droplet breakage, coalescence,relative velocity, and axial dispersion when using droplet populance balance models (DPBM). The hydrodynamics simulation results show that the mean Sauter diameter, hold-up, and concentration profiles could be well predicted, which promotes the use of DPBM models for further applications in industrial scale.

  9. Electronically droplet energy harvesting using piezoelectric cantilevers

    KAUST Repository

    Al Ahmad, Mahmoud Al

    2012-01-01

    A report is presented on free falling droplet energy harvesting using piezoelectric cantilevers. The harvester incorporates a multimorph clamped-free cantilever which is composed of five layers of lead zirconate titanate piezoelectric thick films. During the impact, the droplet kinetic energy is transferred into the form of mechanical stress forcing the piezoelectric structure to vibrate. Experimental results show energy of 0.3 μJ per droplet. The scenario of moderate falling drop intensity, i.e. 230 drops per second, yields a total energy of 400 μJ. © 2012 The Institution of Engineering and Technology.

  10. Optimum Droplet Motion in Fire Plumes

    Directory of Open Access Journals (Sweden)

    Vasily Novozhilov

    2012-06-01

    Full Text Available The present paper introduces analytical model applicable for analysis of motion of water droplets injected into fire-generated plumes. The model is derived from Lagrangian equation of droplet motion.Application of the developed model to the practically important problem that is fire suppression by water sprays is discussed. A criterion for optimum spray dynamics is proposed. An analytical expression is provided for the optimum droplet size in the spray as a function of Heat Release Rate (HRR of fire.The present approach provides a quick estimation of optimum spray parameters for a particular fire suppression application.

  11. Analysis of droplet jumping phenomenon with lattice Boltzmann simulation of droplet coalescence

    Science.gov (United States)

    Peng, Benli; Wang, Sifang; Lan, Zhong; Xu, Wei; Wen, Rongfu; Ma, Xuehu

    2013-04-01

    Droplet jumping from condensing surfaces induced by droplet coalescence during dropwise condensation of mixed steam on a superhydrophobic surface can significantly enhance condensation heat transfer of mixed steam with non-condensable gas. This phenomenon was visually observed and theoretically analyzed in the present paper. The dynamic evolution of droplet and the velocity distribution inside the droplet during coalescence were simulated using multiphase lattice Boltzmann method. The energy distribution released by droplet coalescence was calculated statistically, and the jumping height induced by droplet coalescence on a superhydrophobic surface was predicted based on the energy conservation method. The theoretical predictions obtained by the modified model proposed in this paper agree well with the experimental observations.

  12. The effects of turbulence on droplet drag and secondary droplet breakup

    Science.gov (United States)

    Song, Y.-H.; Coy, E.; Greenfield, S.; Ondas, M.; Prevish, T.; Spegar, T.; Santavicca, D.

    1994-01-01

    The objective of this research is to obtain an improved understanding of the behavior of droplets in vaporizing sprays, particularly under conditions typical of those in high pressure rocket sprays. Experiments are conducted in a variety of high pressure, high temperature, optically-accessible flow systems, including one which is capable of operation at pressures up to 70 atm, temperatures up to 600 K, gas velocities up to 30 m/sec and turbulence intensities up to 40 percent. Single droplets, 50 to 500 micron in diameter, are produced by an aerodynamic droplet generator and transversely injected into the flow. Measurements are made of the droplet position, size, velocity and temperature and of the droplet's vapor wake from which droplet drag, dispersion, heating, vaporization and breakup are characterized.

  13. Self-propelled oil droplets consuming "fuel" surfactant

    DEFF Research Database (Denmark)

    Toyota, Taro; Maru, Naoto; Hanczyc, Martin M;

    2009-01-01

    A micrometer-sized oil droplet of 4-octylaniline containing 5 mol % of an amphiphilic catalyst exhibited a self-propelled motion, producing tiny oil droplets, in an aqueous dispersion of an amphiphilic precursor of 4-octylaniline. The tiny droplets on the surface of the self-propelled droplet wer...

  14. Colonization of a Central Venous Catheter by the Hyaline Fungus Fusarium solani Species Complex: A Case Report and SEM Imaging

    Directory of Open Access Journals (Sweden)

    Alberto Colombo

    2013-01-01

    Full Text Available The incidence of opportunistic infections by filamentous fungi is increasing partly due to the widespread use of central venous catheters (CVC, indwelling medical devices, and antineoplastic/immunosuppressive drugs. The case of a 13-year-old boy under treatment for acute lymphoblastic leukemia is presented. The boy was readmitted to the Pediatric Ward for intermittent fever of unknown origin. Results of blood cultures drawn from peripheral venous sites or through the CVC were compared. CVC-derived bottles (but not those from peripheral veins yielded hyaline fungi that, based on morphology, were identified as belonging to the Fusarium solani species complex. Gene amplification and direct sequencing of the fungal ITS1 rRNA region and the EF-1alpha gene confirmed the isolate as belonging to the Fusarium solani species complex. Portions of the CVC were analyzed by scanning electron microscopy. Fungi mycelia with long protruding hyphae were seen into the lumen. The firm adhesion of the fungal formation to the inner surface of the catheter was evident. In the absence of systemic infection, catheter removal and prophylactic voriconazole therapy were followed by disappearance of febrile events and recovery. Thus, indwelling catheters are prone to contamination by environmental fungi.

  15. Laparoscopic treatment for retroperitoneal hyaline-vascular type localized Castleman's disease (LCD) in the iliac vessel region.

    Science.gov (United States)

    Le, Aiwen; Shan, Lili; Wang, Zhonghai; Dai, Xiaoyun; Xiao, Tianhui; Zhuo, Rong; Yuan, Rui

    2015-01-01

    To improve the understanding, diagnostic levels, and therapeutic levels of retroperitoneal hyaline vascular type LCD in the iliac vessel region. Diagnostic and therapeutic processes of 4 patients with retroperitoneal LCD in the iliac vessel region were retrospectively analyzed. The median ages of the research patients was 31.3 years old, Pelvic vascular dual-source computed tomography (CT) indicated an abnormal pelvic irregular cloddy intensity shadow with heterogeneous densities and punctate calcified lesions. The enhanced scanning showed significantly enhanced lesions and multiple tortuous vascular images inside and around the lesions. Patients' preoperative diagnoses were all "pelvic mass with unknown characteristics", and retroperitoneal masses were successfully stripped off after the laparoscopic surgery. Intra operative findings indicated 1 mass located at the left obturator nerve, 1 at the left internal iliac artery, and 2 at the right external iliac artery. The postoperative pathological reports suggest a diagnosis of Castleman's disease. Retroperitoneal LCD in the iliac vessel region is generally asymptomatic. Preoperative imaging data may help with the diagnosis, but a confirmed diagnosis depends on the results of the pathological examination. Iliac artery embolization is performed prior to laparoscopic mass stripping if the masses have abundant blood supply, while lymphadenectomy is also applied to those with enlarged lymph nodes.

  16. Quasistatic packings of droplets in flat microfluidic channels

    Science.gov (United States)

    Kadivar, Erfan

    2016-02-01

    As observed in recent experiments, monodisperse droplets self-assemble spontaneously in different ordered packings. In this work, we present a numerical study of the droplet packings in the flat rectangular microfluidic channels. Employing the boundary element method, we numerically solve the Stokes equation in two-dimension and investigate the appearance of droplet packing and transition between one and two-row packings of monodisperse emulsion droplets. By calculating packing force applied on the droplet interface, we investigate the effect of flow rate, droplet size, and surface tension on the packing configurations of droplets and transition between different topological packings.

  17. Catching proteins in liquid helium droplets

    CERN Document Server

    Kupser, Peter; Meijer, Gerard; von Helden, Gert

    2010-01-01

    An experimental approach is presented that allows for the incorporation of large mass/charge selected ions in liquid helium droplets. It is demonstrated that droplets can be efficiently doped with a mass/charge selected amino acid as well as with the much bigger m$\\approx$12 000 amu protein Cytochrome C in selected charge states. The sizes of the ion-doped droplets are determined via electrostatic deflection. Under the experimental conditions employed, the observed droplet sizes are very large and range, dependent on the incorporated ion, from 10$^{10}$ helium atoms for protonated Phenylalanine to 10$^{12}$ helium atoms for Cytochrome C. As a possible explanation, a simple model based on the size- and internal energy-dependence of the pickup efficiency is given.

  18. Immersed Boundary Simulations of Active Fluid Droplets

    CERN Document Server

    Whitfield, Carl A

    2016-01-01

    We present numerical simulations of active fluid droplets immersed in an external fluid in 2-dimensions. We use an Immersed Boundary method to simulate the fluid droplet interface as a Lagrangian mesh. We present results from two example systems, firstly a droplet filled with an active polar fluid with polar anchoring at the droplet interface. Secondly, an active isotropic fluid consisting of particles that can bind and unbind from the interface and generate surface tension gradients through active contractility. These two systems demonstrate spontaneous symmetry breaking and steady state dynamics resembling cell motility and division and show complex feedback mechanisms with minimal degrees of freedom. The simulations outlined here will be useful for quantifying the wide range of dynamics observable in these active systems and modelling the effects of confinement in a consistent and adaptable way.

  19. Droplet Microfluidics for Chip-Based Diagnostics

    Directory of Open Access Journals (Sweden)

    Karan V. I. S. Kaler

    2014-12-01

    Full Text Available Droplet microfluidics (DMF is a fluidic handling technology that enables precision control over dispensing and subsequent manipulation of droplets in the volume range of microliters to picoliters, on a micro-fabricated device. There are several different droplet actuation methods, all of which can generate external stimuli, to either actively or passively control the shape and positioning of fluidic droplets over patterned substrates. In this review article, we focus on the operation and utility of electro-actuation-based DMF devices, which utilize one or more micro-/nano-patterned substrates to facilitate electric field-based handling of chemical and/or biological samples. The underlying theory of DMF actuations, device fabrication methods and integration of optical and opto-electronic detectors is discussed in this review. Example applications of such electro-actuation-based DMF devices have also been included, illustrating the various actuation methods and their utility in conducting chip-based laboratory and clinical diagnostic assays.

  20. Droplet Microfluidics for Artificial Lipid Bilayers

    Science.gov (United States)

    Punnamaraju, Srikoundinya; Steckl, Andrew

    2012-02-01

    Droplet interface bilayer is a versatile approach that allows formation of artificial lipid bilayer membrane at the interface of two lipid monolayer coated aqueous droplets in a lipid filled oil medium. Versatility exists in the form of voltage control of DIB area, ability of forming networks of DIBs, volume control of droplets and lipid-oil, and ease of reformation. Significant effect of voltage on the area and capacitance of DIB as well as DIB networks are characterized using simultaneous optical and electrical recordings. Mechanisms behind voltage-induced effects on DIBs are investigated. Photo induced effect on the DIB membrane porosity is obtained by incorporating UVC-sensitive photo-polymerizable lipids in DIB. Photo-induced effects can be extended for in-vitro studies of triggered release of encapsulated contents across membranes. A droplet based low voltage digital microfluidic platform is developed to automate DIB formation, which could potentially be used for forming arrays of lipid bilayer membranes.

  1. Immersed Boundary Simulations of Active Fluid Droplets

    Science.gov (United States)

    Hawkins, Rhoda J.

    2016-01-01

    We present numerical simulations of active fluid droplets immersed in an external fluid in 2-dimensions using an Immersed Boundary method to simulate the fluid droplet interface as a Lagrangian mesh. We present results from two example systems, firstly an active isotropic fluid boundary consisting of particles that can bind and unbind from the interface and generate surface tension gradients through active contractility. Secondly, a droplet filled with an active polar fluid with homeotropic anchoring at the droplet interface. These two systems demonstrate spontaneous symmetry breaking and steady state dynamics resembling cell motility and division and show complex feedback mechanisms with minimal degrees of freedom. The simulations outlined here will be useful for quantifying the wide range of dynamics observable in these active systems and modelling the effects of confinement in a consistent and adaptable way. PMID:27606609

  2. Capillary droplets on Leidenfrost micro-ratchets

    CERN Document Server

    Marin, Alvaro G; Römer, Gertwillem R B E; Pathiraj, B; Veld, Albertus Huis in 't; Lohse, Detlef

    2012-01-01

    Leidenfrost ratchets are structures with the ability of transporting liquid droplets when heated over the critical Leidenfrost temperature. Once this temperature is reached, the droplet levitates over the surface and moves in the direction marked by the slope of the ratchet at terminal velocities around 10 cm/s. Here we provide new experiments with micron-sized ratchets, which have been produced with picosecond pulse laser ablation. In the following work, we use a simple method to measure the thrust driving droplets of capillary size over the micro-ratchets. The mechanism responsible for the force acting on the drop on superheated ratchets has been recently under debate. We extend the recently proposed 'viscous mechanism' proposed by Dupeaux et al. [Europhys. Lett., 96, 58001 (2011)] to capillary droplets and find good agreement with our measurements.

  3. Janus droplet as a catalytic micromotor

    CERN Document Server

    Shklyaev, Sergey

    2015-01-01

    Self-propulsion of a Janus droplet in a solution of surfactant, which reacts on a half of a drop surface, is studied theoretically. The droplet acts as a catalytic motor creating a concentration gradient, which generates its surface-tension-driven motion; the self-propulsion speed is rather high, $60\\; {\\rm \\mu m/s}$ and more. This catalytic motor has several advantages over other micromotors: simple manufacturing, easily attained neutral buoyancy. In contrast to a single-fluid droplet, which demonstrates a self-propulsion as a result of symmetry breaking instability, for Janus one no stability threshold exists; hence, the droplet radius can be scaled down to micrometers. The paper was finalized and submitted by Denis S. Goldobin after Sergey Sklyaev had sadly passed away on June 2, 2014.

  4. Substrate Curvature Gradient Drives Rapid Droplet Motion

    Science.gov (United States)

    Lv, Cunjing; Chen, Chao; Chuang, Yin-Chuan; Tseng, Fan-Gang; Yin, Yajun; Grey, Francois; Zheng, Quanshui

    2014-07-01

    Making small liquid droplets move spontaneously on solid surfaces is a key challenge in lab-on-chip and heat exchanger technologies. Here, we report that a substrate curvature gradient can accelerate micro- and nanodroplets to high speeds on both hydrophilic and hydrophobic substrates. Experiments for microscale water droplets on tapered surfaces show a maximum speed of 0.42 m/s, 2 orders of magnitude higher than with a wettability gradient. We show that the total free energy and driving force exerted on a droplet are determined by the substrate curvature and substrate curvature gradient, respectively. Using molecular dynamics simulations, we predict nanoscale droplets moving spontaneously at over 100 m/s on tapered surfaces.

  5. Manipulation of microfluidic droplets by electrorheological fluid

    KAUST Repository

    Zhang, Menying

    2009-09-01

    Microfluidics, especially droplet microfluidics, attracts more and more researchers from diverse fields, because it requires fewer materials and less time, produces less waste and has the potential of highly integrated and computer-controlled reaction processes for chemistry and biology. Electrorheological fluid, especially giant electrorheological fluid (GERF), which is considered as a kind of smart material, has been applied to the microfluidic systems to achieve active and precise control of fluid by electrical signal. In this review article, we will introduce recent results of microfluidic droplet manipulation, GERF and some pertinent achievements by introducing GERF into microfluidic system: digital generation, manipulation of "smart droplets" and droplet manipulation by GERF. Once it is combined with real-time detection, integrated chip with multiple functions can be realized. © 2009 Wiley-VCH Verlag GmbH & Co. KGaA.

  6. Dispensing nano-pico droplets of ferrofluids

    Science.gov (United States)

    Irajizad, Peyman; Farokhnia, Nazanin; Ghasemi, Hadi

    2015-11-01

    Dispensing miniature volumes of a ferrofluid is of fundamental and practical importance for diverse applications ranging from biomedical devices, optics, and self-assembly of materials. Current dispensing systems are based on microfluidics flow-focusing approaches or acoustic actuation requiring complicated structures. A simple method is presented to continuously dispense the miniature droplets from a ferrofluid reservoir. Once a jet of the ferrofluid is subjected to a constrained flux through a membrane and an inhomogeneous magnetic field, the jet experiences a curvature-driven instability and transforms to a droplet. Ferrofluid droplets in the range of 0.1-1000 nl are dispensed with tunable dispensing frequencies. A model is developed that predicts the dispensed volume of the ferrofluid droplets with an excellent agreement with the measurements.

  7. Quark Matter Droplet Formation in Neutron Stars

    OpenAIRE

    Heiselberg, H.

    1995-01-01

    The formation rate of quark matter droplets in neutron stars is calculated from a combination of bubble formation rates in cold degenerate and high temperature matter. Nuclear matter calculations of the viscosity and thermal conductivity are applied. Results show that droplets form only in the core of neutron stars shortly after supernova collapse, where pressures and temperatures are high, and for sufficiently small interface tension between nuclear and quark matter. Coulomb energies hinder ...

  8. Multi Exposure Droplet Imaging System – MEDIS

    OpenAIRE

    Maimaiti, Abdula

    2011-01-01

    A new fast flash photography fast imaging system is devised to develop for studying the evolution of micron sized droplets travelling from the ink jet nozzle to substrate at 5 - 20 m/s. using flash illumination of 10 short pulses from different angles consecutively, sharp images of evolving droplets are expected to be captured. The electrical and optical characterization of the laser driver and photodetector is presented along with corresponding measurements. Detailed schematics of the whole ...

  9. Edge effects on water droplet condensation

    OpenAIRE

    Medici, Marie-Gabrielle; Mongruel, Anne; Royon, Laurent; Beysens, Daniel

    2014-01-01

    International audience In this study is investigated the effect of geometrical or thermal discontinuities on the growth of water droplets condensing on a cooled substrate. Edges, corners, cooled/non cooled boundaries can have a strong effect on the vapor concentration profile and mass diffusion around the drops. In comparison to growth in a pattern where droplets have to compete to catch vapor, which results in a linear water concentration profile directed perpendicularly to the substrate,...

  10. Fluid Flow in An Evaporating Droplet

    Science.gov (United States)

    Hu, H.; Larson, R.

    1999-01-01

    Droplet evaporation is a common phenomenon in everyday life. For example, when a droplet of coffee or salt solution is dropped onto a surface and the droplet dries out, a ring of coffee or salt particles is left on the surface. This phenomenon exists not only in everyday life, but also in many practical industrial processes and scientific research and could also be used to assist in DNA sequence analysis, if the flow field in the droplet produced by the evaporation could be understood and predicted in detail. In order to measure the fluid flow in a droplet, small particles can be suspended into the fluid as tracers. From the ratio of gravitational force to Brownian force a(exp 4)(delta rho)(g)/k(sub B)T, we find that particle's tendency to settle is proportional to a(exp 4) (a is particle radius). So, to keep the particles from settling, the droplet size should be chosen to be in a range 0.1 -1.0 microns in experiments. For such small particles, the Brownian force will affect the motion of the particle preventing accurate measurement of the flow field. This problem could be overcome by using larger particles as tracers to measure fluid flow under microgravity since the gravitational acceleration g is then very small. For larger particles, Brownian force would hardly affect the motion of the particles. Therefore, accurate flow field could be determined from experiments in microgravity. In this paper, we will investigate the fluid flow in an evaporating droplet under normal gravity, and compare experiments to theories. Then, we will present our ideas about the experimental measurement of fluid flow in an evaporating droplet under microgravity.

  11. Numerical simulation of droplet impact on interfaces

    Science.gov (United States)

    Kahouadji, Lyes; Che, Zhizhao; Matar, Omar; Shin, Seungwon; Chergui, Jalel; Juric, Damir

    2015-11-01

    Simulations of three-dimensional droplet impact on interfaces are carried out using BLUE, a massively-parallel code based on a hybrid Front-Tracking/Level-Set algorithm for Lagrangian tracking of arbitrarily deformable phase interfaces. High resolution numerical results show fine details and features of droplet ejection, crown formation and rim instability observed under similar experimental conditions. EPSRC Programme Grant, MEMPHIS, EP/K0039761/1.

  12. Cloud droplet activation: solubility revisited

    Directory of Open Access Journals (Sweden)

    L. T. Padró

    2007-02-01

    Full Text Available Soluble compounds present in atmospheric aerosol facilitate their transformation into cloud droplets by depressing the equilibrium vapor pressure required for activation. Their impact depends on the amount of dissolved substance in the aerosol aqueous phase, which in turn is controlled by its solubility. This study explores the impact of particle curvature on solubility, expressed in terms of a Kelvin enhancement. The augmented solubility, termed "Curvature Enhanced Solubility" (CES, is then introduced into Köhler theory for assessment of its impact on CCN activity for several organic compounds with a wide range of aqueous solubility. The interfacial energy between solute and aqueous phase required for quantification of CES is determined from existing correlations based on bulk solubility, and concurrent measurements of contact angle and surface tension. A number of important findings arise from this study: i CES can substantially increase solubility and impact CCN activity but only if the aerosol is initially wet, ii CES can stabilize highly supersaturated solutions, and provide a mechanism for retention of an aerosol aqueous phase even at very low relative humidity (RH, and, iii trace amounts of surfactant impurities can magnify the impact of CES.

  13. Lipid droplets, lipophagy, and beyond.

    Science.gov (United States)

    Wang, Chao-Wen

    2016-08-01

    Lipids are essential components for life. Their various structural and physical properties influence diverse cellular processes and, thereby, human health. Lipids are not genetically encoded but are synthesized and modified by complex metabolic pathways, supplying energy, membranes, signaling molecules, and hormones to affect growth, physiology, and response to environmental insults. Lipid homeostasis is crucial, such that excess fatty acids (FAs) can be harmful to cells. To prevent such lipotoxicity, cells convert excess FAs into neutral lipids for storage in organelles called lipid droplets (LDs). These organelles do not simply manage lipid storage and metabolism but also are involved in protein quality management, pathogenesis, immune responses, and, potentially, neurodegeneration. In recent years, a major trend in LD biology has centered around the physiology of lipid mobilization via lipophagy of fat stored within LDs. This review summarizes key findings in LD biology and lipophagy, offering novel insights into this rapidly growing field. This article is part of a Special Issue entitled: The cellular lipid landscape edited by Tim P. Levine and Anant K. Menon. PMID:26713677

  14. Growth and Division of Active Droplets: A Model for Protocells

    OpenAIRE

    Zwicker, David; Seyboldt, Rabea; Weber, Christoph A.; Hyman, Anthony A.; Jülicher, Frank

    2016-01-01

    It has been proposed that during the early steps in the origin of life, small droplets could have formed via the segregation of molecules from complex mixtures by phase separation. These droplets could have provided chemical reaction centers. However, whether these droplets could divide and propagate is unclear. Here we examine the behavior of droplets in systems that are maintained away from thermodynamic equilibrium by an external supply of energy. In these systems, droplets grow by the add...

  15. A pipette dispenses a charged droplet

    Science.gov (United States)

    Choi, Dongwhi; Lee, Horim; Im, Do Jin; Kang, In Seok; Kang, Kwan Hyoung

    2012-11-01

    Micropipettes are widely used in many scientific and engineering fields. However, it is hardly known that a droplet dispensed from a plastic pipette tip has a considerable amount of charges (order of 10-10 C). Here we report that the charged droplet is dispensed from a commercial and disposable plastic pipette tip and this charge is originated from the natural electrification between a solution and the inner surface of the pipette tip. The charge amount is dependent on not only the physicochemical properties of a solution (e.g., pH and a concentration) but also dispensing environments (e.g., atmospheric humidity and type of commercial pipette tip). To investigate the effects of the charge on the droplet dispensing, we calculate the electrical force between the droplet and the pipette tip though numerical simulation. The micropipette users especially, who are dealing with discrete droplets in their experiments, should consider this charge effect in their dispensing of a droplet. This work was supported by the National Research Foundation of Korea (NRF) Grant No. R0A-2007-000-20098-0 funded by the Korea government (MEST) and No. 20090083510 through Multiphenomena CFD Engineering Research Center.

  16. Whole Teflon valves for handling droplets.

    Science.gov (United States)

    Cybulski, Olgierd; Jakiela, Slawomir; Garstecki, Piotr

    2016-06-21

    We propose and test a new whole-Teflon gate valve for handling droplets. The valve allows droplet plugs to pass through without disturbing them. This is possible due to the geometric design, the choice of material and lack of any pulses of flow generated by closing or opening the valve. The duct through the valve resembles a simple segment of tubing, without constrictions, change in lumen or side pockets. There are no extra sealing materials with different wettability or chemical resistance. The only material exposed to liquids is FEP Teflon, which is resistant to aggressive chemicals and fully biocompatible. The valve can be integrated into microfluidic systems: we demonstrate a complex system for culturing bacteria in hundreds of microliter droplet chemostats. The valve effectively isolates modules of the system to increase precision of operations on droplets. We verified that the valve allowed millions of droplet plugs to safely pass through, without any cross-contamination with bacteria between the droplets. The valve can be used in automating complex microfluidic systems for experiments in biochemistry, biology and organic chemistry. PMID:27182628

  17. Scavenging dissolved oxygen via acoustic droplet vaporization.

    Science.gov (United States)

    Radhakrishnan, Kirthi; Holland, Christy K; Haworth, Kevin J

    2016-07-01

    Acoustic droplet vaporization (ADV) of perfluorocarbon emulsions has been explored for diagnostic and therapeutic applications. Previous studies have demonstrated that vaporization of a liquid droplet results in a gas microbubble with a diameter 5-6 times larger than the initial droplet diameter. The expansion factor can increase to a factor of 10 in gassy fluids as a result of air diffusing from the surrounding fluid into the microbubble. This study investigates the potential of this process to serve as an ultrasound-mediated gas scavenging technology. Perfluoropentane droplets diluted in phosphate-buffered saline (PBS) were insonified by a 2 MHz transducer at peak rarefactional pressures lower than and greater than the ADV pressure amplitude threshold in an in vitro flow phantom. The change in dissolved oxygen (DO) of the PBS before and after ADV was measured. A numerical model of gas scavenging, based on conservation of mass and equal partial pressures of gases at equilibrium, was developed. At insonation pressures exceeding the ADV threshold, the DO of air-saturated PBS decreased with increasing insonation pressures, dropping as low as 25% of air saturation within 20s. The decrease in DO of the PBS during ADV was dependent on the volumetric size distribution of the droplets and the fraction of droplets transitioned during ultrasound exposure. Numerically predicted changes in DO from the model agreed with the experimentally measured DO, indicating that concentration gradients can explain this phenomenon. Using computationally modified droplet size distributions that would be suitable for in vivo applications, the DO of the PBS was found to decrease with increasing concentrations. This study demonstrates that ADV can significantly decrease the DO in an aqueous fluid, which may have direct therapeutic applications and should be considered for ADV-based diagnostic or therapeutic applications. PMID:26964964

  18. CFD aided investigation of single droplet coalescence

    Institute of Scientific and Technical Information of China (English)

    Felix Gebauer; Mark W Hlawitschka; Hans-Jrg Bart

    2016-01-01

    This article describes the development of a coalescence model using various CFD work packages, and is validated using as toluene water model system. Numerical studies were performed to describe droplet interactions in liq-uid–liquid test systems. Current models use adjustable parameters to describe these phenomena. The research in the past decades led to different correlations to model coalescence and breakage depending on the chemical sys-tem and the apparatus geometry. Especial y the complexity of droplet coalescence requires a detailed investiga-tion of local phenomena during the droplet interaction. Computational fluid dynamics (CFD) studies of single droplet interactions were performed and validated with experimental results to improve the understanding of the local hydrodynamics and film drainage during coalescence. The CFD simulations were performed for the in-teraction of two differently sized droplets at industrial relevant impact velocities. The experimental verification and validation of the numerical results were done with standardized high-speed imaging studies by using a spe-cial test cel with a pendant and a free rising droplet. An experimental based algorithm was implemented in the open source code OpenFOAM to account for the contact time and the dimple formation. The standard European Federation of Chemical Engineering (EFCE) test system toluene/water was used for the numerical studies and the experimental investigations as wel . The results of the CFD simulations are in good accordance with the observed coalescence behavior in the experimental studies. In addition, a detailed description of local phenomena, like film rupture, velocity gradients, pressures and micro-droplet entrainment could be obtained.

  19. Creeping motion of single droplet and mixing behaviour of coalescing droplets in a tube flow

    Science.gov (United States)

    Muraoka, Masahiro; Ueno, Ichiro; Mizoguchi, Hiroshi; Toshihiko, Kamiyama; Wada, Takuma

    2012-07-01

    Creeping motion of single droplet and coalescence of droplets in a tube flow is expected to be useful for fluid handling technique, controlling chemical reaction and so on. In the case of motion of droplets with suspended particles, Drug delivery system can be cited as one of applications. The problem is also underlying basis on analyzing the flow of multiphase fluids through porous media. Such phenomena can be seen, for instance, in enhanced oil recovery, breaking of emulsions in porous coalescers and so on. Regarding examples of studies of creeping motion of droplets in a tube flow, Hetsroni G. et al[1] considered motion of droplets and bubbles with small d/D(d:undeformed diameter of droplet or bubble, D: tube diameter)theoretically. Higdon et al[2] obtained resistance functions for spherical particles, droplets and bubbles numerically. Olbricht at al.[3,4] investigated mainly coalescence time of coalescence phenomena of droplets. There exists little information, however, on mixing behaviour of coalescing droplets and effects of suspended particles in the droplets concerned on their coalescence. In this experiment, a glass tube of 2.0 mm in inner diameter, 7.0 mm in outer diameter, and 1500 mm in length is used as a test tube. Silicones oil of 50, 1000 and 6000cSt are employed as the test fluid for the droplet. Mixture fluid of glycerol and pure water is used for a surrounding fluid in the tube flow. The density of the droplets is matched to that of the surrounding fluid by adding carbon tetrachloride. An over flow tank is used to keep the flow in the tube steady at a designated averaged velocity V. The test tube is surrounded by a tank filled with a temperature-controlled water to keep the temperature of the system constant. Droplets are injected into the test tube using micro-syringes in front of inlet of the tube. Behaviours of droplets and suspended particles are monitored by a digital video camera and high speed cameras placed on a sliding stage. The motion

  20. New-born infants with severe hyaline membrane disease: radiological evaluation during high frequency oscillatory versus conventional ventilation

    International Nuclear Information System (INIS)

    Objective: The aim of our study was to determine the impact of treatment with exogenous surfactant (ES) and high frequency oscillatory ventilation (HFOV) on the radiological appearance and clinical course of hyaline membrane disease (HMD) in new-born infants. Materials and methods: New-born infants (18) (median weight, 1010 g) with severe HMD (stages 3.5 and 4) who were treated with ES and HFOV were matched by birth weight and severity of disease with 18 new-born infants treated with ES and conventional mechanical ventilation (CV). Chest radiograms taken on days 1, 2/3, 4/5, 7, 14 and 28 were analyzed to check for the severity of generalized parenchymal opacities (GPO), local opacifications, pulmonary interstitial emphysema (PIE), gross air leak, general and localized overinflation, bronchopulmonary dysplasia (BPD) and clinical variables such as survival rates, duration of mechanical ventilation, mean airway pressure and inspired oxygen concentration. Results: At 4 weeks of age, new-born infants treated by HFOV had less severe GPO (median degree 1.5 vs. 3), less PIE (1 vs. 7 patients) and fewer signs of BPD (median BPD degree 1.5 vs. 2.6). The incidence of pneumothorax and of local opacifications were similar in both groups. New-born infants on HFOV had a lower mortality rate (5 vs. 13), needed fewer days of mechanical ventilation (median 15 vs. 23 days) and lower inspiratory oxygen concentrations (median FiO2 0.38 vs. 0.64). Conclusion: In new-born infants with HMD, treatment with ES and HFOV resulted in a favourable radiological and clinical outcome as compared to treatment with ES and CV. (Copyright (c) 1998 Elsevier Science B.V., Amsterdam. All rights reserved.)

  1. Hyalinizing trabecular tumor of the thyroid: diagnosis of a rare tumor using ultrasonography, cytology, and intraoperative frozen sections

    Directory of Open Access Journals (Sweden)

    Hyunsik Jang

    2016-04-01

    Full Text Available Purpose: The goal of this study was to evaluate the clinicopathological and imaging features of thyroid nodules surgically diagnosed as hyaline trabecular tumor (HTT, and to assess the role of cytology and frozen sections (FS in the diagnosis of HTT. Methods: This study included 21 thyroid nodules in 21 patients treated from August 2005 to March 2015 (mean age, 53.3 years who were either diagnosed as HTT or had HTT suggested as a possible diagnosis based on cytology, FS, or the final pathology report. Patients’ medical records were retrospectively reviewed for cytopathologic results and outcomes during the course of follow-up. Sonograms were reviewed and categorized. Results: Twelve nodules from 12 patients were surgically confirmed as HTT. Ultrasonography (US-guided fine needle aspiration (FNA was performed on 11 nodules, of which six (54.5% were papillary thyroid carcinoma (PTC or suspicious for PTC and three (27.3% were HTT or suspicious for HTT. Intraoperative FS suggested the possibility of HTT in seven nodules, of which four (57.1% were confirmed as HTT. US-FNA suggested the diagnosis of HTT in 10 nodules, of which three (30.0% were confirmed as HTT. Common US features of the 12 pathologically confirmed cases of HTT were hypoechogenicity or marked hypoechogenicity (83.4%, absence of calcifications (91.7%, parallel shape (100.0%, presence of vascularity (75.0%, and probable benignity (58.3%. Conclusion: HTT should be included in the differential diagnosis of solid tumors with hypoechogenicity or marked hypoechogenicity and otherwise benign US features that have been diagnosed as PTC through cytology.

  2. A Unique Case of Pulmonary Hyalinizing Granuloma Associated With FDG-avid PET Scan and Deep Venous Thrombosis.

    Science.gov (United States)

    Khalid, Imran; Stone, Chad; Kvale, Paul

    2009-04-01

    An 83-year-old obese woman with a 60-pack-year smoking history was referred for evaluation of an abnormal chest radiograph [chest x-ray (CXR)]. Her past medical history was significant for recurrent deep venous thrombosis without any predisposing factors. CXR showed a large mass in the right mid lung and another nodule at the right apex, highly suspicious for a neoplastic process. These were not present on a CXR from 2 years earlier. An fluorodeoxyglucose (FDG)-positron emission tomography (PET)/computed tomography (CT) scan revealed that all lesions were strongly FDG-avid. Six CT-guided core-needle lung biopsy specimens were obtained from the lung mass and all contained dense, lamellar, or "ropy" keloid-like collagen bundles arranged in a haphazard pattern. The biopsy specimens lacked significant necrosis and granulomas. Congo red stain with polarization was also negative for amyloid. The diagnosis of pulmonary hyalinizing granuloma (PHG) was made. A complete hypercoagulable workup was performed but no underlying abnormalities were found, including a negative lupus anticoagulant and malignancy workup. The patient was maintained on warfarin and followed with serial CT scans for 1 year, with spontaneous regression in the lung mass. The case is unique as it is the first case that reports an association of PHG with recurrent deep venous thrombosis in the absence of autoimmune or procoagulant factors and emphasizes the need for life-long anticoagulation in such scenarios. Also, we report the FDG-avid PET scan findings here that are novel for this disease in adults and add PHG to the list of diseases causing false-positive PET scans when malignancy is suspected. PMID:23168510

  3. New-born infants with severe hyaline membrane disease: radiological evaluation during high frequency oscillatory versus conventional ventilation

    Energy Technology Data Exchange (ETDEWEB)

    Helbich, T.H.; Wunderbaldinger, P.; Herold, C.J. [Department of Radiology, University of Vienna (AKH), Waehringer Guertel 18-20 A-1090 Vienna (Austria); Popow, C.; Dobner, M.; Zekert, M. [Department of Paediatrics, Division of Neonatology University of Vienna (AKH), Waehringer Guertel 18-20 A-1090 Vienna (Austria)

    1998-10-01

    Objective: The aim of our study was to determine the impact of treatment with exogenous surfactant (ES) and high frequency oscillatory ventilation (HFOV) on the radiological appearance and clinical course of hyaline membrane disease (HMD) in new-born infants. Materials and methods: New-born infants (18) (median weight, 1010 g) with severe HMD (stages 3.5 and 4) who were treated with ES and HFOV were matched by birth weight and severity of disease with 18 new-born infants treated with ES and conventional mechanical ventilation (CV). Chest radiograms taken on days 1, 2/3, 4/5, 7, 14 and 28 were analyzed to check for the severity of generalized parenchymal opacities (GPO), local opacifications, pulmonary interstitial emphysema (PIE), gross air leak, general and localized overinflation, bronchopulmonary dysplasia (BPD) and clinical variables such as survival rates, duration of mechanical ventilation, mean airway pressure and inspired oxygen concentration. Results: At 4 weeks of age, new-born infants treated by HFOV had less severe GPO (median degree 1.5 vs. 3), less PIE (1 vs. 7 patients) and fewer signs of BPD (median BPD degree 1.5 vs. 2.6). The incidence of pneumothorax and of local opacifications were similar in both groups. New-born infants on HFOV had a lower mortality rate (5 vs. 13), needed fewer days of mechanical ventilation (median 15 vs. 23 days) and lower inspiratory oxygen concentrations (median FiO{sub 2} 0.38 vs. 0.64). Conclusion: In new-born infants with HMD, treatment with ES and HFOV resulted in a favourable radiological and clinical outcome as compared to treatment with ES and CV. (Copyright (c) 1998 Elsevier Science B.V., Amsterdam. All rights reserved.)

  4. Hyalinizing trabecular tumor of the thyroid: Diagnosed of a rare tumor using ultrasonography, cytology, and intraoperative frozen sections

    Energy Technology Data Exchange (ETDEWEB)

    Jang, Hyun Sik; Kim, Eun Kyung; Kwak, Jin Young; Moon, Hee Jung; Yoon, Jung Hyun [Dept. of Radiology, Severance Hospital, Research Institute of Radiological Science, Yonsei University, College of Medicine, Seoul (Korea, Republic of); Park, Cheol Keun; Son, Eun Ju [Gangnam Severance Hospital, Yonsei University, College of Medicine, Seoul (Korea, Republic of)

    2016-03-15

    The goal of this study was to evaluate the clinicopathological and imaging features of thyroid nodules surgically diagnosed as hyaline trabecular tumor (HTT), and to assess the role of cytology and frozen sections (FS) in the diagnosis of HTT. This study included 21 thyroid nodules in 21 patients treated from August 2005 to March 2015 (mean age, 53.3 years) who were either diagnosed as HTT or had HTT suggested as a possible diagnosis based on cytology, FS, or the final pathology report. Patients' medical records were retrospectively reviewed for cytopathologic results and outcomes during the course of follow-up. Sonograms were reviewed and categorized. Twelve nodules from 12 patients were surgically confirmed as HTT. Ultrasonography (US)-guided fine needle aspiration (FNA) was performed on 11 nodules, of which six (54.5%) were papillary thyroid carcinoma (PTC) or suspicious for PTC and three (27.3%) were HTT or suspicious for HTT. Intraoperative FS suggested the possibility of HTT in seven nodules, of which four (57.1%) were confirmed as HTT. US-FNA suggested the diagnosis of HTT in 10 nodules, of which three (30.0%) were confirmed as HTT. Common US features of the 12 pathologically confirmed cases of HTT were hypoechogenicity or marked hypoechogenicity (83.4%), absence of calcifications (91.7%), parallel shape (100.0%), presence of vascularity (75.0%), and probable benignity (58.3%). HTT should be included in the differential diagnosis of solid tumors with hypoechogenicity or marked hypoechogenicity and otherwise benign US features that have been diagnosed as PTC through cytology.

  5. Small GTPase Rab40c associates with lipid droplets and modulates the biogenesis of lipid droplets.

    Directory of Open Access Journals (Sweden)

    Ran Tan

    Full Text Available The subcellular location and cell biological function of small GTPase Rab40c in mammalian cells have not been investigated in detail. In this study, we demonstrated that the exogenously expressed GFP-Rab40c associates with lipid droplets marked by neutral lipid specific dye Oil red or Nile red, but not with the Golgi or endosomal markers. Further examination demonstrated that Rab40c is also associated with ERGIC-53 containing structures, especially under the serum starvation condition. Rab40c is increasingly recruited to the surface of lipid droplets during lipid droplets formation and maturation in HepG2 cells. Rab40c knockdown moderately decreases the size of lipid droplets, suggesting that Rab40c is involved in the biogenesis of lipid droplets. Stimulation for adipocyte differentiation increases the expression of Rab40c in 3T3-L1 cells. Rab40c interacts with TIP47, and is appositionally associated with TIP47-labeled lipid droplets. In addition, over-expression of Rab40c causes the clustering of lipid droplets independent of its GTPase activity, but completely dependent of the intact SOCS box domain of Rab40c. In addition, Rab40c displayed self-interaction as well as interaction with TIP47 and the SOCS box is essential for its ability to induce clustering of lipid droplets. Our results suggest that Rab40c is a novel Rab protein associated with lipid droplets, and is likely involved in modulating the biogenesis of lipid droplets.

  6. Thermocapillary migration of an isolated droplet and interaction of two droplets in zero gravity

    Science.gov (United States)

    Alhendal, Yousuf; Turan, Ali; Kalendar, Abdulrahim

    2016-09-01

    Fluid transfer within a stagnant liquid presents a significant challenge in zero-gravity conditions due to the lack of buoyancy effects. This challenge can be overcome by the utilisation of the Marangoni effect, or more specifically thermocapillary migration. The thermocapillary migration of droplets is driven by temperature gradients within the multiphase system which bring about a surface tension gradient driving the flow from the cold to the hot region. The migration speed of the droplet is significantly impacted by the heat transfer both inside the droplet and in its surroundings. This paper presents the analysis of drop movement in a stagnant liquid using computational fluid dynamics (CFD). The commercial software package Ansys-Fluent v.13 [1] is used to solve the governing continuum conservation equations for two-phase flow using the Volume of Fluid (VOF) method to track the liquid/liquid interface in 2D domain. This approach has been shown to be a valuable tool for studying the phenomena of liquid-liquid interaction. A strong agreement has been found with experimental observations conducted in microgravity. The inherent velocity of drops has been found to decrease with increasing Marangoni number. This finding is in line with the previous space experiments of Xie et al. (2005) [2] and in contrast to the numerical results of Ma (1999) [3] using the same liquid for the droplet and the host liquid. Data obtained in the present numerical study has been used to derive an expression predicting the scaled droplet velocity as a function of Marangoni number. A numerical study of the interaction of two spherical droplets undergoing thermocapillary migration in microgravity is also presented. The temperature thrust from the leading droplet towards the trailing droplet was found to disturb its migration velocity, but the trailing droplet was found to have no influence on the migration of the leading droplet.

  7. Gel-like double-emulsion droplets

    Science.gov (United States)

    Guzowski, Jan; Korczyk, Piotr; Garstecki, Piotr; Stone, Howard

    2015-11-01

    We experimentally study the problem of packing of micro-droplets inside a droplet of another immiscible liquid phase. We use microfluidics to encapsulate multiple monodisperse aqueous segments inside a drop of oil. For small numbers N (Noil exceeding the close-packing threshold we observe multiple metastable structures with well-defined point-group symmetries. We attribute the observed metastability to the deformability of the droplets which leads to effective many-body interactions and energy barriers for rearrangement. By changing the composition of the oil phase we find that when the surface tensions of the droplets and of the encapsulating phase are comparable, the energy barriers are high enough to trap elongated structures or even linear chains, independently of N. However, when the surface tension of the encapsulating phase is much larger than that of the droplets, non-spherical morphologies are stable only at sufficiently high N. In such a case multiple internal interfaces can hold stresses and prevent relaxation of the global deformations which leads to a plastic, gel-like behavior. Our findings can serve as guidelines for synthesis of functional particles as well as for designing biomimetic materials, e.g. for tissue engineering. J.G. acknowledges financial support from Polish Ministry of Science provided within the framework Mobility Plus.

  8. Minimising oil droplet size using ultrasonic emulsification.

    Science.gov (United States)

    Leong, T S H; Wooster, T J; Kentish, S E; Ashokkumar, M

    2009-08-01

    The efficient production of nanoemulsions, with oil droplet sizes of less than 100nm would facilitate the inclusion of oil soluble bio-active agents into a range of water based foods. Small droplet sizes lead to transparent emulsions so that product appearance is not altered by the addition of an oil phase. In this paper, we demonstrate that it is possible to create remarkably small transparent O/W nanoemulsions with average diameters as low as 40nm from sunflower oil. This is achieved using ultrasound or high shear homogenization and a surfactant/co-surfactant/oil system that is well optimised. The minimum droplet size of 40nm, was only obtained when both droplet deformability (surfactant design) and the applied shear (equipment geometry) were optimal. The time required to achieve the minimum droplet size was also clearly affected by the equipment configuration. Results at atmospheric pressure fitted an expected exponential relationship with the total energy density. However, we found that this relationship changes when an overpressure of up to 400kPa is applied to the sonication vessel, leading to more efficient emulsion production. Oil stability is unaffected by the sonication process. PMID:19321375

  9. MODEL OF LASER INTERACTION WITH LIQUID DROPLET

    Directory of Open Access Journals (Sweden)

    K. N. Volkov,

    2016-09-01

    Full Text Available Subject of Research. A mathematical model of optical breakdown in the dielectric liquid droplets when exposed to pulsed laser radiation was developed. The process is considered in several stages: heating, evaporation of the particle, forming a steam halo, ionization of the steam halo. Numerical study was carried out on the basis of the mathematical model to determine the threshold characteristics of the laser pulse. Main Results.Distributions of pressure, density and temperature of the particle steam halo were obtained by means of a calculation. The temperature field around the liquid droplet was determined. It has been found that at high energies in the gas bubble, the conditions are provided for thermal gas ionization and start of the electron avalanche, leading to plasma formation. Due to the volumetric heat generation, the droplet is overheated and is in a metastable state. The plasma cloud is almost opaque to radiation that causes an abrupt increase of temperature. As a result, an explosion occurs inside the droplet with the formation of a shock wave that is propagating outward. Practical Relevance.The results can be used to assess the performance of high-power laser scanning (LIDAR under the presence of liquid droplets in the atmosphere and other suspensions. Lasers can be used in fire and explosion aerospace systems. Obtained findings can be applied also in the systems of laser ignition and detonation initiation.

  10. Bioeffects due to acoustic droplet vaporization

    Science.gov (United States)

    Bull, Joseph

    2015-11-01

    Encapsulated micro- and nano-droplets can be vaporized via ultrasound, a process termed acoustic droplet vaporization. Our interest is primarily motivated by a developmental gas embolotherapy technique for cancer treatment. In this methodology, infarction of tumors is induced by selectively formed vascular gas bubbles that arise from the acoustic vaporization of vascular microdroplets. Additionally, the microdroplets may be used as vehicles for localized drug delivery, with or without flow occlusion. In this talk, we examine the dynamics of acoustic droplet vaporization through experiments and theoretical/computational fluid mechanics models, and investigate the bioeffects of acoustic droplet vaporization on endothelial cells and in vivo. Early timescale vaporization events, including phase change, are directly visualized using ultra-high speed imaging, and the influence of acoustic parameters on droplet/bubble dynamics is discussed. Acoustic and fluid mechanics parameters affecting the severity of endothelial cell bioeffects are explored. These findings suggest parameter spaces for which bioeffects may be reduced or enhanced, depending on the objective of the therapy. This work was supported by NIH grant R01EB006476.

  11. Bubbles and droplets in magnetic fluids

    Science.gov (United States)

    Yecko, Philip

    2006-11-01

    In this work, the behavior of ferrofluid droplets and of bubbles rising in a ferrofluid is studied using direct numerical simulations based on a volume of fluid (VOF) method. A ferrofluid is a suspension of small (5--15 nm) magnetic particles in a carrier liquid which may be water or a hydrocarbon oil, stabilized against settling by Brownian motion and against agglomeration by coating each particle with a layer of surfactant. Although their main application is the fluid O-ring found in computer hard disk drives, ferrofluids have been more recently recognized for their use in micro- and nano-fluidic pumping, and applications to drug delivery are under investigation. Because ferrofluids are opaque, numerical simulations offer a unique opportunity to visualize flows that cannot be easily visualized experimentally, yet little effort has been directed to numerical simulations of realistic magnetic fluids. In this work, we develop and test a multiphase simulation code, based on Surfer, which can dynamically follow the behavior of small numbers of droplets, bubbles or layers of ferrofluid and ordinary viscous fluid for so-called linear magnetic material. In the rising bubble tests, we quantify the vertical elongation of the bubble and the resulting reduction in drag and rise time. In the falling droplet experiments, we demonstrate the effect of variable magnetic properties on the shape and trajectory of the droplet, including the instability threshold where droplet fission occurs.

  12. Dynamics of Coalescence-Induced Jumping Water Droplets

    CERN Document Server

    Miljkovic, Nenad; Enright, Ryan; Wang, Evelyn N

    2013-01-01

    This fluid dynamics video shows the different interaction mechanisms of coalescence-induced droplet jumping during condensation on a nanostructured superhydrophobic surface. High speed imaging was used to show jumping behavior on superhydrophobic copper oxide and carbon nanotube surfaces. Videos demonstrating multi-jumping droplets, jumping droplet return to the surface, and droplet-droplet electrostatic repulsions were analyzed. Experiments using external electric fields in conjunction with high speed imaging in a custom built experimental chamber were used to show that all coalescence-induced jumping droplets on superhydrophobic surfaces become positively charged upon leaving the surface, which is detailed in the video.

  13. SPH Modeling of Droplet Impact on Solid Boundary

    Institute of Scientific and Technical Information of China (English)

    李大鸣; 白玲; 李玲玲; 赵明宇

    2014-01-01

    A droplet undergoes spreading, rebounding or splashing when it impacts solid boundary, which is a typical phenomenon of free surface flow that exists widely in modern industry. Smoothed particle hydrodynamics (SPH) method is applied to numerically study the dynamical behaviors of the droplet impacting solid boundary, and both the spreading and rebounding phenomena of the droplet are reproduced in the simulation. The droplet deformation, flow fields and pressure fields inside the droplet at different moments are analyzed. Two important factors, the initial veloc-ity and diameter, are discussed in determining the maximum spreading factor, revealing that the maximum spreading factor increases with the increase of the impact velocity and droplet diameter respectively.

  14. Dielectrophoretic levitation of droplets and bubbles

    Science.gov (United States)

    Jones, T. B.

    1982-01-01

    Uncharged droplets and bubbles can be levitated dielectrophoretically in liquids using strong, nonuniform electric fields. The general equations of motion for a droplet or bubble in an axisymmetric, divergence-free electrostatic field allow determination of the conditions necessary and sufficient for stable levitation. The design of dielectrophoretic (DEP) levitation electrode structures is simplified by a Taylor-series expansion of cusped axisymmetric electrostatic fields. Extensive experimental measurements on bubbles in insulating liquids verify the simple dielectrophoretic model. Other have extended dielectrophoretic levitation to very small particles in aqueous media. Applications of DEP levitation to the study of gas bubbles, liquid droplets, and solid particles are discussed. Some of these applications are of special interest in the reduced gravitational field of a spacecraft.

  15. The dynamics of laser droplet generation

    CERN Document Server

    Krese, Blaz; Govekar, Edvard

    2010-01-01

    We propose an experimental setup allowing for the characterization of laser droplet generation in terms of the underlying dynamics, primarily showing that the latter is deterministically chaotic by means of nonlinear time series analysis methods. In particular, we use a laser pulse to melt the end of a properly fed vertically placed metal wire. Due to the interplay of surface tension, gravity force and light-metal interaction, undulating pendant droplets are formed at the molten end, which eventually completely detach from the wire as a consequence of their increasing mass. We capture the dynamics of this process by employing a high-speed infrared camera, thereby indirectly measuring the temperature of the wire end and the pendant droplets. The time series is subsequently generated as the mean value over the pixel intensity of every infrared snapshot. Finally, we employ methods of nonlinear time series analysis to reconstruct the phase space from the observed variable and test it against determinism and stati...

  16. Lattice-Boltzmann simulations of droplet evaporation

    KAUST Repository

    Ledesma-Aguilar, Rodrigo

    2014-09-04

    © the Partner Organisations 2014. We study the utility and validity of lattice-Boltzmann (LB) simulations to explore droplet evaporation driven by a concentration gradient. Using a binary-fluid lattice-Boltzmann algorithm based on Cahn-Hilliard dynamics, we study the evaporation of planar films and 3D sessile droplets from smooth solid surfaces. Our results show that LB simulations accurately reproduce the classical regime of quasi-static dynamics. Beyond this limit, we show that the algorithm can be used to explore regimes where the evaporative and diffusive timescales are not widely separated, and to include the effect of boundaries of prescribed driving concentration. We illustrate the method by considering the evaporation of a droplet from a solid surface that is chemically patterned with hydrophilic and hydrophobic stripes. This journal is

  17. Droplet Growth Kinetics in Various Environments

    Science.gov (United States)

    Raatikainen, T. E.; Lathem, T. L.; Moore, R.; Lin, J. J.; Cerully, K. M.; Padro, L.; Lance, S.; Cozic, J.; Anderson, B. E.; Nenes, A.

    2012-12-01

    The largest uncertainties in the effects of atmospherics aerosols on the global radiation budget are related to their indirect effects on cloud properties (IPCC, the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, 2007). Cloud formation is a kinetic process where the resulting cloud properties depend on aerosol properties and meteorological parameters such as updraft velocity (e.g. McFiggans et al., Atmos. Chem. Phys., 6, 2593-2649, 2006). Droplet growth rates are limited by the water vapor diffusion, but additional kinetic limitations, e.g., due to organic surface films, slow solute dissociation or highly viscous or glassy aerosol states have been hypothesized. Significant additional kinetic limitations can lead to increased cloud droplet number concentration, thus the effect is similar to those of increased aerosol number concentration or changes in vertical velocity (e.g. Nenes et al., Geophys. Res. Lett., 29, 1848, 2002). There are a few studies where slow droplet growth has been observed (e.g. Ruehl et al., Geophys. Res. Lett., 36, L15814, 2009), however, little is currently known about their global occurrence and magnitude. Cloud micro-physics models often describe kinetic limitations by an effective water vapor uptake coefficient or similar parameter. Typically, determining aerosol water vapor uptake coefficients requires experimental observations of droplet growth which are interpreted by a numerical droplet growth model where the uptake coefficient is an adjustable parameter (e.g. Kolb et al., Atmos. Chem. Phys., 10, 10561-10605, 2010). Such methods have not been practical for high time-resolution or long term field measurements, until a model was recently developed for analyzing Droplet Measurement Technologies (DMT) cloud condensation nuclei (CCN) counter data (Raatikainen et al., Atmos. Chem. Phys., 12, 4227-4243, 2012). Model verification experiments showed that the calibration aerosol droplet size can be predicted accurately

  18. Effect of water droplet in solvent sublation

    Institute of Scientific and Technical Information of China (English)

    Peng Yu Bi; Hui Ru Dong; Nan Nan Wang

    2008-01-01

    Aqueous phase layer around bubble and water droplet are two additional processes in solvent sublation. In the dynamic processof mass transfer, they are always neglected, but they are very important in the investigation of thermodynamic equilibrium. In thispaper, the effect of water droplet in solvent sublation was discussed in detail, and the previous mathematical model of solventsubaltion was improved. Matlab 6.5 was used to simulate the process of water droplets, and the comparison between the previoushypothesis and the improvement in this paper showed the superiority, especially in the investigation of thermodynamic equilibrium.Moreover, the separation and concentration of the complex compound dithizone-Co(Ⅱ) from aqueous phase to n-octanol by solventsublation also proved the improved mathematical model was reasonable.2008 Hui Ru Dong. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.

  19. Simulation of Interpersonal Transport of Expiratory Droplets and Droplet Nuclei between Two Standing Manikins

    DEFF Research Database (Denmark)

    Liu, Li; Y, Li,

    2012-01-01

    numerical breathing thermal manikins and a full-scale test room model. Displacement ventilation with a ventilation rate of 6 h-1 was used to introduce ventilation air into the room. Two manikins were set to breathing periodically and their breathing functions were identical and synchronized. The number...... of droplet nuclei inhaled by the susceptible manikin and the numbers of droplet nuclei deposited on the surfaces of the susceptible manikin, e.g. face, front, etc. were recorded at separation distances of 0.5, 1.0, 1.5 and 3.0 m. In our preliminary study, for one breath from the source person, 1,600 droplets...... with an initial diameter of 100 μm were released. All the droplets became droplet nuclei within 16 seconds. Three (3) and nine (9) droplet nuclei were inhaled by the susceptible person at a mutual distance of 0.5 and 1.0 m, respectively. No droplet nuclei were inhaled at 1.5 and 3.0 m. This result illustrates...

  20. Oil droplet collisions with marine snow: effect of manipulating droplet size

    Science.gov (United States)

    Lambert, R. A.; Variano, E. A.

    2013-12-01

    Solid particle aggregates in the ocean, such as marine snow, can scavenge oil droplets as they are transported in the ocean, resulting in the removal of oil from the water column. Often, chemical dispersant is applied to oil spills to manipulate the oil droplet size; we study how such manipulations affect the rate at which oil is removed from the water column by collision with marine snow. We model the collision process using the particle pair methodology. Three dominant collision mechanisms are considered for particle pairs in the ocean environment: turbulent shear, differential settling and Brownian motion. A comparison of the removal rate of oil from the water column for large and small droplets size is conducted at constant volume fraction. The results of the study show that, for a constant volume of oil, droplet size does alter the amount of oil removed from the water column during collisions with marine snow, and that a greater amount of oil is removed when the droplets are large. This finding holds regardless of which collision mechanism is considered. Of the three mechanisms, differential settling results in the largest constant-volume removal rate (since oil droplets rise while marine floc settle downward) while Brownian diffusion results in the lowest removal rate. These finding suggest that using chemical dispersant on deep-sea oil spills to reduce droplet size will reduce the total volume of oil that becomes attached to marine snow and reduce the amount removed from the water column by this mechanism.

  1. Droplet sizes, dynamics and deposition in vertical annular flow

    International Nuclear Information System (INIS)

    The role of droplets in vertical upwards annular flow is investigated, focusing on the droplet size distributions, dynamics, and deposition phenomena. An experimental program was performed based on a new laser optical technique developed in these laboratories and implemented here for annular flow. This permitted the simultaneous measurement of droplet size, axial and radial velocity. The dependence of droplet size distributions on flow conditions is analyzed. The Upper-Log Normal function proves to be a good model for the size distribution. The mechanism controlling the maximum stable drop size was found to result from the interaction of the pressure fluctuations of the turbulent flow of the gas core with the droplet. The average axial droplet velocity showed a weak dependence on gas rates. This can be explained once the droplet size distribution and droplet size-velocity relationship are analyzed simultaneously. The surprising result from the droplet conditional analysis is that larger droplet travel faster than smaller ones. This dependence cannot be explained if the drag curves used do not take into account the high levels of turbulence present in the gas core in annular flow. If these are considered, then interesting new situations of multiplicity and stability of droplet terminal velocities are encountered. Also, the observed size-velocity relationship can be explained. A droplet deposition is formulated based on the particle inertia control. This permitted the calculation of rates of drop deposition directly from the droplet size and velocities data

  2. Rebound of continuous droplet streams from an immiscible liquid pool

    Science.gov (United States)

    Doak, William J.; Laiacona, Danielle M.; German, Guy K.; Chiarot, Paul R.

    2016-05-01

    We report on the rebound of high velocity continuous water droplet streams from the surface of an immiscible oil pool. The droplets have diameters and velocities of less than 90 μm and 15 m/s, respectively, and were created at frequencies up to 60 kHz. The impact and rebound of continuous droplet streams at this scale and velocity have been largely unexplored. This regime bridges the gap between single drop and jet impacts. The impinging droplets create a divot at the surface of the oil pool that had a common characteristic shape across a wide-range of droplet and oil properties. After impact, the reflected droplets maintain the same uniformity and periodicity of the incoming droplets but have significantly lower velocity and kinetic energy. This was solely attributed to the generation of a flow induced in the viscous oil pool by the impacting droplets. Unlike normally directed impact of millimeter-scale droplets with a solid surface, our results show that an air film does not appear to be maintained beneath the droplets during impact. This suggests direct contact between the droplets and the surface of the oil pool. A ballistic failure limit, correlated with the Weber number, was identified where the rebound was suppressed and the droplets were driven through the oil surface. A secondary failure mode was identified for aperiodic incoming streams. Startup effects and early time dynamics of the rebounding droplet stream were also investigated.

  3. The results of treating Hyaline membrane disease with Surfactant during 1 year at Ali-Asghar Hospital, neonatal intensive care unit

    OpenAIRE

    Naeri F; Samaei H

    1999-01-01

    The routine intake of surfactant as a part of HMD (Hyaline Membrane Disease) treatment had significant effect on the prognosis of premature neonates. But since in our country this drug is not widely and routinely used, and there are not records about its use, we decided to make good on this shortcoming through a retrospective study. During 1 year, 54 neonates with HMD were admitted in Ali-Asghar's NICU, 30 of them had gestational age of less than 34 weeks and for 15 cases, surfactant was...

  4. Recent Advances in Applications of Droplet Microfluidics

    Directory of Open Access Journals (Sweden)

    Wei-Lung Chou

    2015-09-01

    Full Text Available Droplet-based microfluidics is a colloidal and interfacial system that has rapidly progressed in the past decade because of the advantages of low fabrication costs, small sample volumes, reduced analysis durations, high-throughput analysis with exceptional sensitivity, enhanced operational flexibility, and facile automation. This technology has emerged as a new tool for many recently used applications in molecular detection, imaging, drug delivery, diagnostics, cell biology and other fields. Herein, we review recent applications of droplet microfluidics proposed since 2013.

  5. Simulation of Droplet Trains in Microfluidic Networks

    CERN Document Server

    Behzad, Mehran Djalali; Ejtehadi, Mohammad Reza

    2009-01-01

    In this work we show that in a microfluidic network and in low Reynolds numbers a system can be irreversible because of hysteresis effects.The network, which is employed in our simulations, is taken from recent experiments. The network consists of one loop connected to input and output pipes. A train of droplets enter the system at a uniform rate, but they may leave it in different patterns, e.g. periodic or even chaotic. The out put pattern depends on the time interval among the incoming droplets as well as the network geometry and for some parameters the system is not reversible.

  6. Evaluating the capabilities and uncertainties of droplet measurements for the fog droplet spectrometer (FM-100

    Directory of Open Access Journals (Sweden)

    J. K. Spiegel

    2012-09-01

    Full Text Available Droplet size spectra measurements are crucial to obtain a quantitative microphysical description of clouds and fog. However, cloud droplet size measurements are subject to various uncertainties. This work focuses on the error analysis of two key measurement uncertainties arising during cloud droplet size measurements with a conventional droplet size spectrometer (FM-100: first, we addressed the precision with which droplets can be sized with the FM-100 on the basis of the Mie theory. We deduced error assumptions and proposed a new method on how to correct measured size distributions for these errors by redistributing the measured droplet size distribution using a stochastic approach. Second, based on a literature study, we summarized corrections for particle losses during sampling with the FM-100. We applied both corrections to cloud droplet size spectra measured at the high alpine site Jungfraujoch for a temperature range from 0 °C to 11 °C. We showed that Mie scattering led to spikes in the droplet size distributions using the default sizing procedure, while the new stochastic approach reproduced the ambient size distribution adequately. A detailed analysis of the FM-100 sampling efficiency revealed that particle losses were typically below 10% for droplet diameters up to 10 μm. For larger droplets, particle losses can increase up to 90% for the largest droplets of 50 μm at ambient wind speeds below 4.4 m s−1 and even to >90% for larger angles between the instrument orientation and the wind vector (sampling angle at higher wind speeds. Comparisons of the FM-100 to other reference instruments revealed that the total liquid water content (LWC measured by the FM-100 was more sensitive to particle losses than to re-sizing based on Mie scattering, while the total number concentration was only marginally influenced by particle losses. Consequently, for further LWC measurements with the FM-100 we strongly recommend to consider (1 the

  7. Evaluating the capabilities and uncertainties of droplet measurements for the fog droplet spectrometer (FM-100

    Directory of Open Access Journals (Sweden)

    J. K. Spiegel

    2012-05-01

    Full Text Available Droplet size spectra measurements are crucial to obtain a quantitative microphysical description of clouds and fog. However, cloud droplet size measurements are subject to various uncertainties. This work focuses on the evaluation of two key measurement uncertainties arising during cloud droplet size measurements with a conventional droplet size spectrometer (FM-100: first, we addressed the precision with which droplets can be sized with the FM-100 on the basis of Mie theory. We deduced error assumptions and proposed how to correct measured size distributions for these errors by redistributing the measured droplet size distribution using a stochastic approach. Second, based on a literature study, we derived corrections for particle losses during sampling with the FM-100. We applied both corrections to cloud droplet size spectra measured at the high alpine site Jungfraujoch for a temperature range from 0 °C to 11 °C. We show that Mie scattering led to spikes in the droplet size distributions using the default sizing procedure, while the stochastic approach reproduced the ambient size distribution adequately. A detailed analysis of the FM-100 sampling efficiency revealed that particle losses were typically below 10% for droplet diameters up to 10 μm. For larger droplets, particle losses can increase up to 90% for the largest droplets of 50 μm at ambient windspeeds below 4.4 m s−1 and even to >90% for larger angles between the instrument orientation and the wind vector (sampling angle at higher wind speeds. Comparisons of the FM-100 to other reference instruments revealed that the total liquid water content (LWC measured by the FM-100 was more sensitive to particle losses than to re-sizing based on Mie scattering, while the total number concentration was only marginally influenced by particle losses. As a consequence, for further LWC measurements with the FM-100 we strongly recommend to consider (1 the error arising due to Mie

  8. Electrostatic Effects on Droplet Suspensions

    Science.gov (United States)

    Tryggvason, Gretar; Fernandez, Arturo; Esmaeeli, Asghar

    2002-11-01

    Direct numerical simulations are used to examine the effect of electric fields on the behavior of a suspensions of drops in channels. The effect of the electric field is modeled using the "leaky dielectric" model, coupled with the full Navier-Stokes equations. The governing equations are solved using a front-tracking/finite volume technique. The method has been validated by detailed comparison with previous results for the axisymmetric interactions of two drops in Stokes flow. An extensive set of two-dimensional simulations has allowed us to explore the effect of the conductivity and permittivity ratios in some detail. The interaction of two drops is controlled by two effects. The drops are driven together due to the charge distribution on the surface. Since the net charge of the drops is zero, the drops see each other as dipoles. This dielectrophoretic motion always leads to drops attraction. The second effect is fluid motion driven by tangential stresses at the fluid interface. The fluid motion depends on the relative magnitude of the permittivity and conductivity ratios. When the permittivity ratio is higher than the conductivity ratio, the tangential forces induce flow from the poles of the drops to the equator. If the center of two such drops lies on a line parallel to the electric field, the flow drains from the region between the drops and they attract each other. When the ratios are equal, no tangential motion is induced and the drops attract each other by dielectrophoretic motion. When an electric field is applied to many drops suspended in a channel flow, drops first attract each other pair-wise and some drops move to the wall. If the forces are strong (compared to the fluid shear) the drops can form columns or fibers, spanning the channel and blocking the two-dimensional flow. Electronic "fibration" of suspensions has been observed in a number of systems, including dispersion of milk droplets and red blood cells. If the attractive forces are weak

  9. Hydrodynamic dispensing and electrical manipulation of attolitre droplets

    Science.gov (United States)

    Zhang, Yanzhen; Zhu, Benliang; Liu, Yonghong; Wittstock, Gunther

    2016-08-01

    Dispensing and manipulation of small droplets is important in bioassays, chemical analysis and patterning of functional inks. So far, dispensing of small droplets has been achieved by squeezing the liquid out of a small orifice similar in size to the droplets. Here we report that instead of squeezing the liquid out, small droplets can also be dispensed advantageously from large orifices by draining the liquid out of a drop suspended from a nozzle. The droplet volume is adjustable from attolitre to microlitre. More importantly, the method can handle suspensions and liquids with viscosities as high as thousands mPa s markedly increasing the range of applicable liquids for controlled dispensing. Furthermore, the movement of the dispensed droplets is controllable by the direction and the strength of an electric field potentially allowing the use of the droplet for extracting analytes from small sample volume or placing a droplet onto a pre-patterned surface.

  10. Steady-state droplet size in montmorillonite stabilised emulsions.

    Science.gov (United States)

    Ganley, William J; van Duijneveldt, Jeroen S

    2016-08-14

    The formation of hexadecane-in-water emulsions stabilised by montmorillonite platelets was studied. In this system the platelets form a monolayer around the droplets and the droplet size decreases with increasing platelet volume fraction. However, the number of platelets present exceeds that required for monolayer coverage. The kinetics of emulsification were investigated and coalescence of droplets during turbulent mixing was found to continue even after the droplets had reached their ultimate size. Non-spherical droplets, resulting from arrested coalescence, were not observed suggesting that particles may be desorbing from the interface during the turbulent flow. A kinetic model based on a competition between droplet break-up and coalescence, mediated by particle adsorption and desorption, reproduces experimental trends in droplet diameter. The model can be used to predict the most efficient formulation to minimise droplet diameters for given materials and mixing conditions and sheds light on the processes occurring during emulsification in this system. PMID:27407026

  11. One-to-one encapsulation based on alternating droplet generation

    Science.gov (United States)

    Hirama, Hirotada; Torii, Toru

    2015-10-01

    This paper reports the preparation of encapsulated particles as models of cells using an alternating droplet generation encapsulation method in which the number of particles in a droplet is controlled by a microchannel to achieve one-to-one encapsulation. Using a microchannel in which wettability is treated locally, the fluorescent particles used as models of cells were successfully encapsulated in uniform water-in-oil-in-water (W/O/W) emulsion droplets. Furthermore, 20% of the particle-containing droplets contained one particle. Additionally, when a surfactant with the appropriate properties was used, the fluorescent particles within each inner aqueous droplet were enclosed in the merged droplet by spontaneous droplet coalescence. This one-to-one encapsulation method based on alternating droplet generation could be used for a variety of applications, such as high-throughput single-cell assays, gene transfection into cells or one-to-one cell fusion.

  12. Encapsulation of emulsion droplets by organo–silica shells

    NARCIS (Netherlands)

    Zoldesi, C.; Steegstra, Patrick; Imhof, Arnout

    2007-01-01

    Surfactant-stabilized emulsion droplets were used as templates for the synthesis of hollow colloidal particles. Monodisperse silicone oil droplets were prepared by hydrolysis and polymerization of dimethyldiethoxysiloxane monomer, in the presence of surfactant: sodium dodecyl sulphate (SDS, anionic)

  13. Combinatorial microfluidic droplet engineering for biomimetic material synthesis

    Science.gov (United States)

    Bawazer, Lukmaan A.; McNally, Ciara S.; Empson, Christopher J.; Marchant, William J.; Comyn, Tim P.; Niu, Xize; Cho, Soongwon; McPherson, Michael J.; Binks, Bernard P.; deMello, Andrew; Meldrum, Fiona C.

    2016-01-01

    Although droplet-based systems are used in a wide range of technologies, opportunities for systematically customizing their interface chemistries remain relatively unexplored. This article describes a new microfluidic strategy for rapidly tailoring emulsion droplet compositions and properties. The approach uses a simple platform for screening arrays of droplet-based microfluidic devices and couples this with combinatorial selection of the droplet compositions. Through the application of genetic algorithms over multiple screening rounds, droplets with target properties can be rapidly generated. The potential of this method is demonstrated by creating droplets with enhanced stability, where this is achieved by selecting carrier fluid chemistries that promote titanium dioxide formation at the droplet interfaces. The interface is a mixture of amorphous and crystalline phases, and the resulting composite droplets are biocompatible, supporting in vitro protein expression in their interiors. This general strategy will find widespread application in advancing emulsion properties for use in chemistry, biology, materials, and medicine.

  14. Drying of liquid food droplets. Enzyme inactivation and multicomponent diffusion.

    OpenAIRE

    Meerdink, G.

    1993-01-01

    In this thesis the drying of liquid food droplets is studied from three different points of view: drying kinetics, enzyme inactivation and multicomponent diffusion. Mathematical models are developed and validated experimentally.Drying experiments are performed with suspended droplets and with free falling droplets under spray-drying conditions. The experiments with the free falling droplets are performed in a specially designed drying tower using a resonance nozzle. The resonance nozzle is ca...

  15. Fluorescent photography of spray droplets using a laser light source

    Science.gov (United States)

    Groeneweg, J.; Hiroyasu, H.; Sowls, R.

    1969-01-01

    Monochromatic laser emission transformed by a fluorescent process into droplet emission over a wavelength band provides high light intensities for obtaining adequate time resolution to stop droplet motion in photographic spray studies. Experiments showed that the Q-switched laser-optical harmonic generator combination produced sharp, well-exposed droplet images.

  16. Colliding droplets in turbulent flows: A numerical study

    NARCIS (Netherlands)

    Perrin, V.E.

    2015-01-01

    Droplets and the way they collide are at the very base of the formation of clouds and the initiation of warm rain. The evolution of a cloud droplet into a rain droplet can be classified into three stages. For each stage different growth mechanisms can be identified. In the first stage condensation is t

  17. Preferred location of droplet collisions in turbulent flows

    NARCIS (Netherlands)

    Perrin, V.E.; Jonker, H.J.J.

    2014-01-01

    This study investigates the local flow characteristics near droplet-droplet collisions by means of direct numerical simulation of isotropic cloudlike turbulence. The key finding is that, generally, droplets do not collide where they preferentially concentrate. Preferential concentration is found to

  18. Moving droplets: The measurement of contact lines

    NARCIS (Netherlands)

    Poelma, C.; Franken, M.J.Z.; Kim, H.; Westerweel, J.

    2014-01-01

    Contact lines are the locations where a gas, liquid and a solid meet. From everyday experience we know that such contact lines can be mobile, for example in the case of a water droplet sliding over a glass surface. However, the continuum description of the flow towards or away from a contact line im

  19. Adjuvants for single droplet application of glyphosate

    DEFF Research Database (Denmark)

    Mathiassen, Solvejg Kopp; Kudsk, Per; Lund, Ivar

    2016-01-01

    Retention and biological activity of droplets of glyphosate deposited onto plant leaves using a Drop on Demand inkjet printer application system, was examined on pot-grown Brassica napus, Solanum nigrum, Chenopodium album, Silene noctiflora and Echinocloa crus-galli plants. Retention was measured...... but the biological activity of glyphosate was not improved....

  20. Adjuvants for single droplet application of glyphosate

    DEFF Research Database (Denmark)

    Mathiassen, Solvejg K.; Kudsk, Per; Lund, Ivar

    Retention and biological activity of droplets of glyphosate deposited onto plant leaves using a Drop on Demand inkjet printer application system, was examined on pot-grown Brassica napus, Solanum nigrum, Chenopodium album, Silene noctiflora and Echinocloa crus-galli plants. Retention was measured...... but the biological activity of glyphosate was not improved....

  1. The Physics of Foams, Droplets and Bubbles

    Science.gov (United States)

    Sarker, Dipak K.

    2013-01-01

    Foams or bubble dispersions are common to milkshakes, bread, champagne froth, shaving mousse, shampoo, crude oil extraction systems, upholstery packing and bubble wrap, whereas the term droplet is often synonymous with either a small drop of water or a drop of oil--a type of coarse dispersion. The latter are seen in butter and milk, household…

  2. Superheated Droplet Detector Response for Temperature

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    Superheated droplet detector has the following advantages: Used repeatedly, recording the cumulative dose, using both indoors and outdoors, compacting; relatively low cost, direct reading of the bubbles using the naked eye, and working in gamma-neutron mixed-field well

  3. 鼻塞式CPAP治疗新生儿肺透明膜病疗效观察%Efficacy of Hyaline Membrane Disease Nasal CPAP Treatment

    Institute of Scientific and Technical Information of China (English)

    艾力甫

    2015-01-01

    目的:观察鼻塞式CPAP(NCPAP)治疗新生儿肺透明膜病的疗效。方法对20例早期新生儿肺透明膜病进行X线检查,根据血气分析结果调整呼吸机参数。结果20例患儿放弃治疗1例,转上级医院治疗1例,余18例顺利撤除鼻塞式CPAP。结论鼻塞式CPAP治疗早期新生儿肺透出明膜病能明显的提高治疗效果,对早产儿非常适用。%Objective To observe the nasal CPAP (NCPAP)therapy hyaline membrane disease.Methods 20 cases of early neonatal hyaline membrane disease,X-ray inspection,adjustment of ventilator parameters based on the results of blood gas analysis.Results 20 patients gave up treatment one case,turn higher hospital one case,more than 18 cases of successful removal of nasal CPAP.Conclusion Nasal CPAP treatment early neonatal lung disease,revealed a clear film can significantly improve the therapeutic ef ect,very suitable for preterm children.

  4. An interface tracking model for droplet electrocoalescence.

    Energy Technology Data Exchange (ETDEWEB)

    Erickson, Lindsay Crowl

    2013-09-01

    This report describes an Early Career Laboratory Directed Research and Development (LDRD) project to develop an interface tracking model for droplet electrocoalescence. Many fluid-based technologies rely on electrical fields to control the motion of droplets, e.g. microfluidic devices for high-speed droplet sorting, solution separation for chemical detectors, and purification of biodiesel fuel. Precise control over droplets is crucial to these applications. However, electric fields can induce complex and unpredictable fluid dynamics. Recent experiments (Ristenpart et al. 2009) have demonstrated that oppositely charged droplets bounce rather than coalesce in the presence of strong electric fields. A transient aqueous bridge forms between approaching drops prior to pinch-off. This observation applies to many types of fluids, but neither theory nor experiments have been able to offer a satisfactory explanation. Analytic hydrodynamic approximations for interfaces become invalid near coalescence, and therefore detailed numerical simulations are necessary. This is a computationally challenging problem that involves tracking a moving interface and solving complex multi-physics and multi-scale dynamics, which are beyond the capabilities of most state-of-the-art simulations. An interface-tracking model for electro-coalescence can provide a new perspective to a variety of applications in which interfacial physics are coupled with electrodynamics, including electro-osmosis, fabrication of microelectronics, fuel atomization, oil dehydration, nuclear waste reprocessing and solution separation for chemical detectors. We present a conformal decomposition finite element (CDFEM) interface-tracking method for the electrohydrodynamics of two-phase flow to demonstrate electro-coalescence. CDFEM is a sharp interface method that decomposes elements along fluid-fluid boundaries and uses a level set function to represent the interface.

  5. Collision of oil droplets with marine aggregates: Effect of droplet size

    Science.gov (United States)

    Lambert, Ruth A.; Variano, Evan A.

    2016-05-01

    Interactions between oil droplets and marine particle aggregates, such as marine snow, may affect the behavior of oil spills. Marine snow is known to scavenge fine particles from the water column, and has the potential to scavenge oil droplets in the same manner. To determine the degree to which such a process is important in the evolution of oil spills, we quantify the collision of oil droplets and marine aggregates using existing collision rate equations. Results show that interaction of drops and aggregates can substantially influence the drop size distribution, but like all such processes this result is sensitive to the local concentration of oil and aggregates. The analysis also shows that as the size distribution of oil droplets shifts toward larger droplets, a greater fraction of the total oil volume collides with marine aggregates. This result is robust to a variety of different assumptions in the collision model. Results also show that there is not always a dominant collision mechanism. For example, when droplets and aggregates are both close to 10 μm in radius, shear and differential settling contribute nearly equally to the collision rate. This overlap suggests that further research on the interaction of shear and differential settling could be useful.

  6. Photophoretic trampoline - Interaction of single airborne absorbing droplets with light

    CERN Document Server

    Esseling, Michael; Alpmann, Christina; Denz, Cornelia

    2012-01-01

    We present the light-induced manipulation of absorbing liquid droplets in air. Ink droplets from a printer cartridge are used to demonstrate that absorbing liquids - just like their solid counterparts - can interact with regions of high light intensity due to the photophoretic force. It is shown that droplets follow a quasi-ballistic trajectory after bouncing off a high intensity light sheet. We estimate the intensities necessary for this rebound of airborne droplets and change the droplet trajectories through a variation of the manipulating light field.

  7. A soft microchannel decreases polydispersity of droplet generation.

    Science.gov (United States)

    Pang, Yan; Kim, Hyoungsoo; Liu, Zhaomiao; Stone, Howard A

    2014-10-21

    We study the effect of softness of the microchannel on the process of droplet generation in two-phase flows in a T-junction microchannel. One side of the microchannel has a flexible thin PDMS layer, which vibrates naturally while droplets are generated; the deformation frequency coincides with the frequency of droplet formation. Furthermore, we compare the polydispersity of water-in-oil droplets formed with a microchannel with one soft wall with those formed in a conventional rigid microchannel. We show that deformation of the soft wall reduces the polydispersity in the droplet size. PMID:25144377

  8. Velocity and rotation measurements in acoustically levitated droplets

    Science.gov (United States)

    Saha, Abhishek; Basu, Saptarshi; Kumar, Ranganathan

    2012-10-01

    The velocity scale inside an acoustically levitated droplet depends on the levitator and liquid properties. Using Particle Imaging Velocimetry (PIV), detailed velocity measurements have been made in a levitated droplet of different diameters and viscosity. The maximum velocity and rotation are normalized using frequency and amplitude of acoustic levitator, and droplet viscosity. The non-dimensional data are fitted for micrometer- and millimeter-sized droplets levitated in different levitators for different viscosity fluids. It is also shown that the rotational speed of nanosilica droplets at an advanced stage of vaporization compares well with that predicted by exponentially fitted parameters.

  9. Investigations of Abrupt Movements of Optically Trapped Water Droplets

    Science.gov (United States)

    Murphy, Shawntel; McCann, Lowell I.

    2007-03-01

    We have used a single beam optical trap (optical tweezers) to capture individual water droplets in air. A 3-dimensional viewing system consisting of a two axis microscope allows the trapped droplet to be viewed from the top and the side simultaneously. The position of the droplet is determined with a digital camera at a rate up to 700Hz. We have observed abrupt movements along the beam in two situations: As a pure water droplet evaporates, the movements occur at specific size intervals as the diameter decreases. For non-evaporating saltwater droplets the movements rapidly occur for certain ranges of beam power, and not at all for other ranges of power.

  10. Aerosol Effect on the Mobility of Cloud Droplets

    CERN Document Server

    Koren, Ilan; Dagan, Guy

    2015-01-01

    Cloud droplet mobility is referred here as a measure of the droplets' ability to move with ambient air. We claim that an important part of the aerosol effect on convective clouds is driven by changes in droplet mobility. We show that the mass-averaged droplet terminal velocity ({\\eta}) and spread ({\\sigma}_{\\eta}) serve as direct measures of this effect. Moreover, we develop analytical estimations for {\\eta} and {\\sigma}_{\\eta} to show that changes in the relative dispersion of {\\eta} ({\\epsilon}_{\\eta}={\\sigma}_{\\eta}/{\\eta}) can serve as a sensitive predictor of the onset of droplet-collection processes.

  11. Hydrodynamics of Leidenfrost droplets in one-component fluids

    KAUST Repository

    Xu, Xinpeng

    2013-04-24

    Using the dynamic van der Waals theory [Phys. Rev. E 75, 036304 (2007)], we numerically investigate the hydrodynamics of Leidenfrost droplets under gravity in two dimensions. Some recent theoretical predictions and experimental observations are confirmed in our simulations. A Leidenfrost droplet larger than a critical size is shown to be unstable and break up into smaller droplets due to the Rayleigh-Taylor instability of the bottom surface of the droplet. Our simulations demonstrate that an evaporating Leidenfrost droplet changes continuously from a puddle to a circular droplet, with the droplet shape controlled by its size in comparison with a few characteristic length scales. The geometry of the vapor layer under the droplet is found to mainly depend on the droplet size and is nearly independent of the substrate temperature, as reported in a recent experimental study [Phys. Rev. Lett. 109, 074301 (2012)]. Finally, our simulations demonstrate that a Leidenfrost droplet smaller than a characteristic size takes off from the hot substrate because the levitating force due to evaporation can no longer be balanced by the weight of the droplet, as observed in a recent experimental study [Phys. Rev. Lett. 109, 034501 (2012)].

  12. Electric-Field-Enhanced Jumping-Droplet Condensation

    Science.gov (United States)

    Miljkovic, Nenad; Preston, Daniel; Enright, Ryan; Limia, Alexander; Wang, Evelyn

    2013-11-01

    When condensed droplets coalesce on a superhydrophobic surface, the resulting droplet can jump due to the conversion of surface energy into kinetic energy. This frequent out-of-plane droplet jumping has the potential to enhance condensation heat and mass transfer. In this work, we demonstrated that these jumping droplets accumulate positive charge that can be used to further increase condensation heat transfer via electric fields. We studied droplet jumping dynamics on silanized nanostructured copper oxide surfaces. By characterizing the droplet trajectories under various applied external electric fields (0 - 50 V/cm), we show that condensation on superhydrophobic surfaces results in a buildup of negative surface charge (OH-) due to dissociated water ion adsorption on the superhydrophobic coating. Consequently, the opposite charge (H3O +) accumulates on the coalesced jumping droplet. Using this knowledge, we demonstrate electric-field-enhanced jumping droplet condensation whereby an external electric field opposes the droplet vapor flow entrainment towards the condensing surface to increase the droplet removal rate and overall surface heat transfer by 100% when compared to state-of-the-art dropwise condensing surfaces. This work not only shows significant condensation heat transfer enhancement through the passive charging of condensed droplets, but promises a low cost approach to increase efficiency for applications such as atmospheric water harvesting and dehumidification.

  13. Supersonic laser-induced jetting of aluminum micro-droplets

    International Nuclear Information System (INIS)

    The droplet velocity and the incubation time of pure aluminum micro-droplets, printed using the method of sub-nanosecond laser induced forward transfer, have been measured indicating the formation of supersonic laser-induced jetting. The incubation time and the droplet velocity were extracted by measuring a transient electrical signal associated with droplet landing on the surface of the acceptor substrate. This technique has been exploited for studying small volume droplets, in the range of 10–100 femto-litters for which supersonic velocities were measured. The results suggest elastic propagation of the droplets across the donor-to-acceptor gap, a nonlinear deposition dynamics on the surface of the acceptor and overall efficient energy transfer from the laser beam to the droplets

  14. Magnetohydrodynamic actuation of droplets for millimetric planar fluidic systems

    Energy Technology Data Exchange (ETDEWEB)

    Ahmadi, A., E-mail: ali.ahmadi@ubc.ca; McDermid, C. M.; Markley, L. [School of Engineering, University of British Columbia, Kelowna, British Columbia V1V 1V7 (Canada)

    2016-01-04

    In this work, a magnetohydrodynamic method is proposed for the actuation of droplets in small-scale planar fluidic systems, providing an alternative to commonly used methods such as electrowetting-on-dielectric. Elementary droplet-based operations, including transport, merging, and mixing, are demonstrated. The forces acting on millimetric droplets are carefully investigated, with a primary focus on the magnetic actuation force and on the unbalanced capillary forces that arise due to hysteresis. A super-hydrophobic channel is 3D printed to guide the droplets, with thin wires installed as contact electrodes and permanent magnets providing a static magnetic field. It is shown that droplet motion is enhanced by increasing the droplet size and minimizing the electrode contact surface. The effects of channel geometry on threshold voltage and minimum moveable droplet volume are characterized. Finally, the presence of electrolysis is investigated and mitigating strategies are discussed.

  15. Non-equilibrium solidification of undercooled droplets during atomization process

    Indian Academy of Sciences (India)

    Prashant Shukla; R K Mandal; S N Ojha

    2001-10-01

    Thermal history of droplets associated with gas atomization of melt has been investigated. A mathematical model, based on classical theory of heterogeneous nucleation and volume separation of nucleants among droplets size distribution, is described to predict undercooling of droplets. Newtonian heat flow condition coupled with velocity dependent heat transfer coefficient is used to obtain cooling rate before and after nucleation of droplets. The results indicate that temperature profile of droplets in the spray during recalescence, segregated and eutectic solidification regimes is dependent on their size and related undercooling. The interface temperature during solidification of undercooled droplets rapidly approaches the liquidus temperature of the alloy with a subsequent decrease in solid–liquid interface velocity. A comparison in cooling rates of atomized powder particles estimated from secondary dendrite arm spacing measurements are observed to be closer to those predicted from the model during segregated solidification regime of large size droplets.

  16. Stick-jump mode in surface droplet dissolution

    CERN Document Server

    Dietrich, Erik; Zhang, Xuehua; Zandvliet, Harold J W; Lohse, Detlef

    2016-01-01

    The analogy between evaporating surface droplets in air to dissolving long-chain alcohol droplets in water is worked out. We show that next to the three known modi for surface droplet evaporation or dissolution (constant contact angle mode, constant contact radius mode, and stick-slide mode), a fourth mode exists for small droplets on supposedly smooth substrates, namely the stick-jump mode: intermittent contact line pinning causes the droplet to switch between sticking and jumping during the dissolution. We present experimental data and compare them to theory to predict the dissolution time in this stick-jump mode. We also explain why these jumps were easily observed for microscale droplets but not for larger droplets.

  17. Structure formation by nanosilica particles suspended in levitated droplet

    CERN Document Server

    Saha, Abhishek; Kumar, Ranganathan; Basu, Saptarshi

    2010-01-01

    Vaporization of liquid droplets containing particles has been studied extensively for its applications in combustion, thermal coating, ink-jet printing, spray cooling, drug delivery, and surface patterning. Droplets containing solid particles show a preferential solute-migration during drying process. Recently we carried out experiments with vaporizing droplet suspended in an acoustic levitator. In this work, we present detailed study of a laser irradiated droplet containing nanosilica particles. Infrared and High speed imaging of the heating process for different concentrations of nanosilica revealed an interesting solute migration pattern. Further investigation with Particle Image Velocimetry shows presence of strong recirculation within the levitated droplet. It also reveals that with increasing viscosity of the liquid the strength of this recirculation decreases. Due to the droplets rotation about the levitator axis, a centrifugal force also dominated the flow field within the droplet. High speed imaging ...

  18. Separation of Iron Droplets From Titania Bearing Slag

    Institute of Scientific and Technical Information of China (English)

    WANG Ming-yu; LOU Tai-ping; ZHANG Li; SUI Zhi-tong

    2008-01-01

    Owing to smelting vanadium-titanium magnetite ore, the amount of iron entrainment in slag as droplets is far higher than that in conventional BF slag. However, the iron droplets can be easily settled by blowing air into the molten slag. The results show that more than 80% of iron droplets in titania bearing slag can be settled and separated after treatment. The temperature rise of molten slag during the oxidizing process and the decreased viscosity caused by the component change of slag as well as air stirring in slag both accelerate the iron droplets settling. The vanadium content in the settled iron droplets and the original iron droplets was obtained by chemical analysis. The possible reason for the increased vanadium in the settled iron droplets was discussed by thermodynamic principles.

  19. Effective doping of low energy ions into superfluid helium droplets

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Jie; Chen, Lei; Freund, William M.; Kong, Wei, E-mail: wei.kong@oregonstate.edu [Department of Chemistry, Oregon State University, Corvallis, Oregon 97331 (United States)

    2015-08-21

    We report a facile method of doping cations from an electrospray ionization (ESI) source into superfluid helium droplets. By decelerating and stopping the ion pulse of reserpine and substance P from an ESI source in the path of the droplet beam, about 10{sup 4} ion-doped droplets (one ion per droplet) can be recorded, corresponding to a pickup efficiency of nearly 1 out of 1000 ions. We attribute the success of this simple approach to the long residence time of the cations in the droplet beam. The resulting size of the doped droplets, on the order of 10{sup 5}/droplet, is measured using deflection and retardation methods. Our method does not require an ion trap in the doping region, which significantly simplifies the experimental setup and procedure for future spectroscopic and diffraction studies.

  20. Sorting and Manipulation of Magnetic Droplets in Continuous Flow

    Science.gov (United States)

    Al-Hetlani, Entesar; Hatt, Oliver J.; Vojtíšek, Martin; Tarn, Mark D.; Iles, Alexander; Pamme, Nicole

    2010-12-01

    We report the rapid on-chip generation and subsequent manipulation of magnetic droplets in continuous flow. Magnetic droplets were formed using aqueous-based ferrofluid as the dispersed phase and fluorocarbon oil as the continuous phase. Droplet manipulation was demonstrated with simple permanent magnets using two microfluidic platforms: (i) flow focusing droplet generation followed by their splitting into daughter droplets containing different amounts of magnetic nanoparticles, and (ii) droplet generation at a T-junction and their downstream deflection across a chamber for sorting based on the applied magnetic field and magnetite loading of the droplet. Both systems show great potential for performing a wide range of high throughput continuous flow processes including sample dilution, cell sorting and screening, and microparticle fabrication.

  1. Global rainbow refractometry for droplet temperature measurement

    Energy Technology Data Exchange (ETDEWEB)

    Pascal Lemaitre; Emmanuel Porcheron; Amandine Nuboer; Philippe Brun; Pierre Cornet; Jeanne Malet; Jacques Vendel; Laurent Bouilloux [Institut de Radioprotection et de Surete Nucleaire DSU/SERAC, BP 68, 91192 Gif-sur-Yvette Cedex (France); Gerard Grehan [UMR 6614 CORIA, Laboratoire d' Electromagnetisme et Systemes Particulaires Site Universitaire du Madrillet, Avenue de l' universite BP 12, 76 801 Saint Etienne du Rouvray Cedex, (France)

    2005-07-01

    Full text of publication follows: In order to establish an accurate database to characterize the heat and mass transfers between a spray and the atmosphere with thermal-hydraulic conditions representative of a hypothetical nuclear reactor accident in the containment enclosure of a pressurized water reactor (PWR), the French Institut de Radioprotection et de Surete Nucleaire (IRSN) has developed the TOSQAN experimental facility. This experiment is highly instrumented with non-intrusive diagnostics allowing to measure droplet size and velocity and gas concentrations [1]. The aim of this work is to present the Global Rainbow Thermometry (GRT), which is an advanced non-intrusive optical diagnostic, developed to measure the mean temperature of a set of falling droplets, in a measurement volume of 1 cm{sup 3}. The final paper will be divided in three parts. In the first one, we will explain the principle of the rainbow formation and how droplet temperature can be deduced from the rainbow analysis [2]. This part will be illustrated with the theoretical background on the rainbow and numerical simulations of the global rainbow. The second part will be devoted to present the global rainbow experimental set-up we have developed on optical table, its experimental qualification and finally its implementation on the TOSQAN facility [3]. Finally, we will present the temperature measurements achieved in TOSQAN for thermal-hydraulic conditions representative of a hypothetical nuclear reactor accident. These measurements are useful to characterize the heat and mass transfers between the spraying droplets and the air-steam mixture composing the atmosphere. This analysis will be exposed in a two companion papers. References: [1] E. Porcheron, P. Brun, P. Cornet, J. Malet, J. Vendel. Optical diagnostics applied for single and multi-phase flow characterization in the TOSQAN facility dedicated for thermal hydraulic containment studies. NURETH-10 Seoul, Korea, October 5-9, 2003. [2] P

  2. Dancing droplets: Chemical space, substrates, and control

    Science.gov (United States)

    Cira, Nate; Benusiglio, Adrien; Prakash, Manu

    2015-11-01

    Previously we showed that droplets of propylene glycol and water display remarkable properties when placed on clean glass due to an interplay between surface tension and evaporation. (Cira, Benusiglio, Prakash: Nature, 2015). We showed that these mechanisms apply to a range of two-component mixtures of miscible liquids where one component has both higher surface tension and higher vapor pressure on a variety of high energy surfaces. We now show how this rule can be cheated using a simple trick. We go on to demonstrate applications for cleaning, and show how this system works on substrates prepared only with sunlight. We finish by demonstrating active control of droplets, allowing access to a host of new possibilities.

  3. Single Molecule Sensitive FRET in Attoliter Droplets

    CERN Document Server

    Milas, Peker; Gamari, Ben D; Goldner, Lori S

    2013-01-01

    Single molecular-pair fluorescence resonance energy transfer (spFRET) has become an cross-disciplinary tool for understanding molecular folding and interactions. While providing detailed information about the individual members of a molecular ensemble, this technique is always limited by fluorophore brightness and stability. In the case of diffusing molecules, the experiment is further limited by the number of photons that can be collected during the time it takes for a molecule to diffuse across the detection volume. To maximize the number of photons it is common to either increase the detection volume at the expense of increased background, or increase the diffusion time by adding glycerol or sucrose to increase viscosity. Here we demonstrate that FRET from attoliter volume (100 nm radius) aqueous droplets in perfluorinated oil has significantly higher signal-to-noise and a much wider dynamic range than FRET from molecules diffusing in solution. However, our measurements also reveal a droplet environment th...

  4. Fundamental thermal noise in droplet microresonators

    CERN Document Server

    Giorgini, Antonio; Malara, Pietro; De Natale, Paolo; Gagliardi, Gianluca

    2016-01-01

    Liquid droplet whispering-gallery-mode microresonators open a new research frontier for optomechanics and photonic devices. At visible wavelengths, where most liquids are transparent, a major contribution to a droplet optical quality factor is expected theoretically from thermal surface distortions and capillary waves. Here, we investigate experimentally these predictions using transient cavity ring-down spectroscopy. In this way, the optical out-coupling and intrinsic loss are measured independently while any perturbation induced by thermal, acoustic and laser-frequency noise is avoided thanks to the ultra-short light-cavity interaction time. The measurements reveal a photon lifetime ten times longer than the thermal limit and suggest that capillary fluctuations activate surface scattering effects responsible for light coupling.

  5. Droplets and Bubbles in Microfluidic Devices

    Science.gov (United States)

    Anna, Shelley Lynn

    2016-01-01

    Precise, tunable emulsions and foams produced in microfluidic geometries have found wide application in biochemical analysis and materials synthesis and characterization. Superb control of the volume, uniformity, and generation rate of droplets and bubbles arises from unique features of the microscale behavior of fluid interfaces. Fluid interfaces confined within microfluidic channels behave quite differently than their counterparts in unbounded flows. Confinement inhibits capillary instabilities so that breakup occurs by largely quasi-static mechanisms. The three-dimensional flow near confined interfaces in rectangular geometries and feedback effects from resistance changes in the entire microfluidic network play important roles in regulating the interfacial deformation. Timescales for transport of surfactants and particles to interfaces compete with flow timescales at the microscale, providing further opportunity for tuning the interfacial coverage and properties of individual droplets and bubbles.

  6. Helium anion formation inside helium droplets

    Science.gov (United States)

    Jabbour Al Maalouf, Elias; Reitshammer, Julia; Ribar, Anita; Scheier, Paul; Denifl, Stephan

    2016-07-01

    The formation of He∗- is examined with improved electron energy resolution of about 100 meV utilizing a hemispherical electron monochromator. The work presented provides a precise determination of the three previously determined resonance peak positions that significantly contribute to the formation of He∗- inside helium nanodroplets in the energy range from 20 eV to 29.5 eV. In addition, a new feature is identified located at 27.69 ± 0.18 eV that we assign to the presence of O2 as a dopant inside the droplet. With increasing droplet size a small blue shift of the resonance positions is observed. Also for the relatively low electron currents used in the present study (i.e., 15-70 nA) a quadratic dependence of the He∗- ion yield on the electron current is observed.

  7. Swimming droplets driven by a surface wave

    Science.gov (United States)

    Ebata, Hiroyuki; Sano, Masaki

    2015-02-01

    Self-propelling motion is ubiquitous for soft active objects such as crawling cells, active filaments, and liquid droplets moving on surfaces. Deformation and energy dissipation are required for self-propulsion of both living and non-living matter. From the perspective of physics, searching for universal laws of self-propelled motions in a dissipative environment is worthwhile, regardless of the objects' details. In this article, we propose a simple experimental system that demonstrates spontaneous migration of a droplet under uniform mechanical agitation. As we vary control parameters, spontaneous symmetry breaking occurs sequentially, and cascades of bifurcations of the motion arise. Equations describing deformable particles and hydrodynamic simulations successfully describe all of the observed motions. This system should enable us to improve our understanding of spontaneous motions of self-propelled objects.

  8. Droplet Impact Dynamics on Micropillared Hydrophobic Surfaces

    CERN Document Server

    Patil, Nagesh D; Sharma, Atul

    2016-01-01

    The effect of pitch of the pillars and impact velocity are studied for the impact dynamics of a microliter water droplet on a micropillared hydrophobic surface. The results are presented qualitatively by the high-speed photography and quantitatively by the temporal variation of wetted diameter and droplet height. A characterization of the transient quantitative results is a novel aspect of our work. Three distinct regimes, namely, non-bouncing, complete bouncing and partial bouncing are presented. A critical pitch as well as impact velocity exists for the transition from one regime to another. This is explained with a demonstration of Cassie to Wenzel wetting transition in which the liquid penetrates in the grooves between the pillars at larger pitch or impact velocity. The regimes are demarcated on a map of pitch and impact velocity. A good agreement is reported between the present measurements and published analytical models.

  9. Ballistic model to estimate microsprinkler droplet distribution

    Directory of Open Access Journals (Sweden)

    Conceição Marco Antônio Fonseca

    2003-01-01

    Full Text Available Experimental determination of microsprinkler droplets is difficult and time-consuming. This determination, however, could be achieved using ballistic models. The present study aimed to compare simulated and measured values of microsprinkler droplet diameters. Experimental measurements were made using the flour method, and simulations using a ballistic model adopted by the SIRIAS computational software. Drop diameters quantified in the experiment varied between 0.30 mm and 1.30 mm, while the simulated between 0.28 mm and 1.06 mm. The greatest differences between simulated and measured values were registered at the highest radial distance from the emitter. The model presented a performance classified as excellent for simulating microsprinkler drop distribution.

  10. Sessile droplet evaporation on superheated superhydrophobic surfaces

    CERN Document Server

    Hays, Robb C; Maynes, Daniel; Webb, Brent W

    2013-01-01

    This fluid dynamics video depicts the evaporation of sessile water droplets placed on heated superhydrophobic (SH) surfaces of varying cavity fraction, F_c, and surface temperature, T_s, above the saturation temperature, T_sat. Images were captured at 10,000 FPS and are played back at 30 FPS in this video. Teflon-coated silicon surfaces of F_c = 0, 0.5, 0.8, and 0.95 were used for these experiments. T_s ranging from 110{\\deg}C to 210{\\deg}C were studied. The video clips show how the boiling behavior of sessile droplets is altered with changes in surface microstructure. Quantitative results from heat transfer rate experiments conducted by the authors are briefly discussed near the end of the video.

  11. Engineering particle morphology with microfluidic droplets

    Science.gov (United States)

    Kang, Zhanxiao; Kong, Tiantian; Lei, Leyan; Zhu, Pingan; Tian, Xiaowei; Wang, Liqiu

    2016-07-01

    The controlled generation of microparticles with non-spherical features is of increasing importance. Such particles are useful for fundamental studies in areas such as self-assembly, as well as biomedical applications from drug carriers to photonic devices. We propose a simple model that captures the dominating factors controlling the size and morphology of non-spherical particles from phase separated droplets. The validity of our model is verified by comparing the generated non-spherical microparticles by droplet microfluidics. This simple relationship between the dominating factors and the final morphologies enables the production of non-spherical particles with well-defined shapes and tightly-controlled dimensions for a variety of applications from drug delivery vehicles to structural materials.

  12. Droplet condensation on polymer surfaces: a review

    OpenAIRE

    UÇAR, İkrime Orkan; ERBİL, Hüsnü Yıldırım

    2013-01-01

    Dropwise condensation on substrates is an important topic of interest because it plays a crucial role in many scientific applications such as heat transfer, water harvesting from the humid atmosphere, and polymer templating. We focused on droplet condensation on polymer surfaces and briefly summarized the drop condensation studies reported in the last 2 decades and their potential applications. The main topics discussed in this review are water harvesting from dew using radiative ...

  13. Spreading of charged micro-droplets

    Directory of Open Access Journals (Sweden)

    Joseph Iaia

    2013-09-01

    Full Text Available We consider the spreading of a charged microdroplet on a flat dielectric surface whose spreading is driven by surface tension and electrostatic repulsion. This leads to a third order nonlinear partial differential equation that gives the evolution of the height profile. Assuming the droplets are circular we are able to prove existence of solutions with infinite contact angle and in many cases we are able to prove nonexistence of solutions with finite contact angle.

  14. Computational Fluid Dynamics of rising droplets

    Energy Technology Data Exchange (ETDEWEB)

    Wagner, Matthew [Lake Superior State University; Francois, Marianne M. [Los Alamos National Laboratory

    2012-09-05

    The main goal of this study is to perform simulations of droplet dynamics using Truchas, a LANL-developed computational fluid dynamics (CFD) software, and compare them to a computational study of Hysing et al.[IJNMF, 2009, 60:1259]. Understanding droplet dynamics is of fundamental importance in liquid-liquid extraction, a process used in the nuclear fuel cycle to separate various components. Simulations of a single droplet rising by buoyancy are conducted in two-dimensions. Multiple parametric studies are carried out to ensure the problem set-up is optimized. An Interface Smoothing Length (ISL) study and mesh resolution study are performed to verify convergence of the calculations. ISL is a parameter for the interface curvature calculation. Further, wall effects are investigated and checked against existing correlations. The ISL study found that the optimal ISL value is 2.5{Delta}x, with {Delta}x being the mesh cell spacing. The mesh resolution study found that the optimal mesh resolution is d/h=40, for d=drop diameter and h={Delta}x. In order for wall effects on terminal velocity to be insignificant, a conservative wall width of 9d or a nonconservative wall width of 7d can be used. The percentage difference between Hysing et al.[IJNMF, 2009, 60:1259] and Truchas for the velocity profiles vary from 7.9% to 9.9%. The computed droplet velocity and interface profiles are found in agreement with the study. The CFD calculations are performed on multiple cores, using LANL's Institutional High Performance Computing.

  15. Droplets and modes of respiratory disease transmission

    Science.gov (United States)

    Bourouiba, Lydia

    2014-11-01

    Direct observation of violent expirations such as sneezes and coughs events reveal that such flows are multiphase turbulent buoyant clouds with suspended droplets of various sizes. The effects of ambient conditions indoors, such as moisture and temperature, coupled with the water content of such clouds are key in shaping the pathogen footprint emitted by potentially sick individuals. Such pathogen footprint can change the patterns of respiratory disease transmission. We discuss how the fluid dynamics of violent expirations can help inform how.

  16. Droplet formation and ejection from a micromachined ultrasonic droplet generator: Visualization and scaling

    Science.gov (United States)

    Meacham, J. M.; Varady, M. J.; Degertekin, F. L.; Fedorov, A. G.

    2005-10-01

    Visualization and scaling of drop-on-demand and continuous-jet fluid atomization of water are presented to elucidate the fluid physics of the ejection process and characterize the modes of operation of a novel micromachined ultrasonic droplet generator. The device comprises a fluid reservoir that is formed between a bulk ceramic piezoelectric transducer and an array of liquid horn structures wet etched into (100) silicon. At resonance, the transducer generates a standing ultrasonic pressure wave within the cavity and the wave is focused at the tip of the nozzle by the horn structure. Device operation has been demonstrated by water droplet ejection from 5to10μm orifices at multiple resonant frequencies between 1 and 5MHz. The intimate interactions between focused ultrasonic pressure waves and capillary waves formed at the liquid-air interface located at the nozzle tip are found to govern the ejection dynamics, leading to different ejection modalities ranging from individual droplets to continuous jet. Specifically, we report the results of high-resolution stroboscopic optical imaging of the liquid-air interface evolution during acoustic pumping to elucidate the role of capillary waves in the droplet formation and ejection process. A basic understanding of the governing physics gained through careful visualization and scaling forms the basis for development of improved theoretical models for the droplet formation and ejection processes by accounting for key fluid mechanical features of the phenomena.

  17. Adaptive Liquid Lens Actuated by Droplet Movement

    Directory of Open Access Journals (Sweden)

    Chao Liu

    2014-08-01

    Full Text Available In this paper we report an adaptive liquid lens actuated by droplet movement. Four rectangular PMMA (Polymethyl Methacrylate substrates are stacked to form the device structure. Two ITO (Indium Tin Oxide sheets stick on the bottom substrate. One PMMA sheet with a light hole is inserted in the middle of the device. A conductive droplet is placed on the substrate and touches the PMMA sheet to form a small closed reservoir. The reservoir is filled with another immiscible non-conductive liquid. The non-conductive liquid can form a smooth concave interface with the light hole. When the device is applied with voltage, the droplet stretches towards the reservoir. The volume of the reservoir reduces, changing the curvature of the interface. The device can thus achieve the function of an adaptive lens. Our experiments show that the focal length can be varied from −10 to −159 mm as the applied voltage changes from 0 to 65 V. The response time of the liquid lens is ~75 ms. The proposed device has potential applications in many fields such as information displays, imaging systems, and laser scanning systems.

  18. Characteristics of droplet motion in effervescent sprays

    Directory of Open Access Journals (Sweden)

    Jedelský Jan

    2014-03-01

    Full Text Available Time resolved droplet size and velocity measurement was made using Phase-Doppler anemometry in an effervescent spray at GLR of 6 % and operation pressure drops 21 – 52 kPa. The spray shows a size dependent variation of mean as well as fluctuating axial and radial velocities of droplets similarly for all operation regimes. Particles under 13 μm follow the gas flow, axially decelerated due to gas expansion. Velocity of medium sized particles is positively size correlated and larger particles keep high velocity, given them during discharge. Fluctuating radial velocity of small particles is larger than that of large particles while fluctuating axial velocity increases with size. Small particles thus reach a ratio of radial to axial velocity fluctuations ~ 0.6 but large particles only ~ 0.1, which indicates large transverse dispersion of small particles. Overall fluctuating velocity ratios smaller than 0.5 document an anisotropic character of the liquid mass fluctuations. Power spectral density (PSD of axial velocity fluctuations of large droplets is uniform up to 1 kHz, while PSD of smaller particles drops down with frequency for frequencies > 100 Hz. Large particles thus preserve the fluctuations imposed during discharge while the gas turbulence drops with frequency. Turbulence intensity reaches 14 to 21 % depending on pressure. Such high-turbulence character of the flow probably results from a heterogeneous gas–liquid mixture at the discharge.

  19. A frictional sliding algorithm for liquid droplets

    Science.gov (United States)

    Sauer, Roger A.

    2016-08-01

    This work presents a new frictional sliding algorithm for liquid menisci in contact with solid substrates. In contrast to solid-solid contact, the liquid-solid contact behavior is governed by the contact line, where a contact angle forms and undergoes hysteresis. The new algorithm admits arbitrary meniscus shapes and arbitrary substrate roughness, heterogeneity and compliance. It is discussed and analyzed in the context of droplet contact, but it also applies to liquid films and solids with surface tension. The droplet is modeled as a stabilized membrane enclosing an incompressible medium. The contact formulation is considered rate-independent such that hydrostatic conditions apply. Three distinct contact algorithms are needed to describe the cases of frictionless surface contact, frictionless line contact and frictional line contact. For the latter, a predictor-corrector algorithm is proposed in order to enforce the contact conditions at the contact line and thus distinguish between the cases of advancing, pinning and receding. The algorithms are discretized within a monolithic finite element formulation. Several numerical examples are presented to illustrate the numerical and physical behavior of sliding droplets.

  20. Rapid crystallization from acoustically levitated droplets.

    Science.gov (United States)

    Cao, Hui-Ling; Yin, Da-Chuan; Guo, Yun-Zhu; Ma, Xiao-Liang; He, Jin; Guo, Wei-Hong; Xie, Xu-Zhuo; Zhou, Bo-Ru

    2012-04-01

    This paper reports on an ultrasonic levitation system developed for crystallization from solution in a containerless condition. The system has been proven to be able to levitate droplets stably and grow crystals rapidly and freely from a levitated droplet. Crystals of four samples, including NaCl, NH(4)Cl, lysozyme, and proteinase K, were obtained successfully utilizing the system. The studies showed that the crystals obtained from the acoustically levitated droplets all exhibited higher growth rates, larger sizes, better shapes, fewer crystals, as well as fewer twins and shards, compared with the control on a vessel wall. The results indicated that containerless ultrasonic levitation could play a key role in improving the crystallization of both inorganic salts and proteins. The ultrasonic levitation system could be used as a ground-based microgravity simulation platform, which could swiftly perform crystallization and screening of crystallization conditions for space crystallization and other ground-based containerless techniques. Moreover, the approach could also be conveniently applied to researching the dynamics and mechanism of crystallization. In addition, the device could be used for the preparation of high-purity materials, analysis of minute or poisonous samples, study of living cells, environmental monitoring, and so on. PMID:22501088

  1. Experimental investigation of interaction processes between droplets and hot walls

    Science.gov (United States)

    Karl, A.; Frohn, A.

    2000-04-01

    A detailed experimental investigation of interaction processes of small liquid droplets with hot walls well above the Leidenfrost temperature has been carried out. The experimental method which uses monodisperse droplet streams in combination with a standard video camera allows very detailed observations and measurements with very high time resolution. The main intent of this paper is to study the mechanical behavior of liquid droplets impacting on hot walls well above the Leidenfrost temperature. A better understanding of this process may lead to a better modeling of two-phase flows, especially for applications in fuel preparation processes, combustion processes, and spray cooling. The loss of momentum of the droplets, the droplet deformation, and the onset of droplet disintegration have been investigated. For all experimental results correlations have been developed, which can be used to improve the numerical modeling of two-phase flows. Using the correlation for the loss of momentum a theoretical approximation for the maximum droplet deformation has been deduced, which yields a very good agreement with our own measurements as well as with results reported in the literature. A minimum impinging angle for droplet disintegration has been discovered for small impinging angles. Below this impinging angle no droplet disintegration is observed. This phenomenon is directly related to the energy dissipation at the wall during the interaction process. With the presented work the understanding of basic interaction processes between droplets and hot walls may be improved.

  2. Droplet combustion experiments in varying forced convection using microgravity environment

    Energy Technology Data Exchange (ETDEWEB)

    Mitsuya, Masaki [Tokyo Gas Corporation, 1-5-20 Kaigan, Minato-ku, Tokyo 105-0022 (Japan); Hanai, Hironao [Chiba University of Science, 3 Shiomi-cho, Choshi, Chiba 288-0025 (Japan); Sakurai, Satoru [Institute of Fluid Science, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577 (Japan); Ogami, Yasuhiro [Institute of Fluid Science, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577 (Japan); Kobayashi, Hideaki [Institute of Fluid Science, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577 (Japan)]. E-mail: kobayashi@ifs.tohoku.ac.jp

    2005-12-15

    A new microscopic model of the interaction between droplet flames and fine vortex tubes which compose a coherent structure of turbulence was developed. Three non-dimensional numbers were introduced to extend the length scale and time scale so as to be suitable for microgravity experiments using droplets of combustion of about 1 mm in diameter. An experimental apparatus for combustion of a single droplet and that of an array of two droplets in varying airflow was developed, and experiments were performed in microgravity and normal gravity at pressures up to 2.0 MPa for n-nonane and ethanol as fuels. Variations of the instantaneous burning rate constant, K {sub i}, in response to the varying flow velocity was successfully observed. At high pressure, the effects of droplet Reynolds number Re on K {sub i} was clearly seen, while the effects of natural convection, which increases K {sub i} with Re, was seen in normal gravity even in the forced airflows. As for the experiments on combustion of an array of two droplets, K {sub i} reduction of the downstream droplet became weak when the flow direction was varied. However, the K {sub i} reduction of the downstream droplet for flow direction variations was clearly seen for n-nonane droplets but almost not for ethanol droplets. The interaction mechanism between upstream and downstream droplets is considered to result from the elimination of oxidizer supply to the downstream droplet, indicating strong interaction effects of n-nonane droplets for a stoichiometric oxygen-fuel ratio of n-nonane (i.e., 14.0) greater than that of ethanol (i.e., 3.0)

  3. Inertial migration of deformable droplets in a microchannel

    International Nuclear Information System (INIS)

    The microfluidic inertial effect is an effective way of focusing and sorting droplets suspended in a carrier fluid in microchannels. To understand the flow dynamics of microscale droplet migration, we conduct numerical simulations on the droplet motion and deformation in a straight microchannel. The results are compared with preliminary experiments and theoretical analysis. In contrast to most existing literature, the present simulations are three-dimensional and full length in the streamwise direction and consider the confinement effects for a rectangular cross section. To thoroughly examine the effect of the velocity distribution, the release positions of single droplets are varied in a quarter of the channel cross section based on the geometrical symmetries. The migration dynamics and equilibrium positions of the droplets are obtained for different fluid velocities and droplet sizes. Droplets with diameters larger than half of the channel height migrate to the centerline in the height direction and two equilibrium positions are observed between the centerline and the wall in the width direction. In addition to the well-known Segré-Silberberg equilibrium positions, new equilibrium positions closer to the centerline are observed. This finding is validated by preliminary experiments that are designed to introduce droplets at different initial lateral positions. Small droplets also migrate to two equilibrium positions in the quarter of the channel cross section, but the coordinates in the width direction are between the centerline and the wall. The equilibrium positions move toward the centerlines with increasing Reynolds number due to increasing deformations of the droplets. The distributions of the lift forces, angular velocities, and the deformation parameters of droplets along the two confinement direction are investigated in detail. Comparisons are made with theoretical predictions to determine the fundamentals of droplet migration in microchannels. In

  4. Recombinant Bone Morphogenetic Protein 2 Stimulates the Remodeling Chitosan-Based Porous Scaffold Into Hyaline-like Cartilage: Study in Heterotopic Implantation

    Directory of Open Access Journals (Sweden)

    Nurshat M. Gaifullin

    2013-09-01

    Full Text Available To study the morphology of remodeling the chitosan-based three-dimensional porous scaffold, containing bone morphogenetic protein-2 (BMP-2 for chondroinduction, the experiments with heterotopic implantation using 28 Wistar rats were carried out. Scaffolds with growth factor (n=12 or without it (n=12, against intact control (n=4 were implanted subcutaneously. Classical methods of histology and morphometry as well as immune histochemical markers (CD-68, CD-31, MMP-9, TIMP-1, and osteonectin expression, one used to investigate zone of remodeling in euthanized animals at 4 and 8 weeks after implantation. The BMP-2 application provides more intensive and rapid new cartilage formation from the scaffold matter. The additional chondroinductive effect proved more intensive settlement and proliferation of chondral cells in the regenerate, expression of chondral phenotype with the building the hyaline-like matrix, and the supporting necessary balance between the matrix metalloproteinases and their tissue inhibitors.

  5. The results of treating Hyaline membrane disease with Surfactant during 1 year at Ali-Asghar Hospital, neonatal intensive care unit

    Directory of Open Access Journals (Sweden)

    Naeri F

    1999-08-01

    Full Text Available The routine intake of surfactant as a part of HMD (Hyaline Membrane Disease treatment had significant effect on the prognosis of premature neonates. But since in our country this drug is not widely and routinely used, and there are not records about its use, we decided to make good on this shortcoming through a retrospective study. During 1 year, 54 neonates with HMD were admitted in Ali-Asghar's NICU, 30 of them had gestational age of less than 34 weeks and for 15 cases, surfactant was used. The results of treating this group were then compared with another group of neonates, who were not given this drug. From a statistical point of view, mortality, the length of the period in which the respirator was used, the use of high pressure in respirator, pneumothorax and pulmonary hemorrhage in neonates under treatment with surfactant was significantly less than those of the other group.

  6. Spontaneous electrical charging of droplets by conventional pipetting

    Science.gov (United States)

    Choi, Dongwhi; Lee, Horim; Im, Do Jin; Kang, In Seok; Lim, Geunbae; Kim, Dong Sung; Kang, Kwan Hyoung

    2013-06-01

    We report that a droplet dispensed from a micropipette almost always has a considerable electrical charge of a magnitude dependent on the constituents of the droplet, on atmospheric humidity and on the coating material of pipette tip. We show that this natural electrification of a droplet originates from the charge separation between a droplet and pipette tip surface by contact with water due to the ionization of surface chemical groups. Charge on a droplet can make it difficult to detach the droplet from the pipette tip, can decrease its surface tension, can affect the chemical characteristics of solutions due to interactions with charged molecules, and can influence the combination and localization of charged bio-molecules; in all cases, the charge may affect results of experiments in which any of these factors is important. Thus, these findings reveal experimental parameters that should be controlled in experiments that use micropipettes.

  7. Magnetophoretic control of water droplets in bulk ferrofluid

    Science.gov (United States)

    Katsikis, Georgios; Bréant, Alexandre; Prakash, Manu

    2015-11-01

    We present a microfluidic platform for 2-D manipulation of water droplets immersed in bulk oil-based ferrofluid. Although non-magnetic, the droplets are exclusively controlled by magnetic fields, without any pressure-driven flow. The diphasic fluid layer is trapped in a submillimeter Hele-Shaw chamber that includes permalloy tracks on its substrate. An in-plane rotating magnetic field magnetizes the permalloy tracks, thus producing local magnetic gradients, while an orthogonal magnetic field magnetizes the bulk ferrofluid. To minimize the magnetostatic energy of the system, droplets are attracted towards the locations of the tracks where ferrofluid is repelled. Using this technique, we demonstrate synchronous propagation of water droplets, analyze PIV data of the bulk ferrofluid flow and study the kinematics of propagation. In addition, we show droplet break-up, merging and derive relevant scaling laws. Finally, we discuss future applications owing to the biocompatibility of the droplets.

  8. Generation and mixing of subfemtoliter aqueous droplets on demand.

    Science.gov (United States)

    Tang, Jianyong; Jofre, Ana M; Kishore, Rani B; Reiner, Joseph E; Greene, Mark E; Lowman, Geoffrey M; Denker, John S; Willis, Christina C C; Helmerson, Kristian; Goldner, Lori S

    2009-10-01

    We describe a novel method of generating monodisperse subfemtoliter aqueous droplets on demand by means of piezoelectric injection. Droplets with volumes down to 200 aL are generated by this technique. The droplets are injected into a low refractive index perfluorocarbon so that they can be optically trapped. We demonstrate the use of optical tweezers to manipulate and mix droplets. For example, using optical tweezers we bring two droplets, one containing a calcium sensitive dye and the other calcium chloride, into contact. The droplets coalesce with a resulting reaction time of about 1 ms. The monodispersity, manipulability, repeatability, small size, and fast mixing afforded by this system offer many opportunities for nanochemistry and observation of chemical reactions on a molecule-by-molecule basis.

  9. Measurement of electric properties of the single supersaturated aerosol droplet

    Institute of Scientific and Technical Information of China (English)

    HE KeJuan; CHENG Hua; ZHU YanYing; WANG LiangYu; ZHANG YunHong

    2008-01-01

    A system for measuring the electric properties of single aerosol droplet is designed and applied to the NaCIO4 aerosol droplet in different relative humidity (RH). The conductance and capacitance are obtained within the whole RH range, especially in the supersaturated state which cannot be acquired from the bulk solution. These results reflect the situation of ions in the droplet macroscopically and supply useful information for other relative study fields, such as crystallogeny and aerography.

  10. Electromagnetic emission of a strongly charged oscillating droplet

    Science.gov (United States)

    Grigor'ev, A. I.; Kolbneva, N. Yu.; Shiryaeva, S. O.

    2016-08-01

    Analytical expressions for electric field in the vicinity of an oscillating strongly charged droplet of nonviscous conducting liquid and intensity of electromagnetic radiation are derived in the linear approximation with respect to perturbation amplitude of the droplet surface. Order-of-magnitude estimations of the radiation intensity are presented. The intensity of electromagnetic radiation of a ball lightning that can be simulated using a charged droplet is not related to the surface oscillations.

  11. The Potential Impact of Droplet Microfluidics in Biology

    OpenAIRE

    Schneider, Thomas; Kreutz, Jason; Chiu, Daniel T.

    2013-01-01

    Droplet microfluidics, which involves micrometer-sized emulsion droplets on a microfabricated platform, is an active research endeavor that evolved out of the larger field of microfluidics. Recently, this subfield of microfluidics has started to attract greater interest because researchers have been able to demonstrate applications of droplets as miniaturized laboratories for biological measurements. This perspective explores the recent developments and the potential future biological applica...

  12. Laser droplet welding of zinc coated steel sheets

    OpenAIRE

    Jerič, Anže; Grabec, Igor; Govekar, Edvard

    2015-01-01

    The weldability of zinc coated steel sheets is often compromised by weld seam defects caused by rapid zinc vaporisation and burned-off zinc. Owing to this, welded seams usually remain unprotected from corrosion and are accompanied by undesirable porosity. In this paper, the laser droplet generation process and its application to laser droplet welding of zinc coated steel sheets are described. The influences of laser droplet generation and welding process control parameters on the properties o...

  13. DNA sequence analysis with droplet-based microfluidics

    OpenAIRE

    Abate, Adam R.; Hung, Tony; Sperling, Ralph A.; Mary, Pascaline; Rotem, Assaf; Agresti, Jeremy J.; Weiner, Michael A.; Weitz, David A.

    2013-01-01

    Droplet-based microfluidic techniques can form and process micrometer scale droplets at thousands per second. Each droplet can house an individual biochemical reaction, allowing millions of reactions to be performed in minutes with small amounts of total reagent. This versatile approach has been used for engineering enzymes, quantifying concentrations of DNA in solution, and screening protein crystallization conditions. Here, we use it to read the sequences of DNA molecules with a FRET-based ...

  14. Colliding droplets in turbulent flows: A numerical study

    OpenAIRE

    Perrin, V.E.

    2015-01-01

    Droplets and the way they collide are at the very base of the formation of clouds and the initiation of warm rain. The evolution of a cloud droplet into a rain droplet can be classified into three stages. For each stage different growth mechanisms can be identified. In the first stage condensation is the only effective mechanism. In the second stage, neither condensation nor gravity induced coalescence are effective, and droplets have to grow past this condensation-coalescence bottleneck to reac...

  15. Droplet morphologies on particles with macroscopic surface roughness.

    Science.gov (United States)

    Stepánek, Frantisek; Rajniak, Pavol

    2006-01-31

    The equilibrium configuration of liquid droplets on the surface of macroscopically rough solid particles was determined by numerical simulations using the volume-of-fluid (VOF) method. The fractional surface coverage of the particle as a function of the droplet size, equilibrium contact angle, and the particle surface roughness amplitude and correlation length has been systematically investigated. Droplet size and contact angle were found to generally have a stronger effect on surface coverage than particle surface roughness. Because of droplet coalescence, a relatively large variation in surface coverage was observed for any given total liquid volume, particularly for larger values of the equilibrium contact angle. PMID:16430249

  16. Cross-Interface Emulsification for Generating Size-Tunable Droplets.

    Science.gov (United States)

    Xu, Peng; Zheng, Xu; Tao, Yi; Du, Wenbin

    2016-03-15

    We report cross-interface emulsification (XiE), a simple method for the generation of monodisperse droplets of controllable volumes from picoliter to nanoliter. A device is set up in which a fused-silica capillary is vibrating across the surface of the continuous phase (mineral oil) in a reservoir, and the flow of the dispersed phase (aqueous solution) in the capillary is segmented into monodisperse droplets at the air/oil interface. We find that the volume of droplets is mainly dominated by the flow rate and vibrating frequency and not significantly influenced by other factors, such as the viscosity of the continuous phase and dispersed phase, the inner diameter of the capillary (20-100 μm), or the shape of the tip (tapered or flat). These features reflect high robustness, flexibility, and precision of XiE for on-demand volume control of droplets. The droplets automatically assemble into planar monolayer droplet arrays (PMDA) in flat-bottomed microwells of 96-well plates, offering excellent convenience for imaging of droplets. As a representative application, we carry out digital loop-mediated isothermal amplification using PMDAs with multivolume droplets for the absolute quantification of nucleic acids. Our results demonstrate that XiE is simple and controllable for the production of monodisperse size-tunable droplets, and it offers opportunities for common laboratories, even without microfabrication facilities, to perform digital quantification, single cell analysis, and other biochemical assays with high throughput. PMID:26849419

  17. Targeting the motor regulator Klar to lipid droplets

    Directory of Open Access Journals (Sweden)

    Einstein Jenifer

    2011-02-01

    Full Text Available Abstract Background In Drosophila, the transport regulator Klar displays tissue-specific localization: In photoreceptors, it is abundant on the nuclear envelope; in early embryos, it is absent from nuclei, but instead present on lipid droplets. Differential targeting of Klar appears to be due to isoform variation. Droplet targeting, in particular, has been suggested to occur via a variant C-terminal region, the LD domain. Although the LD domain is necessary and sufficient for droplet targeting in cultured cells, lack of specific reagents had made it previously impossible to analyze its role in vivo. Results Here we describe a new mutant allele of klar with a lesion specifically in the LD domain; this lesion abolishes both droplet localization of Klar and the ability of Klar to regulate droplet motion. It does not disrupt Klar's function for nuclear migration in photoreceptors. Using a GFP-LD fusion, we show that the LD domain is not only necessary but also sufficient for droplet targeting in vivo; it mediates droplet targeting in embryos, in ovaries, and in a number of somatic tissues. Conclusions Our analysis demonstrates that droplet targeting of Klar occurs via a cis-acting sequence and generates a new tool for monitoring lipid droplets in living tissues of Drosophila.

  18. Numerical simulation of filler metal droplets spreading in laser brazing

    Institute of Scientific and Technical Information of China (English)

    Yanbin Chen; Xiaosong Feng; Liqun Li

    2007-01-01

    A finite element model was constructed using a commercial software Fidap to analyze the Cu-base filler metal droplet spreading process in laser brazing, in which the temperature distribution, droplet geometry,and fluid flow velocity were calculated. Marangoni and buoyancy convection and gravity force were considered, and the effects of laser power and spot size on the spreading process were evaluated. Special attention was focused on the free surface of the droplet, which determines the profile of the brazing spot.The simulated results indicate that surface tension is the dominant flow driving force and laser spot size determines the droplet spreading domain.

  19. Numerical simulation of filler metal droplets spreading in laser brazing

    Science.gov (United States)

    Chen, Yanbin; Feng, Xiaosong; Li, Liqun

    2007-11-01

    A finite element model was constructed using a commercial software Fidap to analyze the Cu-base filler metal droplet spreading process in laser brazing, in which the temperature distribution, droplet geometry, and fluid flow velocity were calculated. Marangoni and buoyancy convection and gravity force were considered, and the effects of laser power and spot size on the spreading process were evaluated. Special attention was focused on the free surface of the droplet, which determines the profile of the brazing spot. The simulated results indicate that surface tension is the dominant flow driving force and laser spot size determines the droplet spreading domain.

  20. Threat representative droplet generation and surface interaction analysis

    Science.gov (United States)

    Simpson, Steven; Chyba, Thomas H.; Jones, Robert M.; Harper, Gordon; Haslam, Diane

    2011-05-01

    We present our experiments with state-of-the-art equipment to dispense threat-representative (3 - 90 nL) freely falling droplets of viscous chemical material (material can be created on demand and the behavior of the droplet on a surface can be monitored as a function of time. Knowledge of how these droplets behave on surfaces is critical in understanding an entire chemical threat scenario and directly impacts the design, testing, and success of standoff surface chemical sensor technology and modeling efforts alike. We are currently working to address this knowledge gap by recording 'cradle-to-grave' droplet dissemination and surface interaction events.

  1. Investigation on Electrostatical Breakup of Bio-Oil Droplets

    Directory of Open Access Journals (Sweden)

    John Z. Wen

    2012-10-01

    Full Text Available In electrostatic atomization, the input electrical energy causes breaking up of the droplet surface by utilizing a mutual repulsion of net charges accumulating on that surface. In this work a number of key parameters controlling the bio-oil droplet breakup process are identified and these correlations among the droplet size distribution, specific charges of droplets and externally applied electrical voltages are quantified. Theoretical considerations of the bag or strip breakup mechanism of biodiesel droplets experiencing electrostatic potential are compared to experimental outcomes. The theoretical analysis suggests the droplet breakup process is governed by the Rayleigh instability condition, which reveals the effects of droplets size, specific charge, surface tension force, and droplet velocities. Experiments confirm that the average droplet diameters decrease with increasing specific charges and this decreasing tendency is non-monotonic due to the motion of satellite drops in the non-uniform electrical field. The measured specific charges are found to be smaller than the theoretical values. And the energy transformation from the electrical energy to surface energy, in addition to the energy loss, Taylor instability breakup, non-excess polarization and some system errors, accounts for this discrepancy. The electrostatic force is the dominant factor controlling the mechanism of biodiesel breakup in electrostatic atomization.

  2. Fractal Analyses of High-Resolution Cloud Droplet Measurements.

    Science.gov (United States)

    Malinowski, Szymon P.; Leclerc, Monique Y.; Baumgardner, Darrel G.

    1994-02-01

    Fractal analyses of individual cloud droplet distributions using aircraft measurements along one-dimensional horizontal cross sections through clouds are performed. Box counting and cluster analyses are used to determine spatial scales of inhomogeneity of cloud droplet spacing. These analyses reveal that droplet spatial distributions do not exhibit a fractal behavior. A high variability in local droplet concentration in cloud volumes undergoing mixing was found. In these regions, thin filaments of cloudy air with droplet concentration close to those observed in cloud cores were found. Results suggest that these filaments may be anisotropic. Additional box counting analyses performed for various classes of cloud droplet diameters indicate that large and small droplets are similarly distributed, except for the larger characteristic spacing of large droplets.A cloud-clear air interface defined by a certain threshold of total droplet count (TDC) was investigated. There are indications that this interface is a convoluted surface of a fractal nature, at least in actively developing cumuliform clouds. In contrast, TDC in the cloud interior does not have fractal or multifractal properties. Finally a random Cantor set (RCS) was introduced as a model of a fractal process with an ill-defined internal scale. A uniform measure associated with the RCS after several generations was introduced to simulate the TDC records. Comparison of the model with real TDC records indicates similar properties of both types of data series.

  3. Freezing of water droplets colliding with kaolinite particles

    DEFF Research Database (Denmark)

    Svensson, Erik Anders; Delval, Christophe Eric Ludovic; Freiherr von Und zu Hessberg, P J H;

    2009-01-01

    Contact freezing of single supercooled water droplets colliding with kaolinite dust particles has been investigated. The experiments were performed with droplets levitated in an electrodynamic balance at temperatures from 240 to 268 K. Under dry conditions freezing 5 was observed to occur below 249...... K, while a freezing threshold of 267 K was observed at high relative humidity. The effect of relative humidity is attributed to an influence on the contact freezing process for the kaolinite-water droplet system, and it is not related to the lifetime of the droplets in the electrodynamic balance...

  4. Sessile multidroplets and salt droplets under high tangential electric fields

    Science.gov (United States)

    Xie, Guoxin; He, Feng; Liu, Xiang; Si, Lina; Guo, Dan

    2016-01-01

    Understanding the interaction behaviors between sessile droplets under imposed high voltages is very important in many practical situations, e.g., microfluidic devices and the degradation/aging problems of outdoor high-power applications. In the present work, the droplet coalescence, the discharge activity and the surface thermal distribution response between sessile multidroplets and chloride salt droplets under high tangential electric fields have been investigated with infrared thermography, high-speed photography and pulse current measurement. Obvious polarity effects on the discharge path direction and the temperature change in the droplets in the initial stage after discharge initiation were observed due to the anodic dissolution of metal ions from the electrode. In the case of sessile aligned multidroplets, the discharge path direction could affect the location of initial droplet coalescence. The smaller unmerged droplet would be drained into the merged large droplet as a result from the pressure difference inside the droplets rather than the asymmetric temperature change due to discharge. The discharge inception voltages and the temperature variations for two salt droplets closely correlated with the ionization degree of the salt, as well as the interfacial electrochemical reactions near the electrodes. Mechanisms of these observed phenomena were discussed. PMID:27121926

  5. Droplet Mobility Manipulation on Porous Media Using Backpressure.

    Science.gov (United States)

    Vourdas, N; Pashos, G; Kokkoris, G; Boudouvis, A G; Stathopoulos, V N

    2016-05-31

    Wetting phenomena on hydrophobic surfaces are strongly related to the volume and pressure of gas pockets residing at the solid-liquid interface. In this study, we explore the underlying mechanisms of droplet actuation and mobility manipulation when backpressure is applied through a porous medium under a sessile pinned droplet. Reversible transitions between the initially sticky state and the slippery states are thus incited by modulating the backpressure. The sliding angles of deionized (DI) water and ethanol in DI water droplets of various volumes are presented to quantify the effect of the backpressure on the droplet mobility. For a 50 μL water droplet, the sliding angle decreases from 45 to 0° when the backpressure increases to ca. 0.60 bar. Significantly smaller backpressure levels are required for lower surface energy liquids. We shed light on the droplet actuation and movement mechanisms by means of simulations encompassing the momentum conservation and the continuity equations along with the Cahn-Hilliard phase-field equations in a 2D computational domain. The droplet actuation mechanism entails depinning of the receding contact line and movement by means of forward wave propagation reaching the front of the droplet. Eventually, the droplet skips forward. The contact line depinning is also corroborated by analytical calculations based on the governing vertical force balance, properly modified to incorporate the effect of the backpressure. PMID:27163363

  6. Printing microstructures in a polymer matrix using a ferrofluid droplet

    Science.gov (United States)

    Abdel Fattah, Abdel Rahman; Ghosh, Suvojit; Puri, Ishwar K.

    2016-03-01

    We print complex curvilinear microstructures in an elastomer matrix using a ferrofluid droplet as the print head. A magnetic field moves the droplet along a prescribed path in liquid polydimethylsiloxane (PDMS). The droplet sheds magnetic nanoparticle (MNP) clusters in its wake, forming printed features. The PDMS is subsequently heated so that it crosslinks, which preserves the printed features in the elastomer matrix. The competition between magnetic and drag forces experienced by the ferrofluid droplet and its trailing MNPs highlight design criteria for successful printing, which are experimentally confirmed. The method promises new applications, such as flexible 3D circuitry.

  7. Dynamic response of vaporizing droplet to pressure oscillation

    Science.gov (United States)

    Yuan, Lei; Shen, Chibing; Zhang, Xinqiao

    2016-06-01

    Combustion instability is a major challenge in the development of the liquid propellant engines, and droplet vaporization is viewed as a potential mechanism for driving instabilities. Based on the previous work, an unsteady droplet heating and vaporization model was developed. The model and numerical method are validated by experimental data available in literature, and then the oscillatory vaporization of n-Heptane droplet exposed to unsteady harmonic nitrogen atmosphere was numerically investigated over a wide range of amplitudes and frequencies. Also, temperature variations inside the droplet were demonstrated under oscillation environments. It was found that the thermal wave is attenuated with significantly reduced wave intensities as it penetrates deep into droplet from the ambient gas. Droplet surface temperature exhibits smaller fluctuation than that of the ambient gas, and it exhibits a time lag with regard to the pressure variation. Furthermore, the mechanism leading to phase lag of vaporization rate with respect to pressure oscillation was unraveled. Results show that this phase lag varies during the droplet lifetime and it is strongly influenced by oscillation frequency, indicating droplet vaporization is only capable of driving combustion instability in some certain frequency domains. Instead, the amplitude of the oscillation does not have very significant effects. It is noteworthy that thermal inertia of the droplet also plays a considerable role in determining the phase lag.

  8. Quark matter droplets in neutron stars

    Science.gov (United States)

    Heiselberg, H.; Pethick, C. J.; Staubo, E. F.

    1993-01-01

    We show that, for physically reasonable bulk and surface properties, the lowest energy state of dense matter consists of quark matter coexisting with nuclear matter in the presence of an essentially uniform background of electrons. We estimate the size and nature of spatial structure in this phase, and show that at the lowest densities the quark matter forms droplets embedded in nuclear matter, whereas at higher densities it can exhibit a variety of different topologies. A finite fraction of the interior of neutron stars could consist of matter in this new phase, which would provide new mechanisms for glitches and cooling.

  9. Propagation of capillary waves and ejection of small droplets in rapid droplet spreading

    KAUST Repository

    Ding, Hang

    2012-03-12

    A new regime of droplet ejection following the slow deposition of drops onto a near-complete wetting solid substrate is identified in experiments and direct numerical simulations; a coalescence cascade subsequent to pinch-off is also observed for the first time. Results of numerical simulations indicate that the propagation of capillary waves that lead to pinch-off is closely related to the self-similar behaviour observed in the inviscid recoil of droplets, and that motions of the crests and troughs of capillary waves along the interface do not depend on the wettability and surface tension (or Ohnesorge number). The simulations also show that a self-similar theory for universal pinch-off can be used for the time evolution of the pinching neck. However, although good agreement is also found with the double-cone shape of the pinching neck for droplet ejection in drop deposition on a pool of the same liquid, substantial deviations are observed in such a comparison for droplet ejection in rapid drop spreading (including the newly identified regime). This deviation is shown to result from interference by the solid substrate, a rapid downwards acceleration of the top of the drop surface and the rapid spreading process. The experiments also confirm non-monotonic spreading behaviour observed previously only in numerical simulations, and suggest substantial inertial effects on the relation between an apparent contact angle and the dimensionless contact-line speed. © 2012 Cambridge University Press.

  10. Droplet migration in a Hele-Shaw microchannel: Effect of the lubrication film on the droplet dynamics

    CERN Document Server

    Ling, Yue; Popinet, Stéphane; Josserand, Christophe

    2016-01-01

    Droplet migration in a Hele-Shaw microchannel is a fundamental multiphase flow problem which is crucial to many microfluidics applications. We focus on the regime at low capillary number, where the droplet keeps a circular shape in the horizontal plane. Parametric studies are performed on the droplet horizontal radius and the capillary number, and particular attention is paid to the effect of the lubrication film on the droplet velocity. For droplets with an horizontal radius larger than half of the channel height, the droplet overfills the channel and a lubrication film is formed between the droplet and the wall. The lubrication film is shown to have a strong impact on the droplet migration velocity and the three-dimensional flow structure. The droplet velocity in the present simulation is shown to be lower than the average inflow velocity, in contrast with the Taylor-Saffman theory for Hele-Shaw flows, but in agreement with experimental measurements. Both the strong shear induced by the lubrication film and...

  11. Effect of viscosity on droplet-droplet collision outcome: Experimental study and numerical comparison

    Science.gov (United States)

    Gotaas, Cecilie; Havelka, Pavel; Jakobsen, Hugo A.; Svendsen, Hallvard F.; Hase, Matthias; Roth, Norbert; Weigand, Bernhard

    2007-10-01

    The influence of viscosity on droplet-droplet collision behavior at ambient conditions was studied experimentally and numerically. N-decane, monoethyleneglycol (MEG), diethyleneglycol (DEG), and triethyleneglycol were used as liquid phase providing viscosities in the range from 0.9to48mPas. Collision Weber numbers ranged approximately from 10 to 420. A direct numerical simulation code, based on the volume-of-fluid concept, was used for the simulations. Experimentally, observations of two droplet streams using a modified stroboscopic technique (aliasing method) were used to investigate the whole range of impact parameters during one experimental run. The experimental method has previously been verified for the water/air system [C. Gotaas et al., Phys. Fluids 19, 102105 (2007)]. In the present work, it was tested and validated for the n-decane/air system. Measured data agree well with those published in the literature. Well-defined regions of stretching separation and coalescence were identified, while reflexive separation regions were not found by using a single sinusoidal disturbance. However, the onset of reflexive separation was identified for MEG and DEG using an amplitude modulation technique. The results show that the criteria for onset of reflexive separation for viscous fluids provided by Y. I. Jiang et al. [J. Fluid Mech. 234, 177 (1992)] are not valid. This is consistent with the results given by K. D. Willis and M. Orme [Exp. Fluids 34, 28 (2003)]. A new empirical correlation for the onset of reflexive separation for high viscosity fluids is presented. The borders between coalescing and stretching separation were shifted toward higher Weber numbers with increasing viscosity. The lack of occurrence of reflexive separation for the single sinusoidal disturbance (small droplets), as well as the stretching separation boundary shift, can be explained by dissipation of collision kinetic energy in viscous flows inside the merged droplet after collision. Results

  12. A numerical study of droplet trapping in microfluidic devices

    Science.gov (United States)

    Nagel, Mathias; Brun, P.-T.; Gallaire, François

    2014-03-01

    Microfluidic channels are powerful means of control of minute volumes such as droplets. These droplets are usually conveyed at will in an externally imposed flow which follows the geometry of the micro-channel. It has recently been pointed out by Dangla et al. ["Trapping microfluidic drops in wells of surface energy," Phys. Rev. Lett. 107(12), 124501 (2011)] that the motion of transported droplets may also be stopped in the flow, when they are anchored to grooves which are etched in the channels top wall. This feature of the channel geometry explores a direction that is usually uniform in microfluidics. Herein, this anchoring effect exploiting the three spatial directions is studied combining a depth averaged fluid description and a geometrical model that accounts for the shape of the droplet in the anchor. First, the presented method is shown to enable the capture and release droplets in numerical simulations. Second, this tool is used in a numerical investigation of the physical mechanisms at play in the capture of the droplet: a localized reduced Laplace pressure jump is found on its interface when the droplet penetrates the groove. This modified boundary condition helps the droplet cope with the linear pressure drop in the surrounding fluid. Held on the anchor the droplet deforms and stretches in the flow. The combination of these ingredients leads to recover the scaling law for the critical capillary number at which the droplets exit the anchors C a^{star} ∝ h2/R2 where h is the channel height and R the droplet undeformed radius.

  13. Spontaneous Capillarity-Driven Droplet Ejection

    CERN Document Server

    Wollman, Andrew; Pettit, Donald; Weislogel, Mark

    2012-01-01

    The first large length-scale capillary rise experiments were conducted by R. Siegel using a drop tower at NASA LeRC shortly after the 1957 launch of Sputnik I. Siegel was curious if the wetting fluid would expel from the end of short capillary tubes in a low-gravity environment. He observed that although the fluid partially left the tubes, it was always pulled back by surface tension, which caused the fluid to remain pinned to the tubes' end. By exploiting tube geometry and fluid properties, we demonstrate that such capillary flows can in fact eject a variety of jets and drops. This fluid dynamics video provides a historical overview of such spontaneous capillarity-driven droplet ejection. Footage of terrestrial and low earth orbit experiments are also shown. Droplets generated in a microgravity environment are $10^6$ times larger than those ejected in a terrestrial environment. The accompanying article provides a summary of the critical parameters and experimental procedures. Scaling the governing equations ...

  14. Helium anion formation inside helium droplets

    Science.gov (United States)

    Maalouf, Elias Jabbour Al; Reitshammer, Julia; Ribar, Anita; Scheier, Paul; Denifl, Stephan

    2016-07-01

    The formation of He∗- is examined with improved electron energy resolution of about 100 meV utilizing a hemispherical electron monochromator. The work presented provides a precise determination of the three previously determined resonance peak positions that significantly contribute to the formation of He∗- inside helium nanodroplets in the energy range from 20 eV to 29.5 eV. In addition, a new feature is identified located at 27.69 ± 0.18 eV that we assign to the presence of O2 as a dopant inside the droplet. With increasing droplet size a small blue shift of the resonance positions is observed. Also for the relatively low electron currents used in the present study (i.e., 15-70 nA) a quadratic dependence of the He∗- ion yield on the electron current is observed. Contribution to the Topical Issue "Advances in Positron and Electron Scattering", edited by Paulo Limao-Vieira, Gustavo Garcia, E. Krishnakumar, James Sullivan, Hajime Tanuma and Zoran Petrovic.

  15. Accelerating Yeast Prion Biology using Droplet Microfluidics

    Science.gov (United States)

    Ung, Lloyd; Rotem, Assaf; Jarosz, Daniel; Datta, Manoshi; Lindquist, Susan; Weitz, David

    2012-02-01

    Prions are infectious proteins in a misfolded form, that can induce normal proteins to take the misfolded state. Yeast prions are relevant, as a model of human prion diseases, and interesting from an evolutionary standpoint. Prions may also be a form of epigenetic inheritance, which allow yeast to adapt to stressful conditions at rates exceeding those of random mutations and propagate that adaptation to their offspring. Encapsulation of yeast in droplet microfluidic devices enables high-throughput measurements with single cell resolution, which would not be feasible using bulk methods. Millions of populations of yeast can be screened to obtain reliable measurements of prion induction and loss rates. The population dynamics of clonal yeast, when a fraction of the cells are prion expressing, can be elucidated. Furthermore, the mechanism by which certain strains of bacteria induce yeast to express prions in the wild can be deduced. Integrating the disparate fields of prion biology and droplet microfluidics reveals a more complete picture of how prions may be more than just diseases and play a functional role in yeast.

  16. Characterization of Acoustic Droplet Vaporization Using MRI

    Science.gov (United States)

    Li, David; Allen, Steven; Hernandez-Garcia, Luis; Bull, Joseph

    2013-11-01

    Acoustic droplet vaporization (ADV) is the selective vaporization of liquid droplets to form larger gas bubbles. The ADV process is currently being researched for biomedical applications such as gas embolotherapy, drug delivery, and phase-change contrast agents. In this study an albumin encapsulated dodecafluoropentane (DDFP, CAS: 678-26-2) microdroplet suspension was vaporized using a single element focused (f/2, D = 19 mm) 3.5 MHz transducer (Panametrics A321S, Olympus, Waltham, MA). The resulting DDFP bubble clouds were imaged using both bright field microscopy and MRI (Varian 7T, Agilent Technologies Inc., Santa Clara, CA). Field distortions due to DDFP bubble generation were characterized against the bright field images as a function of acoustic power and bubble cloud size. Experimentally a direct correlation between bubble cloud dimensions generated and field distortions seen in the MRI was observed. Additionally, MR velocimetry was used to measure the flow field resulting from ADV. The field distortions due to the bubbles were further characterized by modeling Maxwell's equations using COMSOL (COMSOL Inc., Burlington, MA). The ability to characterize ADV with alternative imaging modalities may prove useful in further development of ADV based biomedical therapies.

  17. Locating the source of projectile fluid droplets

    CERN Document Server

    Varney, Christopher R

    2011-01-01

    The ballistically ill-posed projectile problem of finding source height from spattered droplets of viscous fluid is a longstanding obstacle to accident reconstruction and crime scene analysis. It is widely known how to infer the impact angle of droplets on a surface from the elongation of their impact profiles. Due to missing velocity information, however, finding the height of origin from impact position and angle of individual drops is not possible. Turning to aggregate statistics of the spatter and basic equations of projectile motion familiar to physics students, we introduce a reciprocal correlation plot that is effective when the polar angle of launch is concentrated in a narrow range. The horizontal plot coordinate is twice the reciprocal of impact distance, and the vertical coordinate depends on the orientation of the spattered surface; for a level surface this is the tangent of impact angle. In all cases one infers source height as the slope of data points in the reciprocal correlation plot. Such plo...

  18. Droplet evaporation on a soluble substrate

    Science.gov (United States)

    Mailleur, Alexandra; Pirat, Christophe; Colombani, Jean; CNES Collaboration

    2015-11-01

    Stains left by evaporated droplets are ubiquitous in everyday life as well as in industrial processes. Whatever the composition of the evaporating liquid (colloidal suspensions, biological fluids...), the stains are mostly constituted by a deposit at the periphery of the dried drop, similar to a coffee stain (Deegan, 1997). All these studies have been carried with non-reacting solids. In this presentation, we focus on the behavior of a pure-water droplet evaporating on a soluble substrate which is more complex, since three phenomena are strongly interacting: the dissolution of the substrate, the diffusion/convection of the dissolved species into the drop and the evaporation of the liquid. NaCl and KCl single crystals have been chosen for this experimental study as they are fast-dissolving solids. We have observed that the dissolution induces a pinning of the triple line from the beginning of the evaporation, leading to a decrease of the contact angle in time. At the end of the evaporation, a peripheral deposit is always formed, proof of an outward flow inside the drop (coffee-ring effect). The authors would like to thank the CNES for the financial support.

  19. Post-Tanner spreading of nematic droplets

    International Nuclear Information System (INIS)

    The quasistationary spreading of a circular liquid drop on a solid substrate typically obeys the so-called Tanner law, with the instantaneous base radius R(t) growing with time as R∼t1/10-an effect of the dominant role of capillary forces for a small-sized droplet. However, for droplets of nematic liquid crystals, a faster spreading law sets in at long times, so that R∼tα with α significantly larger than the Tanner exponent 1/10. In the framework of the thin film model (or lubrication approximation), we describe this 'acceleration' as a transition to a qualitatively different spreading regime driven by a strong substrate-liquid interaction specific to nematics (antagonistic anchoring at the interfaces). The numerical solution of the thin film equation agrees well with the available experimental data for nematics, even though the non-Newtonian rheology has yet to be taken into account. Thus we complement the theory of spreading with a post-Tanner stage, noting that the spreading process can be expected to cross over from the usual capillarity-dominated stage to a regime where the whole reservoir becomes a diffusive film in the sense of Derjaguin.

  20. Droplet migration in a Hele-Shaw cell: Effect of the lubrication film on the droplet dynamics

    Science.gov (United States)

    Ling, Yue; Fullana, Jose-Maria; Popinet, Stéphane; Josserand, Christophe

    2016-06-01

    Droplet migration in a Hele-Shaw cell is a fundamental multiphase flow problem which is crucial for many microfluidics applications. We focus on the regime at low capillary number and three-dimensional direct numerical simulations are performed to investigate the problem. In order to reduce the computational cost, an adaptive mesh is employed and high mesh resolution is only used near the interface. Parametric studies are performed on the droplet horizontal radius and the capillary number. For droplets with an horizontal radius larger than half the channel height, the droplet overfills the channel and exhibits a pancake shape. A lubrication film is formed between the droplet and the wall and particular attention is paid to the effect of the lubrication film on the droplet velocity. The computed velocity of the pancake droplet is shown to be lower than the average inflow velocity, which is in agreement with experimental measurements. The numerical results show that both the strong shear induced by the lubrication film and the three-dimensional flow structure contribute to the low mobility of the droplet. In this low-migration-velocity scenario, the interfacial flow in the droplet reference frame moves toward the rear on the top and reverses direction moving to the front from the two side edges. The velocity of the pancake droplet and the thickness of the lubrication film are observed to decrease with capillary number. The droplet velocity and its dependence on capillary number cannot be captured by the classic Hele-Shaw equations, since the depth-averaged approximation neglects the effect of the lubrication film.

  1. Absorption of impinging water droplet in porous stones.

    Science.gov (United States)

    Lee, J B; Radu, A I; Vontobel, P; Derome, D; Carmeliet, J

    2016-06-01

    This paper presents an experimental investigation and numerical analysis of the absorption of water droplets impacting porous stones. The absorption process of an impinging droplet is here fully characterized from spreading to evaporation in terms of absorbed mass during droplet depletion and moisture content distribution in a time-resolved manner for three different natural stones. High-speed imaging and neutron radiography are used to quantify moisture absorption in porous stones of varying moisture properties from deposition until depletion. During impact and spreading, the droplet exhibits a dynamic non-wetting behavior. At maximum spreading, the droplet undergoes pinning, resulting into the contact radius remaining constant until droplet depletion. Absorption undergoes two phases: initially, absorption is hindered due a contact resistance attributed to entrapped air; afterwards, a more perfect capillary contact occurs and absorption goes on until depletion, concurrently with evaporation and further redistribution. A finite-element numerical model for isothermal unsaturated moisture transport in porous media captures the phases of mass absorption in good agreement with the experimental data. Droplet spreading and absorption are highly determined by the impact velocity of the droplet, while moisture content redistribution after depletion is much less dependent on impact conditions. PMID:26975034

  2. Sorting of droplets by migration on structured surfaces

    Directory of Open Access Journals (Sweden)

    Wilfried Konrad

    2011-04-01

    Full Text Available Background: Controlled transport of microdroplets is a topic of interest for various applications. It is well known that liquid droplets move towards areas of minimum contact angle if placed on a flat solid surface exhibiting a gradient of contact angle. This effect can be utilised for droplet manipulation. In this contribution we describe how controlled droplet movement can be achieved by a surface pattern consisting of cones and funnels whose length scales are comparable to the droplet diameter.Results: The surface energy of a droplet attached to a cone in a symmetry-preserving way can be smaller than the surface energy of a freely floating droplet. If the value of the contact angle is fixed and lies within a certain interval, then droplets sitting initially on a cone can gain energy by moving to adjacent cones.Conclusion: Surfaces covered with cone-shaped protrusions or cavities may be devised for constructing “band-conveyors” for droplets. In our approach, it is essentially the surface structure which is varied, not the contact angle. It may be speculated that suitably patterned surfaces are also utilised in biological surfaces where a large variety of ornamentations and surface structuring are often observed.

  3. Induced detachment of coalescing droplets on superhydrophobic surfaces.

    Science.gov (United States)

    Farhangi, Mehran M; Graham, Percival J; Choudhury, N Roy; Dolatabadi, Ali

    2012-01-17

    Coalescence of a falling droplet with a stationary sessile droplet on a superhydrophobic surface is investigated by a combined experimental and numerical study. In the experiments, the droplet diameter, the impact velocity, and the distance between the impacting droplets were controlled. The evolution of surface shape during the coalescence of two droplets on the superhydrophobic surface is captured using high speed imaging and compared with numerical results. A two-phase volume of fluid (VOF) method is used to determine the dynamics of droplet coalescence, shape evaluation, and contact line movement. The spread length of two coalesced droplets along their original center is also predicted by the model and compared well with the experimental results. The effect of different parameters such as impact velocity, center to center distance, and droplet size on contact time and restitution coefficient are studied and compared to the experimental results. Finally, the wetting and the self-cleaning properties of superhydrophobic surfaces have been investigated. It has been found that impinging water drops with very small amount of kinetic impact energy were able to thoroughly clean these surfaces. PMID:22171956

  4. Coacervate droplets, proteinoid microspheres, and the genetic apparatus

    Science.gov (United States)

    Fox, S. W.

    1974-01-01

    Differences between typical coacervate droplets and typical proteinoid microspheres are examined. It is pointed out that coacervate droplets are produced from polymers obtained from contemporary organisms. The microspheres considered are aggregates of proteinoid formed from monomeric amino acids under geologically relevant conditions. Aspects regarding the primordial sequence are discussed along with the origin of the genetic apparatus and the genetic code.

  5. Water-in-Water Droplets by Passive Microfluidic Flow Focusing.

    Science.gov (United States)

    Moon, Byeong-Ui; Abbasi, Niki; Jones, Steven G; Hwang, Dae Kun; Tsai, Scott S H

    2016-04-01

    We present a simple microfluidic system that generates water-in-water, aqueous two phase system (ATPS) droplets, by passive flow focusing. ATPS droplet formation is achieved by applying weak hydrostatic pressures, with liquid-filled pipette tips as fluid columns at the inlets, to introduce low speed flows to the flow focusing junction. To control the size of the droplets, we systematically vary the interfacial tension and viscosity of the ATPS fluids and adjust the fluid column height at the fluid inlets. The size of the droplets scales with a power law of the ratio of viscous stresses in the two ATPS phases. Overall, we find a drop size coefficient of variation (CV; i.e., polydispersity) of about 10%. We also find that when drops form very close to the flow focusing junction, the drops have a CV of less than 1%. Our droplet generation method is easily scalable: we demonstrate a parallel system that generates droplets simultaneously and improves the droplet production rate by up to one order of magnitude. Finally, we show the potential application of our system for encapsulating cells in water-in-water emulsions by encapsulating microparticles and cells. To the best of our knowledge, our microfluidic technique is the first that forms low interfacial tension ATPS droplets without applying external perturbations. We anticipate that this simple approach will find utility in drug and cell delivery applications because of the all-biocompatible nature of the water-in-water ATPS environment.

  6. Fluid bed agglomeration with a narrow droplet size distribution

    NARCIS (Netherlands)

    Schaafsma, SH; Vonk, P; Kossen, NWF

    2000-01-01

    In the fluid bed agglomeration processes liquid distribution influences the agglomerate growth. We developed a new nozzle that produces uniform droplets, which allows droplets to be easily controlled in size independently of liquid- and airflow of the nozzle. It was found that the spray rate and the

  7. Droplet Evaporator For High-Capacity Heat Transfer

    Science.gov (United States)

    Valenzuela, Javier A.

    1993-01-01

    Proposed heat-exchange scheme boosts heat transfer per unit area. Key component is generator that fires uniform size droplets of subcooled liquid at hot plate. On impact, droplets spread out and evaporate almost instantly, removing heat from plate. In practice, many generator nozzles arrayed over evaporator plate.

  8. Some considerations about the behaviour of spray droplets

    OpenAIRE

    Fabio R Leiva

    2011-01-01

    Basic and applied features of the phenomena which determine the behaviour of spray droplets are reviewed. The physical parameters concerned with pesticide application techniques and their relationships are explained. Losses due to adverse environmental conditions and the main factors which determine both the droplet impaction and the catch efficiency on plant surfaces, are analized.

  9. Effect of Ambient Temperature and Composition on Liquid Droplet Combustion

    Directory of Open Access Journals (Sweden)

    Shah Shahood Alam

    2014-12-01

    Full Text Available An unsteady, spherically symmetric, single component, diffusion controlled gas phase droplet combustion model was developed assuming infinite kinetics and no radiation effects. Finite difference technique was used to solve time dependent equations of energy and species. Adiabatic flame temperature which is important for calculating thermodynamic properties was calculated by employing a detailed method. Effects of ambient temperature and composition on important combustion parameters like adiabatic flame temperature, droplet mass burning rate, burning constant and droplet lifetime were obtained. Results indicated that flame temperature, burning constant and mass burning rate increased with an increase in ambient temperature while the droplet life time decreased. The present gas phase code was used in conjunction with the Olikara and Borman code for obtaining concentration of important species. Emission results showed that for a 100 m n- heptane droplet burning in standard atmosphere, an increase in ambient temperature led to an increase in NO and CO concentrations and a decrease in CO2 and H2O concentrations. Extinction diameter for a 3000 m n- heptane droplet burning in oxygen-helium environment was determined. Also, effects of ambient temperature and composition were obtained on droplet lifetime and mass burning rate as a function of initial droplet diameter. The present gas phase model is simple but realistic and can be incorporated in spray combustion codes.

  10. Numerical simulation of the drying of inkjet-printed droplets

    NARCIS (Netherlands)

    Siregar, D.P.; Kuerten, J.G.M.; Geld, van der C.W.M.

    2013-01-01

    In this paper we study the behavior of an inkjet-printed droplet of a solute dissolved in a solvent on a solid horizontal surface by numerical simulation. An extended model for drying of a droplet and the final distribution of the solute on an impermeable substrate is proposed. The model extends the

  11. Analytical detection techniques for droplet microfluidics—A review

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Ying [Institute of Microanalytical Systems, Department of Chemistry, Zhejiang University, Hangzhou, 310058 (China); State Key Laboratory of Industrial Control Technology, Institute of Cyber-Systems and Control, Zhejiang University, Hangzhou, 310058 (China); Fang, Qun, E-mail: fangqun@zju.edu.cn [Institute of Microanalytical Systems, Department of Chemistry, Zhejiang University, Hangzhou, 310058 (China)

    2013-07-17

    Graphical abstract: -- Highlights: •This is the first review paper focused on the analytical techniques for droplet-based microfluidics. •We summarized the analytical methods used in droplet-based microfluidic systems. •We discussed the advantage and disadvantage of each method through its application. •We also discuss the future development direction of analytical methods for droplet-based microfluidic systems. -- Abstract: In the last decade, droplet-based microfluidics has undergone rapid progress in the fields of single-cell analysis, digital PCR, protein crystallization and high throughput screening. It has been proved to be a promising platform for performing chemical and biological experiments with ultra-small volumes (picoliter to nanoliter) and ultra-high throughput. The ability to analyze the content in droplet qualitatively and quantitatively is playing an increasing role in the development and application of droplet-based microfluidic systems. In this review, we summarized the analytical detection techniques used in droplet systems and discussed the advantage and disadvantage of each technique through its application. The analytical techniques mentioned in this paper include bright-field microscopy, fluorescence microscopy, laser induced fluorescence, Raman spectroscopy, electrochemistry, capillary electrophoresis, mass spectrometry, nuclear magnetic resonance spectroscopy, absorption detection, chemiluminescence, and sample pretreatment techniques. The importance of analytical detection techniques in enabling new applications is highlighted. We also discuss the future development direction of analytical detection techniques for droplet-based microfluidic systems.

  12. Evaluation of droplet size distributions using univariate and multivariate approaches

    DEFF Research Database (Denmark)

    Gauno, M.H.; Larsen, C.C.; Vilhelmsen, T.;

    2013-01-01

    Pharmaceutically relevant material characteristics are often analyzed based on univariate descriptors instead of utilizing the whole information available in the full distribution. One example is droplet size distribution, which is often described by the median droplet size and the width of the d...

  13. Droplet impact on superheated micro-structured surfaces

    NARCIS (Netherlands)

    Tran, A.T.; Staat, H.J.J.; Susarrey-Arce, A.; Foertsch, T.C.; Houselt, van A.; Gardeniers, J.G.E.; Prosperetti, A.; Lohse, D.; Sun, C.

    2013-01-01

    When a droplet impacts upon a surface heated above the liquid's boiling point, the droplet either comes into contact with the surface and boils immediately (contact boiling), or is supported by a developing vapor layer and bounces back (film boiling, or Leidenfrost state). We study the transition be

  14. Drying of liquid food droplets. Enzyme inactivation and multicomponent diffusion.

    NARCIS (Netherlands)

    Meerdink, G.

    1993-01-01

    In this thesis the drying of liquid food droplets is studied from three different points of view: drying kinetics, enzyme inactivation and multicomponent diffusion. Mathematical models are developed and validated experimentally.Drying experiments are performed with suspended droplets and with free f

  15. Rheological properties of soybean protein isolate gels containing emulsion droplets

    NARCIS (Netherlands)

    Kim, K.H.; Renkema, J.M.S.; Vliet, van T.

    2001-01-01

    Rheological properties of soybean protein gels containing various volume fractions oil droplets have been studied at small and large deformations. Dynamic viscoelastic properties of soybean protein isolate gels were determined as a function of the volume fraction of oil droplets stabilised by the sa

  16. Droplet Undercooling During Containerless Processing in a Drop Tube

    Institute of Scientific and Technical Information of China (English)

    WANG Nan; WEI Bing-Bo

    2004-01-01

    @@ The droplet undercooling prior to crystallization during containerless processing in a drop tube is calculated on the basis of nucleation theory and processing parameters. The influences of droplet size, wetting angle, and cooling rate on undercooling are also evaluated under the situation of heterogeneous nucleation. An experimental study of containerless solidification is performed on Ag28.1 Cu41.4 Ge30.5 ternary alloy in comparison with the theoretical analysis. It is revealed that, in the case of heterogeneous catalysis, the droplet size is only an ostensible parameter to influence undercooling, whereas the wetting angle is the essentially dominating factor. The different cooling rates in such a case also have an effect on droplet undercooling, but this effect is not significant. The calculated results will agree well with the experimental data if the inverse relationship between wetting angle and droplet size is given.

  17. Modelling of heating and evaporation of n-Heptane droplets

    DEFF Research Database (Denmark)

    Yin, Chungen

    2015-01-01

    This study is a part of a project that is targeted to optimize the pyrolysis process of biomass pellets for bio-oil production and to develop new technology to upgrade the bio-oil for use in transportation. Among others, study of pyrolysis of the biomass pellets and evaporation of the pyrolysis bio......-oil droplets are two key tasks. This paper presents an effort towards a generic model that is beneficial to both the tasks. A computer code for droplet heating and evaporation is developed in a generic 3D model framework. The droplets are discretized into a number of control volumes along the radial, polar...... and azimuthal directions, respectively, on each of which the flow, heat and mass transfer are numerically solved using the finite volume method. During the transient heating and evaporation process, the interaction between the moving droplets and free-stream flow are properly considered. Droplet dynamics...

  18. An interfacial mechanism for cloud droplet formation on organic aerosols.

    Science.gov (United States)

    Ruehl, Christopher R; Davies, James F; Wilson, Kevin R

    2016-03-25

    Accurate predictions of aerosol/cloud interactions require simple, physically accurate parameterizations of the cloud condensation nuclei (CCN) activity of aerosols. Current models assume that organic aerosol species contribute to CCN activity by lowering water activity. We measured droplet diameters at the point of CCN activation for particles composed of dicarboxylic acids or secondary organic aerosol and ammonium sulfate. Droplet activation diameters were 40 to 60% larger than predicted if the organic was assumed to be dissolved within the bulk droplet, suggesting that a new mechanism is needed to explain cloud droplet formation. A compressed film model explains how surface tension depression by interfacial organic molecules can alter the relationship between water vapor supersaturation and droplet size (i.e., the Köhler curve), leading to the larger diameters observed at activation. PMID:27013731

  19. Flow invariant droplet formation for stable parallel microreactors

    Science.gov (United States)

    Riche, Carson T.; Roberts, Emily J.; Gupta, Malancha; Brutchey, Richard L.; Malmstadt, Noah

    2016-01-01

    The translation of batch chemistries onto continuous flow platforms requires addressing the issues of consistent fluidic behaviour, channel fouling and high-throughput processing. Droplet microfluidic technologies reduce channel fouling and provide an improved level of control over heat and mass transfer to control reaction kinetics. However, in conventional geometries, the droplet size is sensitive to changes in flow rates. Here we report a three-dimensional droplet generating device that exhibits flow invariant behaviour and is robust to fluctuations in flow rate. In addition, the droplet generator is capable of producing droplet volumes spanning four orders of magnitude. We apply this device in a parallel network to synthesize platinum nanoparticles using an ionic liquid solvent, demonstrate reproducible synthesis after recycling the ionic liquid, and double the reaction yield compared with an analogous batch synthesis. PMID:26902825

  20. Synchronous droplets as a test bed for pulsatory active fluids

    Science.gov (United States)

    Katsikis, Georgios; Prakash, Manu

    2014-11-01

    Collective behavior in many-body systems has been studied extensively focusing on a wide range of interacting entities including: flocking animals, sedimenting particles and microfluidic droplets among others. Here, we propose an experimental platform to explore an oscillatory active fluid with synchronous ferrofluid droplets immersed in an immiscible carrier fluid in a Hele-Shaw configuration. The droplets are organized and actuated on a 2-D uniform grid through application of a precessive magnetic field. The state of our system is dependent on three parameters: the grid occupancy with fluid droplets, the grid geometry and the magnetic field. We study the long range orientational order of our system over a range of those parameters by tracking the motion of the droplets and analyzing the PIV data of the carrier fluid flow. Numerical simulations are juxtaposed with experimental data for prediction of the system's behavior.

  1. Probing droplets on superhydrophobic surfaces by synchrotron radiation scattering techniques

    KAUST Repository

    Accardo, Angelo

    2014-06-10

    Droplets on artificially structured superhydrophobic surfaces represent quasi contact-free sample environments which can be probed by X-ray microbeams and nanobeams in the absence of obstructing walls. This review will discuss basic surface wettability concepts and introduce the technology of structuring surfaces. Quasi contact-free droplets are compared with contact-free droplets; processes related to deposition and evaporation on solid surfaces are discussed. Droplet coalescence based on the electrowetting effect allows the probing of short-time mixing and reaction processes. The review will show for several materials of biological interest that structural processes related to conformational changes, nucleation and assembly during droplet evaporation can be spatially and temporally resolved by raster-scan diffraction techniques. Orientational ordering of anisotropic materials deposited during solidification at pinning sites facilitates the interpretation of structural data. 2014 International Union of Crystallography.

  2. Experimental investigation of flash pyrolysis oil droplet combustion

    DEFF Research Database (Denmark)

    Ibrahim, Norazana; Jensen, Peter A.; Dam-Johansen, Kim;

    2013-01-01

    The aim of this work is to investigate and compare the combustion behaviour of a single droplet of pyrolysis oil derived from wheat straw and heavy fossil oil in a single droplet combustion chamber. The initial oil droplet diameters were in between 500 μm to 2500 μm. The experiments were performed...... at a temperature ranging between 1000 and 1400°C with an initial gas velocity of 1.6 m/s and oxygen concentration of 3%. The evolution of combustion of bio-oil droplets was recorded by a digital video camera. It was observed that the combustion behaviour of pyrolysis oil droplet differ from the heavy oil in terms...... both of ignition, devolatilisation and char oxidation. The pyrolysis oil is more difficult to ignite and has a shorter devolatilisation time and a longer char oxidation time. Copyright © 2013, AIDIC Servizi S.r.l....

  3. A microfluidic abacus channel for controlling the addition of droplets.

    Science.gov (United States)

    Um, Eujin; Park, Je-Kyun

    2009-01-21

    This paper reports the first use of the abacus-groove structure to handle droplets in a wide microchannel, with no external forces integrated to the system other than the pumps. Microfluidic abacus channels are demonstrated for the sequential addition of droplets at the desired location. A control channel which is analogous to biasing in electronics can also be used to precisely determine the number of added droplets, when all other experimental conditions are fixed including the size of the droplets and the frequency of droplet-generation. The device allows programmable and autonomous operations of complex two-phase microfluidics as well as new applications for the method of analysis and computations in lab-on-a-chip devices.

  4. Ecotoxicity assessment using ciliate cells in millifluidic droplets.

    Science.gov (United States)

    Illing, Rico; Burkart, Corinna; Pfitzner, Daniel; Jungmann, Dirk; Baraban, Larysa; Cuniberti, Gianaurelio

    2016-03-01

    Precise analysis of the aquatic cells and their responses to the toxic chemicals, i.e., water disinfective agents, is of crucial importance due to their role in the ecosystem. We demonstrate the application of the droplets based millifluidic tool for isolating and longtime monitoring of single Paramecium tetraurelia cells using a large number of water-in-oil emulsion droplets. Due to the automated monitoring of the fluorescence signal, the droplets containing cells are distinguished from the empty reservoirs. A viability indicator is used to follow the metabolic dynamic of the cells in every single droplet. Finally, we perform ecotoxicity tests in droplets, exposing the encapsulated paramecia cells to silver nitrate for determination of EC50 levels, and compare the output with the conventional microtiter plate assay. PMID:27051472

  5. Condensation and jumping relay of droplets on lotus leaf

    CERN Document Server

    Lv, Cunjing; Yao, Zhaohui; Song, Yu; Zhang, Xiwen; He, Feng

    2013-01-01

    Dynamic behavior of micro water droplet condensed on a lotus leaf with two-tier roughness is studied. Under laboratory environment, the contact angle of the micro droplet on single micro papilla increases smoothly from 80 deg to 160 deg during the growth of condensed water. The best-known "self-clean" phenomenon, will be lost. A striking observation is the out-of-plane jumping relay of condensed droplets triggered by falling droplets, as well as its sustained speed obtained in continuous jumping relays, enhance the automatic removal of dropwise condensation without the help from any external force. The surface tension energy dissipation is the main reason controlling the critical size of jumping droplet and its onset velocity of rebounding.

  6. Condensation and jumping relay of droplets on lotus leaf

    Science.gov (United States)

    Lv, Cunjing; Hao, Pengfei; Yao, Zhaohui; Song, Yu; Zhang, Xiwen; He, Feng

    2013-07-01

    Dynamic behavior of micro water droplet condensed on a lotus leaf with two-tier roughness is studied. Under laboratory environment, the contact angle of the micro droplet on single micro papilla increases smoothly from 80° to 160° during the growth of condensed water. The best-known "self-cleaning" phenomenon will be lost. A striking observation is the out-of-plane jumping relay of condensed droplets triggered by falling droplets, as well as its sustained speed obtained in continuous jumping relays. The underlying mechanism can be used to enhance the automatic removal of dropwise condensation without the help from any external force. The surface tension energy dissipation is the main reason controlling the critical size of jumping droplet and its onset velocity of rebounding.

  7. Communication: Electron diffraction of ferrocene in superfluid helium droplets.

    Science.gov (United States)

    Zhang, Jie; He, Yunteng; Kong, Wei

    2016-06-14

    We report electron diffraction of ferrocene doped in superfluid helium droplets. By taking advantage of the velocity slip in our pulsed droplet beam using a pulsed electron gun, and by doping with a high concentration of ferrocene delivered via a pulsed valve, we can obtain high quality diffraction images from singly doped droplets. Under the optimal doping conditions, 80% of the droplets sampled in the electron beam are doped with just one ferrocene molecule. Extension of this size selection method to dopant clusters has also been demonstrated. However, incomplete separation of dopant clusters might require deconvolution and modeling of the doping process. This method can be used for studies of nucleation processes in superfluid helium droplets. PMID:27305988

  8. A dynamic model of droplet formation in GMA welding

    International Nuclear Information System (INIS)

    A comparative analysis of different approaches is carried out, which mathematically describes the metal droplet formation process in an electrode during gas metal arc (GMA) welding. It was shown that a hydrostatical model of the droplet's free surface could not correctly describe the formation and transfer of electrode metal droplets. The complete hydrodynamic model, which uses the whole system of Navier–Stokes equations, requires significant computer resources for numerical realization. This limits its application to small computational experiments. As an alternative for this model, the approximate hydrodynamic model adapted to GMA welding conditions is considered. It is shown that this model allows the prediction of droplet geometry right up to its detachment. The influence of the welding current and magnetic pressure on the droplet size and detachment frequency is studied. (paper)

  9. Bioreactor droplets from liposome-stabilized all-aqueous emulsions

    Science.gov (United States)

    Dewey, Daniel C.; Strulson, Christopher A.; Cacace, David N.; Bevilacqua, Philip C.; Keating, Christine D.

    2014-08-01

    Artificial bioreactors are desirable for in vitro biochemical studies and as protocells. A key challenge is maintaining a favourable internal environment while allowing substrate entry and product departure. We show that semipermeable, size-controlled bioreactors with aqueous, macromolecularly crowded interiors can be assembled by liposome stabilization of an all-aqueous emulsion. Dextran-rich aqueous droplets are dispersed in a continuous polyethylene glycol (PEG)-rich aqueous phase, with coalescence inhibited by adsorbed ~130-nm diameter liposomes. Fluorescence recovery after photobleaching and dynamic light scattering data indicate that the liposomes, which are PEGylated and negatively charged, remain intact at the interface for extended time. Inter-droplet repulsion provides electrostatic stabilization of the emulsion, with droplet coalescence prevented even for submonolayer interfacial coatings. RNA and DNA can enter and exit aqueous droplets by diffusion, with final concentrations dictated by partitioning. The capacity to serve as microscale bioreactors is established by demonstrating a ribozyme cleavage reaction within the liposome-coated droplets.

  10. Francois Frenkiel Award Lecture: Thermocapillary migration of interfacial droplets

    Science.gov (United States)

    Greco, Edwin F.

    2010-11-01

    Thermocapillary migration of bubbles through the bulk liquid--a process in which tangential surface stresses arising from the variation of surface tension with temperature create a propulsive force on the bubble--has been extensively studied in the past. In contrast, the motion of droplets confined to the free surface of a liquid substrate has received much less attention. Recent developments in microfluidics provided new motivation to understand how applied thermal gradients can affect the motion of, and mixing inside, small aqueous droplets. In particular, the quality and speed of mixing depend rather sensitively on the flow structure inside the droplet. In this talk we describe different approaches that allow one to compute both the flow inside interfacial droplets and the flow in the layer of liquid substrate supporting the droplet and the lessons which can be learned by analyzing these flows.

  11. Droplet detachment by air flow for microstructured superhydrophobic surfaces.

    Science.gov (United States)

    Hao, Pengfei; Lv, Cunjing; Yao, Zhaohui

    2013-04-30

    Quantitative correlation between critical air velocity and roughness of microstructured surface has still not been established systematically until the present; the dynamics of water droplet detachment by air flow from micropillar-like superhydrophobic surfaces is investigated by combining experiments and simulation comparisons. Experimental evidence demonstrates that the onset of water droplet detachment from horizontal micropillar-like superhydrophobic surfaces under air flow always starts with detachment of the rear contact lines of the droplets from the pillar tops, which exhibits a similar dynamic mechanism for water droplet motion under a gravity field. On the basis of theoretical analysis and numerical simulation, an explicit analytical model is proposed for investigating the detaching mechanism, in which the critical air velocity can be fully determined by several intrinsic parameters: water-solid interface area fraction, droplet volume, and Young's contact angle. This model gives predictions of the critical detachment velocity of air flow that agree well with the experimental measurements.

  12. Study on undercooling of metal droplet in rapid solidification

    Institute of Scientific and Technical Information of China (English)

    GAO Yulai; GUAN Wanbing; ZHAI Qijie; XU Kuangdi

    2005-01-01

    A mathematical model for the undercooling of the metal droplet during the rapid solidification is established, by which the factors that influence the undercooling of the metal droplet during the rapid solidification are analyzed, and the parameter ζ=σSL3/ (TLΔH 2 ) is defined as the impact factor of the undercooling for the droplet solidification. Different undercoolings of droplets induced by various rapid solidification conditions are mainly ascribed to the change of the impact factor. Moreover, it is shown that the larger of ζ, the higher the relative undercooling can be gained. Meanwhile, the parameters such as solid-liquid interfacial energy σSL and latent heat of solidification ΔH also vary with the rapid solidification conditions of droplets.

  13. Direct contact droplet heat exchangers for thermal management in space

    Science.gov (United States)

    Bruckner, A. P.; Hertzberg, A.

    1982-01-01

    A liquid droplet heat exchanger for space applications is described which transfers heat between a gas and a liquid metal dispersed into droplets. The ability of the droplet heat exchanger to transfer heat between two media in direct contact over a wide temperature range circumvents many of the material limitations of conventional tube-type heat exchangers and does away with complicated plumbing systems and their tendency toward single point failure. Droplet heat exchangers offer large surface to volume ratios in a compact geometry, very low gas pressure drop, and high effectiveness. The application of the droplet heat exchanger in a high temperature Brayton cycle is discussed to illustrate its performance and operational characteristics.

  14. Director Field in a Bipolar Configured Nematic Droplet

    Institute of Scientific and Technical Information of China (English)

    HUANG Zi-qiang; YANG Wen-jun; ZHOU Xiao-jun

    2004-01-01

    Director field in a bipolar configured nematic droplet is analyzed numerically. Results of the calculation are expressed as the tilted angle of the director in the droplet, which balance between torque by elastic energy and the torque by external electrical field. The tilted angle is expressed as the function depending on latitude angle and relative radius r / R in the spherical droplet. The result shows that the maximum difference of the tilted angle happens at 0.87R, where the tilted angle varies 12℃before applying external field (0 V/μm.) and after applying electrical field (0.62 V/μm). If nematic droplet would be applied as a micro lens, its focus would vary because the refractive index changes due to the change of tilted angle. According to the calculation, maximum modification of refractive index is 0.036, if E7 would be adapted as the nematic phase in the droplet.

  15. Communication: Electron diffraction of ferrocene in superfluid helium droplets

    Science.gov (United States)

    Zhang, Jie; He, Yunteng; Kong, Wei

    2016-06-01

    We report electron diffraction of ferrocene doped in superfluid helium droplets. By taking advantage of the velocity slip in our pulsed droplet beam using a pulsed electron gun, and by doping with a high concentration of ferrocene delivered via a pulsed valve, we can obtain high quality diffraction images from singly doped droplets. Under the optimal doping conditions, 80% of the droplets sampled in the electron beam are doped with just one ferrocene molecule. Extension of this size selection method to dopant clusters has also been demonstrated. However, incomplete separation of dopant clusters might require deconvolution and modeling of the doping process. This method can be used for studies of nucleation processes in superfluid helium droplets.

  16. Microfluidic actuation of insulating liquid droplets in a parallel-plate device

    International Nuclear Information System (INIS)

    In droplet-based microfluidics, the simultaneous movement and manipulation of dielectric and aqueous droplets on a single platform is important. The actuation forces on both dielectric and aqueous droplets can be calculated with an electromechanical model using an equivalent RC circuit. This model predicts that dielectric droplet actuation can be made compatible with electrowetting-based water droplet manipulation if the oil droplet is immersed in water. Operations such as transporting, splitting, merging, and dispensing of dielectric droplets at voltages less than 100 V are demonstrated in a parallel-plate structure. Such capability opens the way to fully automated assembly line formation of single-emulsion droplets.

  17. Numerical simulation of droplet dynamics using level set method

    Energy Technology Data Exchange (ETDEWEB)

    Tadashi Watanabe [Research and Development Group for Numerical Experiment, Japan Atomic Energy Research Institute Tokai-mura, Naka-gun, Ibaraki-ken, 319-1195 (Japan)

    2005-07-01

    Full text of publication follows: A levitated liquid droplet is used to measure the properties of molten metal at high temperature. Viscosity is, for instance, obtained from the damping of an oscillation of the droplet. The levitation of droplets is controlled by using electrostatic force or ultrasonic wave under the gravitational condition. The droplet is not in contact with a container, and the effect of the container wall is eliminated for a detailed measurement. Small disturbances such as an initial deformation or rotation, which can not be neglected completely in the measurement, however, still have a large effect on the measurement, since the relation between the properties and the oscillation parameters is given by the linear theory. In order to study the effect of initial disturbances and nonlinearity of the droplet dynamics on the measurement, numerical simulations of a liquid droplet are performed. Three-dimensional Navier- Stokes equations are solved using the level set method. The level set function, which is the distance from the droplet surface, is calculated by solving the transport equation to obtain the position of the surface. Mass conservation of the droplet is especially taken into account in the calculation of the level set function. The staggered mesh system is used and the second-order upwind differencing scheme is applied for convective terms. The second-order Adams-Bashforth method is used for time integration. Differences between two-dimensional and three-dimensional calculations are shown first, and it is found that the two-dimensional calculation is not suitable for simulating the droplet dynamics. The nonlinearity effect is studied next. The oscillation of the droplet is simulated by changing the amplitude of the initial deformation, which is given by the Legendre polynomial. The period and the damping of the oscillation are obtained, and the effect of the amplitude on the measurement of surface tension and viscosity is discussed. The

  18. Lipid droplets as ubiquitous fat storage organelles in C. elegans

    Directory of Open Access Journals (Sweden)

    Guo Fengli

    2010-12-01

    Full Text Available Abstract Background Lipid droplets are a class of eukaryotic cell organelles for storage of neutral fat such as triacylglycerol (TAG and cholesterol ester (CE. We and others have recently reported that lysosome-related organelles (LROs are not fat storage structures in the nematode C. elegans. We also reported the formation of enlarged lipid droplets in a class of peroxisomal fatty acid β-oxidation mutants. In the present study, we seek to provide further evidence on the organelle nature and biophysical properties of fat storage structures in wild-type and mutant C. elegans. Results In this study, we provide biochemical, histological and ultrastructural evidence of lipid droplets in wild-type and mutant C. elegans that lack lysosome related organelles (LROs. The formation of lipid droplets and the targeting of BODIPY fatty acid analogs to lipid droplets in live animals are not dependent on lysosomal trafficking or peroxisome dysfunction. However, the targeting of Nile Red to lipid droplets in live animals occurs only in mutants with defective peroxisomes. Nile Red labelled-lipid droplets are characterized by a fluorescence emission spectrum distinct from that of Nile Red labelled-LROs. Moreover, we show that the recently developed post-fix Nile Red staining method labels lipid droplets exclusively. Conclusions Our results demonstrate lipid droplets as ubiquitous fat storage organelles and provide a unified explanation for previous studies on fat labelling methods in C. elegans. These results have important applications to the studies of fat storage and lipid droplet regulation in the powerful genetic system, C. elegans.

  19. Droplet Number Concentration Value-Added Product

    Energy Technology Data Exchange (ETDEWEB)

    Riihimaki, L. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); McFarlane, S. [DOE ARM Climate Research Facility, Washington, DC (United States); Sivaraman, C. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2014-06-01

    The ndrop_mfrsr value-added product (VAP) provides an estimate of the cloud droplet number concentration of overcast water clouds retrieved from cloud optical depth from the multi-filter rotating shadowband radiometer (MFRSR) instrument and liquid water path (LWP) retrieved from the microwave radiometer (MWR). When cloud layer information is available from vertically pointing lidar and radars in the Active Remote Sensing of Clouds (ARSCL) product, the VAP also provides estimates of the adiabatic LWP and an adiabatic parameter (beta) that indicates how divergent the LWP is from the adiabatic case. quality control (QC) flags (qc_drop_number_conc), an uncertainty estimate (drop_number_conc_toterr), and a cloud layer type flag (cloud_base_type) are useful indicators of the quality and accuracy of any given value of the retrieval. Examples of these major input and output variables are given in sample plots in section 6.0.

  20. Droplet Splashing by a Slingshot Mechanism

    KAUST Repository

    Thoroddsen, Sigurdur T.

    2011-01-18

    When a drop impacts onto a liquid pool, it ejects a thin horizontal sheet of liquid, which emerges from the neck region connecting the two liquid masses. The leading section of this ejecta bends down to meet the pool liquid. When the sheet touches the pool, at an “elbow,” it ruptures and sends off microdroplets by a slingshot mechanism, driven by surface tension. High-speed imaging of the splashing droplets suggests the liquid sheet is of submicron thickness, as thin as 300 nm. Experiments in partial vacuum show that air resistance plays the primary role in bending the sheet. We identify a parameter regime where this slingshot occurs and also present a simple model for the sheet evolution, capable of reproducing the overall shape.

  1. Evolution of a detonation wave in a cloud of fuel droplets. II - Influence of fuel droplets

    Science.gov (United States)

    Burcat, A.; Eidelman, S.

    1980-10-01

    This is the second part of an investigation in which the whole problem of energy release in a combustible spray-gas mixture is solved. The influence of the droplet size of the spray on the parameters of the shock waves traveling in the media are delineated. The investigation was able to reveal the mechanism of shock wave reinforcement and to show the source of dynamic instabilities encountered with two-phase detonation processes.

  2. Fsp27 promotes lipid droplet growth by lipid exchange and transfer at lipid droplet contact sites

    OpenAIRE

    Gong, Jingyi; Sun, Zhiqi; Wu, Lizhen; Xu, Wenyi; Schieber, Nicole; Xu, Dijin; Shui, Guanghou; Yang, Hongyuan; Parton, Robert G.; Li, Peng

    2011-01-01

    Lipid droplets (LDs) are dynamic cellular organelles that control many biological processes. However, molecular components determining LD growth are poorly understood. Genetic analysis has indicated that Fsp27, an LD-associated protein, is important in controlling LD size and lipid storage in adipocytes. In this paper, we demonstrate that Fsp27 is focally enriched at the LD–LD contacting site (LDCS). Photobleaching revealed the occurrence of lipid exchange between contacted LDs in wild-type a...

  3. Droplet impact on deep liquid pools: Rayleigh jet to formation of secondary droplets

    Science.gov (United States)

    Castillo-Orozco, Eduardo; Davanlou, Ashkan; Choudhury, Pretam K.; Kumar, Ranganathan

    2015-11-01

    The impact of droplets on a deep pool has applications in cleaning up oil spills, spray cooling, painting, inkjet printing, and forensic analysis, relying on the changes in properties such as viscosity, interfacial tension, and density. Despite the exhaustive research on different aspects of droplet impact, it is not clear how liquid properties can affect the instabilities leading to Rayleigh jet breakup and number of daughter drops formed after its pinch-off. In this article, through systematic experiments we investigate the droplet impact phenomena by varying viscosity and surface tension of liquids as well as impact speeds. Further, using numerical simulations, we show that Rayleigh-Plateau instability is influenced by these parameters, and capillary time scale is the appropriate scale to normalize the breakup time. Based on Ohnesorge number (Oh) and impact Weber number (We), a regime map for no breakup, Rayleigh jet breakup, and crown splash is suggested. Interestingly, crown splash is observed to occur at all Ohnesorge numbers; however, at high Oh, a large portion of kinetic energy is dissipated, and thus the Rayleigh jet is suppressed regardless of high impact velocity. The normalized required time for the Rayleigh jet to reach its peak varies linearly with the critical height of the jet.

  4. Heat transfer analysis of atomized droplets during high velocity arc spraying

    Institute of Scientific and Technical Information of China (English)

    ZHU Zi-xin; LIU Yan; CHEN Yong-xiong; XU Bin-shi; ZHANG Wei

    2004-01-01

    The heat transfer problem of the atomized droplets during high velocity arc spraying (HVAS) was modeled and solved by a numerical method using a Fe-Al alloy, and the influences of several important process parameters on the heat transfer behaviors of the atomized droplets were analyzed. The results show that the initial cooling rates of different size droplets range from 105 to 107 K/s, thus producing the coating microstructure with the features of rapid solidification. The droplet size, atomization gas pressure and droplet superheat have great influences on the heat transfer behavior of the droplet. The droplet temperature and cooling rate are much sensitive to the droplet sizes, but insensitive to the atomization gas pressure and droplet superheat. It can be predicted that the properties of HVAS coatings will be improved by decreasing droplet size as well as increasing atomization gas pressure and droplet superheat in certain extents.

  5. The evaporation behavior of sessile droplets from aqueous saline solutions.

    Science.gov (United States)

    Soulié, Virginie; Karpitschka, Stefan; Lequien, Florence; Prené, Philippe; Zemb, Thomas; Moehwald, Helmuth; Riegler, Hans

    2015-09-14

    Quantitative experiments on the evaporation from sessile droplets of aqueous saline (NaCl) solutions show a strong dependence on salt concentration and droplet shape. The experiments were performed with seven decades of initial NaCl concentrations, with various droplet sizes and with different contact angles. The evaporation rate is significantly lower for high salt concentrations and small contact angles than what is expected from the well-accepted diffusion-controlled evaporation scenario for sessile droplets, even if the change of the vapor pressure due to the salt is taken into account. Particle tracking velocimetry reveals that this modification of the evaporation behavior is caused by marangoni flows that are induced by surface tension gradients originating from the local evaporative peripheral salt enrichment. In addition it is found that already very low salt concentrations lead to a pinning of the three phase contact line. Whereas droplets with concentration ≥10(-6) M NaCl are pinned as soon as evaporation starts, droplets with lower salt concentration do evaporate in a constant contact angle mode. Aside from new, fundamental insights the findings are also relevant for a better understanding of the widespread phenomenon of corrosion initiated by sessile droplets.

  6. Study of droplet spray impact on a photomask surface

    Science.gov (United States)

    Singh, SherJang; Dietze, Uwe; Dress, Peter

    2012-11-01

    To overcome the challenge of particle removal without pattern damage, it is important to control and optimize the physical force impact into a narrow energy distribution regime. This can be achieved by gaining in-depth knowledge into the fundamentals of physical cleaning methods as well as the process parameters affecting the performance of these systems. Droplet Spray is considered to be a gentle physical force technique. The droplet size and droplet velocity defines the kinetic energy of a droplet which transfers momentum and pressure onto the substrate surface resulting into particle removal or pattern damage. Droplet pressure is directly influenced by gas and liquid flow rate as well as nozzle design (orifice size, etc.) and process parameters like nozzle distance and scan speed across the substrate surface. In this paper, effect of process and hardware parameters on droplet pressure transfer are presented and related to kinetic energy and momentum as calculated from droplet velocity and size. Effect of these process parameters is also studied on pattern damage and particle removal efficiency. Distance, nozzle hardware, gas and liquid flow rate are found to be independent process parameters which show specific effects on nozzle performance; therefore they all are optimized individually.

  7. Droplet migration in emulsion systems measured using MR methods.

    Science.gov (United States)

    Hollingsworth, K G; Johns, M L

    2006-04-15

    The migration of emulsion droplets under shear flow remains a largely unexplored area of study, despite the existence of an extensive literature on the analogous problem of solid particle migration. A novel methodology is presented to track the shear-induced migration of emulsion droplets based on magnetic resonance imaging (MRI). The work is in three parts: first, single droplets of one Newtonian fluid are suspended in a second Newtonian fluid (water in silicone oil (PDMS)) and are tracked as they migrate within a Couette cell; second, the migration of emulsion droplets in Poiseuille flow is considered; third, water-in-silicone oil emulsions are sheared in a Couette cell. The effect of (a) rotational speed of the Couette, (b) the continuous phase viscosity, and (c) the droplet phase concentration are considered. The equilibrium extent of migration and rate of migration increase with rotational speed for two different emulsion systems and increased continuous phase viscosity, leads to a greater equilibrium extent of migration. The relationship between the droplet phase concentration and migration is however complex. These results for semi-concentrated emulsion systems and wide-gap Couette cells are not well described by existing models of emulsion droplet migration. PMID:16257005

  8. Droplet formation under the effect of a flexible nozzle plate.

    Science.gov (United States)

    Sangplung, S; Liburdy, J A

    2009-09-01

    Droplet formation from a flexible nozzle plate driven by a prescribed-waveform excitation of a piezoelectric is numerically investigated using a computational fluid dynamics (CFD) model with the volume of fluid (VOF) method. The droplet generator with a flexible nozzle plate, which is free to vibrate due to the pressure acting on the plate, is modeled in a CFD computational domain. The CFD analysis includes the fluid-structure interaction between fluid and a flexible plate using large deflection theory. The problem is characterized by the nondimensional variables based on the capillary parameters of time, velocity, and pressure. The CFD model is validated with the experiment results. This study examines the characteristics of the applied waveforms and nozzle plate material properties to change the vibrational characteristics of the nozzle plate. The effect of fluid properties on the droplet formation process is also investigated focusing on surface tension and viscous forces. Increasing the impulse of the piezoelectric can be used to cause a higher droplet velocity and it is shown that the vibration of the nozzle plate has a strong effect on the droplet velocity, shape, and volume. Surface tension has a strong influence on the droplet formation characteristics in contrast to viscous forces. For the combination of a fluid with high surface tension and the most flexible nozzle plate, this system cannot cause the droplet ejected out of the nozzle. PMID:19501837

  9. Flow reversing in the gas layer in droplet impact

    Science.gov (United States)

    Jian, Zhen; Ray, Pascal; Josserand, Christophe; Zaleski, Stephane

    2015-03-01

    Recent numerical and experimental studies demonstrated the crucial role of surrounding gas in droplet impact. Whereas, the mechanism of gas effect in droplet splashing is still far from a crystal clear comprehension. Complicated dynamics occur in a small temporal and spatial scale before direct contact with the target surface, which are related to the origin of the splashing. Direct numerical simulations were executed with a code called Gerris for both droplet impact on a liquid surface and on a solid subtract. New dynamics in the gas layer between the droplet and the target surface were discovered. Unexpectedly, a``reversing'' gas flow (towards the center) is observed as the droplet approaches the target surface. With further descending of the droplet, the flow is reversed and evacuates towards the outside. The reversing of the flow motion direction is followed by the pressure jump and the dimple formation which have been reported as some crucial gas dynamics in droplet splashing mechanism in our previous work. An aerodynamic mechanism is proposed for the flow reversing dynamics.

  10. Numerical simulation of the drying of inkjet-printed droplets.

    Science.gov (United States)

    Siregar, D P; Kuerten, J G M; van der Geld, C W M

    2013-02-15

    In this paper we study the behavior of an inkjet-printed droplet of a solute dissolved in a solvent on a solid horizontal surface by numerical simulation. An extended model for drying of a droplet and the final distribution of the solute on an impermeable substrate is proposed. The model extends the work by Deegan, Fischer and Kuerten by taking into account convection, diffusion and adsorption of the solute in order to describe more accurately the surface coverage on the substrate. A spherically shaped droplet is considered such that the model can be formulated as an axially symmetric problem. The droplet dynamics is driven by the combined action of surface tension and evaporation. The fluid flow in the droplet is modeled by the Navier-Stokes equation and the continuity equation, where the lubrication approximation is applied. The rate of evaporation is determined by the distribution of vapor pressure in the air surrounding the droplet. Numerical results are compared with experimental results for droplets of various sizes. PMID:23137908

  11. Excitation and dynamics of liquid tin micrometer droplet generation

    Science.gov (United States)

    Rollinger, B.; Abhari, R. S.

    2016-07-01

    The dynamics of capillary breakup-based droplet generation are studied for an excitation system based on a tunable piezoelectrically actuated oscillating piston, which generates acoustic pressure waves at the dispenser nozzle. First, the non-ideal pressure boundary conditions of droplet breakup are measured using a fast response pressure probe. A structural analysis shows that the axial modes of the excitation system are the main reasons for the resonance peaks in the pressure response. Second, a correlation between the nozzle inlet pressure and the droplet timing jitter is established with the help of experiments and a droplet formation model. With decreasing wave number, the growth rate of the main excitation decreases, while noise contributions with wave numbers with higher growth rates lead to a non-deterministic structure of the droplet train. A highly coherent and monodisperse droplet stream is obtained when the excitation system is tuned to generate high acoustic pressures at the desired operation frequency and when the noise level on the jet is limited. The jet velocity, hence droplet spacing for a set frequency is then adjusted by varying the reservoir pressure, according to the trade-off between lowest wave number and acceptable timing jitter.

  12. Liquid droplet movement on horizontal surface with gradient surface energy

    Institute of Scientific and Technical Information of China (English)

    LIAO Qiang; WANG Hong; ZHU Xun; LI Mingwei

    2006-01-01

    A surface with gradient surface energy was fabricated on a silicon wafer by using the chemical vapor deposition (CVD) technology with the dodecyltrichlorosilane (C12H25Cl3Si) vapor which was adsorbed chemically on the surface of the silicon wafer to form a self-assemble monolayer (ASM) and thus a gradient profile of wettability. The microscopic contours of the gradient surface were measured with Seiko SPA400 atom force microscope (AFM). And the surface wettability profile was characterized by the sessile drop method, measuring the contact angle of fine water droplets that lay on the gradient surface, to represent the distribution of the surface energy on the surface. Using a high-speed video imaging system, the motion of water droplet on the horizontal gradient surface was visualized and the transient velocity was measured under ambient condition. The experimental results show that the liquid droplets can be driven to move from hydrophobic side to hydrophilic side on the horizontal gradient surface and the velocity of droplet can reach up to 40 mm/s. In addition, the motion of the water droplet can be generally divided into two stages: an acceleration stage and a deceleration stage. The droplet presents a squirming movement on the surface with a lower peak velocity and a larger extent of deceleration motion. And the static advancing contact angle of the droplet is obviously larger than the dynamic advancing contact angle on the gradient energy surface.

  13. The apparent state of droplets on a rough surface

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The factors influencing the state and wetting transition of droplets on a rough surface are both complex and obscure. The change in wetting is directly reflected by changes under the contact condition of the droplets with the surface. The recent study about the wettability of the superhydrophobic surface under the condensing condition arouses the new understanding about the apparent state of droplets on a rough surface. In this work, to validate the existence of droplets in an intermediate state, a microscale pillar topological polydimethylsiloxane (PDMS) surface was manufactured and its wettability under various conditions was studied. According to the experimental data, it is proposed that the wetting state of a rough surface may be embodied using the contact area ratio of a solid/liquid/gas droplet with the projective plane. A general calculation model for the apparent contact angle of droplets is given and expressed diagrammatically. It is found that the measured apparent contact angles of droplets at dif- ferent states on the surface falls within the range predicted by our proposed equation.

  14. Deformation of freezing water droplets on a cold copper surface

    Institute of Scientific and Technical Information of China (English)

    WANG Jieteng; LIU Zhongliang; GOU Yujun; ZHANG Xinhua; CHENG Shuiyuan

    2006-01-01

    Freezing processes of water and peanut oil droplets on a cold surface are investigated in this paper. We observed during our experiments that the base surface of a water droplet that is in direct contact with the cold surface keeps its original shape, but the other part of the droplet shows an obvious growth along the direction normal to the base surface. One small protrusion appears on the top of the water droplet at the end of the freezing process. The experimental observations also show that no obvious shape change happens during the freezing of peanut oil droplets. It is postulated that the effects of surface tension and volume dilatation resulted from liquid-to-solid phase change cause the shape change and protrusions formation. Based on this postulation, a physical and mathematical model is developed. The results of the model of a water droplet's freezing process correspond with our experimental observations. The observed phenomenon that frost-growth speed on the protrusion is higher than that on the other part of the water droplet is also analyzed.

  15. Conditions for super-adiabatic droplet growth after entrainment mixing

    Science.gov (United States)

    Yang, Fan; Shaw, Raymond; Xue, Huiwen

    2016-07-01

    Cloud droplet response to entrainment and mixing between a cloud and its environment is considered, accounting for subsequent droplet growth during adiabatic ascent following a mixing event. The vertical profile for liquid water mixing ratio after a mixing event is derived analytically, allowing the reduction to be predicted from the mixing fraction and from the temperature and humidity for both the cloud and environment. It is derived for the limit of homogeneous mixing. The expression leads to a critical height above the mixing level: at the critical height the cloud droplet radius is the same for both mixed and unmixed parcels, and the critical height is independent of the updraft velocity and mixing fraction. Cloud droplets in a mixed parcel are larger than in an unmixed parcel above the critical height, which we refer to as the "super-adiabatic" growth region. Analytical results are confirmed with a bin microphysics cloud model. Using the model, we explore the effects of updraft velocity, aerosol source in the environmental air, and polydisperse cloud droplets. Results show that the mixed parcel is more likely to reach the super-adiabatic growth region when the environmental air is humid and clean. It is also confirmed that the analytical predictions are matched by the volume-mean cloud droplet radius for polydisperse size distributions. The findings have implications for the origin of large cloud droplets that may contribute to onset of collision-coalescence in warm clouds.

  16. Experiments on the dynamics of droplet collisions in a vacuum

    Science.gov (United States)

    Willis, K. D.; Orme, M. E.

    Highly controlled experiments of binary droplet collisions in a vacuum environment are performed in order to study the collision dynamics devoid of aerodynamic effects that could otherwise obstruct the experimental observations by causing distortion or even disintegration of the coalesced mass. Pre-collision droplets are generated from capillary stream break-up at wavelengths much larger than those generated with the typical Rayleigh droplet formation in order to reduce the interactions among the collision products. Experimental results show that the range of droplet Weber number necessary to describe the boundaries between permanent coalescence and coalescence followed by separation is several orders of magnitude higher than has been reported in experiments conducted at standard atmospheric pressures with lower viscosity liquids (i.e. hydrocarbon fuels and water). Additionally, the time periods of both the oblate and prolate portions of the coalesced droplet oscillation have been measured and it is reported for the first time that the time period for the prolate portion of the oscillation grows exponentially with the Weber number. Finally, new pictorial results are presented for droplet collisions between non-spherical droplets.

  17. Early Stages of Hyaline Membrane Formation Detected in Alveolar Mouths in Diffuse Alveolar-Damage-Associated Diseases: A Detailed Immunohistochemical Study.

    Science.gov (United States)

    Ohtsuki, Yuji; Fujita, Jiro; Yoshinouchi, Takeo; Enzan, Hideaki; Iguchi, Mitsuko; Lee, Gang-Hong; Furihata, Mutsuo

    2015-10-01

    To study the early stages of hyaline membrane (HM) formation, diffuse alveolar damage (DAD) was thoroughly investigated using immunohistochemical methods in 15 autopsy cases, which consisted of various types of interstitial pneumonias and pulmonary diseases derived from nonmalignant or malignant diseases. Alveolar mouths (AMs) that were presumed to be normal were ultrastructurally examined in detail, by using pulmonary tissues in the pneumothorax. It is interesting to note that during the initial stages of HM formation in AMs, fragmented eosinophilic masses were closely attached to AMs as irregular fragments or by a cap-like structure. The ultrastructure revealed some distance between the capillary spaces and surface epithelium of the AMs, indicating that the epithelial cells at the AMs might be often easily damaged even by minor stimuli; they can be considered as "locus minoris resistentiae." HMs were found to be formed initially at the site of AMs derived from fragmented eosinophilic masses in not only pulmonary but also extrapulmonary diseases, including both nonmalignant and malignant diseases. These irregular eosinophilic masses, representing the early shape of HMs, were immunohistochemically positive for the epithelial membrane antigens, namely, surfactant protein A and factor VIII antigen, and occasionally for KL-6 and cytokeratins. These results suggested that fragmented irregular masses represent the initial phase of HM formation. Five of 15 cases were focally negative for KL-6 at the initial irregular mass of HMs. Because KL-6 is one of the fundamental components of pulmonary surface elements, it needs to be studied further by detailed clinicopathological examination. PMID:26183849

  18. Pulmonary hyalinizing granuloma with associated elevation in serum and tissue IgG4 occurring in a patient with a history of sarcoidosis.

    Science.gov (United States)

    Chapman, Erin M; Gown, Allen; Mazziotta, Robert; Churg, Andrew

    2012-05-01

    Pulmonary hyalinizing granulomas (PHGs) are unusual fibrosclerotic inflammatory lung lesions. The organ-based manifestations of the recently defined IgG4-related sclerosing disease typically show dense fibrosis and heavy lymphoplasmacytic infiltrates. IgG4-related sclerosing disease is also defined by increased serum IgG4 levels and increased tissue levels of IgG4-positive plasma cells. The morphologic features of PHG overlap with those seen in IgG4-related sclerosing disease, and this suggests that PHG may be a form of IgG4-related sclerosing disease. We present a case of a 51-year-old man with a history of sarcoidosis who presented with slowly enlarging pulmonary nodules. Histologic evaluation of one of the nodules yielded a diagnosis of PHG. Further investigation demonstrated both elevated serum IgG4 and elevated tissue IgG4-positive plasma cells in the PHG. In previous reports, lesions that are now considered part of IgG4-related sclerosing disease were documented in patients also diagnosed with PHG, although these reports date from before the description of IgG4 sclerosing disease. This case provides the first definitive evidence that PHG is part of the spectrum of IgG4-related sclerosing disease. PMID:22498827

  19. The influence of material hardness on liquid droplet impingement erosion

    International Nuclear Information System (INIS)

    Highlights: • Liquid droplet impingement erosion is studied for various metal materials. • Average power dependency on droplet velocity is found as 7. • Power dependency on Vickers hardness is found as −4.5. • An empirical formula is constructed for erosion rates of metal materials. • Predicted erosion rate is well correlated with experiment within a factor of 1.5. - Abstract: This paper describes the experimental study on the liquid droplet impingement erosion of metal materials to understand the influence of material hardness on the erosion rate. The experiment is carried out using a water spray jet apparatus with a condition of relatively thin liquid film thickness. The metal materials tested are pure aluminum, aluminum alloy, brass, mild steel, carbon steel and stainless steel. The liquid droplets considered are 30 ± 5 μm in volume average diameter of water, which is the same order of droplet diameter in the actual pipeline in nuclear/fossil power plants. In order to understand the influence of material hardness on the liquid droplet impingement erosion, the scanning electron microscope (SEM) observation on the eroded surface and the measurement of erosion rate are carried out in the terminal stage of erosion. The experimental results indicate that the erosion rates are expressed by the droplet velocity, volume flux, Vickers hardness and the liquid film thickness, which are fundamentals of the liquid droplet impingement erosion. The empirical formula shows that the power index for droplet velocity dependency is found to be 7 with a scattering from 5 to 9 depending on the materials, while the power index for Vickers hardness dependency is found as −4.5

  20. Uranium droplet nuclear reactor core with MHD generator

    Science.gov (United States)

    Anghaie, Samim; Kumar, Ratan

    An innovative concept employing liquid uranium droplets as fuel in an ultrahigh-temperature vapor core reactor (UTVR) magnetohydrodynamic (MHD) generator power system for space power generation has been studied. Metallic vapor in superheated form acts as a working fluid for a closed-Rankine-type thermodynamic cycle. Usage of fuel and working fluid in this form assures certain advantages. The major technical issues emerging as a result involve a method for droplet generation, droplet transport in the reactor core, heat generation in the fuel and transport to the metallic vapor, and materials compatibility. A qualitative and quantitative attempt to resolve these issues has indicated the promise and tentative feasibility of the system.

  1. Dropwise condensation: the deposition growth and coalescence of fluid droplets

    Science.gov (United States)

    Meakin, P.

    1992-01-01

    The dropwise condensation of liquid droplets can frequently be described in terms of a four-stage scenario: (1) Nucleation and growth. (2) Growth and coalescence. (3) Growth and coalescence with renucleation in exposed regions. (4) Growth, coalescence and renucleation with removal of larger droplets. All four stages have been simulated using simple computer models and the results of these models can be described in terms of simple scaling theories. These models and scaling theories can be applied to the condensation of D dimensional droplet on d dimensional substrates where D and d can take on essentially any values with D >= d including non-integer (fractal) values.

  2. Modeling of droplet dynamic and thermal behaviour during spray deposition

    Indian Academy of Sciences (India)

    N S Mahesh; Johnson Mendonca; M K Muralidhara; B K Muralidhara; C Ramachandra

    2003-04-01

    Mathematical modeling of supersonic gas atomization for spray forming has been investigated. Influence of the droplet dynamic and thermal behaviour on the resultant microstructure has been studied. Analytical models have been constructed taking into account the higher Reynolds number owing to supersonic gas flow. The impact velocity profiles of the droplets lend credence to the evolution of equiaxed grain morphology through dendrite fragmentation. The thermal history profile along with the fraction solid plot could yield optimized standoff distance to obtain a mushy droplet. A comparison of secondary dendrite arm spacing obtained from the mathematical model showed good agreement with experimental observations.

  3. Thermally induced secondary atomization of droplet in an acoustic field

    Science.gov (United States)

    Basu, Saptarshi; Saha, Abhishek; Kumar, Ranganathan

    2012-01-01

    We study the thermal effects that lead to instability and break up in acoustically levitated vaporizing fuel droplets. For selective liquids, atomization occurs at the droplet equator under external heating. Short wavelength [Kelvin-Helmholtz (KH)] instability for diesel and bio-diesel droplets triggers this secondary atomization. Vapor pressure, latent heat, and specific heat govern the vaporization rate and temperature history, which affect the surface tension gradient and gas phase density, ultimately dictating the onset of KH instability. We develop a criterion based on Weber number to define a condition for the inception of secondary atomization.

  4. Sectorial oscillation of acoustically levitated nanoparticle-coated droplet

    Science.gov (United States)

    Zang, Duyang; Chen, Zhen; Geng, Xingguo

    2016-01-01

    We have investigated the dynamics of a third mode sectorial oscillation of nanoparticle-coated droplets using acoustic levitation in combination with active modulation. The presence of nanoparticles at the droplet surface changes its oscillation amplitude and frequency. A model linking the interfacial rheology and oscillation dynamics has been proposed in which the compression modulus ɛ of the particle layer is introduced into the analysis. The ɛ obtained with the model is in good agreement with that obtained by the Wilhelmy plate approach, highlighting the important role of interfacial rheological properties in the sectorial oscillation of droplets.

  5. Towards a high throughput droplet-based agglutination assay

    KAUST Repository

    Kodzius, Rimantas

    2013-10-22

    This work demonstrates the detection method for a high throughput droplet based agglutination assay system. Using simple hydrodynamic forces to mix and aggregate functionalized microbeads we avoid the need to use magnetic assistance or mixing structures. The concentration of our target molecules was estimated by agglutination strength, obtained through optical image analysis. Agglutination in droplets was performed with flow rates of 150 µl/min and occurred in under a minute, with potential to perform high-throughput measurements. The lowest target concentration detected in droplet microfluidics was 0.17 nM, which is three orders of magnitude more sensitive than a conventional card based agglutination assay.

  6. Power generation from conductive droplet sliding on electret film

    Science.gov (United States)

    Yang, Zhaochu; Halvorsen, Einar; Dong, Tao

    2012-05-01

    Generating electrical power from low frequency vibration to power portable devices is a challenge that potentially can be met by nonresonant electrostatic energy harvesters. We propose a generator employing a conductive droplet sliding on a microfabricated electret film which is sputtered onto an interdigital electrode and charged already during deposition. Droplet motion causes a capacitance variation that is used to generate electric power. A prototype of the fluidic energy harvester demonstrated a peak output power at 0.18 µW with a single droplet having a diameter of 1.2 mm and sliding on a 2 -µm thick electret film.

  7. DNA sequence analysis with droplet-based microfluidics

    Science.gov (United States)

    Abate, Adam R.; Hung, Tony; Sperling, Ralph A.; Mary, Pascaline; Rotem, Assaf; Agresti, Jeremy J.; Weiner, Michael A.; Weitz, David A.

    2014-01-01

    Droplet-based microfluidic techniques can form and process micrometer scale droplets at thousands per second. Each droplet can house an individual biochemical reaction, allowing millions of reactions to be performed in minutes with small amounts of total reagent. This versatile approach has been used for engineering enzymes, quantifying concentrations of DNA in solution, and screening protein crystallization conditions. Here, we use it to read the sequences of DNA molecules with a FRET-based assay. Using probes of different sequences, we interrogate a target DNA molecule for polymorphisms. With a larger probe set, additional polymorphisms can be interrogated as well as targets of arbitrary sequence. PMID:24185402

  8. Nanospiral Formation by Droplet Drying: One Molecule at a Time

    Directory of Open Access Journals (Sweden)

    Wan Lei

    2011-01-01

    Full Text Available Abstract We have created nanospirals by self-assembly during droplet evaporation. The nanospirals, 60–70 nm in diameter, formed when solvent mixtures of methanol and m-cresol were used. In contrast, spin coating using only methanol as the solvent produced epitaxial films of stripe nanopatterns and using only m-cresol disordered structure. Due to the disparity in vapor pressure between the two solvents, droplets of m-cresol solution remaining on the substrate serve as templates for the self-assembly of carboxylic acid molecules, which in turn allows the visualization of solution droplet evaporation one molecule at a time.

  9. Polarizability of Fluid Droplets and the Kerr Effect on Microemulsions

    CERN Document Server

    Lisy, V

    2001-01-01

    Spheroidal fluid droplets immersed in another fluid and thermally fluctuating in the shape are considered. The polarizability of the droplet is evaluated up to the second order in the fluctuation amplitudes. The correlation functions of the polarizability tensor components are found and used to describe the polarized and depolarized scattering of light, and the Kerr effect on microemulsions. By comparison of the theoretical results with the Kerr constant measurements from the literature, we estimate the bending rigidity of the surfactant monolayer that separates the oil and water phases in droplet microemulsions.

  10. Spray Droplet Characterization from a Single Nozzle by High Speed Image Analysis Using an In-Focus Droplet Criterion

    Science.gov (United States)

    Vulgarakis Minov, Sofija; Cointault, Frédéric; Vangeyte, Jürgen; Pieters, Jan G; Nuyttens, David

    2016-01-01

    Accurate spray characterization helps to better understand the pesticide spray application process. The goal of this research was to present the proof of principle of a droplet size and velocity measuring technique for different types of hydraulic spray nozzles using a high speed backlight image acquisition and analysis system. As only part of the drops of an agricultural spray can be in focus at any given moment, an in-focus criterion based on the gray level gradient was proposed to decide whether a given droplet is in focus or not. In a first experiment, differently sized droplets were generated with a piezoelectric generator and studied to establish the relationship between size and in-focus characteristics. In a second experiment, it was demonstrated that droplet sizes and velocities from a real sprayer could be measured reliably in a non-intrusive way using the newly developed image acquisition set-up and image processing. Measured droplet sizes ranged from 24 μm to 543 μm, depending on the nozzle type and size. Droplet velocities ranged from around 0.5 m/s to 12 m/s. The droplet size and velocity results were compared and related well with the results obtained with a Phase Doppler Particle Analyzer (PDPA). PMID:26861338

  11. Spray Droplet Characterization from a Single Nozzle by High Speed Image Analysis Using an In-Focus Droplet Criterion.

    Science.gov (United States)

    Minov, Sofija Vulgarakis; Cointault, Frédéric; Vangeyte, Jürgen; Pieters, Jan G; Nuyttens, David

    2016-01-01

    Accurate spray characterization helps to better understand the pesticide spray application process. The goal of this research was to present the proof of principle of a droplet size and velocity measuring technique for different types of hydraulic spray nozzles using a high speed backlight image acquisition and analysis system. As only part of the drops of an agricultural spray can be in focus at any given moment, an in-focus criterion based on the gray level gradient was proposed to decide whether a given droplet is in focus or not. In a first experiment, differently sized droplets were generated with a piezoelectric generator and studied to establish the relationship between size and in-focus characteristics. In a second experiment, it was demonstrated that droplet sizes and velocities from a real sprayer could be measured reliably in a non-intrusive way using the newly developed image acquisition set-up and image processing. Measured droplet sizes ranged from 24 μm to 543 μm, depending on the nozzle type and size. Droplet velocities ranged from around 0.5 m/s to 12 m/s. The droplet size and velocity results were compared and related well with the results obtained with a Phase Doppler Particle Analyzer (PDPA). PMID:26861338

  12. Droplet morphometry and velocimetry (DMV): a video processing software for time-resolved, label-free tracking of droplet parameters.

    Science.gov (United States)

    Basu, Amar S

    2013-05-21

    Emerging assays in droplet microfluidics require the measurement of parameters such as drop size, velocity, trajectory, shape deformation, fluorescence intensity, and others. While micro particle image velocimetry (μPIV) and related techniques are suitable for measuring flow using tracer particles, no tool exists for tracking droplets at the granularity of a single entity. This paper presents droplet morphometry and velocimetry (DMV), a digital video processing software for time-resolved droplet analysis. Droplets are identified through a series of image processing steps which operate on transparent, translucent, fluorescent, or opaque droplets. The steps include background image generation, background subtraction, edge detection, small object removal, morphological close and fill, and shape discrimination. A frame correlation step then links droplets spanning multiple frames via a nearest neighbor search with user-defined matching criteria. Each step can be individually tuned for maximum compatibility. For each droplet found, DMV provides a time-history of 20 different parameters, including trajectory, velocity, area, dimensions, shape deformation, orientation, nearest neighbour spacing, and pixel statistics. The data can be reported via scatter plots, histograms, and tables at the granularity of individual droplets or by statistics accrued over the population. We present several case studies from industry and academic labs, including the measurement of 1) size distributions and flow perturbations in a drop generator, 2) size distributions and mixing rates in drop splitting/merging devices, 3) efficiency of single cell encapsulation devices, 4) position tracking in electrowetting operations, 5) chemical concentrations in a serial drop dilutor, 6) drop sorting efficiency of a tensiophoresis device, 7) plug length and orientation of nonspherical plugs in a serpentine channel, and 8) high throughput tracking of >250 drops in a reinjection system. Performance metrics

  13. Droplet phase characteristics in liquid-dominated steam--water nozzle flow

    Energy Technology Data Exchange (ETDEWEB)

    Alger, T.W.

    1978-08-09

    An experimental study was undertaken to determine the droplet size distribution, the droplet spatial distribution and the mean droplet velocity in low-quality, steam-water flow from a rectangular cross-section, converging-diverging nozzle. A unique forward light scattering technique was developed for droplet size distribution measurements. Droplet spatial variations were investigated using light transmission measurements, and droplet velocities were measured with a laser-Doppler velocimeter (LDV) system incorporating a confocal Fabry-Perot interferometer. Nozzle throat radius of curvature and height were varied to investigte their effects on droplet size. Droplet size distribution measurements yielded a nominal Sauter mean droplet diameter of 1.7 ..mu..m and a nominal mass-mean droplet diameter of 2.4 ..mu..m. Neither the throat radius of curvature nor the throat height were found to have a significant effect upon the nozzle exit droplet size. The light transmission and LDV measurement results confirmed both the droplet size measurements and demonstrated high spatial uniformity of the droplet phase within the nozzle jet flow. One-dimensional numerical calculations indicated that both the dynamic breakup (thermal equilibrium based on a critical Weber number of 6.0) and the boiling breakup (thermal nonequilibrium based on average droplet temperature) models predicted droplet diameters on the order of 7.5 ..mu..m, which are approximately equal to the maximum stable droplet diameters within the nozzle jet flow.

  14. Oil droplet release from emulsion-filled gels in relation to sensory perception

    NARCIS (Netherlands)

    Sala, G.; Velde, van de F.; Cohen Stuart, M.A.; Aken, van G.A.

    2007-01-01

    Oil droplet release upon shearing was studied in emulsion-filled gels containing oil droplets either bound or unbound to the gel matrix. At 20 °C no release was observed for gels containing droplets bound to the matrix, whereas the release measured for gels with unbound droplets related to the fat c

  15. AC electric field induced droplet deformation in a microfluidic T-junction.

    Science.gov (United States)

    Xi, Heng-Dong; Guo, Wei; Leniart, Michael; Chong, Zhuang Zhi; Tan, Say Hwa

    2016-08-01

    We present for the first time an experimental study on the droplet deformation induced by an AC electric field in droplet-based microfluidics. It is found that the deformation of the droplets becomes stronger with increasing electric field intensity and frequency. The measured electric field intensity dependence of the droplet deformation is consistent with an early theoretical prediction for stationary droplets. We also proposed a simple equivalent circuit model to account for the frequency dependence of the droplet deformation. The model well explains our experimental observations. In addition, we found that the droplets can be deformed repeatedly by applying an amplitude modulation (AM) signal. PMID:27173587

  16. Plasma Propulsion of a Metallic Micro-droplet and its Deformation upon Laser Impact

    CERN Document Server

    Kurilovich, Dmitry; Torretti, Francesco; Lassise, Adam; Hoekstra, Ronnie; Ubachs, Wim; Gelderblom, Hanneke; Versolato, Oscar O

    2016-01-01

    The propulsion of a liquid indium-tin micro-droplet by nanosecond-pulse laser impact is experimentally investigated. We capture the physics of the droplet propulsion in a scaling law that accurately describes the plasma-imparted momentum transfer, enabling the optimization of the laser-droplet coupling. The subsequent deformation of the droplet is described by an analytical model that accounts for the droplet's propulsion velocity and the liquid properties. Comparing our findings to those from vaporization-accelerated mm-sized water droplets, we demonstrate that the hydrodynamic response of laser-impacted droplets is scalable and independent of the propulsion mechanism.

  17. Emulsion ripening through molecular exchange at droplet contacts.

    Science.gov (United States)

    Roger, Kevin; Olsson, Ulf; Schweins, Ralf; Cabane, Bernard

    2015-01-26

    Two coarsening mechanisms of emulsions are well established: droplet coalescence (fusion of two droplets) and Ostwald ripening (molecular exchange through the continuous phase). Here a third mechanism is identified, contact ripening, which operates through molecular exchange upon droplets collisions. A contrast manipulated small-angle neutron scattering experiment was performed to isolate contact ripening from coalescence and Ostwald ripening. A kinetic study was conducted, using dynamic light scattering and monodisperse nanoemulsions, to obtain the exchange key parameters. Decreasing the concentration or adding ionic repulsions between droplets hinders contact ripening by decreasing the collision frequency. Using long surfactant chains and well-hydrated heads inhibits contact ripening by hindering fluctuations in the film. Contact ripening can be controlled by these parameters, which is essential for both emulsion formulation and delivery of hydrophobic ingredients. PMID:25504340

  18. Electrowetting in a water droplet with a movable floating substrate

    Science.gov (United States)

    Shahzad, Amir; Masud, A. R.; Song, Jang-Kun

    2016-05-01

    Electrowetting (EW) enables facile manipulation of a liquid droplet on a hydrophobic surface. In this study, manipulation of an electrolyte droplet having a small floating object on it was investigated on a solid hydrophobic substrate under the EW process. Herein, the floating object exhibited a vertical motion under an applied electric field owing to the spreading and contraction of the droplet on its connecting substrates. The field-induced height variation of the floating object was significantly influenced by the thicknesses of the dielectric and hydrophobic materials. A small mass was also placed on the top floating object and its effect on the spreading of the droplet was observed. In this system, the height of the top floating object is precisely controllable under the application of an electric voltage. The proposed system is expected to be highly useful in the design of nano- and micro-oscillatory systems for microengineering.

  19. Breakup of Droplets in Micro and Nanofluidic T-Junctions

    Directory of Open Access Journals (Sweden)

    A. bedram

    2013-01-01

    Full Text Available We employ numerical simulations to investigate the breakup of droplets in micro- and nanoscale T junctions, which are used to produce small droplets from a large droplet. For this purpose a Volume f Fluid (VOF based method is used and for verifying the reliability of the numerical outcomes, the results are compared with the available experimental and analytical results. Our results reveal that breakup time and breakup length of the droplets play important roles in handling these systems optimally. Our results also indicate that for nanoscale Tjunctions by increasing the capillary number the performance increases while for the micro-scale systems there is a specific capillary number for which the system is in its optimum condition.

  20. Droplet Transport Mechanism on Horizontal Hydrophilic/Hydrophobic Surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Myong, Hyon Kook [Kookmin University, Seoul (Korea, Republic of)

    2014-06-15

    A fluid transport technique is a key issue for the development of microfluidic systems. In this study, the movement of a droplet on horizontal hydrophilic/hydrophobic surfaces, which is a new concept to transport droplets without external power sources that was recently proposed by the author, was simulated using an in-house solution code(PowerCFD). This code employs an unstructured cell-centered method based on a conservative pressure-based finite-volume method with interface capturing method(CICSAM) in a volume of fluid(VOF) scheme for phase interface capturing. The droplet transport mechanism is examined through numerical results that include velocity vectors, pressure contours, and total kinetic energy inside and around the droplet.

  1. Peptide synthesis on glass substrate using acoustic droplet ejector.

    Science.gov (United States)

    Youngki Choe; Shih-Jui Chen; Eun Sok Kim

    2014-03-01

    This paper describes the synthesis of a 9-mers-long peptide ladder structure of glycine on a modified glass surface using a nanoliter droplet ejector. To synthesize peptide on a glass substrate, SPOT peptide synthesis protocol was followed with a nozzleless acoustic droplet ejector being used to eject about 300 droplets of preactivated amino acid solution to dispense 60 nL of the solution per mer. The coupling efficiency of each mer was measured with FITC fluorescent tag to be 96%, resulting in net 70% efficiency for the whole 9-mer-long peptide of glycine. Usage of a nanoliter droplet ejector for SPOT peptide synthesis increases the density of protein array on a chip. PMID:24235271

  2. Enhancing droplet deposition through in-situ precipitation

    Science.gov (United States)

    Damak, Maher; Mahmoudi, Seyed Reza; Hyder, Md Nasim; Varanasi, Kripa K.

    2016-01-01

    Retention of agricultural sprays on plant surfaces is an important challenge. Bouncing of sprayed pesticide droplets from leaves is a major source of soil and groundwater pollution and pesticide overuse. Here we report a method to increase droplet deposition through in-situ formation of hydrophilic surface defects that can arrest droplets during impact. Defects are created by simultaneously spraying oppositely charged polyelectrolytes that induce surface precipitation when two droplets come into contact. Using high-speed imaging, we study the coupled dynamics of drop impact and surface precipitate formation. We develop a physical model to estimate the energy dissipation by the defects and predict the transition from bouncing to sticking. We demonstrate macroscopic enhancements in spray retention and surface coverage for natural and synthetic non-wetting surfaces and provide insights into designing effective agricultural sprays. PMID:27572948

  3. Surfactant-driven flow transitions in evaporating droplets.

    Science.gov (United States)

    Marin, Alvaro; Liepelt, Robert; Rossi, Massimiliano; Kähler, Christian J

    2016-02-01

    An evaporating droplet is a dynamic system in which flow is spontaneously generated to minimize the surface energy, dragging particles to the borders and ultimately resulting in the so-called "coffee-stain effect". The situation becomes more complex at the droplet's surface, where surface tension gradients of different natures can compete with each other yielding different scenarios. With careful experiments and with the aid of 3D particle tracking techniques, we are able to show that different types of surfactants turn the droplet's surface either rigid or elastic, which alters the evaporating fluid flow, either enhancing the classical coffee-stain effect or leading to a total flow inversion. Our measurements lead to unprecedented and detailed measurements of the surface tension difference along the evaporating droplet's surface with good temporal and spatial resolution. PMID:26659361

  4. Size from Specular Highlights for Analyzing Droplet Size Distributions

    Science.gov (United States)

    Jalba, Andrei C.; Westenberg, Michel A.; Grooten, Mart H. M.

    In mechanical engineering, heat-transfer models by dropwise condensation are under development. The condensation process is captured by taking many pictures, which show the formation of droplets, of which the size distribution and area coverage are of interest for model improvement. The current analysis method relies on manual measurements, which is time consuming. In this paper, we propose an approach to automatically extract the positions and radii of the droplets from an image. Our method relies on specular highlights that are visible on the surfaces of the droplets. We show that these highlights can be reliably extracted, and that they provide sufficient information to infer the droplet size. The results obtained by our method compare favorably with those obtained by laborious and careful manual measurements. The processing time per image is reduced by two orders of magnitude.

  5. Accelerated Chemical Reactions and Organic Synthesis in Leidenfrost Droplets.

    Science.gov (United States)

    Bain, Ryan M; Pulliam, Christopher J; Thery, Fabien; Cooks, R Graham

    2016-08-22

    Leidenfrost levitated droplets can be used to accelerate chemical reactions in processes that appear similar to reaction acceleration in charged microdroplets produced by electrospray ionization. Reaction acceleration in Leidenfrost droplets is demonstrated for a base-catalyzed Claisen-Schmidt condensation, hydrazone formation from precharged and neutral ketones, and for the Katritzky pyrylium into pyridinium conversion under various reaction conditions. Comparisons with bulk reactions gave intermediate acceleration factors (2-50). By keeping the volume of the Leidenfrost droplets constant, it was shown that interfacial effects contribute to acceleration; this was confirmed by decreased reaction rates in the presence of a surfactant. The ability to multiplex Leidenfrost microreactors, to extract product into an immiscible solvent during reaction, and to use Leidenfrost droplets as reaction vessels to synthesize milligram quantities of product is also demonstrated.

  6. Method for using magnetic particles in droplet microfluidics

    Science.gov (United States)

    Shah, Gaurav Jitendra (Inventor); Kim, Chang-Jin (Inventor)

    2012-01-01

    Methods of utilizing magnetic particles or beads (MBs) in droplet-based (or digital) microfluidics are disclosed. The methods may be used in enrichment or separation processes. A first method employs the droplet meniscus to assist in the magnetic collection and positioning of MBs during droplet microfluidic operations. The sweeping movement of the meniscus lifts the MBs off the solid surface and frees them from various surface forces acting on the MBs. A second method uses chemical additives to reduce the adhesion of MBs to surfaces. Both methods allow the MBs on a solid surface to be effectively moved by magnetic force. Droplets may be driven by various methods or techniques including, for example, electrowetting, electrostatic, electromechanical, electrophoretic, dielectrophoretic, electroosmotic, thermocapillary, surface acoustic, and pressure.

  7. Surfactant-driven flow transitions in evaporating droplets

    CERN Document Server

    Marin, Alvaro; Rossi, Massimiliano; Kähler, Christian J

    2015-01-01

    An evaporating droplet is a dynamic system in which flow is spontaneously generated to minimize the surface energy, dragging particles to the borders and ultimately resulting in the so-called "coffee-stain effect". The situation becomes more complex at the droplet's surface, where surface tension gradients of different nature can compete with each other yielding different scenarios. With careful experiments and with the aid of 3D particle tracking techniques, we are able to show that different types of surfactants turn the droplet's surface either rigid or elastic, which alters the evaporating fluid flow, either enhancing the classical coffee-stain effect or leading to a total flow inversion. Our measurements lead to unprecedented and detailed measurements of the surface tension difference along an evaporating droplet's surface with good temporal and spatial resolution.

  8. Cavitation-induced fragmentation of an acoustically-levitated droplet

    Science.gov (United States)

    Gonzalez Avila, Silvestre Roberto; Ohl, Claus-Dieter

    2015-12-01

    In this paper we investigate the initial sequence of events that lead to the fragmentation of a millimetre sized water droplets when interacting with a focused ns-laser pulse. The experimental results show complex processes that result from the reflection of an initial shock wave from plasma generation with the soft boundary of the levitating droplet; furthermore, when the reflected waves from the walls of the droplet refocus they leave behind a trail of microbubbles that later act as cavitation inception regions. Numerical simulations of a shock wave impacting and reflecting from a soft boundary are also reported; the simulated results show that the lowest pressure inside the droplet occurs at the equatorial plane. The results of the numerical model display good agreement with the experimental results both in time and in space.

  9. A novel approach for droplet position sensing in electrowetting devices

    CERN Document Server

    Sohail, Shiraz

    2012-01-01

    A droplet position sensing scheme has been proposed, which gives a direct voltage output linearly proportional to droplet position in electrowetting-on-dielectric (EWOD) based devices. This scheme doesn't require any extra electronic circuitry or external optical sensors. In addition, it is also compatible for multiple droplet position detection simultaneously, and provides a better isolation between actuation and sensing line. An extra dielectric and metal layers are required in the bottom substrate for physical realization of the scheme. Two equal capacitors of fixed value are formed due to the extra dielectric and metal layers. These capacitors facilitate direct voltage output proportional to droplet position during transport. Actuation force and sensing output voltage in the proposed scheme have been analyzed analytically using an energy-based model. Results show that the additional dielectric and metal layer in the bottom substrate does not significantly change the driving electrostatic force profile. Th...

  10. Critical parameters for the partial coalescence of a droplet

    CERN Document Server

    Gilet, T; Lecomte, J P; Mulleners, K; Vandewalle, N

    2006-01-01

    The partial coalescence of a droplet onto a planar liquid/liquid interface is investigated theoretically by using a dimensional analysis. It mainly depends on the Bond number (gravity vs. surface tension), the Ohnesorge numbers (viscosity in both fluids in contact vs. surface tension) and the density relative difference. An experimental work on 2000 coalescence events is made in order to study the impact of viscosities and gravity on the coalescence process. Global quantities such as the available surface energy of the droplet has been measured during the coalescence. The surface energy is converted into kinetic energy at a constant rate that is independent of the coalescence outcome. The ratio between the daughter droplet size and the mother droplet size is investigated as a function of the dimensionless numbers. Theoretical models are proposed to fit experimental data. The asymmetrical behavior when liquids are inverted indicates that the viscous dissipation is different in both fluids. In the surrounding f...

  11. Enhancing droplet deposition through in-situ precipitation

    Science.gov (United States)

    Damak, Maher; Mahmoudi, Seyed Reza; Hyder, Md Nasim; Varanasi, Kripa K.

    2016-08-01

    Retention of agricultural sprays on plant surfaces is an important challenge. Bouncing of sprayed pesticide droplets from leaves is a major source of soil and groundwater pollution and pesticide overuse. Here we report a method to increase droplet deposition through in-situ formation of hydrophilic surface defects that can arrest droplets during impact. Defects are created by simultaneously spraying oppositely charged polyelectrolytes that induce surface precipitation when two droplets come into contact. Using high-speed imaging, we study the coupled dynamics of drop impact and surface precipitate formation. We develop a physical model to estimate the energy dissipation by the defects and predict the transition from bouncing to sticking. We demonstrate macroscopic enhancements in spray retention and surface coverage for natural and synthetic non-wetting surfaces and provide insights into designing effective agricultural sprays.

  12. An approximation for homogeneous freezing temperature of water droplets

    Science.gov (United States)

    O, K.-T.; Wood, R.

    2015-11-01

    In this work, based on the well-known formulae of classical nucleation theory (CNT), the temperature TNc = 1 at which the mean number of critical embryos inside a droplet is unity is derived and proposed as a new approximation for homogeneous freezing temperature of water droplets. Without consideration of time dependence and stochastic nature of the ice nucleation process, the approximation TNc = 1 is able to reproduce the dependence of homogeneous freezing temperature on drop size and water activity of aqueous drops observed in a wide range of experimental studies. We use the TNc = 1 approximation to argue that the distribution of homogeneous freezing temperatures observed in the experiments may largely be explained by the spread in the size distribution of droplets used in the particular experiment. It thus appears that this approximation is useful for predicting homogeneous freezing temperatures of water droplets in the atmosphere.

  13. The spreading of a viscoplastic droplet by capillary action

    Science.gov (United States)

    Jalaal, Maziyar; Balmforth, Neil; Stoeber, Boris

    2015-11-01

    The spreading of yield stress liquid droplets on a dry surface occurs in a number of applications such as 3D printing. In the current study, the surface-tension-driven spreading of a yield-stress (Bingham) droplet on a solid wetting surface is studied. Neglecting gravity and using lubrication theory for viscoplastic fluids, we derived the thin film equation in 2D. Equations were solved numerically, where to avoid the moving contact line singularity, we used a pre-wetted film. Numerical solutions show the decelerating spreading of the droplet and its arrest due to the yield stress. Additionally, the final shape of the droplets was constructed, using an asymptotic method. Results were compared with the numerical solutions, where agreements were observed.

  14. Spontaneous droplet self-launching on superhydrophobic surfaces

    Science.gov (United States)

    Schutzius, Thomas; Jung, Stefan; Maitra, Tanmoy; Graeber, Gustav; Poulikakos, Dimos

    2015-11-01

    Spontaneous removal of droplets from surfaces is of significant importance in nature and many technologies, e.g., self-cleaning surfaces. Despite progress, the understanding of phenomena leading to such behavior, combined with surface design promoting their manifestation, remains a challenge. We show how water droplets in contact with superhydrophobic surfaces in a low-pressure environment can self-remove through sudden spontaneous launching and subsequent repeated bouncing behavior. We demonstrate that this bouncing results from the combined effect of droplet vaporization, vapor flow in the surface texture, and substrate adhesion leading to a forced, underdamped, mass-spring-damper system behavior. This work is a step toward understanding inherent physical phenomena of droplet-surface interactions manifesting themselves at conditions promoting vaporization, e.g. low-pressure environments, and shows how surface texture design aware of such phenomena alone, can prohibit water retention on surfaces.

  15. Droplet deformation and fragmentation by ultra-short laser pulses

    CERN Document Server

    Krivokorytov, M S; Sidelnikov, Yu V; Krivtsun, V M; Medvedev, V V; Kompanets, V O; Lash, A A; Koshelev, K N

    2016-01-01

    We report on the experimental studies of the deformation and fragmentation of liquid metal droplets by picosecond and subpicosecond laser pulses. The experiments were performed with laser irradiance varying in 10E13-10E15 W/cm^2 range. The observed evolution of the droplet shape upon the impact dramatically differs from the previously reported for nanosecond laser pulses. Instead of flattening the droplet undergoes rapid asymmetric expansion and transforms into a complex shape which can be interpreted as two conjunct spheroid shells and finally fragments. We explain the described hydrodynamic response to the ultra-short impact as a result of the propagation of the laser-induced convergent shockwave through the volume of droplet.

  16. Gas Dynamic Virtual Nozzle for Generation of Microscopic Droplet Streams

    CERN Document Server

    DePonte, D P; Starodub, D; Schmidt, K; Spence, J C H; Doak, R B

    2008-01-01

    As shown by Ganan-Calvo and co-workers, a free liquid jet can be compressed in iameter through gas-dynamic forces exerted by a co-flowing gas, obviating the need for a solid nozzle to form a microscopic liquid jet and thereby alleviating the clogging problems that plague conventional droplet sources of small diameter. We describe in this paper a novel form of droplet beam source based on this principle. The source is miniature, robust, dependable, easily fabricated, and eminently suitable for delivery of microscopic liquid droplets, including hydrated biological samples, into vacuum for analysis using vacuum instrumentation. Monodisperse, single file droplet streams are generated by triggering the device with a piezoelectric actuator. The device is essentially immune to clogging.

  17. On the acoustic properties of vaporized submicron perfluorocarbon droplets.

    Science.gov (United States)

    Reznik, Nikita; Lajoinie, Guillaume; Shpak, Oleksandr; Gelderblom, Erik C; Williams, Ross; de Jong, Nico; Versluis, Michel; Burns, Peter N

    2014-06-01

    The acoustic characteristics of microbubbles created from vaporized submicron perfluorocarbon droplets with fluorosurfactant coating are examined. Utilizing ultra-high-speed optical imaging, the acoustic response of individual microbubbles to low-intensity diagnostic ultrasound was observed on clinically relevant time scales of hundreds of milliseconds after vaporization. It was found that the vaporized droplets oscillate non-linearly and exhibit a resonant bubble size shift and increased damping relative to uncoated gas bubbles due to the presence of coating material. Unlike the commercially available lipid-coated ultrasound contrast agents, which may exhibit compression-only behavior, vaporized droplets may exhibit expansion-dominated oscillations. It was further observed that the non-linearity of the acoustic response of the bubbles was comparable to that of SonoVue microbubbles. These results suggest that vaporized submicron perfluorocarbon droplets possess the acoustic characteristics necessary for their potential use as ultrasound contrast agents in clinical practice. PMID:24462162

  18. Three-axis acoustic device for levitation of droplets in an open gas stream and its application to examine sulfur dioxide absorption by water droplets.

    Science.gov (United States)

    Stephens, Terrance L; Budwig, Ralph S

    2007-01-01

    Two acoustic devices to stabilize a droplet in an open gas stream (single-axis and three-axis levitators) have been designed and tested. The gas stream was provided by a jet apparatus with a 64 mm exit diameter and a uniform velocity profile. The acoustic source used was a Langevin vibrator with a concave reflector. The single-axis levitator relied primarily on the radial force from the acoustic field and was shown to be limited because of significant droplet wandering. The three-axis levitator relied on a combination of the axial and radial forces. The three-axis levitator was applied to examine droplet deformation and circulation and to investigate the uptake of SO(2) from the gas stream to the droplet. Droplets ranging in diameters from 2 to 5 mm were levitated in gas streams with velocities up to 9 ms. Droplet wandering was on the order of a half droplet diameter for a 3 mm diameter droplet. Droplet circulation ranged from the predicted Hadamard-Rybczynski pattern to a rotating droplet pattern. Droplet pH over a central volume of the droplet was measured by planar laser induced fluorescence. The results for the decay of droplet pH versus time are in general agreement with published theory and experiments. PMID:17503939

  19. Transport mechanism of an initially spherical droplet on a combined hydrophilic/hydrophobic surface

    Energy Technology Data Exchange (ETDEWEB)

    Myong, Hyon Kook; Kwon, Young Hoo [Dept. of Mechanical Engineering, Kookmin University, Seoul (Korea, Republic of)

    2015-11-15

    Fluid transport is a key issue in the development of microfluidic systems. Recently, Myong (2014) has proposed a new concept for droplet transport without external power sources, and numerically validated the results for a hypothetical 2D shape, initially having a hemicylindrical droplet shape. Myong and Kwon (2015) have also examined the transport mechanism for an actual water droplet, initially having a 3D hemispherical shape, on a horizontal hydrophilic/hydrophobic surface, based on the numerical results of the time evolution of the droplet shape, as well as the total kinetic, gravitational, pressure and surface free energies inside the droplet. In this study, a 3D numerical analysis of an initially spherical droplet is carried out to establish a new concept for droplet transport. Further, the transport mechanism of an actual water droplet is examined in detail from the viewpoint of the capillarity force imbalance through the numerical results of droplet shape and various energies inside the droplet.

  20. Investigating the Droplet Formation in a Nucleonic Vapor

    CERN Document Server

    Ogul, R

    2003-01-01

    The droplet formation in a supersaturated vapor which may occur during the expansion of an excited blob of nuclear matter in the metastable region at subnuclear densities is investigated. The free energy change accompanying the formation of a drop is calculated as a function of droplet radius for various saturation ratios on the basis of Fisher's model. The results are related to the experimental data

  1. Super lattice formation of an array of volatile wetting droplets

    OpenAIRE

    Burghaus, R.

    1999-01-01

    For an ordered array of critical volatile wetting droplets the formation of a super lattice by an Ostwald-ripening like competition process is considered. The underlying diffusion problem is treated within a quasistatic approximation and to first order in the inverse droplets distance. The approach is rather general but a square lattice and a triangular lattice are studied explicitly. Dispersion relations for the super-lattice growth of these arrays are calculated.

  2. Controlled synthesis of fluorescent silica nanoparticles inside microfluidic droplets

    OpenAIRE

    Wacker, Josias Basil; Lignos, Ioannis; Parashar, Virendra Kumar; Gijs, Martinus

    2012-01-01

    We study the droplet-based synthesis of fluorescent silica nanoparticles (50–350 nm size) in a microfluidic chip. Fluorescein-isothiocyanate (FITC) dye is first chemically linked to aminopropyl triethoxysilane (APTES) in ethanol and this reaction product is subsequently mixed with tetraethyl orthosilicate (TEOS) to yield a fluorescent silicon alkoxide precursor solution. The latter reacts with an aqueous ethanol–ammonia hydrolysing mixture inside droplets, forming fluorescent silica nanoparti...

  3. Role of natural convection in the dissolution of sessile droplets

    OpenAIRE

    Dietrich, Erik; Wildeman, Sander; Visser, Claas Willem; Hofhuis, Kevin; Kooij, E. Stefan; Zandvliet, Harold J.W.; Lohse, Detlef

    2016-01-01

    The dissolution process of small (initial (equivalent) radius $R_0 < 1$ mm) long-chain alcohol (of various types) sessile droplets in water is studied, disentangling diffusive and convective contributions. The latter can arise for high solubilities of the alcohol, as the density of the alcohol-water mixture is then considerably less as that of pure water, giving rise to buoyancy driven convection. The convective flow around the droplets is measured, using micro-particle image velocimetry ($\\m...

  4. Numerical investigation of the evaporation of two-component droplets

    OpenAIRE

    Strotos, G.; Gavaises, M.; Theodorakakos, A.; Bergeles, G.

    2011-01-01

    A numerical model for the complete thermo-fluid-dynamic and phase-change transport processes of two-component hydrocarbon liquid droplets consisting of n-heptane, n-decane and mixture of the two in various compositions is presented and validated against experimental data. The Navier–Stokes equations are solved numerically together with the VOF methodology for tracking the droplet interface, using an adaptive local grid refinement technique. The energy and concentration equations inside the li...

  5. Material forming apparatus using a directed droplet stream

    Science.gov (United States)

    Holcomb, David E.; Viswanathan, Srinath; Blue, Craig A.; Wilgen, John B.

    2000-01-01

    Systems and methods are described for rapidly forming precision metallic and intermetallic alloy net shape parts directly from liquid metal droplets. A directed droplet deposition apparatus includes a crucible with an orifice for producing a jet of material, a jet destabilizer, a charging structure, a deflector system, and an impact zone. The systems and methods provide advantages in that fully dense, microstructurally controlled parts can be fabricated at moderate cost.

  6. Surfactants in cloud droplet activation: mixed organic-inorganic particles

    OpenAIRE

    N. L. Prisle; T. Raatikainen; Laaksonen, A.; Bilde, M.

    2010-01-01

    Organic compounds with surfactant properties are commonly found in atmospheric aerosol particles. Surface activity can significantly influence the cloud droplet forming ability of these particles. We have studied the cloud droplet formation by two-component particles comprising one of the organic surfactants sodium octanoate, sodium decanoate, sodium dodecanoate, and sodium dodecyl sulfate, mixed with sodium chloride. Critical supersaturations were measured with a static diffusion cloud conde...

  7. Methanol Droplet Combustion in Oxygen-Inert Environments in Microgravity

    Science.gov (United States)

    Nayagam, Vedha; Dietrich, Daniel L.; Hicks, Michael C.; Williams, Forman A.

    2013-01-01

    The Flame Extinguishment (FLEX) experiment that is currently underway in the Combustion Integrated Rack facility onboard the International Space Station is aimed at understanding the effects of inert diluents on the flammability of condensed phase fuels. To this end, droplets of various fuels, including alkanes and alcohols, are burned in a quiescent microgravity environment with varying amounts of oxygen and inert diluents to determine the limiting oxygen index (LOI) for these fuels. In this study we report experimental observations of methanol droplets burning in oxygen-nitrogen-carbon dioxide and oxygen-nitrogen-helium gas mixtures at 0.7 and 1 atmospheric pressures. The initial droplet size varied between approximately 1.5 mm and 4 mm to capture both diffusive extinction brought about by insufficient residence time at the flame and radiative extinction caused by excessive heat loss from the flame zone. The ambient oxygen concentration varied from a high value of 30% by volume to as low as 12%, approaching the limiting oxygen index for the fuel. The inert dilution by carbon dioxide and helium varied over a range of 0% to 70% by volume. In these experiments, both freely floated and tethered droplets were ignited using symmetrically opposed hot-wire igniters and the burning histories were recorded onboard using digital cameras, downlinked later to the ground for analysis. The digital images yielded droplet and flame diameters as functions of time and subsequently droplet burning rate, flame standoff ratio, and initial and extinction droplet diameters. Simplified theoretical models correlate the measured burning rate constant and the flame standoff ratio reasonably well. An activation energy asymptotic theory accounting for time-dependent water dissolution or evaporation from the droplet is shown to predict the measured diffusive extinction conditions well. The experiments also show that the limiting oxygen index for methanol in these diluent gases is around 12% to

  8. Prediction of cloud droplet number in a general circulation model

    Energy Technology Data Exchange (ETDEWEB)

    Ghan, S.J.; Leung, L.R. [Pacific Northwest National Lab., Richland, WA (United States)

    1996-04-01

    We have applied the Colorado State University Regional Atmospheric Modeling System (RAMS) bulk cloud microphysics parameterization to the treatment of stratiform clouds in the National Center for Atmospheric Research Community Climate Model (CCM2). The RAMS predicts mass concentrations of cloud water, cloud ice, rain and snow, and number concnetration of ice. We have introduced the droplet number conservation equation to predict droplet number and it`s dependence on aerosols.

  9. Vibrating Breakup of Jet for Uniform Metal Droplets

    Institute of Scientific and Technical Information of China (English)

    Shengdong GAO; Yingxue YAO; Chengsong CUI

    2007-01-01

    Uniform droplet formation from capillary stream breakup provides promising opportunities for many applications such as solder balls manufacturing, circuit board printing and rapid prototype manufacturing. In this study an apparatus capable of making monosize metal spheres by vibrating breakup has been developed. The droplets were electrically charged to avoid collision and merging with one another during flight. As a result, uniformly sized tin powders (180μm in diameter) were obtained after cooling and solidification.

  10. Switchable Thermal Interfaces Based on Discrete Liquid Droplets

    OpenAIRE

    Yongho Sungtaek Ju; Gilhwan Cha; Yanbing Jia

    2012-01-01

    We present a switchable thermal interface based on an array of discrete liquid droplets initially confined on hydrophilic islands on a substrate. The droplets undergo reversible morphological transition into a continuous liquid film when they are mechanically compressed by an opposing substrate to create low-thermal resistance heat conduction path. We investigate a criterion for reversible switching in terms of hydrophilic pattern size and liquid volume. The dependence of the liquid morpholog...

  11. Controlling droplet incubation using close-packed plug flow

    OpenAIRE

    Mary, Pascaline; Abate, Adam R.; Agresti, Jeremy J.; Weitz, David A.

    2011-01-01

    Controlling droplet incubation is critical for droplet-based microfluidic applications; however, current techniques are either of limited precision or place strict limits on the incubation times that can be achieved. Here, we present a simple technique to control incubation time by exploiting close-packed plug flow. In contrast to other techniques, this technique is applicable to very short and very long incubation times.

  12. Defect modeling in spreading nematic droplets.

    Science.gov (United States)

    Lin, T-S; Kondic, L; Cummings, L J

    2012-01-01

    Experiments by Poulard and Cazabat [Langmuir 21, 6270 (2005)] on spreading droplets of nematic liquid crystal (NLC) reveal a surprisingly rich variety of behavior, including at least two different emerging length scales resulting from a contact line instability. In earlier work [Cummings, Lin, and Kondic, Phys. Fluids 23, 043102 (2011)] we modified a lubrication model for NLCs due to Ben Amar and Cummings [Phys. Fluids 13, 1160 (2001)] and showed that, in a qualitative sense, it can account for two-dimensional (2D) versions of the observed behavior. In the present work we propose a different approach that allows us to explore the effect of anchoring variations on the substrate, again in a 2D geometry. This in turn gives a simple way to model the presence of defects, which are nearly always present in such flows. The present model leads to additional terms in the governing equation. We explore the influence of these additional terms for some simple flow scenarios to gain insight into their influence. PMID:22400607

  13. Structure analysis using acoustically levitated droplets.

    Science.gov (United States)

    Leiterer, J; Delissen, F; Emmerling, F; Thünemann, A F; Panne, U

    2008-06-01

    Synchrotron diffraction with a micrometer-sized X-ray beam permits the efficient characterization of micrometer-sized samples, even in time-resolved experiments, which is important because often the amount of sample available is small and/or the sample is expensive. In this context, we will present acoustic levitation as a useful sample handling method for small solid and liquid samples, which are suspended in a gaseous environment (air) by means of a stationary ultrasonic field. A study of agglomeration and crystallization processes in situ was performed by continuously increasing the concentration of the samples by evaporating the solvent. Absorption and contamination processes on the sample container walls were suppressed strongly by this procedure, and parasitic scattering such as that observed when using glass capillaries was also absent. The samples investigated were either dissolved or dispersed in water droplets with diameters in the range of 1 micrometer to 2 millimeters. Initial results from time-resolved synchrotron small- and wide-angle X-ray scattering measurements of ascorbic acid, acetylsalicylic acid, apoferritin, and colloidal gold are presented. PMID:18373085

  14. Acoustic Droplet Vaporization in Biology and Medicine

    Directory of Open Access Journals (Sweden)

    Chung-Yin Lin

    2013-01-01

    Full Text Available This paper reviews the literature regarding the use of acoustic droplet vaporization (ADV in clinical applications of imaging, embolic therapy, and therapeutic delivery. ADV is a physical process in which the pressure waves of ultrasound induce a phase transition that causes superheated liquid nanodroplets to form gas bubbles. The bubbles provide ultrasonic imaging contrast and other functions. ADV of perfluoropentane was used extensively in imaging for preclinical trials in the 1990s, but its use declined rapidly with the advent of other imaging agents. In the last decade, ADV was proposed and explored for embolic occlusion therapy, drug delivery, aberration correction, and high intensity focused ultrasound (HIFU sensitization. Vessel occlusion via ADV has been explored in rodents and dogs and may be approaching clinical use. ADV for drug delivery is still in preclinical stages with initial applications to treat tumors in mice. Other techniques are still in preclinical studies but have potential for clinical use in specialty applications. Overall, ADV has a bright future in clinical application because the small size of nanodroplets greatly reduces the rate of clearance compared to larger contrast agent bubbles and yet provides the advantages of ultrasonographic contrast, acoustic cavitation, and nontoxicity of conventional perfluorocarbon contrast agent bubbles.

  15. Electric field effects on droplet burning

    Science.gov (United States)

    Patyal, Advitya; Kyritsis, Dimitrios; Matalon, Moshe

    2015-11-01

    The effects of an externally applied electric field are studied on the burning characteristics of a spherically symmetric fuel drop including the structure, mass burning rate and extinction characteristics of the diffusion flame. A reduced three-step chemical kinetic mechanism that reflects the chemi-ionization process for general hydrocarbon fuels has been proposed to capture the production and destruction of ions inside the flame zone. Due to the imposed symmetry, the effect of the ionic wind is simply to modify the pressure field. Our study thus focuses exclusively on the effects of Ohmic heating and kinetic effects on the burning process. Two distinguished limits of weak and strong field are identified, highlighting the relative strength of the internal charge barrier compared to the externally applied field, and numerically simulated. For both limits, significantly different charged species distributions are observed. An increase in the mass burning rate is noticed with increasing field in either limit with negligible change in the flame temperature. Increasing external voltages pushes the flame away from the droplet and causes a strengthening of the flame with a reduction in the extinction Damkhöler number.

  16. Predicting the size of droplets produced through Laplace pressure induced snap-off

    CERN Document Server

    Barkley, Solomon; Weeks, Eric R; Dalnoki-Veress, Kari

    2016-01-01

    Laplace pressure driven snap-off is a technique that is used to produce droplets for emulsions and microfluidics purposes. Previous predictions of droplet size have assumed a quasi-equilibrium low flow limit. We present a simple model to predict droplet sizes over a wide range of flow rates, demonstrating a rich landscape of droplet stability depending on droplet size and growth rate. The model accounts for the easily adjusted experimental parameters of geometry, interfacial tension, and the viscosities of both phases.

  17. A multi-section droplet combustion model for spray combustion simulation

    OpenAIRE

    Wang, F.; Sayma, A. I.; Peng, Z. J.; Huang, Y.

    2011-01-01

    Since 1960s, from experimental observation, there are several stages for liquid droplets in multi-phase combustion: pure heating, pure evaporation without individual droplet combustion, and individual droplet combustion (burning) with individual flame around which enhances evaporation. As for individual burning droplets, they have envelope flame or wake flame regimes. From experimental and theoretical research, in liquid fuel combustion chambers, according to the space between the droplets, t...

  18. Droplet impact behavior on heated micro-patterned surfaces

    Science.gov (United States)

    Zhang, Wenbin; Yu, Tongxu; Fan, Jing; Sun, Weijie; Cao, Zexian

    2016-03-01

    Impact behavior of droplets on a surface is an intriguing research topic, and its control should be very useful in diverse industrial applications. We investigated the impact behavior of water droplets on the textured and chemically treated surface of silicon and obtained the impact mode map on the parameter plane subtended by the Weber number (up to 85) and temperature (up to 320 °C). The patterns comprise of micropillars (14 μm in height) in square lattice with a lattice constant of 10 and 20 μm, and the surface was further made superhydrophobic by coating with graphene nanosheets. Six distinct impact modes are identified. It was found that the impact mode map can be dramatically altered by modifying the texture and chemistry of the surface, and the observations are well explained with regard to heat transfer, vapor/bubble generation and vapor flow beneath the droplet. Instability in the droplet arising from the mismatch between vapor generation rate and exhaust conditions is the dominant factor in determining the impact mode. Our results revealed more facts and features of the droplet impact phenomenon and can be very useful for target-oriented surface design towards precise control of droplet impact behavior on heated substrates.

  19. Ultrasonic monitoring of droplets' evaporation: Application to human whole blood.

    Science.gov (United States)

    Laux, D; Ferrandis, J Y; Brutin, D

    2016-09-01

    During a colloidal droplet evaporation, a sol-gel transition can be observed and is described by the desiccation time τD and the gelation time τG. These characteristic times, which can be linked to viscoelastic properties of the droplet and to its composition, are classically rated by analysis of mass droplet evolution during evaporation. Even if monitoring mass evolution versus time seems straightforward, this approach is very sensitive to environmental conditions (vibrations, air flow…) as mass has to be evaluated very accurately using ultra-sensitive weighing scales. In this study we investigated the potentialities of ultrasonic shear reflectometry to assess τD and τG in a simple and reliable manner. In order to validate this approach, our study has focused on blood droplets evaporation on which a great deal of work has recently been published. Desiccation and gelation times measured with shear ultrasonic reflectometry have been perfectly correlated to values obtained from mass versus time analysis. This ultrasonic method which is not very sensitive to environmental perturbations is therefore very interesting to monitor the drying of blood droplets in a simple manner and is more generally suitable for complex fluid droplets evaporation investigation.

  20. Charge of water droplets in non-polar oils

    Science.gov (United States)

    Schoeler, Andreas M.; Josephides, Dimitris N.; Sajjadi, Shahriar; Lorenz, Christian D.; Mesquida, Patrick

    2013-10-01

    Recent advances in droplet manipulation methods by electric fields and signals require a deeper understanding of water droplet charge. In this paper, we have investigated the electrophoretic motion of individual water microdroplets injected into non-polar silicone and paraffin oil by video optical microscopy on an individual droplet basis to determine droplet charge. It was found that the initial surface charge density of surfactant free droplets directly after injection from a micropipette is positive and of the order of 10-6 C/m2, regardless of pH and ion concentration in the range from pH 4 to pH 10 and from 0.01 mmol/l to 1.5 mol/l, respectively. The experimental results together with molecular dynamics simulations show that the nature and polarity of the charge can be explained by anisotropic orientation of water molecules at the interface rather than selective adsorption of ions. Furthermore, we showed that slip at the liquid-liquid boundary must be taken into account when interpreting electrophoretic measurements of droplets.

  1. Numerical studies of microscopic oil droplets under intense turbulence

    Science.gov (United States)

    Snyder, Murray; Knio, Omar

    2008-11-01

    The rise of small oil droplets in water experiencing isotropic turbulence conditions is analyzed computationally under four different turbulence intensities. The computational method combines DNS of the turbulent flow with Lagrangian tracking of the slightly buoyant droplets using a dynamical equation with buoyancy, virtual mass, pressure, drag, lift and history forces. In our recent work, Snyder et al. (2008), we showed that the puzzling behavior observed by Friedman and Katz (2002), where the rise velocity of droplets smaller than 800 μm in diameter is enhanced by turbulence whereas the rise of larger droplets is retarded, could be explained by significant drop then enhancement of the droplet drag coefficient, and corresponding drop in the virtual mass coefficient. In this study we use the same technique to explain the recent experimental results of Gopalan and Katz (2008), who also showed both suppression and enhancement of droplet rise velocities. Using drag and virtual mass coefficients which vary with Reynolds number, our computations approximate the experimental behavior observed by Gopalan and Katz in isotropic turbulence with 79, 100 and 151 μm Kolmogorov length scales. Combined with close agreement with the Friedman and Katz results, with an 88 μm Kolmogorov scale, our results provide further evidence that both the quasi-steady drag and virtual mass coefficients may be heavily modified under intense turbulence.

  2. Ultrasonic monitoring of droplets' evaporation: Application to human whole blood.

    Science.gov (United States)

    Laux, D; Ferrandis, J Y; Brutin, D

    2016-09-01

    During a colloidal droplet evaporation, a sol-gel transition can be observed and is described by the desiccation time τD and the gelation time τG. These characteristic times, which can be linked to viscoelastic properties of the droplet and to its composition, are classically rated by analysis of mass droplet evolution during evaporation. Even if monitoring mass evolution versus time seems straightforward, this approach is very sensitive to environmental conditions (vibrations, air flow…) as mass has to be evaluated very accurately using ultra-sensitive weighing scales. In this study we investigated the potentialities of ultrasonic shear reflectometry to assess τD and τG in a simple and reliable manner. In order to validate this approach, our study has focused on blood droplets evaporation on which a great deal of work has recently been published. Desiccation and gelation times measured with shear ultrasonic reflectometry have been perfectly correlated to values obtained from mass versus time analysis. This ultrasonic method which is not very sensitive to environmental perturbations is therefore very interesting to monitor the drying of blood droplets in a simple manner and is more generally suitable for complex fluid droplets evaporation investigation. PMID:27150753

  3. Corona discharge from spherical particles and water droplets in air

    International Nuclear Information System (INIS)

    The author has obtained a condition for the initiation of a corona from a free particle located in a uniform external field. The corona ignition condition is that there be a self-sustaining avalanche discharge at the particle surface. His model of the electron avalanche encompasses the basic elementary processes, and photoionization. For spherical particles with radii in the range of 0.1 ≤ a0 ≤ 1 and a relative external pressure 0.1 ≤ δ ≤ 1 he obtains an approximate expression for the dependence of the corona ignition field Ec on the particle radius and external pressure. He also computes Ec for when the particle is charged. When determining Ec for water droplets with radii 0.01 ≤ a0 ≤ 0.1 cm he takes into account that the droplet shape changes with electric field. Because a droplet develops a hydrodynamic instability under certain conditions, he finds conditions under which a instability and discharge from the droplet surface might arise. He derives results concerning the effects of a droplet's intrinsic charge on the ignition field for corona discharge. He finds the critical charge for corona initiation without an external field. He derives an approximate equation for the dependence of the critical charge on the droplet radius and external pressure. Basically, this charge is smaller than the Rayleigh charge; it is larger than the Rayleigh charge only for large drops and high pressures. All the results agree well with existing experimental data

  4. Microfluidic Droplet Dehydration for Concentrating Processes in Biomolecules

    Science.gov (United States)

    Anna, Shelley

    2014-03-01

    Droplets in microfluidic devices have proven useful as picoliter reactors for biochemical processing operations such as polymerase chain reaction, protein crystallization, and the study of enzyme kinetics. Although droplets are typically considered to be self-contained, constant volume reactors, there can be significant transport between the dispersed and continuous phases depending on solubility and other factors. In the present talk, we show that water droplets trapped within a microfluidic device for tens of hours slowly dehydrate, concentrating the contents encapsulated within. We use this slow dehydration along with control of the initial droplet composition to influence gellation, crystallization, and phase separation processes. By examining these concentrating processes in many trapped drops at once we gain insight into the stochastic nature of the events. In one example, we show that dehydration rate impacts the probability of forming a specific crystal habit in a crystallizing amino acid. In another example, we phase separate a common aqueous two-phase system within droplets and use the ensuing two phases to separate DNA from an initial mixture. We further influence wetting conditions between the two aqueous polymer phases and the continuous oil, promoting complete de-wetting and physical separation of the polymer phases. Thus, controlled dehydration of droplets allows for concentration, separation, and purification of important biomolecules on a chip.

  5. Ultralocalized thermal reactions in subnanoliter droplets-in-air.

    Science.gov (United States)

    Salm, Eric; Guevara, Carlos Duarte; Dak, Piyush; Dorvel, Brian Ross; Reddy, Bobby; Alam, Muhammad Ashraf; Bashir, Rashid

    2013-02-26

    Miniaturized laboratory-on-chip systems promise rapid, sensitive, and multiplexed detection of biological samples for medical diagnostics, drug discovery, and high-throughput screening. Within miniaturized laboratory-on-chips, static and dynamic droplets of fluids in different immiscible media have been used as individual vessels to perform biochemical reactions and confine the products. Approaches to perform localized heating of these individual subnanoliter droplets can allow for new applications that require parallel, time-, and space-multiplex reactions on a single integrated circuit. Our method positions droplets on an array of individual silicon microwave heaters on chip to precisely control the temperature of droplets-in-air, allowing us to perform biochemical reactions, including DNA melting and detection of single base mismatches. We also demonstrate that ssDNA probe molecules can be placed on heaters in solution, dried, and then rehydrated by ssDNA target molecules in droplets for hybridization and detection. This platform enables many applications in droplets including hybridization of low copy number DNA molecules, lysing of single cells, interrogation of ligand-receptor interactions, and rapid temperature cycling for amplification of DNA molecules.

  6. Spatial distribution of lipid droplets during starvation: Implications for lipophagy.

    Science.gov (United States)

    Barbosa, Antonio Daniel; Siniossoglou, Symeon

    2016-01-01

    Survival during starvation depends largely on metabolic energy, which is stored in the form of neutral lipids in specialized organelles known as lipid droplets. The precursors for the synthesis of neutral lipids are also used for membrane biogenesis, which is required for cell growth and proliferation. Therefore cells must possess mechanisms to preferentially channel lipid precursors toward either membrane synthesis or lipid droplet storage, in response to nutrient status. How this partitioning is spatially regulated within the endoplasmic reticulum (ER) where lipid droplets co-localize, remains poorly understood. We have recently shown that at the onset of starvation lipid droplets concentrate at a perinuclear ER subdomain flanking the nucleus-vacuole junction (NVJ) and that this is crucial for maintaining proper nuclear shape and ER membrane organization. Here we show that disruption of the NVJ does not block the translocation and internalization of lipid droplets into the vacuole for their degradation, which takes place at later stages of starvation. We propose that alternative pathways of lipid droplet translocation from the ER to the vacuole may exist to enable stationary phase-induced lipophagy. PMID:27574533

  7. Collective oscillations and coupled modes in confined microfluidic droplet arrays

    Science.gov (United States)

    Schiller, Ulf D.; Fleury, Jean-Baptiste; Seemann, Ralf; Gompper, Gerhard

    Microfluidic droplets have a wide range of applications ranging from analytic assays in cellular biology to controlled mixing in chemical engineering. Ensembles of microfluidic droplets are interesting model systems for non-equilibrium many-body phenomena. When flowing in a microchannel, trains of droplets can form microfluidic crystals whose dynamics are governed by long-range hydrodynamic interactions and boundary effects. In this contribution, excitation mechanisms for collective waves in dense and confined microfluidic droplet arrays are investigated by experiments and computer simulations. We demonstrate that distinct modes can be excited by creating specific `defect' patterns in flowing droplet trains. While longitudinal modes exhibit a short-lived cascade of pairs of laterally displacing droplets, transversely excited modes form propagating waves that behave like microfluidic phonons. We show that the confinement induces a coupling between longitudinal and transverse modes. We also investigate the life time of the collective oscillations and discuss possible mechanisms for the onset of instabilities. Our results demonstrate that microfluidic phonons can exhibit effects beyond the linear theory, which can be studied particularly well in dense and confined systems. This work was supported by Deutsche Forschungsgemeinschaft under Grant No. SE 1118/4.

  8. Droplet Impact on Inclined Surfaces for Forensic Bloodstain Analysis

    Science.gov (United States)

    Smith, Marc; Lockard, Michael; Neitzel, G. Paul

    2015-11-01

    During a crime scene investigation, bloodstains are used to infer the size, impact angle, and velocity of the blood droplet that produced the stain. This droplet impact process was explored using experiments and numerical simulations of droplets impacting planar, inclined surfaces with different roughness and wetting properties over a range of Reynolds numbers (1,000 - 5,500) and Weber numbers (200 - 2,000) typical of some forensics applications. Results will be presented showing how the size and shape of the final elliptical bloodstain varies with impact angle and surface roughness. The common forensics practice to predict the impact angle is fairly accurate for near-normal impacts, but it under-predicts the angle for oblique impacts less than about 40° and this effect worsens for rougher surfaces. The spreading of the droplet normal to the impact plane is shown to follow that of a droplet under normal impact as the impact velocity increases. This effect is also lessened by increased surface roughness. The reasons for these effects will be explored using a new GPU-based wavelet-adaptive flow simulation, which can resolve the flows near the solid surface and near the moving contact line of these droplets for the large Reynolds and Weber numbers of these experiments. Supported by the National Institute of Justice.

  9. Quantification of protein interaction kinetics in a micro droplet

    Energy Technology Data Exchange (ETDEWEB)

    Yin, L. L. [Center for Bioelectronics and Biosensors, Biodesign Institute, Arizona State University, Tempe, Arizona 85287 (United States); College of Chemistry and Chemical Engineering, Chongqing University, Chongqing 400044 (China); Wang, S. P., E-mail: shaopeng.wang@asu.edu, E-mail: njtao@asu.edu; Shan, X. N.; Tao, N. J., E-mail: shaopeng.wang@asu.edu, E-mail: njtao@asu.edu [Center for Bioelectronics and Biosensors, Biodesign Institute, Arizona State University, Tempe, Arizona 85287 (United States); Zhang, S. T. [College of Chemistry and Chemical Engineering, Chongqing University, Chongqing 400044 (China)

    2015-11-15

    Characterization of protein interactions is essential to the discovery of disease biomarkers, the development of diagnostic assays, and the screening for therapeutic drugs. Conventional flow-through kinetic measurements need relative large amount of sample that is not feasible for precious protein samples. We report a novel method to measure protein interaction kinetics in a single droplet with sub microliter or less volume. A droplet in a humidity-controlled environmental chamber is replacing the microfluidic channels as the reactor for the protein interaction. The binding process is monitored by a surface plasmon resonance imaging (SPRi) system. Association curves are obtained from the average SPR image intensity in the center area of the droplet. The washing step required by conventional flow-through SPR method is eliminated in the droplet method. The association and dissociation rate constants and binding affinity of an antigen-antibody interaction are obtained by global fitting of association curves at different concentrations. The result obtained by this method is accurate as validated by conventional flow-through SPR system. This droplet-based method not only allows kinetic studies for proteins with limited supply but also opens the door for high-throughput protein interaction study in a droplet-based microarray format that enables measurement of many to many interactions on a single chip.

  10. Slide, Sweep and Vanish: Droplet manipulation by wettability engineering

    Science.gov (United States)

    Ghosh, Aritra; Ganguly, Ranjan; Schutzius, Thomas M.; Megaridis, Constantine M.

    2013-11-01

    Achieving controlled droplet transport on substrates is important for multiphase heat transfer, water harvesting and lab-on-chip applications. We use a facile, scalable surface wettability engineering approach to generate wettability patterned surfaces that comprise of superhydrophilic tracks of various geometrical patterns and length scales (μm -mm) on superhydrophobic backgrounds. Liquid transport on such surfaces harnesses the force arising from the spatial contrast of surface energy on the substrate, providing rapid actuation for micro and nanoliter drops. Considering a variety of dimensions, shapes and strategic locations of the superhydrophilic patterns on the substrate, effective modes of droplet transport through hemiwicking and Laplace pressure-driven flow are analyzed. The work provides proof-of-concept for salient digital microfluidic tasks, e.g. droplet capture, transport, merging and dispensing on such patterned substrates. This droplet manipulation is pumpless and fast. With suitable patterns and wettability contrast, we demonstrate on-chip droplet transport speeds of O(10 cm/s). The study examines the geometric and surface wettability parameters for optimal substrate design for droplet manipulation. On leave from Jadavpur University, India.

  11. Microfluidic droplet-based liquid-liquid extraction.

    Science.gov (United States)

    Mary, Pascaline; Studer, Vincent; Tabeling, Patrick

    2008-04-15

    We study microfluidic systems in which mass exchanges take place between moving water droplets, formed on-chip, and an external phase (octanol). Here, no chemical reaction takes place, and the mass exchanges are driven by a contrast in chemical potential between the dispersed and continuous phases. We analyze the case where the microfluidic droplets, occupying the entire width of the channel, extract a solute-fluorescein-from the external phase (extraction) and the opposite case, where droplets reject a solute-rhodamine-into the external phase (purification). Four flow configurations are investigated, based on straight or zigzag microchannels. Additionally to the experimental work, we performed two-dimensional numerical simulations. In the experiments, we analyze the influence of different parameters on the process (channel dimensions, fluid viscosities, flow rates, drop size, droplet spacing, ...). Several regimes are singled out. In agreement with the mass transfer theory of Young et al. (Young, W.; Pumir, A.; Pomeau, Y. Phys. Fluids A 1989, 1, 462), we find that, after a short transient, the amount of matter transferred across the droplet interface grows as the square root of time and the time it takes for the transfer process to be completed decreases as Pe-2/3, where Pe is the Peclet number based on droplet velocity and radius. The numerical simulation is found in excellent consistency with the experiment. In practice, the transfer time ranges between a fraction and a few seconds, which is much faster than conventional systems. PMID:18351786

  12. Carbon Nanotube Liquid Crystals: Nematic Droplets and Coarsening Dynamics

    Science.gov (United States)

    Behabtu, Natnael; Senyuk, Bohdan; Smalyukh, Ivan; Pasquali, Matteo

    2012-02-01

    On a fundamental basis, carbon nanotubes (CNTs) offer a new model molecule to explore the dynamics and phases of rigid rods and test theories. Their large aspect ratio (100 to 100,000) and persistence length (˜ 100 microns) allow exploring the physics of nematic phases with high Frank elastic constant. Moreover, understanding of CNT liquid crystals is key to their rational processing into ordered materials such as fibers. Here we report the formation of elongated nematic droplets of CNTs in chlorosulfonic acid. In nematic droplets, a continuous transition from a homogeneous to bipolar nematic director field is expected theoretically, as a function of droplet volume; yet, experimental determination of such transition has been elusive. We show that CNT nematic droplets display such transition. We study the coarsening dynamics of positive and negative nematic droplets and observe that two or more droplets merge by matching their nematic director. Merging scenarios that lead to defect formation are not observed. Negative tactoids (isotropic phase in liquid crystalline continuum) merge through attractive forces induced by the nematic director distortion with quadrupolar symmetry.

  13. A Computational Study of Internal Flows in a Heated Water-Oil Emulsion Droplet

    KAUST Repository

    Sim, Jaeheon

    2015-01-05

    The vaporization characteristics of water-oil emulsion droplets are investigated by high fidelity computational simulations. One of the key objectives is to identify the physical mechanism for the experimentally observed behavior that the component in the dispersed micro-droplets always vaporizes first, for both oil-in-water and water-in-oil emulsion droplets. The mechanism of this phenomenon has not been clearly understood. In this study, an Eulerian-Lagrangian method was implemented with a temperature-dependent surface tension model and a dynamic adaptive mesh refinement in order to effectively capture the thermo-capillary effect of a micro-droplet in an emulsion droplet efficiently. It is found that the temperature difference in an emulsion droplet creates a surface tension gradient along the micro-droplet surface, inducing surface movement. Subsequently, the outer shear flow and internal flow circulation inside the droplet, referred to as the Marangoni convection, are created. The present study confirms that the Marangoni effect can be sufficiently large to drive the micro-droplets to the emulsion droplet surface at higher temperature, for both water-in-oil and oil-and-water emulsion droplets. A further parametric study with different micro-droplet sizes and temperature gradients demonstrates that larger micro-droplets move faster with larger temperature gradient. The oil micro-droplet in oil-in-water emulsion droplets moves faster due to large temperature gradients by smaller thermal conductivity.

  14. Laboratory studies of collection efficiency of sub-micrometer aerosol particles by cloud droplets on a single droplet basis

    Directory of Open Access Journals (Sweden)

    K. Ardon-Dryer

    2015-03-01

    Full Text Available An experimental setup has been constructed to measure the Collection Efficiency (CE of sub-micrometer aerosol particles by cloud droplets. Water droplets of a dilute aqueous ammonium sulfate solution with a radius of ~20 μm fall freely into a chamber and collide with sub-micrometer Polystyrene Latex Sphere (PSL particles of variable size and concentrations. Two RH conditions, ~15 and ~88%, hereafter termed "Low" and "High", respectively, were varied with different particles size and concentrations. After passing through the chamber, the droplets and aerosol particles were sent to the Particle Analysis by Laser Mass Spectrometry (PALMS instrument to determine chemical compositions on a single particle basis. Coagulated droplets had mass spectra that contain signatures from both an aerosol particle and a droplet residual. CE values range from 5.7 × 10−3 to 4.6 × 10−2 for the Low RH and from 6.4 × 10−3 to 2.2 × 10−2 for the High RH cases. CE values were, within experimental uncertainty, independent of the aerosol concentrations. CE values in this work were found to be in agreement with previous experimental and theoretical studies. To our knowledge, this is the first coagulation experiment performed on a single droplet basis.

  15. Transgene detection by digital droplet PCR.

    Directory of Open Access Journals (Sweden)

    Dirk A Moser

    Full Text Available Somatic gene therapy is a promising tool for the treatment of severe diseases. Because of its abuse potential for performance enhancement in sports, the World Anti-Doping Agency (WADA included the term 'gene doping' in the official list of banned substances and methods in 2004. Several nested PCR or qPCR-based strategies have been proposed that aim at detecting long-term presence of transgene in blood, but these strategies are hampered by technical limitations. We developed a digital droplet PCR (ddPCR protocol for Insulin-Like Growth Factor 1 (IGF1 detection and demonstrated its applicability monitoring 6 mice injected into skeletal muscle with AAV9-IGF1 elements and 2 controls over a 33-day period. A duplex ddPCR protocol for simultaneous detection of Insulin-Like Growth Factor 1 (IGF1 and Erythropoietin (EPO transgenic elements was created. A new DNA extraction procedure with target-orientated usage of restriction enzymes including on-column DNA-digestion was established. In vivo data revealed that IGF1 transgenic elements could be reliably detected for a 33-day period in DNA extracted from whole blood. In vitro data indicated feasibility of IGF1 and EPO detection by duplex ddPCR with high reliability and sensitivity. On-column DNA-digestion allowed for significantly improved target detection in downstream PCR-based approaches. As ddPCR provides absolute quantification, it ensures excellent day-to-day reproducibility. Therefore, we expect this technique to be used in diagnosing and monitoring of viral and bacterial infection, in detecting mutated DNA sequences as well as profiling for the presence of foreign genetic material in elite athletes in the future.

  16. Numerical simulations of droplet train and free surface jet impingement

    International Nuclear Information System (INIS)

    Highlights: • The impingement heat transfer of a droplet train and free surface jet is compared numerically. • Results show that both jet configurations have higher cooling performance than the droplet train. • Droplet train exhibits pronounced temporal variations in stark contrast with the impinging jets. -- Abstract: The cooling behavior of the impingement of a droplet train, and free surface jets over a heated and pre-wetted surface is explored employing an Algebraic Volume-of-Fluid methodology. The code is based on a modified version of the two-phase numerical solver interFoam (OpenFOAM) (Trujillo and Lewis, 2012). Two versions of the free surface jet are studied. The first consists of a fully-developed profile exiting the nozzle, and the second is characterized by a uniform velocity distribution. Results show that both jet configurations have higher cooling performance than the droplet train locally and globally, with the fully-developed case being the most effective of the two jet arrangements. Locally, the performance is measured by radial profiles of the boundary-layer-displacement thickness and heat transfer coefficient. Globally, the cooling effectiveness is directly proportional to the surface area that resides within the high-convection region, i.e. before the boundary layer separation point. On a temporal basis, the liquid film within the impingement region of the droplet train exhibits pronounced variations in velocity magnitude and film thickness. This is directly attributed to the nature of continuous droplet impacts affecting the impingement region, and gives rise to an unsteady cooling and heating of the fluid near the wall. In contrast for the jets, the film and the corresponding free surface are nearly steady with only minor perturbations

  17. Fabrication of hemispherical liquid encapsulated structures based on droplet molding

    Science.gov (United States)

    Ishizuka, Hiroki; Miki, Norihisa

    2015-12-01

    We have developed and demonstrated a method for forming spherical structures of a thin polydimethylsiloxane (PDMS) membrane encapsulating a liquid. Liquid encapsulation can enhance the performance of microelectromechanical systems (MEMS) devices by providing deformability and improved dielectric properties. Parylene deposition and wafer bonding are applied to encapsulate liquid into a MEMS device. In parylene deposition, a parylene membrane is directly formed onto a liquid droplet. However, since the parylene membrane is stiff, the membrane is fragile. Although wafer bonding can encapsulate liquid between two substrates, the surface of the fabricated structure is normally flat. We propose a new liquid encapsulation method by dispensing liquid droplets. At first, a 20 μl PDMS droplet is dispensed on ethylene glycol. A 70 μl glycerin droplet is dispensed into a PDMS casting solution layer. The droplet forms a layer on heated ethylene glycol. Glycerin and ethylene glycol are chosen for their high boiling points. Additionally, a glycerin droplet is dispensed on the layer and surrounded by a thin PDMS casting solution film. The film is baked for 1 h at 75 °C. As the result, a structure encapsulating a liquid in a flexible PDMS membrane is obtained. We investigate the effects of the volume, surface tension, and guide thickness on the shape of the formed structures. We also evaluated the effect of the structure diameter on miniaturization. The structure can be adapted for various functions by changing the encapsulated liquid. We fabricated a stiffness-tunable structure by dispensing a magnetorheoligical fluid droplet with a stiffness that can be changed by an external magnetic field. We also confirmed that the proposed structure can produce stiffness differences that are distinguishable by humans.

  18. Efficient modelling of droplet dynamics on complex surfaces

    International Nuclear Information System (INIS)

    This work investigates the dynamics of droplet interaction with smooth or structured solid surfaces using a novel sharp-interface scheme which allows the efficient modelling of multiple dynamic contact lines. The liquid–gas and liquid–solid interfaces are treated in a unified context and the dynamic contact angle emerges simply due to the combined action of the disjoining and capillary pressure, and viscous stresses without the need of an explicit boundary condition or any requirement for the predefinition of the number and position of the contact lines. The latter, as it is shown, renders the model able to handle interfacial flows with topological changes, e.g. in the case of an impinging droplet on a structured surface. Then it is possible to predict, depending on the impact velocity, whether the droplet will fully or partially impregnate the structures of the solid, or will result in a ‘fakir’, i.e. suspended, state. In the case of a droplet sliding on an inclined substrate, we also demonstrate the built-in capability of our model to provide a prediction for either static or dynamic contact angle hysteresis. We focus our study on hydrophobic surfaces and examine the effect of the geometrical characteristics of the solid surface. It is shown that the presence of air inclusions trapped in the micro-structure of a hydrophobic substrate (Cassie–Baxter state) result in the decrease of contact angle hysteresis and in the increase of the droplet migration velocity in agreement with experimental observations for super-hydrophobic surfaces. Moreover, we perform 3D simulations which are in line with the 2D ones regarding the droplet mobility and also indicate that the contact angle hysteresis may be significantly affected by the directionality of the structures with respect to the droplet motion. (paper)

  19. Heterogeneous freezing of water droplets containing kaolinite and montmorillonite particles

    Directory of Open Access Journals (Sweden)

    B. J. Murray

    2010-04-01

    Full Text Available Clouds composed of both ice particles and supercooled liquid water droplets exist at temperatures above ~236 K. These mixed phase clouds, which strongly impact climate, are very sensitive to the presence of solid particles that can catalyse freezing. In this paper we describe experiments to determine the rate at which kaolinite and montmorillonite nucleate ice when immersed within water droplets. These are the first immersion mode experiments in which the ice nucleating ability of individual minerals has been determined quantitatively. Water droplets containing a known amount of clay mineral were supported on a hydrophobic surface and cooled at a rate of 10 K min−1. The temperatures at which individual 10–40 μm diameter droplets froze were determined by optical microscopy. As the concentration of kaolinite in the droplets was increased from 0.005 wt% to 1 wt% the median nucleation temperature increased from close to the homogeneous nucleation limit (236 K to 240.8±0.6 K. We go onto show that the probability of freezing scales with surface area of the kaolinite inclusions rather than, as is often assumed, the volume of the droplet. When droplets contained montmorillonite ice always nucleated at 245.8±0.6 K, independent of the mineral concentration. We report temperature dependent nucleation rates and present parameterisations for nucleation by these minerals which capture the surface area and cooling rate dependence of the nucleation rate. We show that our parameterisations produce significantly different results to parameterisations employed in global models. These results also highlight the importance of understanding the ice nucleating properties of individual minerals rather than complex mixtures of minerals found in natural dusts and so-called test dusts.

  20. Droplet size measurements for spray dryer scale-up.

    Science.gov (United States)

    Thybo, Pia; Hovgaard, Lars; Andersen, Sune Klint; Lindeløv, Jesper Saederup

    2008-01-01

    This study was dedicated to facilitate scale-up in spray drying from an atomization standpoint. The purpose was to investigate differences in operating conditions between a pilot and a production scale nozzle. The intension was to identify the operating ranges in which the two nozzles produced similar droplet size distributions. Furthermore, method optimization and validation were also covered. Externally mixing two-fluid nozzles of similar designs were used in this study. Both nozzles are typically used in commercially available spray dryers, and they have been characterized with respect to droplet size distributions as a function of liquid type, liquid flow rate, atomization gas flow rate, liquid orifice diameter, and atomization gas orifice diameter. All droplet size measurements were carried out by using the Malvern Spraytec with nozzle operating conditions corresponding to typical settings for spray drying. This gave droplets with Sauter Mean Diameters less than 40 microm and typically 5-20 microm. A model previously proposed by Mansour and Chigier was used to correlate the droplet size to the operating parameters. It was possible to make a correlation for water incorporating the droplet sizes for both the pilot scale and the production scale nozzle. However, a single correlation was not able to account properly for the physical properties of the liquid to be atomized. Therefore, the droplet size distributions of ethanol could not be adequately predicted on the basis of the water data. This study has shown that it was possible to scale up from a pilot to production scale nozzle in a systematic fashion. However, a prerequisite was that the nozzles were geometrically similar. When externally mixing two-fluid nozzles are used as atomizers, the results obtained from this study could be a useful guideline for selecting appropriate operating conditions when scaling up the spray-drying process. PMID:18379901