Effectiveness of Autologous Serum Eye Drops Combined With Punctal Plugs for the Treatment of Sjögren Syndrome-Related Dry Eye.

Science.gov (United States)

Liu, Ying; Hirayama, Masatoshi; Cui, Xin; Connell, Samuel; Kawakita, Tetsuya; Tsubota, Kazuo

2015-10-01

To evaluate the efficacy and safety of autologous serum (AS) eye drops combined with punctal plugs (PPs) in patients with Sjögren syndrome (SS)-related dry eye. A retrospective clinical study was performed in patients with dry eye caused by SS. We evaluated the Schirmer test value, tear breakup time (tBUT), and fluorescein and Rose Bengal (RB) staining scores at baseline, 3 months, 6 months, 1 year, and >1 year after treatment. The dry eye indexes were also evaluated in 2 subgroups, which determined by the using of PPs, including the AS + PP group and AS only group. A total of 56 eyes of 28 patients were investigated with a mean follow-up of 42.3 ± 26.1 months. After the application of AS eye drops, the Schirmer test showed no significant changes. The tBUT (2.7 ± 1.9 seconds) was significantly improved at each time point (3.9 ± 3.1, 4.5 ± 3.1, 3.7 ± 2.5, and 5.1 ± 4.0; P eye drops was found to be an effective and apparently safe treatment for SS dry eye. Furthermore, PPs in combination with AS eye drops were considered to have an additive effect on SS dry eye.

Thermostatic tissue platform for intravital microscopy: 'the hanging drop' model.

Science.gov (United States)

Pavlovic, Dragan; Frieling, Helge; Lauer, Kai-Stephan; Bac, Vo Hoai; Richter, Joern; Wendt, Michael; Lehmann, Christian; Usichenko, Taras; Meissner, Konrad; Gruendling, Matthias

2006-11-01

Intravital microscopy imposes the particular problem of the combined control of the body temperature of the animal and the local temperature of the observed organ or tissues. We constructed and tested, in the rat ileum microcirculation preparation, a new organ-support platform. The platform consisted of an organ bath filled with physiological solution, and contained a suction tube, a superfusion tube, an intestine-support hand that was attached to a micromanipulator and a thermometer probe. To cover the intestine we used a cover glass plate with a plastic ring glued on its upper surface. After a routine procedure (anaesthesia, monitoring and surgery), the intestine segment (2-3 cm long) was gently exteriorized and placed on the 'hand' of the organ support. A small part of the intestine formed a small 'island' in the bath that was filled with physiological salt solution. The cover glass was secured in place. The physiological salt solution from the superfusion tube, which was pointed to the lower surface of the cover glass, formed a 'hanging drop'. The objective of the microscope was then immersed into distilled water that was formed by the cover glass plastic ring. The 'hanging drop' technique prevented any tissue quenching, ensured undisturbed microcirculation, provided for stable temperature and humidity, and permitted a clear visual field.

Electrowetting-on-dielectrics for manipulation of oil drops and gas bubbles in aqueous-shell compound drops.

Science.gov (United States)

Li, Jiang; Wang, Yixuan; Chen, Haosheng; Wan, Jiandi

2014-11-21

We present the manipulation of oil, organic and gaseous chemicals by electrowetting-on-dielectric (EWOD) technology using aqueous-shell compound drops. We demonstrate that the transport and coalescence of viscous oil drops, the reaction of bromine with styrene in benzene solution, and the reaction of red blood cells with carbon monoxide bubbles can be accomplished using this method.

A combined coalescence gene-dropping tool for evaluating genomic selection in complex scenarios (ms2gs).

Science.gov (United States)

Pérez-Enciso, M; Legarra, A

2016-04-01

We present ms2gs, a combined coalescence - gene dropping (i.e. backward-forward) simulator for complex traits. It therefore aims at combining the advantages of both approaches. It is primarily conceived for very short term, recent scenarios such as those that are of interest in animal and plant breeding. It is very flexible in terms of defining QTL architecture and SNP ascertainment bias, and it allows for easy modelling of alternative markers such as RADs. It can use real sequence or chip data or generate molecular polymorphisms via the coalescence. It can generate QTL conditional on extant molecular information, such as low-density genotyping. It models (simplistically) sequence, imputation or genotyping errors. It requires as input both genotypic data in plink or ms formats, and a pedigree that is used to perform the gene dropping. By default, it compares accuracy for BLUP, SNP ascertained data, sequence, and causal SNPs. It employs VanRaden's linear (GBLUP) and nonlinear method for incorporating molecular information. To illustrate the program, we present a small application in a half-sib population and a multiparental (MAGIC) cross. The program, manual and examples are available at https://github.com/mperezenciso/ms2gs. © 2016 Blackwell Verlag GmbH.

Clinical effect observation of pranoprofen combined with deproteinized calf blood extract eye drops for moderate to severe dry eye

Directory of Open Access Journals (Sweden)

Jing-Hua Qiu

2018-04-01

Full Text Available AIM: To explore clinical effect of pranoprofen combined with deproteinized calf blood extract eye drops for moderate to severe dry eye. METHODS: A total of 84 patients(132 eyeswho received treatment at the Zhengzhou Second Hospital were selected from January 2016 to January 2017. According to random number table method they were divided into control group 42 cases(68 eyesand observation group 42 cases(64 eyes, the control group using polyvinyl alcohol eye drops with pranoprofen, observation group with pranoprofen with deproteinized extract of calf blood eye drops. Subjective and objective scores before and after treatment were recorded. RESULTS: There was no statistically significant difference on the four objective indicators of pretreatment FL, BUT, SⅠt, and vision between the two groups(P>0.05. Dry eye symptom scores of the two groups decreased after treatment, both with significantly different(PPPPCONCLUSION: The clinical effect of praprofen on the treatment of moderate to severe dry eye with the deproteinized calf blood extract is better.

Meta analysis on clinical effectiveness of Chinese medicine physiotherapy combined with tropicamide eye drops for pseudomyopia

OpenAIRE

Dan Li; Ling Shen; En-Li Deng

2018-01-01

AIM:To evaluate the curative effect of Chinese medicine physiotherapy combined with tropicamide eye drops to treat pseudomyopia in children and adolescent. METHODS: We collected randomized controlled trials from CNKI, CBM, Wanfang database, PubMed, EMBASE and Cochrane Library in 2000-2015, and the improved Jadad scale was used to evaluate the methodology of the literature, and the data was extracted. The Review Manager 5.3 statistical software was used for meta analysis. RESULTS: A total of 5...

Drop impact splashing and air entrapment

KAUST Repository

Thoraval, Marie-Jean

2013-03-01

Drop impact is a canonical problem in fluid mechanics, with numerous applications in industrial as well as natural phenomena. The extremely simple initial configuration of the experiment can produce a very large variety of fast and complex dynamics. Scientific progress was made in parallel with major improvements in imaging and computational technologies. Most recently, high-speed imaging video cameras have opened the exploration of new phenomena occurring at the micro-second scale, and parallel computing allowed realistic direct numerical simulations of drop impacts. We combine these tools to bring a new understanding of two fundamental aspects of drop impacts: splashing and air entrapment. The early dynamics of a drop impacting on a liquid pool at high velocity produces an ejecta sheet, emerging horizontally in the neck between the drop and the pool. We show how the interaction of this thin liquid sheet with the air, the drop or the pool, can produce micro-droplets and bubble rings. Then we detail how the breakup of the air film stretched between the drop and the pool for lower impact velocities can produce a myriad of micro-bubbles.

Spectrophotometric determination of iron species using a combination of artificial neural networks and dispersive liquid–liquid microextraction based on solidification of floating organic drop

International Nuclear Information System (INIS)

Moghadam, Masoud Rohani; Shabani, Ali Mohammad Haji; Dadfarnia, Shayessteh

2011-01-01

Highlights: ► Combination of DLLME-SFO/fiber optic-linear array detection/chemometric methods. ► Simultaneous determination of complexes with overlapping spectra. ► A novel DLLME-SFO method is proposed for extraction of iron species. ► The extracted iron species are simultaneous determined using PC-ANNs. ► The enhancement factor of 162 and 125 are achieved for Fe 3+ and Fe 2+ , respectively. - Abstract: A dispersive liquid–liquid microextraction based on solidification of floating organic drop (DLLME-SFO) and artificial neural networks method was developed for the simultaneous separation/preconcentration and speciation of iron in water samples. In this method, an appropriate mixture of ethanol (as the disperser solvent) and 1-undecanol (as the extracting solvent) containing appropriate amount of 2-thenoyltrifluoroacetone (TTA) (as the complexing agent) was injected rapidly into the water sample containing iron (II) and iron (III) species. At this step, the iron species interacted with the TTA and extracted into the 1-undecanol. After the phase separation, the absorbance of the extracted irons was measured in the wavelength region of 450–600 nm. The artificial neural networks were then applied for simultaneous determination of individual iron species. Under optimum conditions, the calibration graphs were linear in the range of 95–1070 μg L −1 and 31–350 μg L −1 with detection limits of 25 and 8 μg L −1 for iron (II) and iron (III), respectively. The relative standard deviations (R.S.D., n = 6) were lower than 4.2%. The enhancement factor of 162 and 125 were obtained for Fe 3+ and Fe 2+ ions, respectively. The procedure was applied to power plant drum water and several potable water samples; and accuracy was assessed through the recovery experiments and independent analysis by graphite furnace atomic absorption spectrometry.

Efficacy and tolerability of preservative-free eye drops containing a fixed combination of dorzolamide and timolol in glaucoma patients.

Science.gov (United States)

Renieri, Giulia; Führer, Katrin; Scheithe, Karl; Lorenz, Katrin; Pfeiffer, Norbert; Thieme, Hagen

2010-12-01

To evaluate the efficacy and tolerability of preservative-free eye drops (dorzolamide/timolol) in routine management of preservative-sensitive glaucoma patients. Data from 2,298 glaucoma patients requiring intraocular pressure (IOP) reduction and suffering from intolerance to benzalkonium chloride or active agents of previously used eye drops were valid for baseline and safety analysis in this prospective, open, noncomparative, multicenter, noninterventional study. Patients were treated with preservative-free dorzolamide/timolol eye drops for 12 weeks. Main efficacy endpoint was IOP reduction after 12 weeks of treatment. Two thousand forty-nine patients were considered for efficacy analysis. Tolerability was assessed by evaluating adverse drug reactions. Mean baseline IOP was 20.8 mmHg. Baseline IOP was reduced to 16.7 mmHg after 12 weeks of treatment corresponding to a mean absolute (percent) change of -4.1 mmHg (-17.3%). The proportion of patients with IOP ≤21 mmHg increased from 59.9% at baseline to 94.6% after 12 weeks. The most frequently reported ocular adverse drug reactions were burning eyes (2.4%) and hyperemia (0.9%). Local tolerability improved in 79.3% of patients compared to their previous glaucoma therapy. This observational study confirms the IOP lowering effect of preservative-free eye drops containing the fixed combination of dorzolamide/timolol in a large patient's population. The drug was well tolerated and improved the local tolerability in the vast majority of patients.

Impact of organic nutrient load on biomass accumulation, feed channel pressure drop increase and permeate flux decline in membrane systems

KAUST Repository

Bucs, Szilard

2014-12-01

The influence of organic nutrient load on biomass accumulation (biofouling) and pressure drop development in membrane filtration systems was investigated. Nutrient load is the product of nutrient concentration and linear flow velocity. Biofouling - excessive growth of microbial biomass in membrane systems - hampers membrane performance. The influence of biodegradable organic nutrient load on biofouling was investigated at varying (i) crossflow velocity, (ii) nutrient concentration, (iii) shear, and (iv) feed spacer thickness. Experimental studies were performed with membrane fouling simulators (MFSs) containing a reverse osmosis (RO) membrane and a 31 mil thick feed spacer, commonly applied in practice in RO and nanofiltration (NF) spiral-wound membrane modules. Numerical modeling studies were done with identical feed spacer geometry differing in thickness (28, 31 and 34 mil). Additionally, experiments were done applying a forward osmosis (FO) membrane with varying spacer thickness (28, 31 and 34 mil), addressing the permeate flux decline and biofilm development. Assessed were the development of feed channel pressure drop (MFS studies), permeate flux (FO studies) and accumulated biomass amount measured by adenosine triphosphate (ATP) and total organic carbon (TOC).Our studies showed that the organic nutrient load determined the accumulated amount of biomass. The same amount of accumulated biomass was found at constant nutrient load irrespective of linear flow velocity, shear, and/or feed spacer thickness. The impact of the same amount of accumulated biomass on feed channel pressure drop and permeate flux was influenced by membrane process design and operational conditions. Reducing the nutrient load by pretreatment slowed-down the biofilm formation. The impact of accumulated biomass on membrane performance was reduced by applying a lower crossflow velocity and/or a thicker and/or a modified geometry feed spacer. The results indicate that cleanings can be delayed

Ultrasonic characterization of single drops of liquids

Energy Technology Data Exchange (ETDEWEB)

Sinha, Dipen N. (Los Alamos, NM)

1998-01-01

Ultrasonic characterization of single drops of liquids. The present invention includes the use of two closely spaced transducers, or one transducer and a closely spaced reflector plate, to form an interferometer suitable for ultrasonic characterization of droplet-size and smaller samples without the need for a container. The droplet is held between the interferometer elements, whose distance apart may be adjusted, by surface tension. The surfaces of the interferometer elements may be readily cleansed by a stream of solvent followed by purified air when it is desired to change samples. A single drop of liquid is sufficient for high-quality measurement. Examples of samples which may be investigated using the apparatus and method of the present invention include biological specimens (tear drops; blood and other body fluid samples; samples from tumors, tissues, and organs; secretions from tissues and organs; snake and bee venom, etc.) for diagnostic evaluation, samples in forensic investigations, and detection of drugs in small quantities.

Ultrasonic characterization of single drops of liquids

Energy Technology Data Exchange (ETDEWEB)

Sinha, D.N.

1998-04-14

Ultrasonic characterization of single drops of liquids is disclosed. The present invention includes the use of two closely spaced transducers, or one transducer and a closely spaced reflector plate, to form an interferometer suitable for ultrasonic characterization of droplet-size and smaller samples without the need for a container. The droplet is held between the interferometer elements, whose distance apart may be adjusted, by surface tension. The surfaces of the interferometer elements may be readily cleansed by a stream of solvent followed by purified air when it is desired to change samples. A single drop of liquid is sufficient for high-quality measurement. Examples of samples which may be investigated using the apparatus and method of the present invention include biological specimens (tear drops; blood and other body fluid samples; samples from tumors, tissues, and organs; secretions from tissues and organs; snake and bee venom, etc.) for diagnostic evaluation, samples in forensic investigations, and detection of drugs in small quantities. 5 figs.

Curative effect of Sodium hyaluronate and bFGF eye drops after corneal rust foreign body removal operation

Directory of Open Access Journals (Sweden)

Jin-Xia Li1

2013-10-01

Full Text Available AIM: To observe the combined effect of Sodium hyaluronate eye drops and recombinant bovine basic fibroblast growth factor(bFGFeye drops on cornea epithelial repair after corneal rust foreign body extraction. METHODS: Alinety-eight cases(98 eyesof corneal rust foreign body patients were randomly distributed to combined treatment group(49 cases, 49 eyesand control group(49 cases, 49 eyes. Hyaluronate eye drops, recombinant bFGF eye drops and levofloxacin hydrochloride were applied in combined treatment group after corneal foreign body extraction. Recombinant bFGF eye drops and levofloxacin hydrochloride were applied in control group. Corneal fluorescein stain, cornea epithelial repair and local symptoms were examined thrice weekly for 2 weeks. RESULTS: General effective rate of treatment in combined group reach 96%, significantly higher than that in control group(88%, PCONCLUSION: Combined application of sodium hyaluronate eye drops and recombinant bFGF eye drops can prominently improve cornea epithelial repair after corneal lesion with proven effectiveness and safety.

High performance ceria-bismuth bilayer electrolyte low temperature solid oxide fuel cells (LT-SOFCs) fabricated by combining co-pressing with drop-coating

KAUST Repository

Hou, Jie

2015-03-24

The Sm0.075Nd0.075Ce0.85O2-δ-Er0.4Bi1.6O3 bilayer structure film, which showed an encouraging performance in LT-SOFCs, was successfully fabricated by a simple low cost technique combining one-step co-pressing with drop-coating.

High performance ceria-bismuth bilayer electrolyte low temperature solid oxide fuel cells (LT-SOFCs) fabricated by combining co-pressing with drop-coating

KAUST Repository

Hou, Jie; Bi, Lei; Qian, Jing; Zhu, Zhiwen; Zhang, Junyu; Liu, Wei

2015-01-01

The Sm0.075Nd0.075Ce0.85O2-δ-Er0.4Bi1.6O3 bilayer structure film, which showed an encouraging performance in LT-SOFCs, was successfully fabricated by a simple low cost technique combining one-step co-pressing with drop-coating.

Seamless Combination of Fluorescence-Activated Cell Sorting and Hanging-Drop Networks for Individual Handling and Culturing of Stem Cells and Microtissue Spheroids.

Science.gov (United States)

Birchler, Axel; Berger, Mischa; Jäggin, Verena; Lopes, Telma; Etzrodt, Martin; Misun, Patrick Mark; Pena-Francesch, Maria; Schroeder, Timm; Hierlemann, Andreas; Frey, Olivier

2016-01-19

Open microfluidic cell culturing devices offer new possibilities to simplify loading, culturing, and harvesting of individual cells or microtissues due to the fact that liquids and cells/microtissues are directly accessible. We present a complete workflow for microfluidic handling and culturing of individual cells and microtissue spheroids, which is based on the hanging-drop network concept: The open microfluidic devices are seamlessly combined with fluorescence-activated cell sorting (FACS), so that individual cells, including stem cells, can be directly sorted into specified culturing compartments in a fully automated way and at high accuracy. Moreover, already assembled microtissue spheroids can be loaded into the microfluidic structures by using a conventional pipet. Cell and microtissue culturing is then performed in hanging drops under controlled perfusion. On-chip drop size control measures were applied to stabilize the system. Cells and microtissue spheroids can be retrieved from the chip by using a parallelized transfer method. The presented methodology holds great promise for combinatorial screening of stem-cell and multicellular-spheroid cultures.

Reassembly of anterior pituitary organization by hanging drop three-dimensional cell culture.

Science.gov (United States)

Tsukada, Takehiro; Kouki, Tom; Fujiwara, Ken; Ramadhani, Dini; Horiguchi, Kotaro; Kikuchi, Motoshi; Yashiro, Takashi

2013-08-29

The anterior pituitary gland comprises 5 types of hormone-producing cells and non-endocrine cells, such as folliculostellate (FS) cells. The cells form a lobular structure surrounded by extracellular matrix (ECM) but are not randomly distributed in each lobule; hormone-producing cells have affinities for specific cell types (topographic affinity), and FS cells form a homotypic meshwork. To determine whether this cell and ECM organization can be reproduced in vitro, we developed a 3-dimensional (3D) model that utilizes hanging drop cell culture. We found that the topographic affinities of hormone-producing cells were indeed maintained (ie, GH to ACTH cells, GH to TSH cells, PRL to LH/FSH cells). Fine structures in hormone-producing cells retained their normal appearance. In addition, FS cells displayed well-developed cytoplasmic protrusions, which interconnected with adjacent FS cells to form a 3D meshwork. In addition, reassembly of gap junctions and pseudofollicles among FS cells was observed in cell aggregates. Major ECM components-collagens and laminin-were deposited and distributed around the cells. In sum, the dissociated anterior pituitary cells largely maintained their in vivo anterior pituitary architectures. This culture system appears to be a powerful experimental tool for detailed analysis of anterior pituitary cell organization.

Drop jumping. II. The influence of dropping height on the biomechanics of drop jumping

NARCIS (Netherlands)

Bobbert, M F; Huijing, P A; van Ingen Schenau, G J

In the literature, athletes preparing for explosive activities are recommended to include drop jumping in their training programs. For the execution of drop jumps, different techniques and different dropping heights can be used. This study was designed to investigate for the performance of bounce

First drop dissimilarity in drop-on-demand inkjet devices

International Nuclear Information System (INIS)

Famili, Amin; Palkar, Saurabh A.; Baldy, William J. Jr.

2011-01-01

As inkjet printing technology is increasingly applied in a broader array of applications, careful characterization of its method of use is critical due to its inherent sensitivity. A common operational mode in inkjet technology known as drop-on-demand ejection is used as a way to deliver a controlled quantity of material to a precise location on a target. This method of operation allows ejection of individual or a sequence (burst) of drops based on a timed trigger event. This work presents an examination of sequences of drops as they are ejected, indicating a number of phenomena that must be considered when designing a drop-on-demand inkjet system. These phenomena appear to be driven by differences between the first ejected drop in a burst and those that follow it and result in a break-down of the linear relationship expected between driving amplitude and drop mass. This first drop, as quantified by high-speed videography and subsequent image analysis, can be different in morphology, trajectory, velocity, and volume from subsequent drops within a burst. These findings were confirmed orthogonally by both volume and mass measurement techniques which allowed quantitation down to single drops.

Insights from the pollination drop proteome and the ovule transcriptome of Cephalotaxus at the time of pollination drop production.

Science.gov (United States)

Pirone-Davies, Cary; Prior, Natalie; von Aderkas, Patrick; Smith, Derek; Hardie, Darryl; Friedman, William E; Mathews, Sarah

2016-05-01

Many gymnosperms produce an ovular secretion, the pollination drop, during reproduction. The drops serve as a landing site for pollen, but also contain a suite of ions and organic compounds, including proteins, that suggests diverse roles for the drop during pollination. Proteins in the drops of species of Chamaecyparis, Juniperus, Taxus, Pseudotsuga, Ephedra and Welwitschia are thought to function in the conversion of sugars, defence against pathogens, and pollen growth and development. To better understand gymnosperm pollination biology, the pollination drop proteomes of pollination drops from two species of Cephalotaxus have been characterized and an ovular transcriptome for C. sinensis has been assembled. Mass spectrometry was used to identify proteins in the pollination drops of Cephalotaxus sinensis and C. koreana RNA-sequencing (RNA-Seq) was employed to assemble a transcriptome and identify transcripts present in the ovules of C. sinensis at the time of pollination drop production. About 30 proteins were detected in the pollination drops of both species. Many of these have been detected in the drops of other gymnosperms and probably function in defence, polysaccharide metabolism and pollen tube growth. Other proteins appear to be unique to Cephalotaxus, and their putative functions include starch and callose degradation, among others. Together, the proteins appear either to have been secreted into the drop or to occur there due to breakdown of ovular cells during drop production. Ovular transcripts represent a wide range of gene ontology categories, and some may be involved in drop formation, ovule development and pollen-ovule interactions. The proteome of Cephalotaxus pollination drops shares a number of components with those of other conifers and gnetophytes, including proteins for defence such as chitinases and for carbohydrate modification such as β-galactosidase. Proteins likely to be of intracellular origin, however, form a larger component of drops

An experimental analysis of flow boiling and pressure drop in a brazed plate heat exchanger for organic Rankine cycle power systems

DEFF Research Database (Denmark)

Desideri, Adriano; Zhang, Ji; Kærn, Martin Ryhl

2017-01-01

Organic Rankine cycle power systems for low quality waste heat recovery applications can play a major role in achieving targets of increasing industrial processes efficiency and thus reducing the emissions of greenhouse gases. Low capacity organic Rankine cycle systems are equipped with brazed...... and pressure drop during vaporization at typical temperatures for low quality waste heat recovery organic Rankine cycle systems are presented for the working fluids HFC-245fa and HFO-1233zd. The experiments were carried out at saturation temperatures of 100°C, 115°C and 130°C and inlet and outlet qualities...

Performance Analysis of an Evaporator for a Diesel Engine–Organic Rankine Cycle (ORC Combined System and Influence of Pressure Drop on the Diesel Engine Operating Characteristics

Directory of Open Access Journals (Sweden)

Chen Bei

2015-06-01

Full Text Available The main purpose of this research is to analyze the performance of an evaporator for the organic Rankine cycle (ORC system and discuss the influence of the evaporator on the operating characteristics of diesel engine. A simulation model of fin-and-tube evaporator of the ORC system is established by using Fluent software. Then, the flow and heat transfer characteristics of the exhaust at the evaporator shell side are obtained, and then the performance of the fin-and-tube evaporator of the ORC system is analyzed based on the field synergy principle. The field synergy angle (β is the intersection angle between the velocity vector and the temperature gradient. When the absolute values of velocity and temperature gradient are constant and β < 90°, heat transfer enhancement can be achieved with the decrease of the β. When the absolute values of velocity and temperature gradient are constant and β >90°, heat transfer enhancement can be achieved with the increase of the β. Subsequently, the influence of the evaporator of the ORC system on diesel engine performance is studied. A simulation model of the diesel engine is built by using GT–Power software under various operating conditions, and the variation tendency of engine power, torque, and brake specific fuel consumption (BSFC are obtained. The variation tendency of the power output and BSFC of diesel engine–ORC combined system are obtained when the evaporation pressure ranges from 1.0 MPa to 3.5 MPa. Results show that the field synergy effect for the areas among the tube bundles of the evaporator main body and the field synergy effect for the areas among the fins on the windward side are satisfactory. However, the field synergy effect in the areas among the fins on the leeward side is weak. As a result of the pressure drop caused by the evaporator of the ORC system, the diesel engine power and torque decreases slightly, whereas the BSFC increases slightly with the increase of exhaust back

STUDY ON SOFTENING AND DROPPING PROPERTIES OF METALIZED BURDEN INSIDE BLAST FURNACE

Directory of Open Access Journals (Sweden)

Bi-yang Tuo

2014-12-01

Full Text Available The inferences of burden metallization rate on softening-melting dropping properties were investigated through softening-melting dropping test of three kinds of metalized burden pressure drop. The results indicated that the softeningmelting temperature interval of pre-reduction mixed burden is bigger than primeval mixed burden, the melting interval narrow with the rise of metallization rate of ferric burden as well as dropping temperature interval. The average pressure drop, maximum pressure drop and softening-melting dropping properties eigenvalue decrease with the rise of metallization rate of ferric burden. Besides, the dropping temperature of burden reduces with the rise of carbon content of molten iron. The combination high metalized burden and higher carbon content of molten iron is benefit to decreasing thickness of cohesive zone and improve permeability of cohesive zone.

O the Electrohydrodynamics of Drop Extraction from a Conductive Liquid Meniscus

Science.gov (United States)

Wright, Graham Scott

This thesis is concerned with the use of an electric field in the extraction of liquid drops from a capillary orifice or nozzle. The motivating application is ink jet printing. Current drop-on-demand ink jets use pressure pulses to eject drops. Literature on electrostatic spraying suggests that by using an electric field, drops could be produced with a wider range of sizes and speeds than is possible with pressure ejection. Previous efforts to apply electric spraying to printing or similar selective coating tasks have taken an experimental approach based on steady or periodic spraying phenomena, without attempting cycle -by-cycle drop control. The centerpiece of this thesis is a simulation tool developed to explore such possibilities. A simplified analytic model is developed as a preliminary step, yielding formulas for force and time scales that provide an appropriate basis for nondimensionalization of the governing differential equations; important dimensionless parameters are identified. The complete self-consistent model permits simulation of meniscus behavior under time -varying applied voltage or pressure, with the electric field solution continually updated as the surface changes shape. The model uses a quasi-one-dimensional hydrodynamic formulation and a two-dimensional axisymmetric boundary element solution for the electric field. The simulation is checked against experimental results for meniscus stability, resonant modes, and drop emission under electric field. The simulation faithfully captures important qualitative aspects of meniscus behavior and gives reasonable quantitative agreement within the limitations of the model. Insights gained in simulation point the way to a successful laboratory demonstration of drop extraction using a shaped voltage pulse. Drop size control is pursued in simulation using pressure and voltage pulses both alone and in combination, for both light and viscous liquids. Combining pressure and field pulses is shown to be

A novel Caulimovirus associated with a complete fruit drop symptom in ‘Bluecrop’ blueberry

Science.gov (United States)

Here we describe the nucleotide sequence and genome organization of a novel virus in the family Caulimoviridae from ‘Bluecrop’ blueberry plants that exhibited fruit drop symptoms. The virus is tentatively named Blueberry fruit drop associated virus (BFDaV). Blueberry fruit drop disease (BFDD) was fi...

Rapid determination of caffeine in one drop of beverages and foods using drop-to-drop solvent microextraction with gas chromatography/mass spectrometry.

Science.gov (United States)

Shrivas, Kamlesh; Wu, Hui-Fen

2007-11-02

A simple and rapid sample cleanup and preconcentration method for the quantitative determination of caffeine in one drop of beverages and foods by gas chromatography/mass spectrometry (GC/MS) has been proposed using drop-to-drop solvent microextraction (DDSME). The best optimum experimental conditions for DDSME were: chloroform as the extraction solvent, 5 min extraction time, 0.5 microL exposure volume of the extraction phase and no salt addition at room temperature. The optimized methodology exhibited good linearity between 0.05 and 5.0 microg/mL with correlation coefficient of 0.980. The relative standard deviation (RSD) and limits of detection (LOD) of the DDSME/GC/MS method were 4.4% and 4.0 ng/mL, respectively. Relative recovery of caffeine in beverages and foods were found to be 96.6-101%, which showing good reliability of this method. This DDSME excludes the major disadvantages of conventional method of caffeine extraction, like large amount of organic solvent and sample consumption and long sample pre-treatment process. So, this approach proves that the DDSME/GC/MS technique can be applied as a simple, fast and feasible diagnosis tool for environmental, food and biological application for extremely small amount of real sample analysis.

Drop Impact Dynamics with Sessile Drops and Geometries: Spreading, Jetting, and Fragmentation

Science.gov (United States)

Tilger, Christopher F.

The tendency of surface tension to cause small parcels of fluid to form into drops allows convenient packaging, transport, dispersal of liquid phase matter. Liquid drop impacts with solids, liquids, and other drops have realized and additional future applications in biological, manufacturing, heat transfer, and combustion systems. Experiments were conducted to investigate the dynamics of multiple drop collisions, rather than the most-studied phenomenon of single drop impacts. Additional drop impacts were performed on rigid hemispheres representing sessile drops, angled substrates, and into the vertex of two tilted surfaces arranged into a vee shape. A qualitative inspection of drop-sessile drop impacts shows distinct post-impact shapes depending on the offset distance between the drops. At intermediate offset distances, distinct jets issue from the overlap region between the two drops projected areas. These jets are observed to reach their maximum extent at a critical offset distance ratio, epsilon epsilon ˜ 0.75-0.80, with substrate contact angle and W e having a lesser effect. Capillary waves that traverse the sessile drop after collision cause a lower aspect ratio liquid column to emanate from the sessile drop opposite the impact. In order to better understand the jetting phenomenon seen in the offset drop-sessile drop impacts, simpler solid geometries are investigated that elicit a similar behavior. Solid hemispheres do not show the singular jetting observed in the fluidic case, however, a simple vee formed by two intersection planar substrates do jet in a similar fashion to the fluidic case. A geometric model with partnered experiments is developed to describe the bisymmetric spread of an impacting drop on an angled substrate. This geometric model is used to guide a time of arrival based model for various features of the drop impact, which is used to predict jetting in various vee channel experiments.

Cavity optomechanics in a levitated helium drop

Science.gov (United States)

Childress, L.; Schmidt, M. P.; Kashkanova, A. D.; Brown, C. D.; Harris, G. I.; Aiello, A.; Marquardt, F.; Harris, J. G. E.

2017-12-01

We describe a proposal for a type of optomechanical system based on a drop of liquid helium that is magnetically levitated in vacuum. In the proposed device, the drop would serve three roles: its optical whispering-gallery modes would provide the optical cavity, its surface vibrations would constitute the mechanical element, and evaporation of He atoms from its surface would provide continuous refrigeration. We analyze the feasibility of such a system in light of previous experimental demonstrations of its essential components: magnetic levitation of mm-scale and cm-scale drops of liquid He , evaporative cooling of He droplets in vacuum, and coupling to high-quality optical whispering-gallery modes in a wide range of liquids. We find that the combination of these features could result in a device that approaches the single-photon strong-coupling regime, due to the high optical quality factors attainable at low temperatures. Moreover, the system offers a unique opportunity to use optical techniques to study the motion of a superfluid that is freely levitating in vacuum (in the case of 4He). Alternatively, for a normal fluid drop of 3He, we propose to exploit the coupling between the drop's rotations and vibrations to perform quantum nondemolition measurements of angular momentum.

Optimization of dispersive liquid-phase microextraction based on solidified floating organic drop combined with high-performance liquid chromatography for the analysis of glucocorticoid residues in food.

Science.gov (United States)

Huang, Yuan; Zheng, Zhiqun; Huang, Liying; Yao, Hong; Wu, Xiao Shan; Li, Shaoguang; Lin, Dandan

2017-05-10

A rapid, simple, cost-effective dispersive liquid-phase microextraction based on solidified floating organic drop (SFOD-LPME) was developed in this study. Along with high-performance liquid chromatography, we used the developed approach to determine and enrich trace amounts of four glucocorticoids, namely, prednisone, betamethasone, dexamethasone, and cortisone acetate, in animal-derived food. We also investigated and optimized several important parameters that influenced the extraction efficiency of SFOD-LPME. These parameters include the extractant species, volumes of extraction and dispersant solvents, sodium chloride addition, sample pH, extraction time and temperature, and stirring rate. Under optimum experimental conditions, the calibration graph exhibited linearity over the range of 1.2-200.0ng/ml for the four analytes, with a reasonable linearity(r 2 : 0.9990-0.9999). The enrichment factor was 142-276, and the detection limits was 0.39-0.46ng/ml (0.078-0.23μg/kg). This method was successfully applied to analyze actual food samples, and good spiked recoveries of over 81.5%-114.3% were obtained. Copyright © 2017. Published by Elsevier B.V.

Water Penetration through a Superhydrophobic Mesh During a Drop Impact

Science.gov (United States)

Ryu, Seunggeol; Sen, Prosenjit; Nam, Youngsuk; Lee, Choongyeop

2017-01-01

When a water drop impacts a mesh having submillimeter pores, a part of the drop penetrates through the mesh if the impact velocity is sufficiently large. Here we show that different surface wettability, i.e., hydrophobicity and superhydrophobicity, leads to different water penetration dynamics on a mesh during drop impact. We show, despite the water repellence of a superhydrophobic surface, that water can penetrate a superhydrophobic mesh more easily (i.e., at a lower impact velocity) over a hydrophobic mesh via a penetration mechanism unique to a superhydrophobic mesh. On a superhydrophobic mesh, the water penetration can occur during the drop recoil stage, which appears at a lower impact velocity than the critical impact velocity for water penetration right upon impact. We propose that this unique water penetration on a superhydrophobic mesh can be attributed to the combination of the hydrodynamic focusing and the momentum transfer from the water drop when it is about to bounce off the surface, at which point the water drop retrieves most of its kinetic energy due to the negligible friction on superhydrophobic surfaces.

Speciation and determination of ultra trace amounts of chromium by solidified floating organic drop microextraction (SFODME) and graphite furnace atomic absorption spectrometry

Energy Technology Data Exchange (ETDEWEB)

Moghadam, Masoud Rohani [Department of Chemistry, Faculty of Science, Yazd University, Yazd 89195-741 (Iran, Islamic Republic of); Dadfarnia, Shayessteh, E-mail: sdadfarnia@yazduni.ac.ir [Department of Chemistry, Faculty of Science, Yazd University, Yazd 89195-741 (Iran, Islamic Republic of); Haji Shabani, Ali Mohammad [Department of Chemistry, Faculty of Science, Yazd University, Yazd 89195-741 (Iran, Islamic Republic of)

2011-02-15

Solidified floating organic drop microextraction (SFODME) method in combination with graphite furnace atomic absorption spectrometry (GFAAS) has been used for the determination of chromium species in water and urine samples. 1-undecanol containing 2-thenoyltrifluoroacetone (TTA) was used as a selective chelating agent for the extraction of Cr(III). The total Cr was determined after the reduction of Cr(VI) to Cr(III) with hydroxylamine. The concentration of Cr(VI) was determined from the difference between the concentration of total chromium and the Cr(III). Several variables such as the sample pH, concentration of TTA, salt concentration, extraction time and the sample volume were investigated in detail. Under the optimum conditions, the limit of detection of the proposed method was 0.006 {mu}g l{sup -1} for Cr(III) and the relative standard deviation for six replicate determinations at 0.1 {mu}g l{sup -1} Cr(III) was 5.1%. The proposed method was successfully applied for the determination of chromium species in tap water, well water, mineral water, and urine samples.

Role of Structural Asymmetry in Controlling Drop Spacing in Microfluidic Ladder Networks

Science.gov (United States)

Wang, William; Maddala, Jeevan; Vanapalli, Siva; Rengasamy, Raghunathan

2012-02-01

Manipulation of drop spacing is crucial to many processes in microfluidic devices including drop coalescence, detection and storage. Microfluidic ladder networks ---where two droplet-carrying parallel channels are connected by narrow bypass channels through which the motion of drops is forbidden---have been proposed as a means to control relative separation between pairs of drops. Prior studies in microfluidic ladder networks with vertical bypasses, which possess fore-aft structural symmetry, have revealed that pairs of drops can only undergo reduction in drop spacing at the ladder exit. We investigate the dynamics of drops in microfluidic ladder networks with both vertical and slanted bypasses. Our analytical results indicate that unlike symmetric ladder networks, structural asymmetry introduced by a single slanted bypass can be used to modulate the relative spacing between drops, enabling them to contract, synchronize, expand or even flip at the ladder exit. Our experiments confirm all the behaviors predicted by theory. Numerical analysis further shows that ladders containing several identical bypasses can only linearly transform the input drop spacing. Finally, we find that ladders with specific combinations of vertical and slanted bypasses can generate non-linear transformation of input drop spacing, despite the absence of drop decision-making events at the bypass junctions.

Treatment of bacterial ulcers of the cornea in the rabbit: a comparison of administration by eye drops and subconjunctival injections.

OpenAIRE

Baum, J

1982-01-01

The various routes of antibiotic administration available to treat a bacterial corneal ulcer were reviewed and compared, and the pharmacokinetics and efficacy of each route analyzed in the rabbit. I then evaluated the efficacy of eye drops and subconjunctival injections in the treatment of bacterial corneal ulcers for each of the following drug-organism combinations: staphylococcal ulcers/cefazolin, staphylococcal ulcers/gentamicin and Pseudomonas ulcers/gentamicin. Both topical and subconjun...

[Optimize dropping process of Ginkgo biloba dropping pills by using design space approach].

Science.gov (United States)

Shen, Ji-Chen; Wang, Qing-Qing; Chen, An; Pan, Fang-Lai; Gong, Xing-Chu; Qu, Hai-Bin

2017-07-01

In this paper, a design space approach was applied to optimize the dropping process of Ginkgo biloba dropping pills. Firstly, potential critical process parameters and potential process critical quality attributes were determined through literature research and pre-experiments. Secondly, experiments were carried out according to Box-Behnken design. Then the critical process parameters and critical quality attributes were determined based on the experimental results. Thirdly, second-order polynomial models were used to describe the quantitative relationships between critical process parameters and critical quality attributes. Finally, a probability-based design space was calculated and verified. The verification results showed that efficient production of Ginkgo biloba dropping pills can be guaranteed by operating within the design space parameters. The recommended operation ranges for the critical dropping process parameters of Ginkgo biloba dropping pills were as follows: dropping distance of 5.5-6.7 cm, and dropping speed of 59-60 drops per minute, providing a reference for industrial production of Ginkgo biloba dropping pills. Copyright© by the Chinese Pharmaceutical Association.

Lambda-dropping

DEFF Research Database (Denmark)

Danvy, Olivier; Schultz, Ulrik Pagh

1997-01-01

Lambda-lifting a functional program transforms it into a set of recursive equations. We present the symmetric transformation: lambda-dropping. Lambda-dropping a set of recursive equations restores block structure and lexical scope.For lack of scope, recursive equations must carry around all...... the parameters that any of their callees might possibly need. Both lambda-lifting and lambda-dropping thus require one to compute a transitive closure over the call graph:• for lambda-lifting: to establish the Def/Use path of each free variable (these free variables are then added as parameters to each...... of the functions in the call path);• for lambda-dropping: to establish the Def/Use path of each parameter (parameters whose use occurs in the same scope as their definition do not need to be passed along in the call path).Without free variables, a program is scope-insensitive. Its blocks are then free...

Hydrocarbon Degradation In Poultry Droppings And Cassava Peels ...

African Journals Online (AJOL)

This greenhouse study was aimed at determining the potentials of poultry droppings (PD) and cassava peels (CP) for nutrient-enhanced biodegradation of petroleum hydrocarbon (THC) in a well drained Typic Paleustults using the THC levels and degradation duration as remediation indices. The performance of the organic ...

Controlling charge on levitating drops.

Science.gov (United States)

Hilger, Ryan T; Westphall, Michael S; Smith, Lloyd M

2007-08-01

Levitation technologies are used in containerless processing of materials, as microscale manipulators and reactors, and in the study of single drops and particles. Presented here is a method for controlling the amount and polarity of charge on a levitating drop. The method uses single-axis acoustic levitation to trap and levitate a single, initially neutral drop with a diameter between 400 microm and 2 mm. This drop is then charged in a controllable manner using discrete packets of charge in the form of charged drops produced by a piezoelectric drop-on-demand dispenser equipped with a charging electrode. The magnitude of the charge on the dispensed drops can be adjusted by varying the voltage applied to the charging electrode. The polarity of the charge on the added drops can be changed allowing removal of charge from the trapped drop (by neutralization) and polarity reversal. The maximum amount of added charge is limited by repulsion of like charges between the drops in the trap. This charging scheme can aid in micromanipulation and the study of charged drops and particles using levitation.

The smallest jet drops produced by bursting bubbles

Science.gov (United States)

Brasz, Frederik; Bartlett, Casey; Walls, Peter; Flynn, Elena; Bird, James

2017-11-01

Aerosol droplets are produced from the breakup of jets formed when small air bubbles burst at an air-liquid interface. These jet drops transfer sea salt and organic matter from the oceans to the atmosphere, where they act as cloud condensation nuclei and can spread pathogens. The smallest aerosols persist the longest in the air and advect the furthest from their source, but because they are too small to be observed directly, little is known about what size ocean bubbles create them or how their formation depends on seawater properties. We show, both experimentally and numerically, that the minimum size of primary jet drops is set by the interplay between viscous and inertial-capillary forces and is significantly smaller than previous estimates. We find that viscous stresses modify both the shape of the collapsing bubble and the breakup of the resulting jet, leading to a non-monotonic size relationship between the bubble and primary jet drop. Supported by the National Science Foundation under Grant No. 1351466.

Adding the 'heart' to hanging drop networks for microphysiological multi-tissue experiments.

Science.gov (United States)

Rismani Yazdi, Saeed; Shadmani, Amir; Bürgel, Sebastian C; Misun, Patrick M; Hierlemann, Andreas; Frey, Olivier

2015-11-07

Microfluidic hanging-drop networks enable culturing and analysis of 3D microtissue spheroids derived from different cell types under controlled perfusion and investigating inter-tissue communication in multi-tissue formats. In this paper we introduce a compact on-chip pumping approach for flow control in hanging-drop networks. The pump includes one pneumatic chamber located directly above one of the hanging drops and uses the surface tension at the liquid-air-interface for flow actuation. Control of the pneumatic protocol provides a wide range of unidirectional pulsatile and continuous flow profiles. With the proposed concept several independent hanging-drop networks can be operated in parallel with only one single pneumatic actuation line at high fidelity. Closed-loop medium circulation between different organ models for multi-tissue formats and multiple simultaneous assays in parallel are possible. Finally, we implemented a real-time feedback control-loop of the pump actuation based on the beating of a human iPS-derived cardiac microtissue cultured in the same system. This configuration allows for simulating physiological effects on the heart and their impact on flow circulation between the organ models on chip.

A PIV Study of Drop-interface Coalescence with Surfactants

Science.gov (United States)

Weheliye, Weheliye Hashi; Dong, Teng; Angeli, Panagiota

2017-11-01

In this work, the coalescence of a drop with an aqueous-organic interface was studied by Particle Image Velocimetry (PIV). The effect of surfactants on the drop surface evolution, the vorticity field and the kinetic energy distribution in the drop during coalescence were investigated. The coalescence took place in an acrylic rectangular box with 79% glycerol solution at the bottom and Exxsol D80 oil above. The glycerol solution drop was generated through a nozzle fixed at 2cm above the aqueous/oil interface and was seeded with Rhodamine particles. The whole process was captured by a high-speed camera. Different mass ratios of non-ionic surfactant Span80 to oil were studied. The increase of surfactant concentration promoted deformation of the interface before the rupture of the trapped oil film. At the early stages after film rupture, two counter-rotating vortices appeared at the bottom of the drop which then travelled to the upper part. The propagation rates, as well as the intensities of the vortices decreased at high surfactant concentrations. At early stages, the kinetic energy was mainly distributed near the bottom part of the droplet, while at later stages it was distributed near the upper part of the droplet. Programme Grant MEMPHIS, Chinese Scholarship Council (CSC).

Liquid drops attract or repel by the inverted Cheerios effect.

Science.gov (United States)

Karpitschka, Stefan; Pandey, Anupam; Lubbers, Luuk A; Weijs, Joost H; Botto, Lorenzo; Das, Siddhartha; Andreotti, Bruno; Snoeijer, Jacco H

2016-07-05

Solid particles floating at a liquid interface exhibit a long-ranged attraction mediated by surface tension. In the absence of bulk elasticity, this is the dominant lateral interaction of mechanical origin. Here, we show that an analogous long-range interaction occurs between adjacent droplets on solid substrates, which crucially relies on a combination of capillarity and bulk elasticity. We experimentally observe the interaction between droplets on soft gels and provide a theoretical framework that quantitatively predicts the interaction force between the droplets. Remarkably, we find that, although on thick substrates the interaction is purely attractive and leads to drop-drop coalescence, for relatively thin substrates a short-range repulsion occurs, which prevents the two drops from coming into direct contact. This versatile interaction is the liquid-on-solid analog of the "Cheerios effect." The effect will strongly influence the condensation and coarsening of drops on soft polymer films, and has potential implications for colloidal assembly and mechanobiology.

Dynamics of deforming drops

OpenAIRE

Bouwhuis, W.

2015-01-01

Liquid drops play a dominant role in numerous industrial applications, such as spray coating, spray painting, inkjet printing, lithography processes, and spraying/sprinkling in agriculture or gardening. In all of these examples, the generation, flight, impact, and spreading of drops are separate stages of the corresponding industrial processes, which are all thoroughly studied for many years. This thesis focuses on drop dynamics, impact phenomena, Leidenfrost drops, and pouring flows. Based o...

Scanning drop sensor

Energy Technology Data Exchange (ETDEWEB)

Jin, Jian; Xiang, Chengxiang; Gregoire, John

2017-05-09

Electrochemical experiments are performed on a collection of samples by suspending a drop of electrolyte solution between an electrochemical experiment probe and one of the samples that serves as a test sample. During the electrochemical experiment, the electrolyte solution is added to the drop and an output solution is removed from the drop. The probe and collection of samples can be moved relative to one another so the probe can be scanned across the samples.

Drop splashing: the role of surface wettability and liquid viscosity

Science.gov (United States)

Almohammadi, Hamed; Amirfazli, Alidad; -Team

2017-11-01

There are seemingly contradictory results in the literature about the role of surface wettability and drop viscosity for the splashing behavior of a drop impacting onto a surface. Motivated by such issues, we conducted a systematic experimental study where splashing behavior for a wide range of the liquid viscosity (1-100 cSt) and surface wettability (hydrophilic to hydrophobic) are examined. The experiments were performed for the liquids with both low and high surface tensions ( 20 and 72 mN/m). We found that the wettability affects the splashing threshold at high or low contact angle values. At the same drop velocity, an increase of the viscosity (up to 4 cSt) promotes the splashing; while, beyond such value, any increase in viscosity shows the opposite effect. It is also found that at a particular combination of liquid surface tension and viscosity (e.g. silicone oil, 10 cSt), an increase in the drop velocity changes the splashing to spreading. We relate such behaviors to the thickness, shape, and the velocity of the drop's lamella. Finally, to predict the splashing, we developed an empirical correlation which covers all of the previous reported data, hence clarifying the ostensible existing contradictions.

Epileptic negative drop attacks in atypical benign partial epilepsy: a neurophysiological study.

Science.gov (United States)

Hirano, Yoshiko; Oguni, Hirokazu; Osawa, Makiko

2009-03-01

We conducted a computer-assisted polygraphic analysis of drop attacks in a child with atypical benign partial epilepsy (ABPE) to investigate neurophysiological characteristics. The patient was a six-year two-month-old girl, who had started to have focal motor seizures, later combined with daily epileptic negative myoclonus (ENM) and drop attacks, causing multiple injuries. We studied episodes of ENM and drop attacks using video-polygraphic and computer-assisted back-averaging analysis. A total of 12 ENM episodes, seven involving the left arm (ENMlt) and five involving both arms (ENMbil), and five drop attacks were captured for analysis. All episodes were time-locked to spike-and-wave complexes (SWC) arising from both centro-temporo-parietal (CTP) areas. The latency between the onset of SWC and ENMlt, ENMbil, and drop attacks reached 68 ms, 42 ms, and 8 ms, respectively. The height of the spike as well as the slow-wave component of SWC for drop attacks were significantly larger than that for both ENMlt and ENMbil (p negative myoclonus involving not only upper proximal but also axial muscles, causing the body to fall. Thus, drop attacks in ABPE are considered to be epileptic negative drop attacks arising from bilateral CTP foci and differ from drop attacks of a generalized origin seen in Lennox-Gastaut syndrome and myoclonic-astatic epilepsy.

[Keratomycosis due to Fusarium oxysporum treated with the combination povidone iodine eye drops and oral fluconazole].

Science.gov (United States)

Diongue, K; Sow, A S; Nguer, M; Seck, M C; Ndiaye, M; Badiane, A S; Ndiaye, J M; Ndoye, N W; Diallo, M A; Diop, A; Ndiaye, Y D; Dieye, B; Déme, A; Ndiaye, I M; Ndir, O; Ndiaye, D

2015-12-01

In developing countries where systemic antifungal are often unavailable, treatment of filamentous fungi infection as Fusarium is sometimes very difficult to treat. We report the case of a keratomycosis due to Fusarium oxysporum treated by povidone iodine eye drops and oral fluconazole. The diagnosis of abscess in the cornea was retained after ophthalmological examination for a 28-year-old man with no previous ophthalmological disease, addressed to the Ophthalmological clinic at the University Hospital Le Dantec in Dakar for a left painful red eye with decreased visual acuity lasting for 15 days. The patient did not receive any foreign body into the eye. Samples by corneal scraping were made for microbiological analysis and the patient was hospitalized and treated with a reinforced eye drops based treatment (ceftriaxone+gentamicin). The mycological diagnosis revealed the presence of a mold: F. oxysporum, which motivated the replacement of the initial treatment by eye drops containing iodized povidone solution at 1% because of the amphotericin B unavailability. Due to the threat of visual loss, oral fluconazole was added to the local treatment with eye drops povidone iodine. The outcome was favorable with a healing abscess and visual acuity amounted to 1/200th. Furthermore, we noted sequels such as pannus and pillowcase. The vulgarization of efficient topical antifungal in developing countries would be necessary to optimize fungal infection treatment. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

Gradual DropIn of Layers to Train Very Deep Neural Networks

OpenAIRE

Smith, Leslie N.; Hand, Emily M.; Doster, Timothy

2015-01-01

We introduce the concept of dynamically growing a neural network during training. In particular, an untrainable deep network starts as a trainable shallow network and newly added layers are slowly, organically added during training, thereby increasing the network's depth. This is accomplished by a new layer, which we call DropIn. The DropIn layer starts by passing the output from a previous layer (effectively skipping over the newly added layers), then increasingly including units from the ne...

Scanning drop sensor

Energy Technology Data Exchange (ETDEWEB)

Jin, Jian; Xiang, Chengxiang; Gregoire, John M.; Shinde, Aniketa A.; Guevarra, Dan W.; Jones, Ryan J.; Marcin, Martin R.; Mitrovic, Slobodan

2017-05-09

Electrochemical or electrochemical and photochemical experiments are performed on a collection of samples by suspending a drop of electrolyte solution between an electrochemical experiment probe and one of the samples that serves as a test sample. During the electrochemical experiment, the electrolyte solution is added to the drop and an output solution is removed from the drop. The probe and collection of samples can be moved relative to one another so the probe can be scanned across the samples.

Sessile Drop Evaporation and Leidenfrost Phenomenon

OpenAIRE

A. K. Mozumder; M. R. Ullah; A. Hossain; M. A. Islam

2010-01-01

Problem statement: Quenching and cooling are important process in manufacturing industry for controlling the mechanical properties of materials, where evaporation is a vital mode of heat transfer. Approach: This study experimentally investigated the evaporation of sessile drop for four different heated surfaces of Aluminum, Brass, Copper and Mild steel with a combination of four different liquids as Methanol, Ethanol, Water and NaCl solution. The time of evaporation for the droplet on the hot...

D.R.O.P. The Durable Reconnaissance and Observation Platform

Science.gov (United States)

McKenzie, Clifford; Parness, Aaron

2012-01-01

The Durable Reconnaissance and Observation Platform (DROP) is a prototype robotic platform with the ability to climb concrete surfaces up to 85deg at a rate of 25cm/s, make rapid horizontal to vertical transitions, carry an audio/visual reconnaissance payload, and survive impacts from 3 meters. DROP is manufactured using a combination of selective laser sintering (SLS) and shape deposition manufacturing (SDM) techniques. The platform uses a two-wheel, two-motor design that delivers high mobility with low complexity. DROP extends microspine climbing technology from linear to rotary applications, providing improved transition ability, increased speeds, and simpler body mechanics while maintaining microspines ability to opportunistically grip rough surfaces. Various aspects of prototype design and performance are discussed, including the climbing mechanism, body design, and impact survival.

Dynamic response of an electrostatically actuated microbeam to drop-table test

International Nuclear Information System (INIS)

Ouakad, Hassen M; Younis, Mohammad I; Alsaleem, Fadi

2012-01-01

In this paper, we present a theoretical and experimental investigation into the dynamic response of an electrostatically actuated microbeam when subjected to drop-table test. For the theoretical part, a reduced-order model based on an Euler–Bernoulli beam model is utilized. The model accounts for the electrostatic bias on the microbeam and the shock pulse of the drop-table test. Simulation results are presented showing the combined effect of electrostatic force and mechanical shock in triggering early pull-in instability of the cantilever microbeams. The analytical simulation results are validated by finite-element results for the static response. Dynamic pull-in threshold as a function of the mechanical shock amplitude is shown over a wide range of shock spanning hundreds of thousands of g up to zero g. For the experimental part, a micromachined cantilever beam made of gold of length 50 µm is subjected to drop-table tests while being biased by electrostatic loads. Several experimental data are shown demonstrating the phenomenon of collapse due to the combined shock and electrostatic forces. It is also demonstrated that by biasing short and too stiff microbeams with electrostatic voltages, their stiffness is weakened. This lowers their threshold of collapse considerably to the range of acceleration that enables testing them with in-house shock testing equipments, such as drop-table tests. (paper)

Experimental validation of plugging during drop formation in a T-junction.

Science.gov (United States)

Abate, Adam R; Mary, Pascaline; van Steijn, Volkert; Weitz, David A

2012-04-21

At low capillary number, drop formation in a T-junction is dominated by interfacial effects: as the dispersed fluid flows into the drop maker nozzle, it blocks the path of the continuous fluid; this leads to a pressure rise in the continuous fluid that, in turn, squeezes on the dispersed fluid, inducing pinch-off of a drop. While the resulting drop volume predicted by this "squeezing" mechanism has been validated for a range of systems, as of yet, the pressure rise responsible for the actual pinch-off has not been observed experimentally. This is due to the challenge of measuring the pressures in a T-junction with the requisite speed, accuracy, and localization. Here, we present an empirical study of the pressures in a T-junction during drop formation. Using Laplace sensors, pressure probes we have developed, we confirm the central ideas of the squeezing mechanism; however, we also uncover other findings, including that the pressure of the dispersed fluid is not constant but rather oscillates in anti-phase with that of the continuous fluid. In addition, even at the highest capillary number for which monodisperse drops can be formed, pressure oscillations persist, indicating that drop formation in confined geometries does not transition to an entirely shear-driven mechanism, but to a mechanism combining squeezing and shearing.

Organic matter in central California radiation fogs.

Science.gov (United States)

Herckes, Pierre; Lee, Taehyoung; Trenary, Laurie; Kang, Gongunn; Chang, Hui; Collett, Jeffrey L

2002-11-15

Organic matter was studied in radiation fogs in the San Joaquin Valley of California during the California Regional Particulate Air Quality Study (CRPAQS). Total organic carbon (TOC) concentrations ranged from 2 to 40 ppm of C. While most organic carbon was found in solution as dissolved organic carbon (DOC), 23% on average was not dissolved inside the fog drops. We observe a clear variation of organic matter concentration with droplet size. TOC concentrations in small fog drops (fogwater, consistent with the enrichment of the organic matter in smaller fog drops with lower terminal settling velocities.

The role of jet and film drops in controlling the mixing state of submicron sea spray aerosol particles

Energy Technology Data Exchange (ETDEWEB)

Wang, Xiaofei; Deane, Grant B.; Moore, Kathryn A.; Ryder, Olivia S.; Stokes, M. Dale; Beall, Charlotte M.; Collins, Douglas B.; Santander, Mitchell V.; Burrows, Susannah M.; Sultana, Camille M.; Prather, Kimberly A.

2017-06-19

Covering 71% of the Earth’s surface, oceans represent a significant global source of atmospheric aerosols. The size and composition of sea spray aerosols (SSA) affect their ability to serve as cloud seeds and thus understanding the factors controlling their composition is critical to predicting their impact on clouds and climate. SSA particles have been shown to be an external mixture of particles with different compositions. Film and jet drop production mechanisms ultimately determine the individual particle compositions which are comprised of an array of salt/organic mixtures ranging from pure sea salt to nearly pure organic particles. It is often assumed that the majority of submicron SSA are formed by film drops produced from bursting hydrophobic organic-rich bubble film caps at the sea surface, and in contrast, jet drops are postulated to produce larger supermicron particles from underlying seawater comprised largely of salts and water soluble organic species. However, here we show that jet drops produced by bursting sub-100 m bubbles account for up to 40 % of all submicron particles. They have distinct chemical compositions, organic volume fractions and ice nucleating activities from submicron film drops. Thus a substantial fraction of submicron particles will not necessarily be controlled by the composition of the sea surface microlayer as has been assumed in many studies. This finding has significant ramifications for the size-resolved mixing states of SSA particles which must be taken into consideration when accessing SSA impacts on clouds.

Adding the ‘heart’ to hanging drop networks for microphysiological multi-tissue experiments†

Science.gov (United States)

Yazdi, Saeed Rismani; Shadmani, Amir; Bürgel, Sebastian C.; Misun, Patrick M.; Hierlemann, Andreas; Frey, Olivier

2017-01-01

Microfluidic hanging-drop networks enable culturing and analysis of 3D microtissue spheroids derived from different cell types under controlled perfusion and investigating inter-tissue communication in multi-tissue formats. In this paper we introduce a compact on-chip pumping approach for flow control in hanging-drop networks. The pump includes one pneumatic chamber located directly above one of the hanging drops and uses the surface tension at the liquid–air-interface for flow actuation. Control of the pneumatic protocol provides a wide range of unidirectional pulsatile and continuous flow profiles. With the proposed concept several independent hanging-drop networks can be operated in parallel with only one single pneumatic actuation line at high fidelity. Closed-loop medium circulation between different organ models for multi-tissue formats and multiple simultaneous assays in parallel are possible. Finally, we implemented a real-time feedback control-loop of the pump actuation based on the beating of a human iPS-derived cardiac microtissue cultured in the same system. This configuration allows for simulating physiological effects on the heart and their impact on flow circulation between the organ models on chip. PMID:26401602

Effect of different combining patterns of radionuclides in marine organisms

International Nuclear Information System (INIS)

Ueda, T.; Suzuki, Y.; Nakamura, R.; Nakahara, M.

1981-01-01

Information on the environmental factors (level of radioactivity in sea water, salinity, temperature, etc.), the biological factors (growth stage, species of organism, etc.), and the metabolism of radionuclides in marine organisms should be taken into account so as to understand the mechanism of radioactive contamination of marine organisms. From this viewpoint, the combining of radionuclides with constituents in marine organisms was studied, indicating the differences as follows: (a) Different appearances of radioactive cobalt in the liver of the abalone due to chemical forms: From the gel filtration profiles on Sephadex it was observed that 57 Co accumulated in the liver of the abalone from sea water labelled by complexed 57 Co combines with a constituent in the liver that has a molecular weight of about 40,000. However, 60 Co taken up from sea water containing ionic 60 Co combines with other constituents in the liver. (b) Appearance of radionuclides in fish due to pathways (sea water and food): In fish liver, most 137 Cs from both sea water and food combines with only one constituent substance; the molecular weight of this substance was estimated at 1100-1300. Cobalt-60 from both sea water and food associates with two different molecular weight constituents, but 65 Zn made a considerable difference in the gel filtration profiles between sea water and food. These results indicate that the metabolism of radionuclides in marine organisms may possibly be varied by the chemical forms of radionuclides in sea water and the pathways of radionuclides. (author)

Reconfigurable microfluidic hanging drop network for multi-tissue interaction and analysis.

Science.gov (United States)

Frey, Olivier; Misun, Patrick M; Fluri, David A; Hengstler, Jan G; Hierlemann, Andreas

2014-06-30

Integration of multiple three-dimensional microtissues into microfluidic networks enables new insights in how different organs or tissues of an organism interact. Here, we present a platform that extends the hanging-drop technology, used for multi-cellular spheroid formation, to multifunctional complex microfluidic networks. Engineered as completely open, 'hanging' microfluidic system at the bottom of a substrate, the platform features high flexibility in microtissue arrangements and interconnections, while fabrication is simple and operation robust. Multiple spheroids of different cell types are formed in parallel on the same platform; the different tissues are then connected in physiological order for multi-tissue experiments through reconfiguration of the fluidic network. Liquid flow is precisely controlled through the hanging drops, which enable nutrient supply, substance dosage and inter-organ metabolic communication. The possibility to perform parallelized microtissue formation on the same chip that is subsequently used for complex multi-tissue experiments renders the developed platform a promising technology for 'body-on-a-chip'-related research.

Ultrasensitive determination of mercury in human saliva by atomic fluorescence spectrometry based on solidified floating organic drop microextraction

International Nuclear Information System (INIS)

Yuan, C.-G.; Wang, J.; Jin, Y.

2012-01-01

We report on a new, rapid and simple method for the determination of ultra-trace quantities of mercury ion in human saliva. It is based on solidified floating organic drop microextraction and detection by cold vapor atomic fluorescence spectrometry (CV-AFS). Mercury ion was complexed with diethyldithiocarbamate, and the hydrophobic complex was then extracted into fine droplets of 1-undecanol. By cooling in an ice bath after extraction, the droplets in solution solidify to form a single ball floating on the surface of solution. The solidified micro drop containing the mercury complex was then transferred for determination by CV-AFS. The effects of pH value, concentration of chelating reagent, quantity of 1-undecanol, sample volume, equilibration temperature and time were investigated. Under the optimum conditions, the preconcentration of a 25-mL sample is accomplished with an enrichment factor of 182. The limit of detection is 2.5 ng L -1 . The relative standard deviation for seven replicate determinations at 0.1 ng mL -1 level is 4.1%. The method was applied to the determination of mercury in saliva samples collected from four volunteers. Two volunteers having dental amalgam fillings had 0.4 ng mL -1 mercury in their saliva, whereas mercury was not detectable in the saliva of two volunteers who had no dental fillings. (author)

Drop rebound after impact: the role of the receding contact angle.

Science.gov (United States)

Antonini, C; Villa, F; Bernagozzi, I; Amirfazli, A; Marengo, M

2013-12-31

Data from the literature suggest that the rebound of a drop from a surface can be achieved when the wettability is low, i.e., when contact angles, measured at the triple line (solid-liquid-air), are high. However, no clear criterion exists to predict when a drop will rebound from a surface and which is the key wetting parameter to govern drop rebound (e.g., the "equilibrium" contact angle, θeq, the advancing and the receding contact angles, θA and θR, respectively, the contact angle hysteresis, Δθ, or any combination of these parameters). To clarify the conditions for drop rebound, we conducted experimental tests on different dry solid surfaces with variable wettability, from hydrophobic to superhydrophobic surfaces, with advancing contact angles 108° contact angles 89° contact angle is the key wetting parameter that influences drop rebound, along with surface hydrophobicity: for the investigated impact conditions (drop diameter 2.4 contact angles higher than 100°. Also, the drop rebound time decreased by increasing the receding contact angle. It was also shown that in general care must be taken when using statically defined wetting parameters (such as advancing and receding contact angles) to predict the dynamic behavior of a liquid on a solid surface because the dynamics of the phenomenon may affect surface wetting close to the impact point (e.g., as a result of the transition from the Cassie-Baxter to Wenzel state in the case of the so-called superhydrophobic surfaces) and thus affect the drop rebound.

Determination of bisphenol A in thermal printing papers treated by alkaline aqueous solution using the combination of single-drop microextraction and HPLC.

Science.gov (United States)

Gao, Leihong; Zou, Jing; Liu, Haihong; Zeng, Jingbin; Wang, Yiru; Chen, Xi

2013-04-01

A method for the quantitative determination of bisphenol A in thermal printing paper was developed and validated. Bisphenol A was extracted from the paper samples using 2% NaOH solution, then the extracted analyte was enriched using single-drop microextraction followed by HPLC analysis. Several parameters relating to the single-drop microextraction efficiency including extraction solvent, extraction temperature and time, stirring rate, and pH of donor phase were studied and optimized. Spiked recovery of bisphenol A at 20 and 5 mg/g was found to be 95.8 and 108%, and the method detection limit and method quantification limit was 0.03 and 0.01 mg/g, respectively. Under the optimized conditions, the proposed method was applied to the determination of bisphenol A in seven types of thermal printing paper samples, and the concentration of bisphenol A was found in the range of 0.53-20.9 mg/g. The considerably minimum usage of organic solvents (5 μL 1-octanol) and high enrichment factor (189-197) in the sample preparation are the two highlighted advantages in comparison with previously published works. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Cutting a drop of water pinned by wire loops using a superhydrophobic surface and knife.

Directory of Open Access Journals (Sweden)

Ryan Yanashima

Full Text Available A water drop on a superhydrophobic surface that is pinned by wire loops can be reproducibly cut without formation of satellite droplets. Drops placed on low-density polyethylene surfaces and Teflon-coated glass slides were cut with superhydrophobic knives of low-density polyethylene and treated copper or zinc sheets, respectively. Distortion of drop shape by the superhydrophobic knife enables a clean break. The driving force for droplet formation arises from the lower surface free energy for two separate drops, and it is modeled as a 2-D system. An estimate of the free energy change serves to guide when droplets will form based on the variation of drop volume, loop spacing and knife depth. Combining the cutting process with an electrofocusing driving force could enable a reproducible biomolecular separation without troubling satellite drop formation.

Hanging drop crystal growth apparatus

Science.gov (United States)

Naumann, Robert J. (Inventor); Witherow, William K. (Inventor); Carter, Daniel C. (Inventor); Bugg, Charles E. (Inventor); Suddath, Fred L. (Inventor)

1990-01-01

This invention relates generally to control systems for controlling crystal growth, and more particularly to such a system which uses a beam of light refracted by the fluid in which crystals are growing to detect concentration of solutes in the liquid. In a hanging drop apparatus, a laser beam is directed onto drop which refracts the laser light into primary and secondary bows, respectively, which in turn fall upon linear diode detector arrays. As concentration of solutes in drop increases due to solvent removal, these bows move farther apart on the arrays, with the relative separation being detected by arrays and used by a computer to adjust solvent vapor transport from the drop. A forward scattering detector is used to detect crystal nucleation in drop, and a humidity detector is used, in one embodiment, to detect relative humidity in the enclosure wherein drop is suspended. The novelty of this invention lies in utilizing angular variance of light refracted from drop to infer, by a computer algorithm, concentration of solutes therein. Additional novelty is believed to lie in using a forward scattering detector to detect nucleating crystallites in drop.

Dropping and semimicrotest glass reactions on beryllium, lenthanum, vanadyl and uranyl cations with synthetic organic dyes and their mutual determination in binary mixtures

International Nuclear Information System (INIS)

Shemyakin, F.M.; Novikova, A.A.; Reshetnyak, V.Yu.; Teplyakov, G.K.; Nekrasov, E.L.

1978-01-01

Coloured reactions for beryllium, lanthanum, vanadyl and uranyl cations with a number of organic dyes, have been studied. These reactions are used in dropping analysis on papers, impregnated with relevant dyes, and for semimicro-test glass reactions on the above cations. Sensitivity and maximum permissible dilution have been determined for each of the reactions. Mutual determinations of relevant couples of the above cations have been performed. It is shown, that such binary mixtures enable to freely open relevant cations

Combined Turbine and Cycle Optimization for Organic Rankine Cycle Power Systems—Part B: Application on a Case Study

Directory of Open Access Journals (Sweden)

Angelo La Seta

2016-05-01

Full Text Available Organic Rankine cycle (ORC power systems have recently emerged as promising solutions for waste heat recovery in low- and medium-size power plants. Their performance and economic feasibility strongly depend on the expander. The design process and efficiency estimation are particularly challenging due to the peculiar physical properties of the working fluid and the gas-dynamic phenomena occurring in the machine. Unlike steam Rankine and Brayton engines, organic Rankine cycle expanders combine small enthalpy drops with large expansion ratios. These features yield turbine designs with few highly-loaded stages in supersonic flow regimes. Part A of this two-part paper has presented the implementation and validation of the simulation tool TURAX, which provides the optimal preliminary design of single-stage axial-flow turbines. The authors have also presented a sensitivity analysis on the decision variables affecting the turbine design. Part B of this two-part paper presents the first application of a design method where the thermodynamic cycle optimization is combined with calculations of the maximum expander performance using the mean-line design tool described in part A. The high computational cost of the turbine optimization is tackled by building a model which gives the optimal preliminary design of an axial-flow turbine as a function of the cycle conditions. This allows for estimating the optimal expander performance for each operating condition of interest. The test case is the preliminary design of an organic Rankine cycle turbogenerator to increase the overall energy efficiency of an offshore platform. For an increase in expander pressure ratio from 10 to 35, the results indicate up to 10% point reduction in expander performance. This corresponds to a relative reduction in net power output of 8.3% compared to the case when the turbine efficiency is assumed to be 80%. This work also demonstrates that this approach can support the plant designer

Vibration-Induced Climbing of Drops

Science.gov (United States)

Brunet, P.; Eggers, J.; Deegan, R. D.

2007-10-01

We report an experimental study of liquid drops moving against gravity, when placed on a vertically vibrating inclined plate, which is partially wetted by the drop. The frequency of vibrations ranges from 30 to 200 Hz, and, above a threshold in vibration acceleration, drops experience an upward motion. We attribute this surprising motion to the deformations of the drop, as a consequence of an up or down symmetry breaking induced by the presence of the substrate. We relate the direction of motion to contact angle measurements. This phenomenon can be used to move a drop along an arbitrary path in a plane, without special surface treatments or localized forcing.

D.R.O.P: The Durable Reconnaissance and Observation Platform

Science.gov (United States)

McKenzie, Clifford; Parness, Aaron

2011-01-01

Robots can provide a remote presence in areas that are either inaccessible or too dangerous for humans. However, robots are often limited by their ability to adapt to the terrain or resist environmental factors. The Durable Reconnaissance and Observation Platform (DROP) is a lightweight robot that addresses these challenges with the capability to survive falls from significant heights, carry a useable payload, and traverse a variety of surfaces, including climbing vertical surfaces like wood, stone, and concrete. DROP is manufactured using a combination of rapid prototyping and shape deposition manufacturing. It uses microspine technology to create a new wheel-like design for vertical climbing. To date, DROP has successfully engaged several vertical surfaces, hanging statically without assistance, and traversed horizontal surfaces at approximately 30 cm/s. Unassisted vertical climbing is capable on surfaces up to 85deg at a rate of approximately 25cm*s(sup -1). DROP can also survive falls from up to 3 meters and has the ability to be thrown off of and onto rooftops. Future efforts will focus on improving the microspine wheels, selecting more resilient materials, customizing the controls, and performing more rigorous and quantifiable testing.

The formation of intestinal organoids in a hanging drop culture.

Science.gov (United States)

Panek, Malgorzata; Grabacka, Maja; Pierzchalska, Malgorzata

2018-01-25

Recently organoids have become widely used in vitro models of many tissue and organs. These type of structures, originated from embryonic or adult mammalian intestines, are called "mini guts". They organize spontaneously when intestinal crypts or stem cells are embedded in the extracellular matrix proteins preparation scaffold (Matrigel). This approach has some disadvantages, as Matrigel is undefined (the concentrations of growth factors and other biologically active components in it may vary from batch to batch), difficult to handle and expensive. Here we show that the organoids derived from chicken embryo intestine are formed in a hanging drop without embedding, providing an attractive alternative for currently used protocols. Using this technique we obtained compact structures composed of contiguous organoids, which were generally similar to chicken organoids cultured in Matrigel in terms of morphology and expression of intestinal epithelial markers. Due to the simplicity, high reproducibility and throughput capacity of hanging drop technique our model may be applied in various studies concerning the gut biology.

Drop Tower Physics

Science.gov (United States)

Dittrich, William A.

2014-01-01

The drop towers of yesteryear were used to make lead shot for muskets, as described in "The Physics Teacher" in April 2012. However, modern drop towers are essentially elevators designed so that the cable can "break" on demand, creating an environment with microgravity for a short period of time, currently up to nine seconds at…

Drop "impact" on an airfoil surface.

Science.gov (United States)

Wu, Zhenlong

2018-05-17

Drop impact on an airfoil surface takes place in drop-laden two-phase flow conditions such as rain and icing, which are encountered by wind turbines or airplanes. This phenomenon is characterized by complex nonlinear interactions that manifest rich flow physics and pose unique modeling challenges. In this article, the state of the art of the research about drop impact on airfoil surface in the natural drop-laden two-phase flow environment is presented. The potential flow physics, hazards, characteristic parameters, droplet trajectory calculation, drop impact dynamics and effects are discussed. The most key points in establishing the governing equations for a drop-laden flow lie in the modeling of raindrop splash and water film. The various factors affecting the drop impact dynamics and the effects of drop impact on airfoil aerodynamic performance are summarized. Finally, the principle challenges and future research directions in the field as well as some promising measures to deal with the adverse effects of drop-laden flows on airfoil performance are proposed. Copyright © 2017 Elsevier B.V. All rights reserved.

Conversion Disorder; an Unusual Etiology of Unilateral Foot Drop.

Science.gov (United States)

Ayaz, Saeed Bin; Matee, Sumeera; Malik, Riffat; Ahmad, Khalil

2015-06-01

Foot drop is generally a consequence of common peroneal or sciatic nerve injury or L5 radiculopathy but rarely, it can be a manifestation of conversion disorder. A 24-year-old male presented with a foot drop on left side that developed overnight. He had difficulty walking with a trunk tilt towards right side and numbness in left leg up to mid-thigh. The initial diagnosis by the general practitioner was common peroneal nerve injury, which was not supported by the subsequent detailed examination in the physiatry department. Routine laboratory investigations, computed tomographic scan of brain and electrophysiological evaluation were normal. In a multidisciplinary team evaluation involving a psychiatrist, he was diagnosed to be suffering from conversion disorder and was advised gait retraining, cognitive and behavioral therapy and tablet venlafaxine. By sixth day of treatment, the patient was able to walk independently with a normal gait pattern and reported complete recovery of his symptoms. In the absence of an identifiable organic cause of foot drop in a patient, conversion disorder may be considered necessitating early intervention by a psychiatrist.

Mass transfer intensification of nanofluid single drops with effect of temperature

Energy Technology Data Exchange (ETDEWEB)

Saien, Javad; Zardoshti, Mahdi [Bu-Ali Sina University, Hamedan (Iran, Islamic Republic of)

2015-11-15

The hydrodynamics and mass transfer of organic nanofluid single drops in liquid-liquid extraction process were investigated within temperature range of 20 to 40 .deg. C. Nanofluid drops of toluene+acetic acid, containing surface modified magnetite nanoparticles (NPs) with concentration within the range of (0.0005-0.005) wt%, were conducted in aqueous continuous phase. The rate of solute mass transfer was generally enhanced with NPs until about 0.002wt%, and small drops benefited more. The enhancement reached 184.1% with 0.002 wt% of NPs at 40 .deg. C; however, adding more NPs led to the mass transfer to either remain constant or face a reduction, depending on the applied temperature. The mass transfer coefficient was nicely reproduced using a developed correlation for enhancement factor of molecular diffusivity as a function of Reynolds and Schmidt numbers.

Flow boiling heat transfer and pressure drop characteristics of R134a, R1234yf and R1234ze in a plate heat exchanger for organic Rankine cycle units

DEFF Research Database (Denmark)

Zhang, Ji; Desideri, Adriano; Kærn, Martin Ryhl

2017-01-01

. This paper is aimed at obtaining flow boiling heat transfer and pressure drop characteristics in a plate heat exchanger under the working conditions prevailing in the evaporator of organic Rankine cycle units. Two hydrofluoroolefins R1234yf and R1234ze, and one hydrofluorocarbon R134a, were selected...... as the working fluids. The heat transfer coefficients and pressure drops of the three working fluids were measured with varying saturation temperatures, mass fluxes, heat fluxes and outlet vapour qualities, which range from 60°C to 80°C, 86 kg/m2 s to 137 kg/m2 s, 9.8 kW/m2 to 36.8 kW/m2 and 0.5 to 1...... developed that are more suitable for evaporation in organic Rankine cycles. The experimental results indicate that heat transfer coefficients are strongly dependent upon the heat flux and saturation temperature. Moreover, the results suggest better thermal-hydraulic performance for R1234yf than the other...

Control of stain geometry by drop evaporation of surfactant containing dispersions.

Science.gov (United States)

Erbil, H Yildirim

2015-08-01

Control of stain geometry by drop evaporation of surfactant containing dispersions is an important topic of interest because it plays a crucial role in many applications such as forming templates on solid surfaces, in ink-jet printing, spraying of pesticides, micro/nano material fabrication, thin film coatings, biochemical assays, deposition of DNA/RNA micro-arrays, and manufacture of novel optical and electronic materials. This paper presents a review of the published articles on the diffusive drop evaporation of pure liquids (water), the surfactant stains obtained from evaporating drops that do not contain dispersed particles and deposits obtained from drops containing polymer colloids and carbon based particles such as carbon nanotubes, graphite and fullerenes. Experimental results of specific systems and modeling attempts are discussed. This review also has some special subtopics such as suppression of coffee-rings by surfactant addition and "stick-slip" behavior of evaporating nanosuspension drops. In general, the drop evaporation process of a surfactant/particle/substrate system is very complex since dissolved surfactants adsorb on both the insoluble organic/inorganic micro/nanoparticles in the drop, on the air/solution interface and on the substrate surface in different extends. Meanwhile, surfactant adsorbed particles interact with the substrate giving a specific contact angle, and free surfactants create a solutal Marangoni flow in the drop which controls the location of the particle deposition together with the rate of evaporation. In some cases, the presence of a surfactant monolayer at the air/solution interface alters the rate of evaporation. At present, the magnitude of each effect cannot be predicted adequately in advance and consequently they should be carefully studied for any system in order to control the shape and size of the final deposit. Copyright © 2014 Elsevier B.V. All rights reserved.

Vortex flow in acoustically levitated drops

Energy Technology Data Exchange (ETDEWEB)

Yan, Z.L.; Xie, W.J. [Department of Applied Physics, Northwestern Polytechnical University, Xi' an 710072 (China); Wei, B., E-mail: bbwei@nwpu.edu.cn [Department of Applied Physics, Northwestern Polytechnical University, Xi' an 710072 (China)

2011-08-29

The internal flow of acoustically levitated water drops is investigated experimentally. This study reveals a kind of vortex flow which rotates in the meridional plane of the levitated drop. The magnitude of fluid velocity is nearly vanishing at the drop center, whereas it increases toward the free surface of a levitated drop until the maximum value of about 80 mm/s. A transition of streamline shapes from concentric circles to ellipses takes place at the distance of about 1.2 mm from the drop center. The fluid velocity distribution is plotted as a function of polar angle for seven characteristic streamlines. -- Highlights: → We experimentally observe the internal flow of acoustically levitated water drops. → We present a fascinating structure of vortex flow inside the levitated water drop. → This vortex flow rotates around the drop center in the meridional plane. → Velocity distribution information of this vortex flow is quantitatively analyzed.

Vortex flow in acoustically levitated drops

International Nuclear Information System (INIS)

Yan, Z.L.; Xie, W.J.; Wei, B.

2011-01-01

The internal flow of acoustically levitated water drops is investigated experimentally. This study reveals a kind of vortex flow which rotates in the meridional plane of the levitated drop. The magnitude of fluid velocity is nearly vanishing at the drop center, whereas it increases toward the free surface of a levitated drop until the maximum value of about 80 mm/s. A transition of streamline shapes from concentric circles to ellipses takes place at the distance of about 1.2 mm from the drop center. The fluid velocity distribution is plotted as a function of polar angle for seven characteristic streamlines. -- Highlights: → We experimentally observe the internal flow of acoustically levitated water drops. → We present a fascinating structure of vortex flow inside the levitated water drop. → This vortex flow rotates around the drop center in the meridional plane. → Velocity distribution information of this vortex flow is quantitatively analyzed.

Effect Various Combination of Organic Waste on Compost Quality

Directory of Open Access Journals (Sweden)

Hapsoh

2015-01-01

Full Text Available Municipal solid waste and agricultural waste have different ratio C/N and nutrients contents. They can be used as compost row materials. The purpose of the research was to get an optimum combination of both wastes to improve compost quality, to meet the Indonesian National Standard 19-7030-2004. Composting process use pots. The treatments were twelve combination of municipal solid waste (garbage market, household waste, restaurant waste and agricultural waste (rice straw, empty fruit bunches of oil palm, cassava peel, banana skin with a ratio of 1:1 and enriche by chicken manure, cow manure, wood ash and cellulolytic microorganisme. The treatment were replicated three times. The results showd that the nutrients content of compost were 0.77 to 1.19% nitrogen, 0.23 to 0.30% phosphorus, 0.46 to 0.69% potassium and 15.48 to 34.69% organic matter. The combination of agricultural waste and municipal solid waste affected the quality of compost. Compost that meets SNI 19-7030-2004 is a combination of rice straw+market waste that contains 1.12% nitrogen, 0.28% phosphorus, 0.63% potassium, ratio C/N 19.50, pH 7.42, and organic matters 37.65%.

A Novel Virus Causes Scale Drop Disease in Lates calcarifer.

Directory of Open Access Journals (Sweden)

Ad de Groof

2015-08-01

Full Text Available From 1992 onwards, outbreaks of a previously unknown illness have been reported in Asian seabass (Lates calcarifer kept in maricultures in Southeast Asia. The most striking symptom of this emerging disease is the loss of scales. It was referred to as scale drop syndrome, but the etiology remained enigmatic. By using a next-generation virus discovery technique, VIDISCA-454, sequences of an unknown virus were detected in serum of diseased fish. The near complete genome sequence of the virus was determined, which shows a unique genome organization, and low levels of identity to known members of the Iridoviridae. Based on homology of a series of putatively encoded proteins, the virus is a novel member of the Megalocytivirus genus of the Iridoviridae family. The virus was isolated and propagated in cell culture, where it caused a cytopathogenic effect in infected Asian seabass kidney and brain cells. Electron microscopy revealed icosahedral virions of about 140 nm, characteristic for the Iridoviridae. In vitro cultured virus induced scale drop syndrome in Asian seabass in vivo and the virus could be reisolated from these infected fish. These findings show that the virus is the causative agent for the scale drop syndrome, as each of Koch's postulates is fulfilled. We have named the virus Scale Drop Disease Virus. Vaccines prepared from BEI- and formalin inactivated virus, as well as from E. coli produced major capsid protein provide efficacious protection against scale drop disease.

Coalescence collision of liquid drops I: Off-center collisions of equal-size drops

Directory of Open Access Journals (Sweden)

Alejandro Acevedo-Malavé

2011-09-01

Full Text Available The Smoothed Particle Hydrodynamics method (SPH is used here to model off-center collisions of equal-size liquid drops in a three-dimensional space. In this study the Weber number is calculated for several conditions of the droplets dynamics and the velocity vector fields formed inside the drops during the collision process are shown. For the permanent coalescence the evolution of the kinetic and internal energy is shown and also the approaching to equilibrium of the resulting drop. Depending of the Weber number three possible outcomes for the collision of droplets is obtained: permanent coalescence, flocculation and fragmentation. The fragmentation phenomena are modeled and the formation of small satellite drops can be seen. The ligament that is formed follows the “end pinching” mechanism and it is transformed into a flat structure.

"Self-Shaping" of Multicomponent Drops.

Science.gov (United States)

Cholakova, Diana; Valkova, Zhulieta; Tcholakova, Slavka; Denkov, Nikolai; Smoukov, Stoyan K

2017-06-13

In our recent study we showed that single-component emulsion drops, stabilized by proper surfactants, can spontaneously break symmetry and transform into various polygonal shapes during cooling [ Denkov Nature 2015 , 528 , 392 - 395 ]. This process involves the formation of a plastic rotator phase of self-assembled oil molecules beneath the drop surface. The plastic phase spontaneously forms a frame of plastic rods at the oil drop perimeter which supports the polygonal shapes. However, most of the common substances used in industry appear as mixtures of molecules rather than pure substances. Here we present a systematic study of the ability of multicomponent emulsion drops to deform upon cooling. The observed trends can be summarized as follows: (1) The general drop-shape evolution for multicomponent drops during cooling is the same as with single-component drops; however, some additional shapes are observed. (2) Preservation of the particle shape upon freezing is possible for alkane mixtures with chain length difference Δn ≤ 4; for greater Δn, phase separation within the droplet is observed. (3) Multicomponent particles prepared from alkanes with Δn ≤ 4 plastify upon cooling due to the formation of a bulk rotator phase within the particles. (4) If a compound, which cannot induce self-shaping when pure, is mixed with a certain amount of a compound which induces self-shaping, then drops prepared from this mixture can also self-shape upon cooling. (5) Self-emulsification phenomena are also observed for multicomponent drops. In addition to the three recently reported mechanisms of self-emulsification [ Tcholakova Nat. Commun. 2017 , ( 8 ), 15012 ], a new (fourth) mechanism is observed upon freezing for alkane mixtures with Δn > 4. It involves disintegration of the particles due to a phase separation of alkanes upon freezing.

Simultaneous extraction and determination of albendazole and triclabendazole by a novel syringe to syringe dispersive liquid phase microextraction-solidified floating organic drop combined with high performance liquid chromatography.

Science.gov (United States)

Asadi, Mohammad; Dadfarnia, Shayessteh; Haji Shabani, Ali Mohammad

2016-08-17

A syringe to syringe dispersive liquid phase microextraction-solidified floating organic drop was introduced and used for the simultaneous extraction of trace amounts of albendazole and triclabendazole from different matrices. The extracted analytes were determined by high performance liquid chromatography along with fluorescence detection. The analytical parameters affecting the microextraction efficiency including the nature and volume of the extraction solvent, sample volume, sample pH, ionic strength and the cycles of extraction were optimized. The calibration curves were linear in the range of 0.1-30.0 μg L(-1) and 0.2-30.0 μg L(-1) with determination coefficients of 0.9999 and 0.9998 for albendazole and triclabendazole respectively. The detection limits defined as three folds of the signal to noise ratio were found to be 0.02 μg L(-1) for albendazole and 0.06 μg L(-1) for triclabendazole. The inter-day and intra-day precision (RSD%) for both analytes at three concentration levels (0.5, 2.0 and 10.0 μg L(-1)) were in the range of 6.3-10.1% and 5.0-7.5% respectively. The developed method was successfully applied to determine albendazole and triclabendazole in water, cow milk, honey, and urine samples. Copyright © 2016. Published by Elsevier B.V.

Dynamics of deforming drops

NARCIS (Netherlands)

Bouwhuis, W.

2015-01-01

Liquid drops play a dominant role in numerous industrial applications, such as spray coating, spray painting, inkjet printing, lithography processes, and spraying/sprinkling in agriculture or gardening. In all of these examples, the generation, flight, impact, and spreading of drops are separate

Drop weld thermal injuries to the middle ear.

LENUS (Irish Health Repository)

Keogh, I J

2009-01-01

Drop weld injuries to the tympanic membrane and middle ear caused by hot sparks or molten slag are a rare but significant injury. Steel workers and welders who are regularly exposed to flying sparks and molten metal slag are predisposed. This type of transtympanic thermal injury occurs when the slag literally drops into the external auditory canal and burns through the tympanic membrane. A spectrum of severity of injury occurs which includes chronic tympanic membrane perforation, chronic otorrhoea, facial nerve injury and deafness. Chronic tympanic membrane perforation is the most common sequelae and is perhaps one of the most challenging of all perforations to repair The combination of direct thermal injury and foreign body reaction results in continuing or recurrent suppuration. The foreign body reaction is due to the embedding of metal slag in the promontorial mucosa. We present a case of drop weld injury to the left tympanic membrane, resulting in chronic middle ear inflammation, otorrhoea and tympanic perforation. CAT scan clearly demonstrated a metallic promontorial foreign body with localised bone erosion. We emphasise the importance of removing these foreign bodies and recommend a cartilage reinforced underlay tympanoplasty technique to repair these perforations. Transtympanic thermal trauma is a preventable occupational injury, which is best, avoided by earplugs and increased awareness.

Electrohydrodynamics of a viscous drop with inertia.

Science.gov (United States)

Nganguia, H; Young, Y-N; Layton, A T; Lai, M-C; Hu, W-F

2016-05-01

Most of the existing numerical and theoretical investigations on the electrohydrodynamics of a viscous drop have focused on the creeping Stokes flow regime, where nonlinear inertia effects are neglected. In this work we study the inertia effects on the electrodeformation of a viscous drop under a DC electric field using a novel second-order immersed interface method. The inertia effects are quantified by the Ohnesorge number Oh, and the electric field is characterized by an electric capillary number Ca_{E}. Below the critical Ca_{E}, small to moderate electric field strength gives rise to steady equilibrium drop shapes. We found that, at a fixed Ca_{E}, inertia effects induce larger deformation for an oblate drop than a prolate drop, consistent with previous results in the literature. Moreover, our simulations results indicate that inertia effects on the equilibrium drop deformation are dictated by the direction of normal electric stress on the drop interface: Larger drop deformation is found when the normal electric stress points outward, and smaller drop deformation is found otherwise. To our knowledge, such inertia effects on the equilibrium drop deformation has not been reported in the literature. Above the critical Ca_{E}, no steady equilibrium drop deformation can be found, and often the drop breaks up into a number of daughter droplets. In particular, our Navier-Stokes simulations show that, for the parameters we use, (1) daughter droplets are larger in the presence of inertia, (2) the drop deformation evolves more rapidly compared to creeping flow, and (3) complex distribution of electric stresses for drops with inertia effects. Our results suggest that normal electric pressure may be a useful tool in predicting drop pinch-off in oblate deformations.

von Kármán Vortex Street within an Impacting Drop

KAUST Repository

Thoraval, Marie-Jean

2012-06-29

The splashing of a drop impacting onto a liquid pool produces a range of different sized microdroplets. At high impact velocities, the most significant source of these droplets is a thin liquid jet emerging at the start of the impact from the neck that connects the drop to the pool. We use ultrahigh-speed video imaging in combination with high-resolution numerical simulations to show how this ejecta gives way to irregular splashing. At higher Reynolds numbers, its base becomes unstable, shedding vortex rings into the liquid from the free surface in an axisymmetric von Kármán vortex street, thus breaking the ejecta sheet as it forms.

von Kármán Vortex Street within an Impacting Drop

KAUST Repository

Thoraval, Marie-Jean; Takehara, Kohsei; Etoh, Takeharu Goji; Popinet, Sté phane; Ray, Pascal; Josserand, Christophe; Zaleski, Sté phane; Thoroddsen, Sigurdur T

2012-01-01

The splashing of a drop impacting onto a liquid pool produces a range of different sized microdroplets. At high impact velocities, the most significant source of these droplets is a thin liquid jet emerging at the start of the impact from the neck that connects the drop to the pool. We use ultrahigh-speed video imaging in combination with high-resolution numerical simulations to show how this ejecta gives way to irregular splashing. At higher Reynolds numbers, its base becomes unstable, shedding vortex rings into the liquid from the free surface in an axisymmetric von Kármán vortex street, thus breaking the ejecta sheet as it forms.

Impact analysis of spent fuel dry casks under accidental drop scenarios

International Nuclear Information System (INIS)

Braverman, J.I.; Morante, R.J.; Xu, J.; Hofmayer, C.H.; Shaukat, S.K.

2003-01-01

A series of analyses were performed to assess the structural response of spent nuclear fuel dry casks subjected to various handling and on-site transfer events. The results of these analyses are being used by the Nuclear Regulatory Commission (NRC) to perform a probabilistic risk assessment (PRA). Although the PRA study is being performed for a specific nuclear plant, the PRA study is also intended to provide a framework for a general methodology that could also be applied to other dry cask systems at other nuclear plants. The dry cask system consists of a transfer cask, used for handling and moving the multi-purpose canister (MPC) that contains the fuel, and a storage cask, used to store the MPC and fuel on a concrete pad at the site. This paper describes the analyses of the casks for two loading events. The first loading consists of dropping the transfer cask while it is lowered by a crane to a concrete floor at ground elevation. The second loading consists of dropping the storage cask while it is being transferred to the concrete storage pad outdoors. Three dimensional finite element models of the transfer cask and storage cask, containing the MPC and fuel, were utilized to perform the drop analyses. These models were combined with finite element models of the target structures being impacted. The transfer cask drop analyses considered various drop heights for the cask impacting the reinforced concrete floor at ground level. The finite element model of the target included a section of the concrete floor and concrete wall supporting the floor. The storage cask drop analyses evaluated a 30.5 cm (12 in.) drop of the cask impacting three different surfaces: reinforced concrete, asphalt, and gravel. (author)

Magnetically focused liquid drop radiator

Science.gov (United States)

Botts, Thomas E.; Powell, James R.; Lenard, Roger

1986-01-01

A magnetically focused liquid drop radiator for application in rejecting rgy from a spacecraft, characterized by a magnetizable liquid or slurry disposed in operative relationship within the liquid droplet generator and its fluid delivery system, in combination with magnetic means disposed in operative relationship around a liquid droplet collector of the LDR. The magnetic means are effective to focus streams of droplets directed from the generator toward the collector, thereby to assure that essentially all of the droplets are directed into the collector, even though some of the streams may be misdirected as they leave the generator. The magnetic focusing means is also effective to suppress splashing of liquid when the droplets impinge on the collector.

Education Exclusion and Dropping out in Public Schools of Costa Rica

Directory of Open Access Journals (Sweden)

Wendy Jiménez-Asenjo

2013-03-01

Full Text Available This paper reports on the findings obtained from a study conducted in 2009: “Exclusión educativa y abandono (deserción escolar en la enseñanza secundaria en Costa Rica” [Education Exclusion and Dropping out in Costa Rica], focused on the students from the 7th to the 11th grades of the General Basic Education. For this research, fieldwork was carried out in 22 institutions, in different educational regions of the country. Interviews were conducted with the school principals and counselors in each of the institutions visited. Focal groups were organized with students and parents in order to –as naturalism and qualitative focus suggest –understand the meaning of education exclusion and dropping out from the point of view of the different agents involved– principals, counselors, students, parents. A relevant conceptual aspect included in this study is the analysis of the problems related to dropping out and exclusion, generally, in a nonjudgmental way, to characterize this phenomenon.

Effect of combined application of organic P and inorganic N ...

African Journals Online (AJOL)

A study was undertaken to assess the effect of combined application of organic-P and inorganic-N fertilizers on post harvest quality of carrot (Daucus carota l.) stored at 1°C and ambient conditions (8.6 - 24.8°C). For the fertilizer treatments, 309 kg orga ha-1 (for P) in combination with each of six rates of urea (0, 68.5, 267.2, ...

Effect of non-uniform Hall parameter on the electrode voltage drop in Faraday-type combustion MHD generators

International Nuclear Information System (INIS)

Gupta, G.P.; Rohatgi, V.K.

1982-01-01

Following a simplified approach, an expression is derived for the gas-dynamic voltage drop in a finitely segmented Faraday-type combustion MHD generator, taking into account the non-uniform Hall parameter across the channel. Combining the electrical sheath voltage drop, discussed briefly, with the gas-dynamic voltage drop, the effect of a non-uniform Hall parameter on the electrode voltage drop is studied using the theoretical and experimental input parameters of the Indian MHD channel test. The condition for the validity of the usual assumption of uniform Hall parameter across the channel is pointed out. Analysis of the measured electrode voltage drop predicts the real gas conductivity in the core to be in the range of 60 to 75 per cent of the theoretically calculated core conductivity. (author)

Measurement and characterization of lift forces on drops and bubbles in microchannels

Science.gov (United States)

Stan, Claudiu; Guglielmini, Laura; Ellerbee, Audrey; Caviezel, Daniel; Whitesides, George; Stone, Howard

2013-11-01

The transverse motion of drops and bubbles within liquids flowing in pipes and channels is determined by the combination of several types of hydrodynamic lift forces with external forces. In microfluidic channels, lift forces have been used to position and sort particles with high efficiency and high accuracy. We measured lift forces on drops and bubbles and discriminated between different lift mechanisms under conditions characterized by low particle capillary numbers (0.0003 bubbles. We will present new experimental data that supports a dynamic interfacial mechanism for the second type of lift force, and discuss possible avenues for creating an analytical model for it.

Turbulence, bubbles and drops

NARCIS (Netherlands)

van der Veen, Roeland

2016-01-01

In this thesis, several questions related to drop impact and Taylor-Couette turbulence are answered. The deformation of a drop just before impact can cause a bubble to be entrapped. For many applications, such as inkjet printing, it is crucial to control the size of this entrapped bubble. To study

Photoassisted vapor generation in the presence of organic acids for ultrasensitive determination of Se by electrothermal-atomic absorption spectrometry following headspace single-drop microextraction

International Nuclear Information System (INIS)

Figueroa, Raul; Garcia, Monica; Lavilla, Isela; Bendicho, Carlos

2005-01-01

A method is described for the determination of selenium at the pg/mL level by electrothermal-atomic absorption spectrometry using in situ photogeneration of Se vapors, headspace sequestration onto an aqueous microdrop containing Pd(II) and subsequent injection in a graphite tube. Several organic acids (formic, oxalic, acetic, citric and ethylenediaminetetraacetic) have been tried for photoreduction of Se(IV) into volatile Se compounds under UV irradiation. Experimental variables such as UV irradiation time, organic acid concentration, Pd(II) concentration in the drop, sample and drop volumes, extraction time and pH were fully optimized. Low-molecular weight acids such as formic and acetic provided optimal photogeneration of volatile Se species at a 0.6 mol/L concentration. Citric and ethylenediaminetetraacetic acid allowed to use a concentration as low as 1 mmol/L, but extraction times were longer than for formic and acetic acids. Photogeneration of (CH 3 ) 2 Se from Se(IV) in the presence of acetic acid provided a detection limit of 20 pg/mL, a preconcentration factor of nearly 285 and a precision, expressed as relative standard deviation, of 4%. Analytical performance seemed to depend not only on the photogeneration efficiency obtained with each acid but also on the stability of the vapors in the headspace. The method showed a high freedom from interferences caused by saline matrices, but interferences were observed for transition metals at a relatively low concentration

Axisymmetric Liquid Hanging Drops

Science.gov (United States)

Meister, Erich C.; Latychevskaia, Tatiana Yu

2006-01-01

The geometry of drops hanging on a circular capillary can be determined by numerically solving a dimensionless differential equation that is independent on any material properties, which enables one to follow the change of the height, surface area, and contact angle of drops hanging on a particular capillary. The results show that the application…

CANFLEX fuel bundle junction pressure drop

International Nuclear Information System (INIS)

Chung, H. J.; Chung, C. H.; Jun, J. S.; Hong, S. D.; Chang, S. K.; Kim, B. D.

1996-11-01

This report describes the junction pressure drop test results which are to used to determine the alignment angle between bundles to achieve the most probable fuel string pressure drop for randomly aligned bundles for use in the fuel string total pressure drop test. (author). 4 tabs., 17 figs

CANFLEX fuel bundle junction pressure drop

Energy Technology Data Exchange (ETDEWEB)

Chung, H. J.; Chung, C. H.; Jun, J. S.; Hong, S. D.; Chang, S. K.; Kim, B. D.

1996-11-01

This report describes the junction pressure drop test results which are to used to determine the alignment angle between bundles to achieve the most probable fuel string pressure drop for randomly aligned bundles for use in the fuel string total pressure drop test. (author). 4 tabs., 17 figs.

49 CFR 178.603 - Drop test.

Science.gov (United States)

2010-10-01

... used for the hydrostatic pressure or stacking test. Exceptions for the number of steel and aluminum..., non-resilient, flat and horizontal surface. (e) Drop height. Drop heights, measured as the vertical... than flat drops, the center of gravity of the test packaging must be vertically over the point of...

Liquid-gas mass transfer at drop structures

DEFF Research Database (Denmark)

Matias, Natércia; Nielsen, Asbjørn Haaning; Vollertsen, Jes

2017-01-01

-water mass transfer, little is known about hydrogen sulfide emission under highly turbulent conditions (e.g., drop structures, hydraulic jumps). In this study, experimental work was carried out to analyze the influence of characteristics of drops on reaeration. Physical models were built, mimicking typical...... sewer drop structures and allowing different types of drops, drop heights, tailwater depths and flow rates. In total, 125 tests were performed. Based on their results, empirical expressions translating the relationship between the mass transfer of oxygen and physical parameters of drop structures were...... established. Then, by applying the two-film theory with two-reference substances, the relation to hydrogen sulfide release was defined. The experiments confirmed that the choice of the type of drop structure is critical to determine the uptake/emission rates. By quantifying the air-water mass transfer rates...

Nonlinear oscillations of inviscid free drops

Science.gov (United States)

Patzek, T. W.; Benner, R. E., Jr.; Basaran, O. A.; Scriven, L. E.

1991-01-01

The present analysis of free liquid drops' inviscid oscillations proceeds through solution of Bernoulli's equation to obtain the free surface shape and of Laplace's equation for the velocity potential field. Results thus obtained encompass drop-shape sequences, pressure distributions, particle paths, and the temporal evolution of kinetic and surface energies; accuracy is verified by the near-constant drop volume and total energy, as well as the diminutiveness of mass and momentum fluxes across drop surfaces. Further insight into the nature of oscillations is provided by Fourier power spectrum analyses of mode interactions and frequency shifts.

Operator care and eco-concerned development of a fast, facile and economical assay for basic nitrogenous drugs based on simplified ion-pair mini-scale extraction using safer solvent combined with drop-based spectrophotometry.

Science.gov (United States)

Plianwong, Samarwadee; Sripattanaporn, Areerut; Waewsa-nga, Kwanrutai; Buacheen, Parin; Opanasopit, Praneet; Ngawhirunpat, Tanasait; Rojanarata, Theerasak

2012-08-30

A fast, facile, and economical assay for basic nitrogenous drugs has been developed based on the mini-scale extraction of the drug-dye ion pair complex combined with the use of safe-for-analyst and eco-friendlier organic extractant and drop-based micro-spectrophotometry. Instead of using large volume devices, the extraction was simply carried out in typical 1.5 mL microcentrifuge tubes along with the use of micropipettes for accurate transfer of liquids, vortex mixer for efficient partitioning of solutes and benchtop centrifuge for rapid phase separation. In the last step, back-extraction was performed by using the microvolume of acidic solution in order to concentrate the colored species into a confined aqueous microdrop and to keep the analyst away from unwanted contact and inhalation of organic solvents during the quantitation step which was achieved by using cuvetteless UV-vis micro-spectrophotometry without any prior dilutions. Using chlorpheniramine maleate as a representative analyte and n-butyl acetate as a less toxic and non-ozone depleting extractant, the miniaturized method was less laborious and much faster. It was accurate, precise and insensitive to the interferences from common excipients. Notably, it gave the assay results of drug in tablets and oral solution comparable to the large-scale pharmacopeial method while the consumption of organic solvents and the release of wastes were lowered by 200-400 folds. Copyright © 2012 Elsevier B.V. All rights reserved.

The Drop Tower Bremen -Experiment Operation

Science.gov (United States)

Könemann, Thorben; von Kampen, Peter; Rath, Hans J.

The idea behind the drop tower facility of the Center of Applied Space Technology and Micro-gravity (ZARM) in Bremen is to provide an inimitable technical opportunity of a daily access to short-term weightlessness on earth. In this way ZARM`s european unique ground-based microgravity laboratory displays an excellent economic alternative for research in space-related conditions at low costs comparable to orbital platforms. Many national and international ex-perimentalists motivated by these prospects decide to benefit from the high-quality and easy accessible microgravity environment only provided by the Drop Tower Bremen. Corresponding experiments in reduced gravity could open new perspectives of investigation methods and give scientists an impressive potential for a future technology and multidisciplinary applications on different research fields like Fundamental Physics, Astrophysics, Fluid Dynamics, Combus-tion, Material Science, Chemistry and Biology. Generally, realizing microgravity experiments at ZARM`s drop tower facility meet new requirements of the experimental hardware and may lead to some technical constraints in the setups. In any case the ZARM Drop Tower Operation and Service Company (ZARM FAB mbH) maintaining the drop tower facility is prepared to as-sist experimentalists by offering own air-conditioned laboratories, clean rooms, workshops and consulting engineers, as well as scientific personal. Furthermore, ZARM`s on-site apartment can be used for accommodations during the experiment campaigns. In terms of approaching drop tower experimenting, consulting of experimentalists is mandatory to successfully accomplish the pursued drop or catapult capsule experiment. For this purpose there will be a lot of expertise and help given by ZARM FAB mbH in strong cooperation to-gether with the experimentalists. However, in comparison to standard laboratory setups the drop or catapult capsule setup seems to be completely different at first view. While defining a

Pendent_Drop: An ImageJ Plugin to Measure the Surface Tension from an Image of a Pendent Drop

Directory of Open Access Journals (Sweden)

Adrian Daerr

2016-01-01

Full Text Available The pendent drop method for surface tension measurement consists in analysing the shape of an axisymmetric drop hanging from a capillary tube. This software is an add-on for the public domain image processing software ImageJ which matches a theoretical profile to the contour of a pendent drop, either interactively or by automatically minimising the mismatch. It provides an estimate of the surface tension, drop volume and surface area from the best matching parameters. It can be used in a headless setup. It is hosted on http://fiji.sc/List_of_update_sites with the source code on https://github.com/adaerr/pendent-drop

A hanging drop culture method to study terminal erythroid differentiation.

Science.gov (United States)

Gutiérrez, Laura; Lindeboom, Fokke; Ferreira, Rita; Drissen, Roy; Grosveld, Frank; Whyatt, David; Philipsen, Sjaak

2005-10-01

To design a culture method allowing the quantitative and qualitative analysis of terminal erythroid differentiation. Primary erythroid progenitors derived either from mouse tissues or from human umbilical cord blood were differentiated using hanging drop cultures and compared to methylcellulose cultures. Cultured cells were analyzed by FACS to assess differentiation. We describe a practical culture method by adapting the previously described hanging drop culture system to conditions allowing terminal differentiation of primary erythroid progenitors. Using minimal volumes of media and small numbers of cells, we obtained quantitative terminal erythroid differentiation within two days of culture in the case of murine cells and 4 days in the case of human cells. The established methods for ex vivo culture of primary erythroid progenitors, such as methylcellulose-based burst-forming unit-erythroid (BFU-E) and colony-forming unit-erythroid (CFU-E) assays, allow the detection of committed erythroid progenitors but are of limited value to study terminal erythroid differentiation. We show that the application of hanging drop cultures is a practical alternative that, in combination with clonogenic assays, enables a comprehensive assessment of the behavior of primary erythroid cells ex vivo in the context of genetic and drug-induced perturbations.

Pressure drop and arterial compliance - Two arterial parameters in one measurement.

Science.gov (United States)

Rotman, Oren M; Zaretsky, Uri; Shitzer, Avraham; Einav, Shmuel

2017-01-04

Coronary artery pressure-drop and distensibility (compliance) are two major, seemingly unrelated, parameters in the cardiovascular clinical setting, which are indicative of coronary arteries patency and atherosclerosis severity. While pressure drop is related to flow, and therefore serves as a functional indicator of a stenosis severity, the arterial distensibility is indicative of the arterial stiffness, and hence the arterial wall composition. In the present study, we hypothesized that local pressure drops are dependent on the arterial distensibility, and hence can provide information on both indices. The clinical significance is that a single measurement of pressure drop could potentially provide both functional and bio-mechanical metrics of lesions, and thus assist in real-time decision making prior to stenting. The goal of the current study was to set the basis for understanding this relationship, and define the accuracy and sensitivity required from the pressure measurement system. The investigation was performed using numerical fluid-structure interaction (FSI) simulations, validated experimentally using our high accuracy differential pressure measurement system. Simplified silicone mock coronary arteries with zero to intermediate size stenoses were used, and various combinations of arterial distensibility, diameter, and flow rate were simulated. Results of hyperemic flow cases were also compared to fractional flow reserve (FFR). The results indicate the potential clinical superiority of a high accuracy pressure drop-based parameter over FFR, by: (i) being more lesion-specific, (ii) the possibility to circumvent the FFR dependency on pharmacologically-induced hyperemia, and, (iii) by providing both functional and biomechanical lesion-specific information. Copyright © 2016 Elsevier Ltd. All rights reserved.

Total Site Heat Integration Considering Pressure Drops

Directory of Open Access Journals (Sweden)

Kew Hong Chew

2015-02-01

Full Text Available Pressure drop is an important consideration in Total Site Heat Integration (TSHI. This is due to the typically large distances between the different plants and the flow across plant elevations and equipment, including heat exchangers. Failure to consider pressure drop during utility targeting and heat exchanger network (HEN synthesis may, at best, lead to optimistic energy targets, and at worst, an inoperable system if the pumps or compressors cannot overcome the actual pressure drop. Most studies have addressed the pressure drop factor in terms of pumping cost, forbidden matches or allowable pressure drop constraints in the optimisation of HEN. This study looks at the implication of pressure drop in the context of a Total Site. The graphical Pinch-based TSHI methodology is extended to consider the pressure drop factor during the minimum energy requirement (MER targeting stage. The improved methodology provides a more realistic estimation of the MER targets and valuable insights for the implementation of the TSHI design. In the case study, when pressure drop in the steam distribution networks is considered, the heating and cooling duties increase by 14.5% and 4.5%.

An AMOLED AC-Biased Pixel Design Compensating the Threshold Voltage and I-R Drop

Directory of Open Access Journals (Sweden)

Ching-Lin Fan

2011-01-01

Full Text Available We propose a novel pixel design and an AC bias driving method for active-matrix organic light-emitting diode (AM-OLED displays using low-temperature polycrystalline silicon thin-film transistors (LTPS-TFTs. The proposed threshold voltage and I-R drop compensation circuit, which comprised three transistors and one capacitor, have been verified to supply uniform output current by simulation work using the Automatic Integrated Circuit Modeling Simulation Program with Integrated Circuit Emphasis (AIM-SPICE simulator. The simulated results demonstrate excellent properties such as low error rate of OLED anode voltage variation (<0.7% and low voltage drop of VDD power line. The proposed pixel circuit effectively enables threshold-voltage-deviation correction of driving TFT and compensates for the voltage drop of VDD power line using AC bias on OLED cathode.

Drop size measurements in Venturi scrubbers

Energy Technology Data Exchange (ETDEWEB)

Fernandez Alonso, D.; Azzopardi, B.J. [Nottingham Univ. (United Kingdom). Dept. of Chemical Engineering; Goncalves, J.A.S.; Coury, J.R. [Universidade Federal de Sao Carlos (Brazil). Departamento de Engenharia Quimica

2001-07-01

Venturi scrubbers are high efficiency gas cleaners in which suspended particles are removed from gas streams by drops formed by liquid atomisation, usually in the Venturi throat. The size of the drops formed are of fundamental importance to the performance of the equipment, both in terms of pressure drop and dust removal efficiency. In this study, drop sizes in a cylindrical laboratory-scale Venturi scrubber were measured using a laser diffraction technique. Gas velocity and liquid to gas ratios varied from 50 to 90 m/s and 0.5 to 2.0 1/m{sup 3}, respectively. Water was injected using two different arrangements: either as jets in the throat or as a film just upstream of the convergence. Drop size measurements were performed at three positions in the case of jet injection: two located along the throat, and the last one at the end of the diffuser. The present data shows that the Sauter mean diameter of the spray can be well correlated by the equation of Boll et al. (J. Air Pollut. Control Assoc. 24 (1974) 932). Drop size distributions are satisfactorily represented by a Rosin-Rammler function. This paper also provides a simple method for calculating the parameters of the Rosin-Rammler function. As a result of this work, drop sizes in Venturi scrubbers can be estimated with much higher accuracy. (Author)

Sepsis from dropped clips at laparoscopic cholecystectomy

International Nuclear Information System (INIS)

Hussain, Sarwat

2001-01-01

We report seven patients in whom five dropped surgical clips and two gallstones were visualized in the peritoneal cavity, on radiological studies. In two, subphrenic abscesses and empyemas developed as a result of dropped clips into the peritoneal cavity during or following laparoscopic cholecystectomy. In one of these two, a clip was removed surgically from the site of an abscess. In two other patients dropped gallstones, and in three, dropped clips led to no complications. These were seen incidentally on studies done for other indications. Abdominal abscess secondary to dropped gallstones is a well-recognized complication of laparoscopic cholecystectomy (LC). We conclude that even though dropped surgical clips usually do not cause problems, they should be considered as a risk additional to other well-known causes of post-LC abdominal sepsis

Micro-splashing by drop impacts

KAUST Repository

Thoroddsen, Sigurdur T; Takehara, Kohsei; Etoh, Takeharugoji

2012-01-01

We use ultra-high-speed video imaging to observe directly the earliest onset of prompt splashing when a drop impacts onto a smooth solid surface. We capture the start of the ejecta sheet travelling along the solid substrate and show how it breaks up immediately upon emergence from the underneath the drop. The resulting micro-droplets are much smaller and faster than previously reported and may have gone unobserved owing to their very small size and rapid ejection velocities, which approach 100 m s-1, for typical impact conditions of large rain drops. We propose a phenomenological mechanism which predicts the velocity and size distribution of the resulting microdroplets. We also observe azimuthal undulations which may help promote the earliest breakup of the ejecta. This instability occurs in the cusp in the free surface where the drop surface meets the radially ejected liquid sheet. © 2012 Cambridge University Press.

Micro-splashing by drop impacts

KAUST Repository

Thoroddsen, Sigurdur T.

2012-07-18

We use ultra-high-speed video imaging to observe directly the earliest onset of prompt splashing when a drop impacts onto a smooth solid surface. We capture the start of the ejecta sheet travelling along the solid substrate and show how it breaks up immediately upon emergence from the underneath the drop. The resulting micro-droplets are much smaller and faster than previously reported and may have gone unobserved owing to their very small size and rapid ejection velocities, which approach 100 m s-1, for typical impact conditions of large rain drops. We propose a phenomenological mechanism which predicts the velocity and size distribution of the resulting microdroplets. We also observe azimuthal undulations which may help promote the earliest breakup of the ejecta. This instability occurs in the cusp in the free surface where the drop surface meets the radially ejected liquid sheet. © 2012 Cambridge University Press.

Pressure drop in ET-RR-1

International Nuclear Information System (INIS)

Khattab, M.; Mina, A.R.

1990-01-01

Measurements of pressure drop through a bundle comprising 16 rods and their lower arrangement grid as well as orifices similar to those of ET-RR-1 core have been done. Experiments are carried out under adiabatic turbulent flow conditions at about 35 degree C. Bundle Reynolds number range is 4 x 10 -2 x 10. Orifices of diameters 4.5, 3.25 or 2.5 cm. are mounted underneath the bundle. The bundle and lower grid pressure drop coefficients are 3.75 and 1.8 respectively. Orifices pressure drop coefficients are 2.65, 19.67 and 53.55 respectively. The ratio of bundle pressure drop to that of 4.5 cm. Orifice diameter is 1.415. The pressure drop coefficients are utilizer to calculate flow through bundles. The flow rate per bundle is 39.1, 20.4 or 13.1 m 3 /hr. Depending on orifice diameter

Drop trampoline

Science.gov (United States)

Chantelot, Pierre; Coux, Martin; Clanet, Christophe; Quere, David

2017-11-01

Superhydrophobic substrates inspired from the lotus leaf have the ability to reflect impacting water drops. They do so very efficiently and contact lasts typically 10 ms for millimetric droplets. Yet unlike a lotus leaf most synthetic substrates are rigid. Focusing on the interplay between substrate flexibility and liquid repellency might allow us to understand the dynamic properties of natural surfaces. We perform liquid marbles impacts at velocity V onto thin ( 0.01 mm) stretched circular PDMS membranes. We obtain contact time reductions of up to 70%. The bouncing mechanism is drastically modified compared to that on a rigid substrate: the marble leaves the substrate while it is still spread in a disk shape as it is kicked upwards by the membrane. We show that the bouncing is controlled by an interplay between the dynamics of the drop and the membrane.

Drop Spreading with Random Viscosity

Science.gov (United States)

Xu, Feng; Jensen, Oliver

2016-11-01

Airway mucus acts as a barrier to protect the lung. However as a biological material, its physical properties are known imperfectly and can be spatially heterogeneous. In this study we assess the impact of these uncertainties on the rate of spreading of a drop (representing an inhaled aerosol) over a mucus film. We model the film as Newtonian, having a viscosity that depends linearly on the concentration of a passive solute (a crude proxy for mucin proteins). Given an initial random solute (and hence viscosity) distribution, described as a Gaussian random field with a given correlation structure, we seek to quantify the uncertainties in outcomes as the drop spreads. Using lubrication theory, we describe the spreading of the drop in terms of a system of coupled nonlinear PDEs governing the evolution of film height and the vertically-averaged solute concentration. We perform Monte Carlo simulations to predict the variability in the drop centre location and width (1D) or area (2D). We show how simulation results are well described (at much lower computational cost) by a low-order model using a weak disorder expansion. Our results show for example how variability in the drop location is a non-monotonic function of the solute correlation length increases. Engineering and Physical Sciences Research Council.

Thermocapillary reorientation of Janus drops

Science.gov (United States)

Rosales, Rodolfo; Saenz, Pedro

2017-11-01

Janus drops, named after the Ancient Roman two-faced god, are liquid drops formed from two immiscible fluids. Experimental observations indicate that a Janus drop may re-orientate in response to an applied external thermal gradient due to the Marangoni effect. Depending on the angle between the interior interface and the direction of the temperature gradient, disparities in the physical properties of the constituent liquids may lead to asymmetries in the thermocapillary flow. As a result, the drop will move along a curved path until a torque-free configuration is achieved, point after which it will continue on a straight trajectory. Here, we present the results of a theoretical investigation of this realignment phenomenon in the Stokes regime and in the limit of non-deformable interfaces. A 3D semi-analytical method in terms of polar spherical harmonics is developed to characterize and rationalize the hydrodynamic response (forces and torques), flow (velocity and temperature distribution) and trajectory of a Janus drop moving during the temperature-driven reorientation process. Furthermore, we discuss how this phenomenon may be exploited to develop dynamically reconfigurable micro-lenses. This work was partially supported by the US National Science Foundation through Grants DMS-1614043 and DMS-1719637.

CPAS Preflight Drop Test Analysis Process

Science.gov (United States)

Englert, Megan E.; Bledsoe, Kristin J.; Romero, Leah M.

2015-01-01

Throughout the Capsule Parachute Assembly System (CPAS) drop test program, the CPAS Analysis Team has developed a simulation and analysis process to support drop test planning and execution. This process includes multiple phases focused on developing test simulations and communicating results to all groups involved in the drop test. CPAS Engineering Development Unit (EDU) series drop test planning begins with the development of a basic operational concept for each test. Trajectory simulation tools include the Flight Analysis and Simulation Tool (FAST) for single bodies, and the Automatic Dynamic Analysis of Mechanical Systems (ADAMS) simulation for the mated vehicle. Results are communicated to the team at the Test Configuration Review (TCR) and Test Readiness Review (TRR), as well as at Analysis Integrated Product Team (IPT) meetings in earlier and intermediate phases of the pre-test planning. The ability to plan and communicate efficiently with rapidly changing objectives and tight schedule constraints is a necessity for safe and successful drop tests.

Blood drop patterns: Formation and applications.

Science.gov (United States)

Chen, Ruoyang; Zhang, Liyuan; Zang, Duyang; Shen, Wei

2016-05-01

The drying of a drop of blood or plasma on a solid substrate leads to the formation of interesting and complex patterns. Inter- and intra-cellular and macromolecular interactions in the drying plasma or blood drop are responsible for the final morphologies of the dried patterns. Changes in these cellular and macromolecular components in blood caused by diseases have been suspected to cause changes in the dried drop patterns of plasma and whole blood, which could be used as simple diagnostic tools to identify the health of humans and livestock. However, complex physicochemical driving forces involved in the pattern formation are not fully understood. This review focuses on the scientific development in microscopic observations and pattern interpretation of dried plasma and whole blood samples, as well as the diagnostic applications of pattern analysis. Dried drop patterns of plasma consist of intricate visible cracks in the outer region and fine structures in the central region, which are mainly influenced by the presence and concentration of inorganic salts and proteins during drying. The shrinkage of macromolecular gel and its adhesion to the substrate surface have been thought to be responsible for the formation of the cracks. Dried drop patterns of whole blood have three characteristic zones; their formation as functions of drying time has been reported in the literature. Some research works have applied engineering treatment to the evaporation process of whole blood samples. The sensitivities of the resultant patterns to the relative humidity of the environment, the wettability of the substrates, and the size of the drop have been reported. These research works shed light on the mechanisms of spreading, evaporation, gelation, and crack formation of the blood drops on solid substrates, as well as on the potential applications of dried drop patterns of plasma and whole blood in diagnosis. Crown Copyright © 2016. Published by Elsevier B.V. All rights reserved.

Effect of ambient temperature and relative humidity on interfacial temperature during early stages of drop evaporation.

Science.gov (United States)

Fukatani, Yuki; Orejon, Daniel; Kita, Yutaku; Takata, Yasuyuki; Kim, Jungho; Sefiane, Khellil

2016-04-01

Understanding drop evaporation mechanisms is important for many industrial, biological, and other applications. Drops of organic solvents undergoing evaporation have been found to display distinct thermal patterns, which in turn depend on the physical properties of the liquid, the substrate, and ambient conditions. These patterns have been reported previously to be bulk patterns from the solid-liquid to the liquid-gas drop interface. In the present work the effect of ambient temperature and humidity during the first stage of evaporation, i.e., pinned contact line, is studied paying special attention to the thermal information retrieved at the liquid-gas interface through IR thermography. This is coupled with drop profile monitoring to experimentally investigate the effect of ambient temperature and relative humidity on the drop interfacial thermal patterns and the evaporation rate. Results indicate that self-generated thermal patterns are enhanced by an increase in ambient temperature and/or a decrease in humidity. The more active thermal patterns observed at high ambient temperatures are explained in light of a greater temperature difference generated between the apex and the edge of the drop due to greater evaporative cooling. On the other hand, the presence of water humidity in the atmosphere is found to decrease the temperature difference along the drop interface due to the heat of adsorption, absorption and/or that of condensation of water onto the ethanol drops. The control, i.e., enhancement or suppression, of these thermal patterns at the drop interface by means of ambient temperature and relative humidity is quantified and reported.

Influence of decontamination of the WWER-440 primary circuit equipment on pressure drop in the reactor

International Nuclear Information System (INIS)

Kritsky, V.; Rodionov, Y.; Beresina, I.

2003-01-01

Over 40 reactor cycles at four WWER-440 type reactors have been analyzed in order to explain the increase of the pressure drop under certain combination of conditions. It is shown that the staff radiation exposure and the dose rate at first circuit segments are inversely correlated with the value of the pressure drop at the reactor, which is connected with the mechanism of redistribution of deposits and radioactive nuclides between the reactor and the rest part of the circuit. The influence of pH T on the formation of the dose rate from equipment and the change of pressure drop in the reactor WWER-440 is studied. The optimal range of pH T values for these parameters is determined to be 6.95-7.05 and these values are within the range of the water chemistry standards. The correlation between the changes of pressure drop and the number of decontaminated steam generators is established. This correlation shows that the pressure drop at the reactor grows with the increase of steam generators decontaminated during a preventive maintenance

Liquid-phase microextraction with solidification of the organic floating drop for the preconcentration and determination of mercury traces by electrothermal atomic absorption spectrometry

Energy Technology Data Exchange (ETDEWEB)

Lopez-Garcia, I.; Rivas, R.E.; Hernandez-Cordoba, M. [Faculty of Chemistry, University of Murcia, Department of Analytical Chemistry, Murcia (Spain)

2010-04-15

A procedure for the determination of traces of mercury by liquid-phase microextraction based on solidification of a floating organic droplet for separation and electrothermal atomic absorption spectrometry for final measurement has been developed. For this purpose, 50 {mu}L of pre-heated (50 C) undecanoic acid (UA), are added to 25 mL of aqueous sample solution at pH 5. The mixture, maintained at 50 C, is stirred for 10 min using a high stirring rate in order to fragment the UA drop into droplets, thus favoring the extraction process. Next, the vial is immersed in an ice bath, which results in the solidification of the UA drop that is easily separated. Injection into the atomizer is carried out after gentle heating. The pyrolytic atomizers are coated with electrolytically reduced palladium that acts as an effective chemical modifier for more than 500 firings. Under the optimized conditions, the detection limit was 70 ng L{sup -1} mercury with an enrichment factor of 430. The relative standard deviation of the measurements was in the 2.1-3.5% range. Recovery studies applied to the determination of mercuric ions in bottled and tap water samples were in the 92-104% range. (orig.)

Investigation of the quality of stored red blood cells after simulated air drop in the maritime environment.

Science.gov (United States)

Meli, Athinoula; Hancock, Vicky; Doughty, Heidi; Smedley, Steve; Cardigan, Rebecca; Wiltshire, Michael

2018-02-01

Maritime medical capability may be compromised by blood resupply. Air-dropped red blood cells (RBCs) is a possible mitigation factor. This study set out to evaluate RBC storage variables after a simulated parachute air drop into the sea, as limited data exist. The air load construction for the air drop of blood was subject to static drop assessment to simulate a worst-case parachute drop scenario. One control and two test Golden Hour shipping containers were each packaged with 10 RBC units. The control box was not dropped; Test Boxes 1 and 2 were further reinforced with waterproof boxes and underwent a simulated air drop on Day 7 or Day 8 postdonation, respectively. One day after the drop and once a week thereafter until Day 43 of storage, RBCs from each box were sampled and tested for full blood counts, hemolysis, adenosine triphosphate, 2,3-diphosphoglycerate, pH, extracellular potassium, glucose, lactate, deformability, and RBC microvesicles. The packaging configuration completed the air drop with no water ingress or physical damage. All units met UK specifications for volume, hemoglobin, and hemolysis. There were no significant differences for any of the variables studied between RBCs in the control box compared to RBCs in Test Boxes 1 and 2 combined over storage. The test proved that the packaging solution and the impact of a maritime air drop as performed in this study, on Day 7 or Day 8 postdonation, did not affect the in vitro quality of RBCs in SAGM over storage for 35 days. © 2017 AABB.

Preconcentration of lead using solidification of floating organic drop and its determination by electrothermal atomic absorption spectrometry

Directory of Open Access Journals (Sweden)

Mahmoud Chamsaz

2013-07-01

Full Text Available A simple microextraction method based on solidification of a floating organic drop (SFOD was developed for preconcentration of lead prior to its determination by electrothermal atomic absorption spectrometry (ETAAS. Ammonium pyrolidinedithiocarbamate (APDC was used as complexing agent, and the formed complex was extracted into a 20 μL of 1-undecanol. The extracted complex was diluted with ethanol and injected into a graphite furnace. An orthogonal array design (OAD with OA16 (45 matrix was employed to study the effects of different parameters such as pH, APDC concentration, stirring rate, sample solution temperature and the exposure time on the extraction efficiency. Under the optimized experimental conditions the limit of detection (based on 3 s and the enhancement factor were 0.058 μg L−1 and 113, respectively. The relative standard deviation (RSD for 8 replicate determinations of 1 μg L−1 of Pb was 8.8%. The developed method was validated by the analysis of certified reference materials and was successfully applied to the determination of lead in water and infant formula base powder samples.

Hydrothermal waves in evaporating sessile drops

OpenAIRE

Brutin, D.; Rigollet, F.; Niliot, C. Le

2009-01-01

Drop evaporation is a simple phenomena but still unclear concerning the mechanisms of evaporation. A common agreement of the scientific community based on experimental and numerical work evidences that most of the evaporation occurs at the triple line. However, the rate of evaporation is still empirically predicted due to the lack of knowledge on the convection cells which develop inside the drop under evaporation. The evaporation of sessile drop is more complicated than it appears due to the...

Assessment of agro-ecological service crop managements combined with organic fertilisation strategies in organic melon crop

Directory of Open Access Journals (Sweden)

Mariangela Diacono

2018-05-01

Full Text Available In organic horticultural systems, cover crops could provide several ecological services, therefore, they can be defined agroecological service crops (ASCs. The objective of this two-year research was to study the suitability on melon production of different ASC termination strategies, in combination with organic fertilisers application. In a split-block design, the main-plot was the ASC management, comparing: i green manure, in which the vetch was chopped and plowed into the soil; and ii roller-crimper (RC, in which the vetch was flattened by a roller-crimper; with iii fallow control, without vetch. The subplot consisted of offfarm organic inputs: i commercial humified fertiliser; ii anaerobic digestate fertiliser; iii composted municipal solid wastes; which were compared to iv unfertilised control (N0. At vetch termination, above soil biomass and nitrogen (N content were determined. At harvesting, crop yield performance and quality, N status and N efficiency were investigated. Also, main soil characteristics were assessed at the end of the trial. Among the ASC managements, the slightly reduced yield in the RC plots particularly in combination with N0 might have been the result of less N supplied by the vetch during the melon cycle. Anyway, no negative effects were observed for yield quality. The use of the RC showed a great potential in enhancing soil fertility. Our study suggests the suitability in organic farming of properly matching management of ASC and fertilisation strategies on melon crop.

The Measurement of the Surface Energy of Solids by Sessile Drop Accelerometry

Science.gov (United States)

Calvimontes, Alfredo

2018-05-01

A new physical method, the sessile drop accelerometry (SDACC) for the study and measurement of the interfacial energies of solid-liquid-gas systems, is tested and discussed in this study. The laboratory instrument and technique—a combination of a drop shape analyzer with high-speed camera and a laboratory drop tower- and the evaluation algorithms, were designed to calculate the interfacial energies as a function of the geometrical changes of a sessile droplet shape due to the effect of "switching off" gravity during the experiment. The method bases on Thermodynamics of Interfaces and differs from the conventional approach of the two hundred-years-old Young's equation in that it assumes a thermodynamic equilibrium between interfaces, rather than a balance of tensions on a point of the solid-liquid-gas contour line. A comparison of the mathematical model that supports the method with the widely accepted Young`s equation is discussed in detail in this study. The method opens new possibilities to develop surface characterization procedures by submitting the solid-liquid-system to artificial generated and uniform force fields.

Parametric resonance in acoustically levitated water drops

International Nuclear Information System (INIS)

Shen, C.L.; Xie, W.J.; Wei, B.

2010-01-01

Liquid drops can be suspended in air with acoustic levitation method. When the sound pressure is periodically modulated, the levitated drop is usually forced into an axisymmetric oscillation. However, a transition from axisymmetric oscillation into sectorial oscillation occurs when the modulation frequency approaches some specific values. The frequency of the sectorial oscillation is almost exactly half of the modulation frequency. It is demonstrated that this transition is induced by the parametric resonance of levitated drop. The natural frequency of sectorial oscillation is found to decrease with the increase of drop distortion extent.

Parametric resonance in acoustically levitated water drops

Energy Technology Data Exchange (ETDEWEB)

Shen, C.L.; Xie, W.J. [Department of Applied Physics, Northwestern Polytechnical University, Xi' an 710072 (China); Wei, B., E-mail: bbwei@nwpu.edu.c [Department of Applied Physics, Northwestern Polytechnical University, Xi' an 710072 (China)

2010-05-10

Liquid drops can be suspended in air with acoustic levitation method. When the sound pressure is periodically modulated, the levitated drop is usually forced into an axisymmetric oscillation. However, a transition from axisymmetric oscillation into sectorial oscillation occurs when the modulation frequency approaches some specific values. The frequency of the sectorial oscillation is almost exactly half of the modulation frequency. It is demonstrated that this transition is induced by the parametric resonance of levitated drop. The natural frequency of sectorial oscillation is found to decrease with the increase of drop distortion extent.

Understanding evaporation characteristics of a drop of distilled sulfur mustard (HD) chemical agent from stainless steel and aluminum substrates

Energy Technology Data Exchange (ETDEWEB)

Jung, H., E-mail: junghs@add.re.kr; Lee, H.W.

2014-05-01

Highlights: • Evaporation rates of HD are obtained from stainless steel and aluminum substrates. • The rates increase with temperature and are linearly proportional to drop size. • HD evaporation from stainless steel follows only constant contact area mechanism. • HD evaporation from aluminum proceeds by a combined mechanism. - Abstract: We report herein the evaporation rates and mechanism of a drop of distilled sulfur mustard (HD) agent from stainless steel and aluminum substrates. For systematic analysis, we used a laboratory-sized wind tunnel, thermal desorption (TD) connected to gas chromatograph/mass spectrometry (GC/MS) and drop shape analysis (DSA). We found that the evaporation rates of HD from stainless steel and aluminum increased with temperature. The rates were also linearly proportional to drop size. The time-dependent contact angle measurement showed that the evaporation of the drop of HD proceeded only by constant contact area mechanism from stainless steel surface. On the other hand, the evaporation of HD from aluminum proceeded by a combined mechanism of constant contact area mode and constant contact angle mode. Our experimental data sets and analysis could be used to predict vapor and contact hazard persistence of chemical warfare agents (CWAs) in the air and on exterior surfaces with chemical releases, which assists the military decision influencing personnel safety and decontamination of the site upon a chemical attack event.

Understanding evaporation characteristics of a drop of distilled sulfur mustard (HD) chemical agent from stainless steel and aluminum substrates

International Nuclear Information System (INIS)

Jung, H.; Lee, H.W.

2014-01-01

Highlights: • Evaporation rates of HD are obtained from stainless steel and aluminum substrates. • The rates increase with temperature and are linearly proportional to drop size. • HD evaporation from stainless steel follows only constant contact area mechanism. • HD evaporation from aluminum proceeds by a combined mechanism. - Abstract: We report herein the evaporation rates and mechanism of a drop of distilled sulfur mustard (HD) agent from stainless steel and aluminum substrates. For systematic analysis, we used a laboratory-sized wind tunnel, thermal desorption (TD) connected to gas chromatograph/mass spectrometry (GC/MS) and drop shape analysis (DSA). We found that the evaporation rates of HD from stainless steel and aluminum increased with temperature. The rates were also linearly proportional to drop size. The time-dependent contact angle measurement showed that the evaporation of the drop of HD proceeded only by constant contact area mechanism from stainless steel surface. On the other hand, the evaporation of HD from aluminum proceeded by a combined mechanism of constant contact area mode and constant contact angle mode. Our experimental data sets and analysis could be used to predict vapor and contact hazard persistence of chemical warfare agents (CWAs) in the air and on exterior surfaces with chemical releases, which assists the military decision influencing personnel safety and decontamination of the site upon a chemical attack event

Deformed liquid marbles: Freezing drop oscillations with powders

KAUST Repository

Marston, Jeremy; Zhu, Y.; Vakarelski, Ivan Uriev; Thoroddsen, Sigurdur T

2012-01-01

In this work we show that when a liquid drop impacts onto a fine-grained hydrophobic powder, the final form of the drop can be very different from the spherical form with which it impacts. In all cases, the drop rebounds due to the hydrophobic nature of the powder. However, we find that above a critical impact speed, the drop undergoes a permanent deformation to a highly non-spherical shape with a near-complete coverage of powder, which then freezes the drop oscillations during rebound. © 2012 Elsevier B.V.

Deformed liquid marbles: Freezing drop oscillations with powders

KAUST Repository

Marston, Jeremy

2012-09-01

In this work we show that when a liquid drop impacts onto a fine-grained hydrophobic powder, the final form of the drop can be very different from the spherical form with which it impacts. In all cases, the drop rebounds due to the hydrophobic nature of the powder. However, we find that above a critical impact speed, the drop undergoes a permanent deformation to a highly non-spherical shape with a near-complete coverage of powder, which then freezes the drop oscillations during rebound. © 2012 Elsevier B.V.

Headspace liquid-phase microextraction of methamphetamine and amphetamine in urine by an aqueous drop

International Nuclear Information System (INIS)

He Yi; Vargas, Angelica; Kang, Youn-Jung

2007-01-01

This study developed a headspace liquid-phase microextraction (LPME) method by using a single aqueous drop in combination with high performance liquid chromatography (HPLC)-UV detection for the determination of methamphetamine (MAP) and amphetamine (AP) in urine samples. The analytes, volatile and basic, were released from sample matrix into the headspace first, and then protonated and dissolved in an aqueous H 3 PO 4 drop hanging in the headspace by a HPLC syringe. After extraction, this drop was directly injected into HPLC. Parameters affecting extraction efficiency were investigated and optimized. This method showed good linearity in the investigated concentration range of 1.0-1500 μg L -1 , repeatability of the extraction (R.S.D. -1 for both analytes). Enrichment factors of about 400-fold and 220-fold were achieved for MAP and AP, respectively, at optimum conditions. The feasibility of the method was demonstrated by analyzing human urine samples

Levitation of a drop over a film flow

Science.gov (United States)

Sreenivas, K. R.; de, P. K.; Arakeri, Jaywant H.

1999-02-01

A vertical jet of water impinging on a horizontal surface produces a radial film flow followed by a circular hydraulic jump. We report a phenomenon where fairly large (1 ml) drops of liquid levitate just upstream of the jump on a thin air layer between the drop and the film flow. We explain the phenomenon using lubrication theory. Bearing action both in the air film and the water film seems to be necessary to support large drops. Horizontal support is given to the drop by the hydraulic jump. A variety of drop shapes is observed depending on the volume of the drop and liquid properties. We show that interaction of the forces due to gravity, surface tension, viscosity and inertia produces these various shapes.

Impact of a single drop on the same liquid: formation, growth and disintegration of jets

Science.gov (United States)

Agbaglah, G. Gilou; Deegan, Robert

2015-11-01

One of the simplest splashing scenarios results from the impact of a single drop on on the same liquid. The traditional understanding of this process is that the impact generates a jet that later breaks up into secondary droplets. Recently it was shown that even this simplest of scenarios is more complicated than expected because multiple jets can be generated from a single impact event and there are bifurcations in the multiplicity of jets. First, we study the formation, growth and disintegration of jets following the impact of a drop on a thin film of the same liquid using a combination of numerical simulations and linear stability theory. We obtain scaling relations from our simulations and use these as inputs to our stability analysis. We also use experiments and numerical simulations of a single drop impacting on a deep pool to examine the bifurcation from a single jet into two jets. Using high speed X-ray imaging methods we show that vortex separation within the drop leads to the formation of a second jet long after the formation of the ejecta sheet.

Drop Test Results of CRDM under Seismic Loads

International Nuclear Information System (INIS)

Choi, Myoung-Hwan; Cho, Yeong-Garp; Kim, Gyeong-Ho; Sun, Jong-Oh; Huh, Hyung

2016-01-01

This paper describes the test results to demonstrate the drop performance of CRDM under seismic loads. The top-mounted CRDM driven by the stepping motor for Jordan Research and Training Reactor (JRTR) has been developed in KAERI. The CRDM for JRTR has been optimized by the design improvement based on that of the HANARO. It is necessary to verify the drop performance under seismic loads such as operating basis earthquake (OBE) and safe shutdown earthquake (SSE). Especially, the CAR drop times are important data for the safety analysis. confirm the drop performance under seismic loads. The delay of drop time at Rig no. 2 due to seismic loads is greater than that at Rig no. 3. The total pure drop times under seismic loads are estimated as 1.169 and 1.855, respectively

Drop Test Results of CRDM under Seismic Loads

Energy Technology Data Exchange (ETDEWEB)

Choi, Myoung-Hwan; Cho, Yeong-Garp; Kim, Gyeong-Ho; Sun, Jong-Oh; Huh, Hyung [KAERI, Daejeon (Korea, Republic of)

2016-05-15

This paper describes the test results to demonstrate the drop performance of CRDM under seismic loads. The top-mounted CRDM driven by the stepping motor for Jordan Research and Training Reactor (JRTR) has been developed in KAERI. The CRDM for JRTR has been optimized by the design improvement based on that of the HANARO. It is necessary to verify the drop performance under seismic loads such as operating basis earthquake (OBE) and safe shutdown earthquake (SSE). Especially, the CAR drop times are important data for the safety analysis. confirm the drop performance under seismic loads. The delay of drop time at Rig no. 2 due to seismic loads is greater than that at Rig no. 3. The total pure drop times under seismic loads are estimated as 1.169 and 1.855, respectively.

Impact of granular drops

KAUST Repository

Marston, J. O.

2013-07-15

We investigate the spreading and splashing of granular drops during impact with a solid target. The granular drops are formed from roughly spherical balls of sand mixed with water, which is used as a binder to hold the ball together during free-fall. We measure the instantaneous spread diameter for different impact speeds and find that the normalized spread diameter d/D grows as (tV/D)1/2. The speeds of the grains ejected during the “splash” are measured and they rarely exceed twice that of the impact speed.

Impact of granular drops

KAUST Repository

Marston, J. O.; Mansoor, Mohammad M.; Thoroddsen, Sigurdur T

2013-01-01

We investigate the spreading and splashing of granular drops during impact with a solid target. The granular drops are formed from roughly spherical balls of sand mixed with water, which is used as a binder to hold the ball together during free-fall. We measure the instantaneous spread diameter for different impact speeds and find that the normalized spread diameter d/D grows as (tV/D)1/2. The speeds of the grains ejected during the “splash” are measured and they rarely exceed twice that of the impact speed.

Development of Active Learning Curriculum for CASPER's Microgravity Drop Tower

Science.gov (United States)

Carmona-Reyes, Jorge; Wang, Li; York, Judy; Matthews, Lorin; Laufer, Rene; Cook, Mike; Schmoke, Jimmy; Hyde, Truell

2016-10-01

As CASPER's new drop tower comes on line, plans for correlated educational research curricula are underway. CASPER's educational research team is working on developing curricula specific to the CASPER drop tower, modeled on a contest currently in use by (BEST) Robotics Inc. within central Texas independent school districts. The curricula integrates age specific use of computer programming software packages such as ``Scratch'' with industry standard communication protocols and augmented reality applications. Content is constructed around an earth and space science framework, covering subjects such as stars and galaxies, matter and energy, fusion and fission at a middle school level. CASPER faculty are partnering with the Region 12 Service Center; this combination provides a wide range of expertise that includes professional development, pedagogical methods, computational thinking in addition to microgravity and space science research expertise. The details of this work will be presented and samples of the manner in which it is impacting the CASPER research and educational outreach partnership will be discussed.

An algorithm for selecting the most accurate protocol for contact angle measurement by drop shape analysis.

Science.gov (United States)

Xu, Z N

2014-12-01

In this study, an error analysis is performed to study real water drop images and the corresponding numerically generated water drop profiles for three widely used static contact angle algorithms: the circle- and ellipse-fitting algorithms and the axisymmetric drop shape analysis-profile (ADSA-P) algorithm. The results demonstrate the accuracy of the numerically generated drop profiles based on the Laplace equation. A significant number of water drop profiles with different volumes, contact angles, and noise levels are generated, and the influences of the three factors on the accuracies of the three algorithms are systematically investigated. The results reveal that the above-mentioned three algorithms are complementary. In fact, the circle- and ellipse-fitting algorithms show low errors and are highly resistant to noise for water drops with small/medium volumes and contact angles, while for water drop with large volumes and contact angles just the ADSA-P algorithm can meet accuracy requirement. However, this algorithm introduces significant errors in the case of small volumes and contact angles because of its high sensitivity to noise. The critical water drop volumes of the circle- and ellipse-fitting algorithms corresponding to a certain contact angle error are obtained through a significant amount of computation. To improve the precision of the static contact angle measurement, a more accurate algorithm based on a combination of the three algorithms is proposed. Following a systematic investigation, the algorithm selection rule is described in detail, while maintaining the advantages of the three algorithms and overcoming their deficiencies. In general, static contact angles over the entire hydrophobicity range can be accurately evaluated using the proposed algorithm. The ease of erroneous judgment in static contact angle measurements is avoided. The proposed algorithm is validated by a static contact angle evaluation of real and numerically generated water drop

Significance of personality disorders in the face of drop-outs from psychiatric hospitalizations. The case of selected psychiatric units.

Science.gov (United States)

Biała, Maja; Kiejna, Andrzej

2017-06-18

The World Health Organization's estimations indicate that about 50% of patients in well-developed countries may not adhere to long-term therapies. In the field of psychiatry, drop-outs from psychiatric treatment are particularly important. Personality disorders are a significant part of this sphere. The aim of this research was to empirically verify the hypothesis regarding the relation between comorbid personality disorders and drop-outs from treatment among patients of psychiatric wards. This study was a prospective cohort study. 110 patients, hospitalized in 3 different psychiatric wards, were included. Personality disorders were assessed with the Structured Clinical Interview For DSM-IV Personality Disorders (SCID-II). The research was financed by the Polish National Science Center (DEC-2011/01/N/NZ5/05364). The response rate was 89.1%. 72.56% of patients suffered from personality disorders (SCID-II) (among them the most prevalent were: personality disorder - not otherwise specified - 40.7% and borderline personality disorder - 12.38%; 22.95% of patients dropped out from treatment). However, occurrence of personality disorders was not relevant for those drop-outs. On the other hand, relationships at the level of certain criteria of borderline personality disorders and passive-aggressive personality have been revealed. These relationships became stronger when considered from the perspective of differences in the organization of treatment at individual wards. Some personality disorders may play an important role in drop-outs from psychiatric treatment. Presented results require further research.

Chemical analysis of acoustically levitated drops by Raman spectroscopy.

Science.gov (United States)

Tuckermann, Rudolf; Puskar, Ljiljana; Zavabeti, Mahta; Sekine, Ryo; McNaughton, Don

2009-07-01

An experimental apparatus combining Raman spectroscopy with acoustic levitation, Raman acoustic levitation spectroscopy (RALS), is investigated in the field of physical and chemical analytics. Whereas acoustic levitation enables the contactless handling of microsized samples, Raman spectroscopy offers the advantage of a noninvasive method without complex sample preparation. After carrying out some systematic tests to probe the sensitivity of the technique to drop size, shape, and position, RALS has been successfully applied in monitoring sample dilution and preconcentration, evaporation, crystallization, an acid-base reaction, and analytes in a surface-enhanced Raman spectroscopy colloidal suspension.

Headspace liquid-phase microextraction of methamphetamine and amphetamine in urine by an aqueous drop

Energy Technology Data Exchange (ETDEWEB)

He Yi [Department of Sciences, John Jay College of Criminal Justice, City University of New York, 445 W 59th Street, New York, NY 10019 (United States)]. E-mail: yhe@jjay.cuny.edu; Vargas, Angelica [Department of Sciences, John Jay College of Criminal Justice, City University of New York, 445 W 59th Street, New York, NY 10019 (United States); Kang, Youn-Jung [Department of Sciences, John Jay College of Criminal Justice, City University of New York, 445 W 59th Street, New York, NY 10019 (United States)

2007-04-25

This study developed a headspace liquid-phase microextraction (LPME) method by using a single aqueous drop in combination with high performance liquid chromatography (HPLC)-UV detection for the determination of methamphetamine (MAP) and amphetamine (AP) in urine samples. The analytes, volatile and basic, were released from sample matrix into the headspace first, and then protonated and dissolved in an aqueous H{sub 3}PO{sub 4} drop hanging in the headspace by a HPLC syringe. After extraction, this drop was directly injected into HPLC. Parameters affecting extraction efficiency were investigated and optimized. This method showed good linearity in the investigated concentration range of 1.0-1500 {mu}g L{sup -1}, repeatability of the extraction (R.S.D. < 5%, n = 6), and low detection limits (0.3 {mu}g L{sup -1} for both analytes). Enrichment factors of about 400-fold and 220-fold were achieved for MAP and AP, respectively, at optimum conditions. The feasibility of the method was demonstrated by analyzing human urine samples.

Seismic II over I Drop Test Program results and interpretation

International Nuclear Information System (INIS)

Thomas, B.

1993-03-01

The consequences of non-seismically qualified (Category 2) objects falling and striking essential seismically qualified (Category 1) objects has always been a significant, yet analytically difficult problem, particularly in evaluating the potential damage to equipment that may result from earthquakes. Analytical solutions for impact problems are conservative and available for mostly simple configurations. In a nuclear facility, the open-quotes sourcesclose quotes and open-quotes targetsclose quotes requiring evaluation are frequently irregular in shape and configuration, making calculations and computer modeling difficult. Few industry or regulatory rules are available on this topic even though it is a source of considerable construction upgrade costs. A drop test program was recently conducted to develop a more accurate understanding of the consequences of seismic interactions. The resulting data can be used as a means to improve the judgment of seismic qualification engineers performing interaction evaluations and to develop realistic design criteria for seismic interactions. Impact tests on various combinations of sources and targets commonly found in one Savannah River Site (SRS) nuclear facility were performed by dropping the sources from various heights onto the targets. This report summarizes results of the Drop Test Program. Force and acceleration time history data are presented as well as general observations on the overall ruggedness of various targets when subjected to impacts from different types of sources

Seismic II over I Drop Test Program results and interpretation

Energy Technology Data Exchange (ETDEWEB)

Thomas, B.

1993-03-01

The consequences of non-seismically qualified (Category 2) objects falling and striking essential seismically qualified (Category 1) objects has always been a significant, yet analytically difficult problem, particularly in evaluating the potential damage to equipment that may result from earthquakes. Analytical solutions for impact problems are conservative and available for mostly simple configurations. In a nuclear facility, the {open_quotes}sources{close_quotes} and {open_quotes}targets{close_quotes} requiring evaluation are frequently irregular in shape and configuration, making calculations and computer modeling difficult. Few industry or regulatory rules are available on this topic even though it is a source of considerable construction upgrade costs. A drop test program was recently conducted to develop a more accurate understanding of the consequences of seismic interactions. The resulting data can be used as a means to improve the judgment of seismic qualification engineers performing interaction evaluations and to develop realistic design criteria for seismic interactions. Impact tests on various combinations of sources and targets commonly found in one Savannah River Site (SRS) nuclear facility were performed by dropping the sources from various heights onto the targets. This report summarizes results of the Drop Test Program. Force and acceleration time history data are presented as well as general observations on the overall ruggedness of various targets when subjected to impacts from different types of sources.

Seismic II over I Drop Test Program results and interpretation

Energy Technology Data Exchange (ETDEWEB)

Thomas, B.

1993-03-01

The consequences of non-seismically qualified (Category 2) objects falling and striking essential seismically qualified (Category 1) objects has always been a significant, yet analytically difficult problem, particularly in evaluating the potential damage to equipment that may result from earthquakes. Analytical solutions for impact problems are conservative and available for mostly simple configurations. In a nuclear facility, the [open quotes]sources[close quotes] and [open quotes]targets[close quotes] requiring evaluation are frequently irregular in shape and configuration, making calculations and computer modeling difficult. Few industry or regulatory rules are available on this topic even though it is a source of considerable construction upgrade costs. A drop test program was recently conducted to develop a more accurate understanding of the consequences of seismic interactions. The resulting data can be used as a means to improve the judgment of seismic qualification engineers performing interaction evaluations and to develop realistic design criteria for seismic interactions. Impact tests on various combinations of sources and targets commonly found in one Savannah River Site (SRS) nuclear facility were performed by dropping the sources from various heights onto the targets. This report summarizes results of the Drop Test Program. Force and acceleration time history data are presented as well as general observations on the overall ruggedness of various targets when subjected to impacts from different types of sources.

Thyrotoxicosis Presenting as Unilateral Drop Foot.

Science.gov (United States)

Hara, Kenju; Miyata, Hajime; Motegi, Takahide; Shibano, Ken; Ishiguro, Hideaki

2017-01-01

Neuromuscular disorders associated with hyperthyroidism have several variations in their clinical phenotype, such as ophthalmopathy, periodic paralysis, and thyrotoxic myopathy. We herein report an unusual case of thyrotoxic myopathy presenting as unilateral drop foot. Histopathological examinations of the left tibialis anterior muscle showed marked variation in the fiber size, mild inflammatory cell infiltration, and necrotic and regenerated muscle fibers with predominantly type 1 fiber atrophy. Medical treatment with propylthiouracil resulted in complete improvement of the left drop foot. This case expands the phenotype of thyrotoxicosis and suggests that thyrotoxicosis be considered as a possible cause of unilateral drop foot.

Bubble and Drop Nonlinear Dynamics (BDND)

Science.gov (United States)

Trinh, E. H.; Leal, L. Gary; Thomas, D. A.; Crouch, R. K.

1998-01-01

Free drops and bubbles are weakly nonlinear mechanical systems that are relatively simple to characterize experimentally in 1-G as well as in microgravity. The understanding of the details of their motion contributes to the fundamental study of nonlinear phenomena and to the measurement of the thermophysical properties of freely levitated melts. The goal of this Glovebox-based experimental investigation is the low-gravity assessment of the capabilities of a modular apparatus based on ultrasonic resonators and on the pseudo- extinction optical method. The required experimental task is the accurate measurements of the large-amplitude dynamics of free drops and bubbles in the absence of large biasing influences such as gravity and levitation fields. A single-axis levitator used for the positioning of drops in air, and an ultrasonic water-filled resonator for the trapping of air bubbles have been evaluated in low-gravity and in 1-G. The basic feasibility of drop positioning and shape oscillations measurements has been verified by using a laptop-interfaced automated data acquisition and the optical extinction technique. The major purpose of the investigation was to identify the salient technical issues associated with the development of a full-scale Microgravity experiment on single drop and bubble dynamics.

Drop Testing Representative Multi-Canister Overpacks

Energy Technology Data Exchange (ETDEWEB)

Snow, Spencer D. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Morton, Dana K. [Idaho National Lab. (INL), Idaho Falls, ID (United States)

2015-06-01

The objective of the work reported herein was to determine the ability of the Multi- Canister Overpack (MCO) canister design to maintain its containment boundary after an accidental drop event. Two test MCO canisters were assembled at Hanford, prepared for testing at the Idaho National Engineering and Environmental Laboratory (INEEL), drop tested at Sandia National Laboratories, and evaluated back at the INEEL. In addition to the actual testing efforts, finite element plastic analysis techniques were used to make both pre-test and post-test predictions of the test MCOs structural deformations. The completed effort has demonstrated that the canister design is capable of maintaining a 50 psig pressure boundary after drop testing. Based on helium leak testing methods, one test MCO was determined to have a leakage rate not greater than 1x10^-5 std cc/sec (prior internal helium presence prevented a more rigorous test) and the remaining test MCO had a measured leakage rate less than 1x10^-7 std cc/sec (i.e., a leaktight containment) after the drop test. The effort has also demonstrated the capability of finite element methods using plastic analysis techniques to accurately predict the structural deformations of canisters subjected to an accidental drop event.

Spent Nuclear Fuel (SNF) Bounding Drop Support Calculations

International Nuclear Information System (INIS)

CHENAULT, D.M.

1999-01-01

This report evaluates different drop heights, concrete and other impact media to which the transport package and/or the MCO is dropped. A prediction method is derived for estimating the resultant impact factor for determining the bounding drop case for the SNF Project

Wetting and evaporation of binary mixture drops.

Science.gov (United States)

Sefiane, Khellil; David, Samuel; Shanahan, Martin E R

2008-09-11

Experimental results on the wetting behavior of water, methanol, and binary mixture sessile drops on a smooth, polymer-coated substrate are reported. The wetting behavior of evaporating water/methanol drops was also studied in a water-saturated environment. Drop parameters (contact angle, shape, and volume) were monitored in time. The effects of the initial relative concentrations on subsequent evaporation and wetting dynamics were investigated. Physical mechanisms responsible for the various types of wetting behavior during different stages are proposed and discussed. Competition between evaporation and hydrodynamic flow are evoked. Using an environment saturated with water vapor allowed further exploration of the controlling mechanisms and underlying processes. Wetting stages attributed to differential evaporation of methanol were identified. Methanol, the more volatile component, evaporates predominantly in the initial stage. The data, however, suggest that a small proportion of methanol remained in the drop after the first stage of evaporation. This residual methanol within the drop seems to influence subsequent wetting behavior strongly.

Endurance of lead-free assembly under board level drop test and thermal cycling

Energy Technology Data Exchange (ETDEWEB)

Xia Yanghua [State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050 (China)], E-mail: xia_yanghua@hotmail.com; Xie Xiaoming [State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050 (China)

2008-06-12

The reliability of lead-free electronic assemblies under board level drop test and thermal cycling was investigated. TSOP (thin small outline package) devices with FeNi leads were reflow soldered on FR4 PCB (printed circuit board) with Sn3.0Ag0.5Cu (wt%) solder. The effects of different PCB finishes (organic solderability preservative (OSP) and electroless nickel immersion gold (ENIG)) on the reliability performance were studied. The results show that the assemblies with ENIG finishes reveal better reliability performance than its OSP counterparts under drop test, however, the OSP samples outperform those with ENIG finishes under thermal cycling. The failure mechanism is different under these two test conditions: the solder joints fracture into the intermetallic compounds (IMCs) layer under drop test, and cracks initiate in the bulk solder under thermal cycling. The surface finishes have an effect on the failure mode. The propagation of crack in the ENIG case is along the device/solder interface, while in the case of OSP, the crack extends parallel to the solder/PCB interface.

The effect of clebopride-simethicone combination therapy on echographic visualization of retrogastric organs.

Science.gov (United States)

Herrerías Gutiérrez, J M; García Montes, J

1994-01-01

The main objective of this study was to determine whether the effect of a combination of clebopride (0.5 mg) and simethicone (200 mg) would improve echographic visualization of retrogastric organs. An experimental aerogastric induction model was used in 50 healthy volunteers, who received 30 mL of beaten egg white to decrease the quality of echographic visualization. Improvements were evaluated after treatment. The results show that the combination of clebopride and simethicone was better than placebo in reducing gastric distension and in improving the quality of echographic images of the organs located behind the stomach, that is, the gallbladder, pancreas, and left kidney.

Drop-out from a psychodynamic group psychotherapy outpatient unit.

Science.gov (United States)

Jensen, Hans Henrik; Mortensen, Erik Lykke; Lotz, Martin

2014-11-01

BACKGROUND. Drop-out from psychotherapy is common and represents a considerable problem in clinical practice and research. Aim. To explore pre-treatment predictors of early and late drop-out from psychodynamic group therapy in a public outpatient unit for non-psychotic disorders in Denmark. Methods. Naturalistic design including 329 patients, the majority with mood, neurotic and personality disorders referred to 39-session group therapy. Predictors were socio-demographic and clinical variables, self-reported symptoms (Symptom Check List-90-Revised) and personality style (Millon Clinical Multiaxial Inventory-II). Drop-out was classified into early and late premature termination excluding patients who dropped out for external reasons. Results. Drop-out comprised 20.6% (68 patients) of the sample. Logistic regression revealed social functioning, vocational training, alcohol problems and antisocial behavior to be related to drop-out. However, early drop-outs had prominent agoraphobic symptoms, lower interpersonal sensitivity and compulsive personality features, and late drop-outs cognitive and somatic anxiety symptoms and antisocial personality features. Clinical and psychological variables accounted for the major part of variance in predictions of drop-out, which ranged from 15.6% to 19.5% (Nagelkerke Pseudo R-Square). Conclusion. Social functioning was consistently associated with drop-out, but personality characteristics and anxiety symptoms differentiated between early and late drop-out. Failure to discriminate between stages of premature termination may explain some of the inconsistencies in the drop-out literature. Clinical implications. Before selection of patients to time-limited psychodynamic groups, self-reported symptoms should be thoroughly considered. Patients with agoraphobic symptoms should be offered alternative treatment. Awareness of and motivation to work with interpersonal issues may be essential for compliance with group therapy.

Reducing Variability in Stress Drop with Root-Mean Acceleration

Science.gov (United States)

Crempien, J.; Archuleta, R. J.

2012-12-01

Stress drop is a fundamental property of the earthquake source. For a given tectonic region stress drop is assumed to be constant allowing for the scaling of earthquake spectra. However, the variability of the stress drop, either for worldwide catalogs or regional catalogs, is quite large. The variability around the median value is on the order of 1.5 in log10 units. One question that continues to pervade the analysis of stress drop is whether this variability is an inherent characteristic of the Earth or is an artifact of the determination of stress drop via the use of the spectral analysis. It is simple to see that the stress drop determined by seismic moment times corner frequency cubed that errors in the corner frequency will strongly influence the variability in the stress drop. To avoid this strong dependence on corner frequency cubed, we have examined the determination of stress drop based on the approach proposed by Hanks (1979), namely using the root-mean-square acceleration. The stress drop determined using rms acceleration may be advantageous because the stress drop is only affected by the square root of the corner frequency. To test this approach we have determined stress drops for the 2000 Tottori earthquake and its aftershocks. We use both the classic method of fitting to a spectrum as well as using rms acceleration. For a preliminary analysis of eight aftershocks and the mainshock we find that the variability in stress drop is reduced by about a factor of two. This approach needs more careful analysis of more events, which will be shown at the meeting.

Why Do Students Drop Advanced Mathematics?

Science.gov (United States)

Horn, Ilana

2004-01-01

Students, especially black, Latino and Native American youth and students of low socio-economic status drop out of advanced mathematics. Teachers must coordinate their expectations, their knowledge of students and their teaching practices in order to stop struggling students from dropping out of advanced math classes.

Delayed frost growth on jumping-drop superhydrophobic surfaces.

Science.gov (United States)

Boreyko, Jonathan B; Collier, C Patrick

2013-02-26

Self-propelled jumping drops are continuously removed from a condensing superhydrophobic surface to enable a micrometric steady-state drop size. Here, we report that subcooled condensate on a chilled superhydrophobic surface are able to repeatedly jump off the surface before heterogeneous ice nucleation occurs. Frost still forms on the superhydrophobic surface due to ice nucleation at neighboring edge defects, which eventually spreads over the entire surface via an interdrop frost wave. The growth of this interdrop frost front is shown to be up to 3 times slower on the superhydrophobic surface compared to a control hydrophobic surface, due to the jumping-drop effect dynamically minimizing the average drop size and surface coverage of the condensate. A simple scaling model is developed to relate the success and speed of interdrop ice bridging to the drop size distribution. While other reports of condensation frosting on superhydrophobic surfaces have focused exclusively on liquid-solid ice nucleation for isolated drops, these findings reveal that the growth of frost is an interdrop phenomenon that is strongly coupled to the wettability and drop size distribution of the surface. A jumping-drop superhydrophobic condenser minimized frost formation relative to a conventional dropwise condenser in two respects: preventing heterogeneous ice nucleation by continuously removing subcooled condensate, and delaying frost growth by limiting the success of interdrop ice bridge formation.

Hanging drop crystal growth apparatus and method

Science.gov (United States)

Carter, Daniel C. (Inventor); Smith, Robbie E. (Inventor)

1989-01-01

An apparatus (10) is constructed having a cylindrical enclosure (16) within which a disc-shaped wicking element (18) is positioned. A well or recess (22) is cut into an upper side (24) of this wicking element, and a glass cover plate or slip (28) having a protein drop disposed thereon is sealably positioned on the wicking element (18), with drop (12) being positioned over well or recess (22). A flow of control fluid is generated by a programmable gradient former (16), with this control fluid having a vapor pressure that is selectively variable. This flow of control fluid is coupled to the wicking element (18) where control fluid vapor diffusing from walls (26) of the recess (22) is exposed to the drop (12), forming a vapor pressure gradient between the drop (12) and the control fluid vapor. Initially, this gradient is adjusted to draw solvent from the drop (12) at a relatively high rate, and as the critical supersaturation point is approached (the point at which crystal nucleation occurs), the gradient is reduced to more slowly draw solvent from the drop (12). This allows discrete protein molecules more time to orient themselves into an ordered crystalline lattice, producing protein crystals which, when processed by X-ray crystallography, possess a high degree of resolution.

Free drop impact analysis of shipping cask

International Nuclear Information System (INIS)

Pfeiffer, P.A.; Kennedy, J.M.

1989-01-01

The WHAMS-2D and WHAMS-3D codes were used to analyze the dynamic response of the RAS/TREAT shielded shipping cask subjected to transient leadings for the purpose of assessing potential damage to the various components that comprise the the cask. The paper describes how these codes can be used to provide and intermediate level of detail between full three-dimensional finite element calculations and hand calculations which are cost effective for design purposes. Three free drops were adressed: (1) a thirty foot axial drop on either end; (2) a thirty foot oblique angle drop with the cask having several different orientations from the vertical with impact on the cask corner; and (3) a thirty foot side drop with simultaneous impact on the lifting trunnion and the bottom end. Results are presented for two models of the side and oblique angle drops; one model includes only the mass of the lapped sleeves of depleted uranium (DU) while the other includes the mass and stiffness of the DU. The results of the end drop analyses are given for models with and without imperfections in the cask. Comparison of the analysis to hand calculations and simplified analyses are given. (orig.)

The influence of organic substances type on the properties of mineral-organic fertilizers

Science.gov (United States)

Huculak-Mä Czka, Marta; Hoffmann, Krystyna; Hoffmann, Józef

2010-05-01

In presented research the lignite coal, peat, poultry droppings and their composts were suggested as a components of mineral-organic fertilizers. Fertility of soil is conditioned by an ability to supply plants with water and nutrients essential to their growth and development. The soil is described as tri-phase system consisting of solid, liquid and gas phase. In solid phase the soil minerals and organic matter can be distinguished. The content of micro-organisms contained in the soil i.e. microfauna and microflora is indispensable for high soil fertility. Nutrients should occur in the forms available for plants in order to obtain high yields of the high quality crops. Organic fertilizing has versatile activity. Increasing contents of humus, providing mineral nutrients included in organic substance and the improvement in physical properties of the soil belong to its main purposes. Due to applying organic fertilizers heavy soils is getting loosen and in consequence become more airy what probably influences stimulation of soil micro-organisms activity. An aqueous as well as sorption capacity of light soils is also increasing, buffer range and the stabilization of the proper level of pH value of the soil, plants are provided with basic macro and micronutrients. Conventional organic fertilizers applied in an arable farms are manure, dung, green manures and composts of different kind. Within compost group the following types can be distinguished: compost from farming, urban wastes, shredded straw, poultry droppings, industrial wastes, bark of coniferous tree etc. Properly developed fertilizer formulas should contain in their composition both mineral as well as organic elements. Such fertilizer should fit its composition to the soil and plant requirements. It should contain organic substance being characterized by a high aqueous and cations sorption capacity, substance undergoing the fast mineralization with the large calcium content. Inorganic substances e.g. bentonites

A Titanium–Organic Framework as an Exemplar of Combining the Chemistry of Metal– and Covalent–Organic Frameworks

Energy Technology Data Exchange (ETDEWEB)

Nguyen, Ha L.; Gándara, Felipe; Furukawa, Hiroyasu; Doan, Tan L. H.; Cordova, Kyle E.; Yaghi, Omar M.

2016-04-06

A crystalline material with a two-dimensional structure, termed metal–organic framework-901 (MOF-901), was prepared using a strategy that combines the chemistry of MOFs and covalent–organic frameworks (COFs). This strategy involves in situ generation of an amine-functionalized titanium oxo cluster, Ti6O6(OCH3)6(AB)6 (AB = 4-aminobenzoate), which was linked with benzene-1,4-dialdehyde using imine condensation reactions, typical of COFs. The crystal structure of MOF-901 is composed of hexagonal porous layers that are likely stacked in staggered conformation (hxl topology). This MOF represents the first example of combining metal cluster chemistry with dynamic organic covalent bond formation to give a new crystalline, extended framework of titanium metal, which is rarely used in MOFs. The incorporation of Ti(IV) units made MOF-901 useful in the photocatalyzed polymerization of methyl methacrylate (MMA). The resulting polyMMA product was obtained with a high-number-average molar mass (26 850 g mol–1) and low polydispersity index (1.6), which in many respects are better than those achieved by the commercially available photocatalyst (P-25 TiO2). Additionally, the catalyst can be isolated, reused, and recycled with no loss in performance.

Studying the field induced breakup of acoustically levitated drops

Science.gov (United States)

Warschat, C.; Riedel, J.

2017-10-01

Coulomb fission of charged droplets (The terms drop and droplet are often used synonymous. Throughout this manuscript, to avoid confusion, the terms drop and droplet will be used for liquid spheres with radii in the millimeter range and the micrometer range, respectively. In our experiments, the first correspond to the parent drop while the latter describes the ejected progeny droplets.) is a well-studied natural phenomenon. Controlled droplet fission is already successfully employed in several technological applications. Still, since the occurring surface rupture relies on the exact understanding and description of the liquid gas boundary, some details are still under debate. Most empirical systematic studies observe falling micrometer droplets passing through the electric field inside a plate capacitor. This approach, although easily applicable and reliable, limits the experimental degrees of freedom regarding the observable time and the maximum size of the drops and can only be performed in consecutive individual observations of different subsequent drops. Here we present a novel setup to study the field induced breakup of acoustically levitated drops. The design does not bear any restrictions towards the temporal window of observation, and allows handling of drops of a tunable radius ranging from 10 μm to several millimeters and a real-time monitoring of one single drop. Our comprehensive study includes a time resolved visual inspection, laser shadowgraphy, laser induced fluorescence imaging, and ambient mass spectrometric interrogation of the nascent Taylor cone. The results shown for a millimeter sized drop, previously inaccessible for Coulomb fission experiments, are mostly comparable with previous results for smaller drops. The major difference is the time scale and the threshold potential of the drop rupture. Both values, however, resemble theoretically extrapolations to the larger radius. The technique allows for a systematic study of breakup behavior of

Motion of a drop driven by substrate vibrations

Science.gov (United States)

Brunet, P.; Eggers, J.; Deegan, R. D.

2009-01-01

We report an experimental study of liquid drops moving against gravity, when placed on a vertically vibrating inclined plate, which is partially wet by the drop. Frequency of vibrations ranges from 30 to 200 Hz, and above a threshold in vibration acceleration, drops experience an upward motion. We attribute this surprising motion to the deformations of the drop, as a consequence of an up/down symmetry-breaking induced by the presence of the substrate. We relate the direction of motion to contact angle measurements.

The new Drop Tower catapult system

Science.gov (United States)

von Kampen, Peter; Kaczmarczik, Ulrich; Rath, Hans J.

2006-07-01

The Center of Applied Space Technology and Microgravity (ZARM) was founded in 1985 as an institute of the University Bremen, which focuses on research on gravitational and space-related phenomena. In 1988, the construction of the "Drop Tower" began. Since then, the eye-catching tower with a height of 146 m and its characteristic glass roof has become the emblem of the technology centre in Bremen. The Drop Tower Bremen provides a facility for experiments under conditions of weightlessness. Items are considered weightless, when they are in "free fall", i.e. moving without propulsion within the gravity field of the earth. The height of the tower limits the simple "free fall" experiment period to max. 4.74 s. With the inauguration of the catapult system in December 2004, the ZARM is entering a new dimension. This world novelty will meet scientists' demands of extending the experiment period up to 9.5 s. Since turning the first sod on May 3rd, 1988, the later installation of the catapult system has been taken into account by building the necessary chamber under the tower. The catapult system is located in a chamber 10 m below the base of the tower. This chamber is almost completely occupied by 12 huge pressure tanks. These tanks are placed around the elongation of the vacuum chamber of the drop tube. In its centre there is the pneumatic piston that accelerates the drop capsule by the pressure difference between the vacuum inside the drop tube and the pressure inside the tanks. The acceleration level is adjusted by means of a servo hydraulic breaking system controlling the piston velocity. After only a quarter of a second the drop capsule achieves its lift-off speed of 175 km/h. With this exact speed, the capsule will rise up to the top of the tower and afterwards fall down again into the deceleration unit which has been moved under the drop tube in the meantime. The scientific advantages of the doubled experiment time are obvious: during almost 10 s of high

Theory of magnetostriction of electron-hole drops in Ge

International Nuclear Information System (INIS)

Markiewicz, R.S.

1978-01-01

A large mass of electron-hole liquid (γ drop) formed in a strain-induced potential well in Ge is known to distort its shape significantly in a magnetic field B > or approx. = 1 kG. It is shown in this paper that the shape change can be understood in detail as due to a ''recombination current'' of electron-hole pairs needed to replace those pairs which recombine in the drop volume. The Lorentz force deflects this current and produces a macroscopic dipole current loop inside the drop. The drop then changes shape to minimize its total energy, including magnetic, strain, and surface energies. While the drop usually flattens along the field direction, both para- and diamagnetic effects (elongated drops) are found to be possible, depending on excitation conditions, in accord with experiment. Similar effects are predicted to occur in small drops in unstrained Ge. This paper presents a magnetohydrodynamic theory of the magnetostriction which takes into account density variations which occur in the strain well and in high magnetic fields. A simpler theory is given for the special case in which the drop may be considered incompressible (small drops and moderate fields). Effects of carrier mass anisotropy and fluid viscosity are taken into consideration

Ground Motion Prediction Equations Empowered by Stress Drop Measurement

Science.gov (United States)

Miyake, H.; Oth, A.

2015-12-01

Significant variation of stress drop is a crucial issue for ground motion prediction equations and probabilistic seismic hazard assessment, since only a few ground motion prediction equations take into account stress drop. In addition to average and sigma studies of stress drop and ground motion prediction equations (e.g., Cotton et al., 2013; Baltay and Hanks, 2014), we explore 1-to-1 relationship for each earthquake between stress drop and between-event residual of a ground motion prediction equation. We used the stress drop dataset of Oth (2013) for Japanese crustal earthquakes ranging 0.1 to 100 MPa and K-NET/KiK-net ground motion dataset against for several ground motion prediction equations with volcanic front treatment. Between-event residuals for ground accelerations and velocities are generally coincident with stress drop, as investigated by seismic intensity measures of Oth et al. (2015). Moreover, we found faster attenuation of ground acceleration and velocities for large stress drop events for the similar fault distance range and focal depth. It may suggest an alternative parameterization of stress drop to control attenuation distance rate for ground motion prediction equations. We also investigate 1-to-1 relationship and sigma for regional/national-scale stress drop variation and current national-scale ground motion equations.

Pressure Drop of Chamfer on Spacer Grid Strap

Energy Technology Data Exchange (ETDEWEB)

Kim, Euijae; Kim, Kanghoon; Kim, Kyounghong; Nahm, Keeyil [KEPCO Nuclear Fuel Co., Daejeon (Korea, Republic of)

2014-05-15

A swirl flow and cross flow are generated by the spacer grid with mixing vane that enhances the thermal performance and critical heat flux (CHF). The additional pressure drop makes it difficult to meet acceptance criteria for overall pressure drop in fuel assembly depending upon the pump capacity. The chamfer on the end of spacer grid strap is one solution to reduce additional pressure drop without any adverse effect on flow fields. In this research, the pressure drop tests for spacer grid with and without chamfer were carried out at the hydraulic test facility. The result can be applied to develop high performance nuclear fuel assemblies for Pressurized Water Reactor (PWR) plants. The pressure drop tests for 5x5 spacer grid with and without chamfer as well as 6x6 spacer grid with and without chamfer were carried out at the INFINIT test facility. The Reynolds number ranged about from 16000 to 75000. The sweep-up and sweep-down test showed that the direction of sweep did not affect the pressure drop. The chamfer on spacer grid strap reduced the pressure drop due to the decreased in ratio of inlet area to outlet area. The pressure loss coefficient for spacer grid with chamfer was by up to 13.8 % lower than that for spacer grid without chamfer. Hence, the chamfer on spacer grid strap was one of effective ways to reduce the pressure drop.

Drop impact entrapment of bubble rings

KAUST Repository

Thoraval, M.-J.

2013-04-29

We use ultra-high-speed video imaging to look at the initial contact of a drop impacting on a liquid layer. We observe experimentally the vortex street and the bubble-ring entrapments predicted numerically, for high impact velocities, by Thoraval et al. (Phys. Rev. Lett., vol. 108, 2012, article 264506). These dynamics mainly occur within 50 -s after the first contact, requiring imaging at 1 million f.p.s. For a water drop impacting on a thin layer of water, the entrapment of isolated bubbles starts through azimuthal instability, which forms at low impact velocities, in the neck connecting the drop and pool. For Reynolds number Re above -12 000, up to 10 partial bubble rings have been observed at the base of the ejecta, starting when the contact is -20% of the drop size. More regular bubble rings are observed for a pool of ethanol or methanol. The video imaging shows rotation around some of these air cylinders, which can temporarily delay their breakup into micro-bubbles. The different refractive index in the pool liquid reveals the destabilization of the vortices and the formation of streamwise vortices and intricate vortex tangles. Fine-scale axisymmetry is thereby destroyed. We show also that the shape of the drop has a strong influence on these dynamics. 2013 Cambridge University Press.

Marangoni Flow Induced Evaporation Enhancement on Binary Sessile Drops.

Science.gov (United States)

Chen, Pin; Harmand, Souad; Ouenzerfi, Safouene; Schiffler, Jesse

2017-06-15

The evaporation processes of pure water, pure 1-butanol, and 5% 1-butanol aqueous solution drops on heated hydrophobic substrates are investigated to determine the effect of temperature on the drop evaporation behavior. The evolution of the parameters (contact angle, diameter, and volume) during evaporation measured using a drop shape analyzer and the infrared thermal mapping of the drop surface recorded by an infrared camera were used in investigating the evaporation process. The pure 1-butanol drop does not show any thermal instability at different substrate temperatures, while the convection cells created by the thermal Marangoni effect appear on the surface of the pure water drop from 50 °C. Because 1-butanol and water have different surface tensions, the infrared video of the 5% 1-butanol aqueous solution drop shows that the convection cells are generated by the solutal Marangoni effect at any substrate temperature. Furthermore, when the substrate temperature exceeds 50 °C, coexistence of the thermal and solutal Marangoni flows is observed. By analyzing the relation between the ratio of the evaporation rate of pure water and 1-butanol aqueous solution drops and the Marangoni number, a series of empirical equations for predicting the evaporation rates of pure water and 1-butanol aqueous solution drops at the initial time as well as the equations for the evaporation rate of 1-butanol aqueous solution drop before the depletion of alcohol are derived. The results of these equations correspond fairly well to the experimental data.

Drop-out rate and drop-out reasons among promising Norwegian track and field athletes: a 25 year study

OpenAIRE

Enoksen, Eystein

2011-01-01

© Eystein Enoksen, 2011 The aim of the present study was to identify the total drop-out rate and drop-out reasons for a group of promising track and field athletes. 202 males and 98 females, aged 16 ±2 years, took part in this study. Questionnaires were administrated in 1975, 1983, and 1989. In-depth interviews were conducted in 1989 and in 2000. A chi-square test was administrated to test the difference between males and females dropping out and to test the most significant reasons influe...

University Drop-Out: An Italian Experience

Science.gov (United States)

Belloc, Filippo; Maruotti, Antonello; Petrella, Lea

2010-01-01

University students' drop-out is a crucial issue for the universities' efficiency evaluation and funding. In this paper, we analyze the drop-out rate of the Economics and Business faculty of Sapienza University of Rome. We use administrative data on 9,725 undergraduates students enrolled in three-years bachelor programs from 2001 to 2007 and…

Acoustic forcing of a liquid drop

Science.gov (United States)

Lyell, M. J.

1992-01-01

The development of systems such as acoustic levitation chambers will allow for the positioning and manipulation of material samples (drops) in a microgravity environment. This provides the capability for fundamental studies in droplet dynamics as well as containerless processing work. Such systems use acoustic radiation pressure forces to position or to further manipulate (e.g., oscillate) the sample. The primary objective was to determine the effect of a viscous acoustic field/tangential radiation pressure forcing on drop oscillations. To this end, the viscous acoustic field is determined. Modified (forced) hydrodynamic field equations which result from a consistent perturbation expansion scheme are solved. This is done in the separate cases of an unmodulated and a modulated acoustic field. The effect of the tangential radiation stress on the hydrodynamic field (drop oscillations) is found to manifest as a correction to the velocity field in a sublayer region near the drop/host interface. Moreover, the forcing due to the radiation pressure vector at the interface is modified by inclusion of tangential stresses.

Evaporation of a sessile water drop and a drop of aqueous salt solution.

Science.gov (United States)

Misyura, S Y

2017-11-07

The influence of various factors on the evaporation of drops of water and aqueous salt solution has been experimentally studied. Typically, in the studies of drop evaporation, only the diffusive vapor transfer, radiation and the molecular heat conduction are taken into account. However, vapor-gas convection plays an important role at droplet evaporation. In the absence of droplet boiling, the influence of gas convection turns out to be the prevailing factor. At nucleate boiling, a prevailing role is played by bubbles generation and vapor jet discharge at a bubble collapse. The gas convection behavior for water and aqueous salt solution is substantially different. With a growth of salt concentration over time, the influence of the convective component first increases, reaches an extremum and then significantly decreases. At nucleate boiling in a salt solution it is incorrect to simulate the droplet evaporation and the heat transfer in quasi-stationary approximation. The evaporation at nucleate boiling in a liquid drop is divided into several characteristic time intervals. Each of these intervals is characterized by a noticeable change in both the evaporation rate and the convection role.

The origin of star-shaped oscillations of Leidenfrost drops

Science.gov (United States)

Ma, Xiaolei; Burton, Justin C.

We experimentally investigate the oscillations of Leidenfrost drops of water, liquid nitrogen, ethanol, methanol, acetone and isopropyl alcohol. The drops levitate on a cushion of evaporated vapor over a hot, curved surface which keeps the drops stationary. We observe star-shaped modes along the periphery of the drop, with mode numbers n = 2 to 13. The number of observed modes is sensitive to the properties of the liquid. The pressure oscillation frequency in the vapor layer under the drop is approximately twice that of the drop frequency, which is consistent with a parametric forcing mechanism. However, the Rayleigh and thermal Marangoni numbers are of order 10,000, indicating that convection should play a dominating role as well. Surprisingly, we find that the wavelength and frequency of the oscillations only depend on the thickness of the liquid, which is twice the capillary length, and do not depend on the mode number, substrate temperature, or the substrate curvature. This robust behavior suggests that the wavelength for the oscillations is set by thermal convection inside the drop, and is less dependent on the flow in the vapor layer under the drop

DROpS: an object of learning in computer simulation of discrete events

Directory of Open Access Journals (Sweden)

Hugo Alves Silva Ribeiro

2015-09-01

Full Text Available This work presents the “Realistic Dynamics Of Simulated Operations” (DROpS, the name given to the dynamics using the “dropper” device as an object of teaching and learning. The objective is to present alternatives for professors teaching content related to simulation of discrete events to graduate students in production engineering. The aim is to enable students to develop skills related to data collection, modeling, statistical analysis, and interpretation of results. This dynamic has been developed and applied to the students by placing them in a situation analogous to a real industry, where various concepts related to computer simulation were discussed, allowing the students to put these concepts into practice in an interactive manner, thus facilitating learning

Effect of flow rate and temperature on transmembrane blood pressure drop in an extracorporeal artificial lung.

Science.gov (United States)

Park, M; Costa, E L V; Maciel, A T; Barbosa, E V S; Hirota, A S; Schettino, G de P; Azevedo, L C P

2014-11-01

Transmembrane pressure drop reflects the resistance of an artificial lung system to blood transit. Decreased resistance (low transmembrane pressure drop) enhances blood flow through the oxygenator, thereby, enhancing gas exchange efficiency. This study is part of a previous one where we observed the behaviour and the modulation of blood pressure drop during the passage of blood through artificial lung membranes. Before and after the induction of multi-organ dysfunction, the animals were instrumented and analysed for venous-venous extracorporeal membrane oxygenation, using a pre-defined sequence of blood flows. Blood flow and revolutions per minute (RPM) of the centrifugal pump varied in a linear fashion. At a blood flow of 5.5 L/min, pre- and post-pump blood pressures reached -120 and 450 mmHg, respectively. Transmembrane pressures showed a significant spread, particularly at blood flows above 2 L/min; over the entire range of blood flow rates, there was a positive association of pressure drop with blood flow (0.005 mmHg/mL/minute of blood flow) and a negative association of pressure drop with temperature (-4.828 mmHg/(°Celsius). These associations were similar when blood flows of below and above 2000 mL/minute were examined. During its passage through the extracorporeal system, blood is exposed to pressure variations from -120 to 450 mmHg. At high blood flows (above 2 L/min), the drop in transmembrane pressure becomes unpredictable and highly variable. Over the entire range of blood flows investigated (0-5500 mL/min), the drop in transmembrane pressure was positively associated with blood flow and negatively associated with body temperature. © The Author(s) 2014.

Propelling a water drop with the vapor-mediated Marangoni effect

Science.gov (United States)

Kim, Seungho; Kim, Ho-Young

2013-11-01

We show that a water drop on solid surfaces can be propelled just by placing a volatile alcohol drop nearby. It is found to be because the water-air interface near the alcohol drop mixes with alcohol vapor, thereby locally lowering the surface tension. The surface-tension-gradient induces the motion of the water drop, enabling the trajectory control of water drops through the motion of remote alcohol drops. This vapor-mediated Marangoni effect also gives rise to other interesting interfacial flow phenomena, such as nucleation of holes on a water film and ballooning of a water drop hanging from a syringe needle with the approach of an alcohol drop. We visualize such interfacial dynamics with a high-speed camera and rationalize their salient features by scaling analysis. This work was supported by the National Research Foundation of Korea (grant no. 2012-008023).

Allelic drop-out probabilities estimated by logistic regression

DEFF Research Database (Denmark)

Tvedebrink, Torben; Eriksen, Poul Svante; Asplund, Maria

2012-01-01

We discuss the model for estimating drop-out probabilities presented by Tvedebrink et al. [7] and the concerns, that have been raised. The criticism of the model has demonstrated that the model is not perfect. However, the model is very useful for advanced forensic genetic work, where allelic drop-out...... is occurring. With this discussion, we hope to improve the drop-out model, so that it can be used for practical forensic genetics and stimulate further discussions. We discuss how to estimate drop-out probabilities when using a varying number of PCR cycles and other experimental conditions....

Drop Performance Test of CRDMs for JRTR

Energy Technology Data Exchange (ETDEWEB)

Choi, Myoung-Hwan; Cho, Yeong-Garp; Chung, Jong-Ha [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Kim, Jung-Hyun [POSCO Plandtec Co. Ltd, Ulsan (Korea, Republic of); Lee, Kwan-Hee [RIST, Pohang (Korea, Republic of)

2015-10-15

The drop test results of CRDMs with AC-type electromagnet show that the initial delay times are not satisfied with the requirement, 0.15 seconds. After the replacement of the electromagnet from AC-type to DCtype, the drop times of CARs and accelerations due to the impact of moving parts are satisfied with all requirements. As a result, it is found that four CRDMs to be installed at site have a good drop performance, and meet all performance requirements. A control rod drive mechanism (CRDM) is a device to control the position of a control absorber rod (CAR) in the core by using a stepping motor which is commanded by the reactor regulating system (RRS) to control the reactivity during the normal operation of the reactor. The top-mounted CRDM driven by the stepping motor for Jordan Research and Training Reactor (JRTR) has been developed in KAERI. The CRDM for JRTR has been optimized by the design improvement based on that of the HANARO. It is necessary to verify the performances such as the stepping, drop, endurance, vibration, seismic and structural integrity for active components. Especially, the CAR drop curves are important data for the safety analysis. This paper describes the test results to demonstrate the drop performances of a prototype and 4 CRDMs to be installed at site. The tests are carried out at a test rig simulating the actual reactor's conditions.

Research on combustion of black-liquor drops

International Nuclear Information System (INIS)

Macek, A.

1999-01-01

Black liquor, the major by-product of the kraft process for production of pulp, is one of the most important industrial fuels. It is burned in recovery boilers in the form of large spray drops (mm), with the objective of simultaneous recovery of heat and chemicals (sodium and sulfur). Even though black-liquor combustion in boilers has been practised for over half a century, research efforts toward improvement of combustion efficiency and abatement of environmental emissions are much more recent. The present paper addresses a specific aspect of that research, namely, elucidation of processes which occur during combustion of black-liquor drops in boiler-gas streams. The paper (a) gives a brief description of the kraft process, (b) reviews the experimental and theoretical (modeling) research advances on combustion of kraft-liquor drops during the 1980s and 1990s, (c) re-examines the results of an earlier combustion study in which black-liquor drops were observed in free flight at temperatures near those in recovery boilers, and (d) recommends input for the modeling of in-flight combustion of kraft-liquor drops in recovery boilers. (author)

The evaporation of the charged and uncharged water drops

Indian Academy of Sciences (India)

Drop evaporation; ventilation coefficient; evaporation-effect of electrical forces. ... to study the effect of ventilation on the rate of evaporation of the millimeter sized ... a ventilated drop to reach its equilibrium temperature increases with the drop ...

Triple-line behavior and wettability controlled by nanocoated substrates: influence on sessile drop evaporation.

Science.gov (United States)

Sobac, B; Brutin, D

2011-12-20

In this article, we investigate the influence of the surface properties of substrates on the evaporation process. Using various nanocoatings, it is possible to modify the surface properties of substrates, such as the roughness and the surface energy, while maintaining constant thermal properties. Experiments are conducted under atmospheric conditions with five fluids (methanol, ethanol, propanol, toluene and water) and four coatings (PFC, PTFE, SiOC, and SiO(x)). The various combinations of these fluids and coatings allow for a wide range of drop evaporation properties to be studied: the dynamics of the triple line, the volatility of fluids, and a large range of wettabilities (from 17 to 135°). The experimental data are in very good quantitative agreement with existing models of quasi-steady, diffusion-driven evaporation. The experimental results show that the dynamics of the evaporative rate are proportional to the dynamics of the wetting radius. Thus, the models succeed in describing the evaporative dynamics throughout the evaporation process regardless of the behavior of the triple line. Moreover, the use of various liquids reveals the validity of the models regardless of their volatility. The results also confirm the recent finding of a universal relation for the time evolution of the drop mass, independent of the drop size and initial contact angle. Finally, this study highlights the separate and coupled roles of the triple line and the wettability on the sessile drop evaporation process. Data reveal that the more wet and pinned a drop, the shorter the evaporation time. © 2011 American Chemical Society

Generic versus brand-name North American topical glaucoma drops.

Science.gov (United States)

Mammo, Zaid N; Flanagan, John G; James, David F; Trope, Graham E

2012-02-01

To determine whether brand-name glaucoma drops differ from generic equivalents in bottle design, viscosity, surface tension, and volume in North America. Experimental study. We studied 5 bottles each of 11 kinds of glaucoma drops. Density-based calculations of drop volume were assessed using 0.1 mg analytic balance. Viscosity was measured using rotational rheometery. Bottle tip diameter was measured using 0.05 mm Vernier calipers. Surface tension was measured using a Fisher Scientific (Ottawa, ON) tensiometer. For the American brand-name Timoptic XE, the average drop volume was 38 ± 3.1 μL versus 24 ± 1.5 μL of Timolol GFS (p brand-name Timoptic XE, the average drop volume was 42 ± 4.0 μL versus 25 ± 2 μL of timolol maleate EX (p brand-name Timoptic drop volume was 28 ± 1.4 μL versus 35 ± 1.9 μL Apo-Timop (p brand-name Timoptic delivered significantly smaller drop volumes than generic Apo-Timop. Careful consideration should be given to drop viscosity and bottle design when generic ophthalmic products are evaluated for interchangeability and market entry. Copyright © 2012 Canadian Ophthalmological Society. Published by Elsevier Inc. All rights reserved.

Electric generation and ratcheted transport of contact-charged drops

Science.gov (United States)

Cartier, Charles A.; Graybill, Jason R.; Bishop, Kyle J. M.

2017-10-01

We describe a simple microfluidic system that enables the steady generation and efficient transport of aqueous drops using only a constant voltage input. Drop generation is achieved through an electrohydrodynamic dripping mechanism by which conductive drops grow and detach from a grounded nozzle in response to an electric field. The now-charged drops are transported down a ratcheted channel by contact charge electrophoresis powered by the same voltage input used for drop generation. We investigate how the drop size, generation frequency, and transport velocity depend on system parameters such as the liquid viscosity, interfacial tension, applied voltage, and channel dimensions. The observed trends are well explained by a series of scaling analyses that provide insight into the dominant physical mechanisms underlying drop generation and ratcheted transport. We identify the conditions necessary for achieving reliable operation and discuss the various modes of failure that can arise when these conditions are violated. Our results demonstrate that simple electric inputs can power increasingly complex droplet operations with potential opportunities for inexpensive and portable microfluidic systems.

Inverse Leidenfrost effect: self-propelling drops on a bath

Science.gov (United States)

Gauthier, Anais; van der Meer, Devaraj; Lohse, Detlef; Physics of Fluids Team

2017-11-01

When deposited on very hot solid, volatile drops can levitate over a cushion of vapor, in the so-called Leidenfrost state. This phenomenon can also be observed on a hot bath and similarly to the solid case, drops are very mobile due to the absence of contact with the substrate that sustains them. We discuss here a situation of ``inverse Leidenfrost effect'' where room-temperature drops levitate on a liquid nitrogen pool - the vapor is generated here by the bath sustaining the relatively hot drop. We show that the drop's movement is not random: the liquid goes across the bath in straight lines, a pattern only disrupted by elastic bouncing on the edges. In addition, the drops are initially self-propelled; first at rest, they accelerate for a few seconds and reach velocities of the order of a few cm/s, before slowing down. We investigate experimentally the parameters that affect their successive acceleration and deceleration, such as the size and nature of the drops and we discuss the origin of this pattern.

Many Drops Interactions I: Simulation of Coalescence, Flocculation and Fragmentation of Multiple Colliding Drops with Smoothed Particle Hydrodynamics

Directory of Open Access Journals (Sweden)

Alejandro Acevedo-Malavé

2012-06-01

Full Text Available Smoothed Particle Hydrodynamics (SPH is a Lagrangian mesh-free formalism and has been useful to model continuous fluid. This formalism is employed to solve the Navier-Stokes equations by replacing the fluid with a set of particles. These particles are interpolation points from which properties of the fluid can be determined. In this study, the SPH method is applied to simulate the hydrodynamics interaction of many drops, showing some settings for the coalescence, fragmentation and flocculation problem of equally sized liquid drops in three-dimensional spaces. For small velocities the drops interact only through their deformed surfaces and the flocculation of the droplets arises. This result is very different if the collision velocity is large enough for the fragmentation of droplets takes place. We observe that for velocities around 15 mm/ms the coalescence of droplets occurs. The velocity vector fields formed inside the drops during the collision process are shown.

Immersed single-drop microextraction interfaced with sequential injection analysis for determination of Cr(VI) in natural waters by electrothermal-atomic absorption spectrometry

International Nuclear Information System (INIS)

Pena, Francisco; Lavilla, Isela; Bendicho, Carlos

2008-01-01

Single-drop microextraction (SDME) and sequential injection analysis have been hyphenated for ultratrace metal determination by Electrothermal-Atomic Absorption Spectrometry (ETAAS). The novel method was targeted on extraction of the Cr(VI)-APDC chelate and encompasses the potential of SDME as a miniaturized and virtually solvent-free preconcentration technique, the ability of sequential injection analysis to handle samples and the versatility of furnace autosamplers for introducing microliter samples in ETAAS. The variables influencing the microextraction of Cr(VI) onto an organic solvent drop, i.e., type of organic solvent, microextraction time, stirring rate of the sample solution, drop volume, immersion depth of the drop, salting-out effect, temperature of the sample, concentration of the complexing agent and pH of the sample solution were fully investigated. For a 5 and 20 min microextraction time, the preconcentration factors were 20 and 70, respectively. The detection limit was 0.02 μg/L of Cr(VI) and the repeatability expressed as relative standard deviation was 7%. The SDME-SIA-ETAAS technique was validated against BCR CRM 544 (lyophilized solution) and applied to ultrasensitive determination of Cr(VI) in natural waters

Immersed single-drop microextraction interfaced with sequential injection analysis for determination of Cr(VI) in natural waters by electrothermal-atomic absorption spectrometry

Energy Technology Data Exchange (ETDEWEB)

Pena, Francisco; Lavilla, Isela [Departamento de Quimica Analitica y Alimentaria, Area de Quimica Analitica, Facultad de Quimica, Universidad de Vigo, Campus As Lagoas-Marcosende, s/n, 36310 Vigo (Spain); Bendicho, Carlos [Departamento de Quimica Analitica y Alimentaria, Area de Quimica Analitica, Facultad de Quimica, Universidad de Vigo, Campus As Lagoas-Marcosende, s/n, 36310 Vigo (Spain)], E-mail: bendicho@uvigo.es

2008-04-15

Single-drop microextraction (SDME) and sequential injection analysis have been hyphenated for ultratrace metal determination by Electrothermal-Atomic Absorption Spectrometry (ETAAS). The novel method was targeted on extraction of the Cr(VI)-APDC chelate and encompasses the potential of SDME as a miniaturized and virtually solvent-free preconcentration technique, the ability of sequential injection analysis to handle samples and the versatility of furnace autosamplers for introducing microliter samples in ETAAS. The variables influencing the microextraction of Cr(VI) onto an organic solvent drop, i.e., type of organic solvent, microextraction time, stirring rate of the sample solution, drop volume, immersion depth of the drop, salting-out effect, temperature of the sample, concentration of the complexing agent and pH of the sample solution were fully investigated. For a 5 and 20 min microextraction time, the preconcentration factors were 20 and 70, respectively. The detection limit was 0.02 {mu}g/L of Cr(VI) and the repeatability expressed as relative standard deviation was 7%. The SDME-SIA-ETAAS technique was validated against BCR CRM 544 (lyophilized solution) and applied to ultrasensitive determination of Cr(VI) in natural waters.

Effective liquid drop description for alpha decay of atomic nuclei

International Nuclear Information System (INIS)

Tavares, O.A.P.; Duarte, S.B.; Rodriguez, O.; Guzman, F.; Goncalves, M.; Garcia, F.

1998-06-01

Alpha decay half-lives are presented in the framework of an effective liquid drop model for different combination of mass transfer descriptions and inertia coefficients. Calculated half-life-values for ground-state to ground-state favoured alpha transitions are compared with available, updated experimental data. Results have shown that the present model is very suitable to treat the alpha decay process on equal foot as cluster radioactivity and cold fission processes. Better agreement with the data is found when the sub-set of even-even alpha emitters are considered in the calculation. (author)

Drop formation of black liquor spraying; Mustalipeaen pisaroituminen

Energy Technology Data Exchange (ETDEWEB)

Fogelholm, C J; Kankkunen, A; Nieminen, K; Laine, J; Miikkulainen, P [Helsinki Univ. of Technology, Otaniemi (Finland): Lab. of Energy Technology and Environmental Protection

1997-10-01

Black liquor is a spent liquor of the pulp and paper industry. It is burned in kraft recovery boilers for chemical and energy recovery. The high dry solids content and viscosity of black liquor require a high spraying temperature. This affects the performance of the boiler. Kraft recovery boiler deposit formation, emissions and chemical recovery are strongly affected by the drop size and the velocity of the black liquor spray formed by a splashplate nozzle. The sheet breakup mechanism is studied with a system based on a video and image-analysis. The drop size of mill-scale nozzles was measured also with an image-analysis-system. Measurements were carried out in a spray test chamber. The sheet breakup mechanism and drop size tests were carried out both below and over the boiling point of black liquor. Special attention was paid to the effect of flashing on drop formation. Temperature increase normally decreases drop size. In the temperature where the wavy-sheet disintegration changes to perforated-sheet disintegration the drop size increases. Spray velocity rises when the temperature is increased above the boiling point. (orig.)

Ultrasonic defect-sizing using decibel drop methods. I

International Nuclear Information System (INIS)

Murphy, R.V.

1987-03-01

Results are reported of a study performed to investigate the accuracy and repeatability of various ultrasonic decibel (dB) drop sizing methods in determining the length, vertical extent and orientation of artificial and real weld flaws in thin steel sections. Seven artificial flaws and nine real weld flaws were examined; over 200 data plots were produced. The general findings are: a) length and vertical extent are assessed most accurately when using a 14 dB drop from the maximum indication amplitude; b) decibel drops less that 14 dB generally undersize flaws while decibel drops greater than 14 dB generally oversize flaws; c) flaws which are smaller than the width of the sound beam cannot be assessed accurately using dB drop methods; d) large flaws are assessed most accurately when the sound beam strikes the flaws at near normal incidence; e) the vertical extent and orientation of large flaws are plotted most accurately using the beam centre line method as opposed to the beam profile method; and, f) the limitations of dB-drop-sizing methods have considerable ramifications for CAN3-N285.4-M83 and ASME XI evaluation criteria

Drop test of reinforced concrete slab onto storage cask

International Nuclear Information System (INIS)

Kato, Y.; Hattori, S.; Ito, C.; Sirai, K.; Ozaki, S.; Kato, O.

1993-01-01

In this research, drop tests onto full-scale casks considering the specifications of a falling object (weight, construction, drop height, etc.) demonstrate and evaluate the integrity of casks in case a heavy object drops into the storage facilities. (J.P.N.)

Liquid-drop model applied to heavy ions irradiation

International Nuclear Information System (INIS)

De Cicco, Hernan; Alurralde, Martin A.; Saint-Martin, Maria L. G.; Bernaola, Omar A.

1999-01-01

Liquid-drop model is used, previously applied in the study of radiation damage in metals, in an energy range not covered by molecular dynamics, in order to understand experimental data of particle tracks in an organic material (Makrofol E), which cannot be accurately described by the existing theoretical methods. The nuclear and electronic energy depositions are considered for each ion considered and the evolution of the thermal explosion is evaluated. The experimental observation of particle tracks in a region previously considered as 'prohibited' are justified. Although the model used has free parameters and some discrepancies with the experimental diametrical values exist, the agreement obtained is highly superior than that of other existing models. (author)

Impact of ultra-viscous drops: air-film gliding and extreme wetting

KAUST Repository

Langley, Kenneth; Li, Erqiang; Thoroddsen, Sigurdur T

2017-01-01

water drop, the viscous-dominated flow in the thin air layer counteracts the inertia of the drop liquid. For highly viscous drops the viscous stresses within the liquid also affect the interplay between the drop and the gas. Here the drop also forms a

Effect of humidity on the filter pressure drop

International Nuclear Information System (INIS)

Vendel, J.; Letourneau, P.

1995-01-01

The effects of humidity on the filter pressure drop have been reported in some previous studies in which it is difficult to draw definite conclusions. These studies show contradictory effects of humidity on the pressure drop probably due to differences in the hygroscopicity of the test aerosols. The objective of this paper is to present experimental results on the evolution of the filter pressure drop versus mass loading, for different test aerosols and relative humidities. Present results are compared to those found in various publication. An experimental device has been designed to measure filter pressure drop as the function of the areal density for relative humidity varying in the range of 9 % to 85 %. Experiments have been conducted with hygroscopic: (CsOH) and nonhygroscopic aerosols (TiO 2 ). Cesium hydroxyde (CsOH) of size of 2 μ M AMMD has been generated by an ultrasonic generator and the 0.7 μm AMMD titanium oxyde has been dispersed by a open-quotes turn-tableclose quotes generator. As it is noted in the BISWAS'publication [3], present results show, in the case of nonhygroscopic aerosols, a linear relationship of pressure drop to mass loading. For hygroscopic aerosols two cases must be considered: for relative humidity below the deliquescent point of the aerosol, the relationship of pressure drop to mass loading remains linear; above the deliquescent point, the results show a sudden increase in the pressure drop and the mass capacity of the filter is drastically reduced

Effect of humidity on the filter pressure drop

Energy Technology Data Exchange (ETDEWEB)

Vendel, J.; Letourneau, P. [Institut de Protection et de Surete Nucleaire, Gif-sur-Yvette (France)

1995-02-01

The effects of humidity on the filter pressure drop have been reported in some previous studies in which it is difficult to draw definite conclusions. These studies show contradictory effects of humidity on the pressure drop probably due to differences in the hygroscopicity of the test aerosols. The objective of this paper is to present experimental results on the evolution of the filter pressure drop versus mass loading, for different test aerosols and relative humidities. Present results are compared to those found in various publication. An experimental device has been designed to measure filter pressure drop as the function of the areal density for relative humidity varying in the range of 9 % to 85 %. Experiments have been conducted with hygroscopic: (CsOH) and nonhygroscopic aerosols (TiO{sub 2}). Cesium hydroxyde (CsOH) of size of 2 {mu} M AMMD has been generated by an ultrasonic generator and the 0.7 {mu}m AMMD titanium oxyde has been dispersed by a {open_quotes}turn-table{close_quotes} generator. As it is noted in the BISWAS`publication [3], present results show, in the case of nonhygroscopic aerosols, a linear relationship of pressure drop to mass loading. For hygroscopic aerosols two cases must be considered: for relative humidity below the deliquescent point of the aerosol, the relationship of pressure drop to mass loading remains linear; above the deliquescent point, the results show a sudden increase in the pressure drop and the mass capacity of the filter is drastically reduced.

Life-History Traits of the Model Organism Pristionchus pacificus Recorded Using the Hanging Drop Method: Comparison with Caenorhabditis elegans.

Science.gov (United States)

Gilarte, Patricia; Kreuzinger-Janik, Bianca; Majdi, Nabil; Traunspurger, Walter

2015-01-01

The nematode Pristionchus pacificus is of growing interest as a model organism in evolutionary biology. However, despite multiple studies of its genetics, developmental cues, and ecology, the basic life-history traits (LHTs) of P. pacificus remain unknown. In this study, we used the hanging drop method to follow P. pacificus at the individual level and thereby quantify its LHTs. This approach allowed direct comparisons with the LHTs of Caenorhabditis elegans recently determined using this method. When provided with 5×10(9) Escherichia coli cells ml(-1) at 20°C, the intrinsic rate of natural increase of P. pacificus was 1.125 (individually, per day); mean net production was 115 juveniles produced during the life-time of each individual, and each nematode laid an average of 270 eggs (both fertile and unfertile). The mean age of P. pacificus individuals at first reproduction was 65 h, and the average life span was 22 days. The life cycle of P. pacificus is therefore slightly longer than that of C. elegans, with a longer average life span and hatching time and the production of fewer progeny.

Life-History Traits of the Model Organism Pristionchus pacificus Recorded Using the Hanging Drop Method: Comparison with Caenorhabditis elegans.

Directory of Open Access Journals (Sweden)

Patricia Gilarte

Full Text Available The nematode Pristionchus pacificus is of growing interest as a model organism in evolutionary biology. However, despite multiple studies of its genetics, developmental cues, and ecology, the basic life-history traits (LHTs of P. pacificus remain unknown. In this study, we used the hanging drop method to follow P. pacificus at the individual level and thereby quantify its LHTs. This approach allowed direct comparisons with the LHTs of Caenorhabditis elegans recently determined using this method. When provided with 5×10(9 Escherichia coli cells ml(-1 at 20°C, the intrinsic rate of natural increase of P. pacificus was 1.125 (individually, per day; mean net production was 115 juveniles produced during the life-time of each individual, and each nematode laid an average of 270 eggs (both fertile and unfertile. The mean age of P. pacificus individuals at first reproduction was 65 h, and the average life span was 22 days. The life cycle of P. pacificus is therefore slightly longer than that of C. elegans, with a longer average life span and hatching time and the production of fewer progeny.

Ballistic Jumping Drops on Superhydrophobic Surfaces via Electrostatic Manipulation.

Science.gov (United States)

Li, Ning; Wu, Lei; Yu, Cunlong; Dai, Haoyu; Wang, Ting; Dong, Zhichao; Jiang, Lei

2018-02-01

The ballistic ejection of liquid drops by electrostatic manipulating has both fundamental and practical implications, from raindrops in thunderclouds to self-cleaning, anti-icing, condensation, and heat transfer enhancements. In this paper, the ballistic jumping behavior of liquid drops from a superhydrophobic surface is investigated. Powered by the repulsion of the same kind of charges, water drops can jump from the surface. The electrostatic acting time for the jumping of a microliter supercooled drop only takes several milliseconds, even shorter than the time for icing. In addition, one can control the ballistic jumping direction precisely by the relative position above the electrostatic field. The approach offers a facile method that can be used to manipulate the ballistic drop jumping via an electrostatic field, opening the possibility of energy efficient drop detaching techniques in various applications. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Annual Occurrence of Meteorite-Dropping Fireballs

Science.gov (United States)

Konovalova, Natalia; Jopek, Tadeusz J.

2016-07-01

The event of Chelyabinsk meteorite has brought about change the earlier opinion about limits of the sizes of potentially dangerous asteroidal fragments that crossed the Earth's orbit and irrupted in the Earth's atmosphere making the brightest fireball. The observations of the fireballs by fireball networks allows to get the more precise data on atmospheric trajectories and coordinates of predicted landing place of the meteorite. For the reason to search the periods of fireball activity is built the annual distribution of the numbers of meteorites with the known fall dates and of the meteorite-dropping fireballs versus the solar longitude. The resulting profile of the annual activity of meteorites and meteorite-dropping fireballs shows several periods of increased activity in the course of the year. The analysis of the atmospheric trajectories and physical properties of sporadic meteorite-dropping fireballs observed in Tajikistan by instrumental methods in the summer‒autumn periods of increased fireballs activity has been made. As a result the structural strength, the bulk density and terminal mass of the studied fireballs that can survive in the Earth atmosphere and became meteorites was obtained. From the photographic IAU MDC_2003 meteor database and published sources based on the orbit proximity as determined by D-criterion of Southworth and Hawkins the fireballs that could be the members of group of meteorite-dropping fireballs, was found. Among the near Earth's objects (NEOs) the searching for parent bodies for meteorite-dropping fireballs was made and the evolution of orbits of these objects in the past on a long interval of time was investigated.

The effect of dropping impact on bruising pomegranate fruit

Directory of Open Access Journals (Sweden)

M Mohammad Shafie

2016-04-01

Full Text Available Introduction: The pomegranate journey from orchard to supermarket is very complex and pomegranates are subjected to the variety of static and dynamic loads that could result in this damage and bruise occurring. Bruise area and bruise volume are the most important parameters to evaluate fruit damage occurred in harvest and postharvest stages. The bruising is defined as damage to fruit flesh usually with no abrasion of the peel. The two different types of dynamic loading which can physically cause fruit bruising are impact and vibration. The impact and vibration loadings may occur during picking or sorting as the pomegranates are dropped into storage bins and during transportation. The focus of this work was on the impact loading as this appeared to be the most prevalent. In view of the limitations of conventional testing methods (ASTM D3332 Standard Test Methods for Mechanical Shock Fragility of Products, the method and procedure for determining dropping bruise boundary of fruit were also established by adapting free-fall dropping tests. Materials and Methods: After the ‘Malas-e-Saveh’ pomegranates had been selected, they were numbered, and the weight and dimension of each sample were measured and recorded. Firmness in cheek region of each fruit was also measured. Fruit firmness was determined by measuring the maximum force during perforating the sample to a depth of 10 mm at a velocity of 100 mm min-1 with an 8 mm diameter cylindrical penetrometer mounted onto a STM-5 Universal Testing Machine (SANTAM, Design CO. LTD., England. Free-fall dropping tests with a series of drop heights (6, 7, 10, 15, 30 and 60 cm were conducted on fresh ‘Malas-e-Saveh’ pomegranates. Three samples were used for each dropping height, and each sample was subjected to impact on two different positions. Before the test was started, it was necessary to control the sample's drop position. The cheek of sample was placed on the fruit holder. An aluminum plate mounted

Liquid toroidal drop under uniform electric field

Science.gov (United States)

Zabarankin, Michael

2017-06-01

The problem of a stationary liquid toroidal drop freely suspended in another fluid and subjected to an electric field uniform at infinity is addressed analytically. Taylor's discriminating function implies that, when the phases have equal viscosities and are assumed to be slightly conducting (leaky dielectrics), a spherical drop is stationary when Q=(2R2+3R+2)/(7R2), where R and Q are ratios of the phases' electric conductivities and dielectric constants, respectively. This condition holds for any electric capillary number, CaE, that defines the ratio of electric stress to surface tension. Pairam and Fernández-Nieves showed experimentally that, in the absence of external forces (CaE=0), a toroidal drop shrinks towards its centre, and, consequently, the drop can be stationary only for some CaE>0. This work finds Q and CaE such that, under the presence of an electric field and with equal viscosities of the phases, a toroidal drop having major radius ρ and volume 4π/3 is qualitatively stationary-the normal velocity of the drop's interface is minute and the interface coincides visually with a streamline. The found Q and CaE depend on R and ρ, and for large ρ, e.g. ρ≥3, they have simple approximations: Q˜(R2+R+1)/(3R2) and CaE∼3 √{3 π ρ / 2 } (6 ln ⁡ρ +2 ln ⁡[96 π ]-9 )/ (12 ln ⁡ρ +4 ln ⁡[96 π ]-17 ) (R+1 ) 2/ (R-1 ) 2.

9 m side drop test of scale model

International Nuclear Information System (INIS)

Ku, Jeong-Hoe; Chung, Seong-Hwan; Lee, Ju-Chan; Seo, Ki-Seog

1993-01-01

A type B(U) shipping cask had been developed in KAERI for transporting PWR spent fuel. Since the cask is to transport spent PWR fuel, it must be designed to meet all of the structural requirements specified in domestic packaging regulations and IAEA safety series No.6. This paper describes the side drop testing of a one - third scale model cask. The crush and deformations of the shock absorbing covers directly control the deceleration experiences of the cask during the 9 m side drop impact. The shock absorbing covers greatly mitigated the inertia forces of the cask body due to the side drop impact. Compared with the side drop test and finite element analysis, it was verified that the 1/3 scale model cask maintain its structural integrity of the model cask under the side drop impact. The test and analysis results could be used as the basic data to evaluate the structural integrity of the real cask. (J.P.N.)

Recycling of organic wastes by employing Eisenia fetida.

Science.gov (United States)

Yadav, Anoop; Garg, V K

2011-02-01

This paper reports the recycling of nutrients by vermicomposting of cow dung (CD), poultry droppings (PD) and food industry sludge (FIS) employing earthworms (Eisenia fetida). A total of six vermicomposting units were established and dynamics of chemical and biological parameters has been studied for 13 weeks. The waste mixture containing 50% CD+25% PD+25% FIS had better fertilizer value among studied waste combinations. At the end of experiment, vermicomposts showed decrease in pH and organic C, but increase in EC, total Kjeldhal N, total available P and total K contents. The C:N ratio of final vermicomposts also reduced to 10.7-12.7 from 22.8 to 56 in different waste combinations. The earthworms have good biomass gain and cocoon production in all vermicomposting units but CD alone and 50% CD+25% PD+25% FIS were better than other studied combinations. Copyright © 2010 Elsevier Ltd. All rights reserved.

Air-drop blood supply in the French Army.

Science.gov (United States)

Javaudin, Olivier; Baillon, A; Varin, N; Martinaud, C; Pouget, T; Civadier, C; Clavier, B; Sailliol, A

2018-02-12

Haemorrhagic shock remains the leading cause of preventable death in overseas and austere settings. Transfusion of blood components is critical in the management of this kind of injury. For French naval and ground military units, this supply often takes too long considering the short shelf-life of red blood cell concentrates (RBCs) and the limited duration of transport in cooling containers (five to six days). Air-drop supply could be an alternative to overcome these difficulties on the condition that air-drop does not cause damage to blood units. After a period of study and technical development of packaging, four air-drops at medium and high altitudes were performed with an aircraft of the French Air Force. After this, one air-drop was carried out at medium altitude with 10 RBCs and 10 French lyophilised plasma (FLYP). A second air-drop was performed with a soldier carrying one FLYP unit at 12 000 feet. For these air-drops real blood products were used, and quality control testing and temperature monitoring were performed. The temperatures inside the containers were within the normal ranges. Visual inspection indicated that transfusion packaging and dumped products did not undergo deterioration. The quality control data on RBCs and FLYP, including haemostasis, suggested no difference before and after air-drop. The operational implementation of the air-drop of blood products seems to be one of the solutions for the supply of blood products in military austere settings or far forward on battlefield, allowing safe and early transfusion. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Nectar and pollination drops: how different are they?

Science.gov (United States)

Nepi, Massimo; von Aderkas, Patrick; Wagner, Rebecca; Mugnaini, Serena; Coulter, Andrea; Pacini, Ettore

2009-08-01

Pollination drops and nectars (floral nectars) are secretions related to plant reproduction. The pollination drop is the landing site for the majority of gymnosperm pollen, whereas nectar of angiosperm flowers represents a common nutritional resource for a large variety of pollinators. Extrafloral nectars also are known from all vascular plants, although among the gymnosperms they are restricted to the Gnetales. Extrafloral nectars are not generally involved in reproduction but serve as 'reward' for ants defending plants against herbivores (indirect defence). Although very different in their task, nectars and pollination drops share some features, e.g. basic chemical composition and eventual consumption by animals. This has led some authors to call these secretions collectively nectar. Modern techniques that permit chemical analysis and protein characterization have very recently added important information about these sugary secretions that appear to be much more than a 'reward' for pollinating (floral nectar) and defending animals (extrafloral nectar) or a landing site for pollen (pollination drop). Nectar and pollination drops contain sugars as the main components, but the total concentration and the relative proportions are different. They also contain amino acids, of which proline is frequently the most abundant. Proteomic studies have revealed the presence of common functional classes of proteins such as invertases and defence-related proteins in nectar (floral and extrafloral) and pollination drops. Invertases allow for dynamic rearrangement of sugar composition following secretion. Defence-related proteins provide protection from invasion by fungi and bacteria. Currently, only few species have been studied in any depth. The chemical composition of the pollination drop must be investigated in a larger number of species if eventual phylogenetic relationships are to be revealed. Much more information can be provided from further proteomic studies of both

Controlling Vapor Pressure In Hanging-Drop Crystallization

Science.gov (United States)

Carter, Daniel C.; Smith, Robbie

1988-01-01

Rate of evaporation adjusted to produce larger crystals. Device helps to control vapor pressure of water and other solvents in vicinity of hanging drop of solution containing dissolved enzyme protein. Well of porous frit (sintered glass) holds solution in proximity to drop of solution containing protein or enzyme. Vapor from solution in frit controls evaporation of solvent from drop to control precipitation of protein or enzyme. With device, rate of nucleation limited to decrease number and increase size (and perhaps quality) of crystals - large crystals of higher quality needed for x-ray diffraction studies of macromolecules.

Application of Proteomics to the Study of Pollination Drops

Directory of Open Access Journals (Sweden)

Natalie Prior

2013-04-01

Full Text Available Premise of the study: Pollination drops are a formative component in gymnosperm pollen-ovule interactions. Proteomics offers a direct method for the discovery of proteins associated with this early stage of sexual reproduction. Methods: Pollination drops were sampled from eight gymnosperm species: Chamaecyparis lawsoniana (Port Orford cedar, Ephedra monosperma, Ginkgo biloba, Juniperus oxycedrus (prickly juniper, Larix ×marschlinsii, Pseudotsuga menziesii (Douglas-fir, Taxus ×media, and Welwitschia mirabilis. Drops were collected by micropipette using techniques focused on preventing sample contamination. Drop proteins were separated using both gel and gel-free methods. Tandem mass spectrometric methods were used including a triple quadrupole and an Orbitrap. Results: Proteins are present in all pollination drops. Consistency in the protein complement over time was shown in L. ×marschlinsii. Representative mass spectra from W. mirabilis chitinase peptide and E. monosperma serine carboxypeptidase peptide demonstrated high quality results. We provide a summary of gymnosperm pollination drop proteins that have been discovered to date via proteomics. Discussion: Using proteomic methods, a dozen classes of proteins have been identified to date. Proteomics presents a way forward in deepening our understanding of the biological function of pollination drops.

Inertial Gait Phase Detection for control of a drop foot stimulator: Inertial sensing for gait phase detection

NARCIS (Netherlands)

Kotiadis, D.; Hermens, Hermanus J.; Veltink, Petrus H.

An Inertial Gait Phase Detection system was developed to replace heel switches and footswitches currently being used for the triggering of drop foot stimulators. A series of four algorithms utilising accelerometers and gyroscopes individually and in combination were tested and initial results are

Self-excited hydrothermal waves in evaporating sessile drops

Science.gov (United States)

Sefiane, K.; Moffat, J. R.; Matar, O. K.; Craster, R. V.

2008-08-01

Pattern formation driven by the spontaneous evaporation of sessile drops of methanol, ethanol, and FC-72 using infrared thermography is observed and, in certain cases, interpreted in terms of hydrothermal waves. Both methanol and ethanol drops exhibit thermal wave trains, whose wave number depends strongly on the liquid volatililty and substrate thermal conductivity. The FC-72 drops develop cellular structures whose size is proportional to the local thickness. Prior to this work, hydrothermal waves have been observed in the absence of evaporation in shallow liquid layers subjected to an imposed temperature gradient. In contrast, here both the temperature gradients and the drop thickness vary spatially and temporally and are a natural consequence of the evaporation process.

Drop Impact on Textile Material: Effect of Fabric Properties

Directory of Open Access Journals (Sweden)

Romdhani Zouhaier

2014-09-01

Full Text Available This paper presents an experimental study of impact of water drop on a surface in a spreading regime with no splashing. Three surfaces were studied: virgin glass, coating film and woven cotton fabric at different construction parameters. All experiments were carried out using water drop with the same free fall high. Digidrop with high-resolution camera is used to measure the different parameters characterising this phenomenon. Results show an important effect of the height of the free fall on the drop profile and the spreading behaviour. An important drop deformation at the surface impact was observed. Then, fabric construction as the weft count deeply affects the drop impact. For plain weave, an increase of weft count causes a decrease in penetration and increase in the spreading rate. The same result was obtained for coated fabric. Therefore, the impact energy was modified and the drop shape was affected, which directly influenced the spreading rate.

A study of fungi on droppings of certain birds

Directory of Open Access Journals (Sweden)

C. S. Singh

2014-08-01

Full Text Available Droppings of fowl, owl, parrot, pigeon and sparrow were asepticaly collected in sterilized bottles from different places at Gorakhpur, 54 fungi were isolated. The number of fungi was more in the pigeon showing considerable decrease in the fowl and the sparrow. In the parrot and the owl, however. the fungi were egual in number. The number of Phycomycetes was almost the same on droppings of all birds, from parrot only one species could be isolated. A larger number of Ascomyteces was recorded from fowl, less from pigeon and owl and the least (two each on sparrow and parrot droppings. The Basidiomycetes, represented by two species only, were recorded on owl and pigeon droppings. Pigeon droppings yielded the largest number of Deuteromycetes. They were egual in numbers on owl and parrot while on fowl and sparrow their number was comparatively less. Mycelia sterilia, though poor in their numbers, were recorded on all the bird droppings excepting owl.

Afterlife of a Drop Impacting a Liquid Pool

Science.gov (United States)

Saha, Abhishek; Wei, Yanju; Tang, Xiaoyu; Law, Chung K.

2017-11-01

Drop impact on liquid pool is ubiquitous in industrial processes, such as inkjet printing and spray coating. While merging of drop with the impacted liquid surface is essential to facilitate the printing and coating processes, it is the afterlife of this merged drop and associated mixing which control the quality of the printed or coated surface. In this talk we will report an experimental study on the structural evolution of the merged droplet inside the liquid pool. First, we will analyze the depth of the crater created on the pool surface by the impacted drop for a range of impact inertia, and we will derive a scaling relation and the associated characteristic time-scale. Next, we will focus on the toroidal vortex formed by the moving drop inside the liquid pool and assess the characteristic time and length scales of the penetration process. The geometry of the vortex structure which qualitatively indicates the degree of mixedness will also be discussed. Finally, we will present the results from experiments with various viscosities to demonstrate the role of viscous dissipation on the geometry and structure formed by the drop. This work is supported by the Army Research Office and the Xerox Corporation.

Drop shape visualization and contact angle measurement on curved surfaces.

Science.gov (United States)

Guilizzoni, Manfredo

2011-12-01

The shape and contact angles of drops on curved surfaces is experimentally investigated. Image processing, spline fitting and numerical integration are used to extract the drop contour in a number of cross-sections. The three-dimensional surfaces which describe the surface-air and drop-air interfaces can be visualized and a simple procedure to determine the equilibrium contact angle starting from measurements on curved surfaces is proposed. Contact angles on flat surfaces serve as a reference term and a procedure to measure them is proposed. Such procedure is not as accurate as the axisymmetric drop shape analysis algorithms, but it has the advantage of requiring only a side view of the drop-surface couple and no further information. It can therefore be used also for fluids with unknown surface tension and there is no need to measure the drop volume. Examples of application of the proposed techniques for distilled water drops on gemstones confirm that they can be useful for drop shape analysis and contact angle measurement on three-dimensional sculptured surfaces. Copyright © 2011 Elsevier Inc. All rights reserved.

Device for making liquid drops

International Nuclear Information System (INIS)

Yamada, Masao; Fukuda, Fumito; Nishikawa, Masana; Ishii, Takeshi.

1976-01-01

Object: To provide a device for producing liquid drops in the form of liquefied gases indispensable to make deuterium and tritium ice pellets used as a fusion fuel in a tokamak type fusion reactor. Structure: First, pressure P 1 at the upper surface of liquefied gas in a container and outlet pressure P 2 of a nozzle disposed at the lower part of the container are adjusted into the state of P 1 >= P 2 , and it is preset so that even under such conditions, the liquefied gas from the nozzle is not naturally flown out. Next, a vibration plate disposed within the container is rapidly downwardly advanced toward the nozzle through a predetermined distance. As a result, pressure of the liquefied gas within a depression under the vibration plate rises instantaneously or in a pulse fashion to dissatisfy the aforesaid set condition whereby the liquefied gas may be flown out from the nozzle in the form of liquid drops. In accordance with the present device, it is possible to produce a suitable number of drops at a suitable point. (Yoshihara, H.)

Vertical vibration dynamics of acoustically levitated drop containing two immiscible liquids

Science.gov (United States)

Zang, Duyang; Zhai, Zhicong; Li, Lin; Lin, Kejun; Li, Xiaoguang; Geng, Xingguo

2016-09-01

We have studied the levitation and oscillation dynamics of complex drops containing two immiscible liquids. Two types of drops, core-shell drop and abnormal-shaped drop, have been obtained depending on the levitation procedures. The oscillation dynamics of the drops have been studied using a high speed camera. It has been found that the oscillation of the abnormal-shaped drop has a longer oscillation period and decays much faster than that of the core-shell drop, which cannot be accounted for by the air resistance itself. The acoustic streaming induced by ultrasound may bring an additional force against the motion of the drop due to the Bernoulli effect. This is responsible for the enhanced damping during the oscillation in acoustic levitation.

Drop-In Clinics for Environmental Science Students

Directory of Open Access Journals (Sweden)

Marcie Lynne Jacklin

2008-12-01

Full Text Available This paper describes the use of drop in clinics as a new pedagogical approach in information literacy instruction. Although drop in clinics have been used before for library instruction purposes, they are generally aligned with improvement of student academic writing. In the scenario described in this article, in contrast, the drop in clinic is used in a different manner. The drop in clinic as described here offers students an opportunity to engage in self-directed learning by letting them control the content of the instruction. The clinic is offered to students as a way for them to direct their own learning of the course content. It is facilitated by the librarian but it is not controlled by the librarian. The use of this innovative approach is grounded in the example of environmental science and tourism students at a medium sized university in Ontario and it is an approach that has been jointly promoted to students by both the librarian and the course instructor.

Self-excited hydrothermal waves in evaporating sessile drops

OpenAIRE

Sefiane K.; Moffat J.R.; Matar O.K.; Craster R.V.

2008-01-01

Pattern formation driven by the spontaneous evaporation of sessile drops of methanol, ethanol, and FC-72 using infrared thermography is observed and, in certain cases, interpreted in terms of hydrothermal waves. Both methanol and ethanol drops exhibit thermal wave trains, whose wave number depends strongly on the liquid volatililty and substrate thermal conductivity. The FC- 72 drops develop cellular structures whose size is proportional to the local thickness. Prior to this work, hydrotherma...

Drop tests of the Three Mile Island knockout canister

International Nuclear Information System (INIS)

Box, W.D.; Aaron, W.S.; Shappert, L.B.; Childress, P.C.; Quinn, G.J.; Smith, J.V.

1987-01-01

A type of Three Mile Island Unit 2 (TMI-2) defueling canister, called a ''knockout'' canister, was subjected to a series of drop tests at the Oak Ridge National Laboratory's Drop Test Facility. These tests confirmed the structural integrity of internal fixed neutron poisons in support of a request for NRC licensing of this type of canister for the shipment of TMI-2 reactor fuel debris to the Idaho National Engineering Laboratory (INEL) for the Core Examination R and D Program. This report presents the data generated and the results obtained from a series of four drop tests that included two drops with the test assembly in the vertical position and two drops with the assembly in the horizontal position

Multiscale modification of the conductive PEDOT:PSS polymer for the analysis of biological mixtures in a super-hydrophobic drop

KAUST Repository

Coppedè, Nicola

2016-03-18

Conducting polymers are materials displaying high electrical conductivity, easy of fabrication, flexibility and biocompatibility, for this, they are routinely employed in organic electronics, printed electronics, and bioelectronics. Organic electrochemical transistors (OECTs) are a second generation of organic thin transistors, in which the insulator layer is an electrolyte medium and the conductive polymer is electrochemically active. OECT devices have been demonstrated in chemical and biological sensing: while accurate in determining the size of individual ions in solution, similar devices break down if challenged with complex mixtures. Here, we combine a conductive PEODOT:PSS polymer with a super-hydrophobic scheme to obtain a family of advanced devices, in which the ability to manipulate a biological solution couples to a precise texture of the substrate (which incorporates five micro-electrodes in a line, and each is a site specific measurement point), and this permits to realize time and space resolved analysis of a solution. While the competition between convection and diffusion in a super-hydrophobic drop operates the separation of different species based on their size and charge, the described device delivers the ability to register a similar difference. In the following, we demonstrate the device in the sensing of a solution in which CTAB and adrenaline are separated with good sensitivity, selectivity and reliability.

Multiscale modification of the conductive PEDOT:PSS polymer for the analysis of biological mixtures in a super-hydrophobic drop

KAUST Repository

Coppedè , Nicola; Ferrara, Lorenzo; Bifulco, Paolo; Villani, Marco; Iannotta, Salvatore; Zappettini, Andrea; Cesarelli, Mario; Di Fabrizio, Enzo M.; Gentile, Francesco

2016-01-01

Conducting polymers are materials displaying high electrical conductivity, easy of fabrication, flexibility and biocompatibility, for this, they are routinely employed in organic electronics, printed electronics, and bioelectronics. Organic electrochemical transistors (OECTs) are a second generation of organic thin transistors, in which the insulator layer is an electrolyte medium and the conductive polymer is electrochemically active. OECT devices have been demonstrated in chemical and biological sensing: while accurate in determining the size of individual ions in solution, similar devices break down if challenged with complex mixtures. Here, we combine a conductive PEODOT:PSS polymer with a super-hydrophobic scheme to obtain a family of advanced devices, in which the ability to manipulate a biological solution couples to a precise texture of the substrate (which incorporates five micro-electrodes in a line, and each is a site specific measurement point), and this permits to realize time and space resolved analysis of a solution. While the competition between convection and diffusion in a super-hydrophobic drop operates the separation of different species based on their size and charge, the described device delivers the ability to register a similar difference. In the following, we demonstrate the device in the sensing of a solution in which CTAB and adrenaline are separated with good sensitivity, selectivity and reliability.

Vertical vibration and shape oscillation of acoustically levitated water drops

International Nuclear Information System (INIS)

Geng, D. L.; Xie, W. J.; Yan, N.; Wei, B.

2014-01-01

We present the vertical harmonic vibration of levitated water drops within ultrasound field. The restoring force to maintain such a vibration mode is provided by the resultant force of acoustic radiation force and drop gravity. Experiments reveal that the vibration frequency increases with the aspect ratio for drops with the same volume, which agrees with the theoretical prediction for those cases of nearly equiaxed drops. During the vertical vibration, the floating drops undergo the second order shape oscillation. The shape oscillation frequency is determined to be twice the vibration frequency.

Vertical vibration and shape oscillation of acoustically levitated water drops

Energy Technology Data Exchange (ETDEWEB)

Geng, D. L.; Xie, W. J.; Yan, N.; Wei, B., E-mail: bbwei@nwpu.edu.cn [Department of Applied Physics, Northwestern Polytechnical University, Xi' an 710072 (China)

2014-09-08

We present the vertical harmonic vibration of levitated water drops within ultrasound field. The restoring force to maintain such a vibration mode is provided by the resultant force of acoustic radiation force and drop gravity. Experiments reveal that the vibration frequency increases with the aspect ratio for drops with the same volume, which agrees with the theoretical prediction for those cases of nearly equiaxed drops. During the vertical vibration, the floating drops undergo the second order shape oscillation. The shape oscillation frequency is determined to be twice the vibration frequency.

Individual and combined effects of organic, toxic, and hydraulic shocks on sequencing batch reactor in treating petroleum refinery wastewater

Energy Technology Data Exchange (ETDEWEB)

Mizzouri, Nashwan Sh., E-mail: nashwan_mizzouri@yahoo.com [Department of Civil Engineering, University of Malaya, Lembah Pantai, 50603 Kuala Lumpur (Malaysia); Department of Civil Engineering, University of Duhok, Kurdistan (Iraq); Shaaban, Md Ghazaly [Department of Civil Engineering, University of Malaya, Lembah Pantai, 50603 Kuala Lumpur (Malaysia)

2013-04-15

Highlights: ► This research focuses on the combined impact of shock loads on the PRWW treatment. ► System failure resulted when combined shock of organic and hydraulic was applied. ► Recovery was achieved by replacing glucose with PRWW and OLR was decreased to half. ► Worst COD removals were 68.9, and 57.8% for organic, and combined shocks. -- Abstract: This study analyzes the effects of toxic, hydraulic, and organic shocks on the performance of a lab-scale sequencing batch reactor (SBR) with a capacity of 5 L. Petroleum refinery wastewater (PRWW) was treated with an organic loading rate (OLR) of approximately 0.3 kg chemical oxygen demand (COD)/kg MLSS d at 12.8 h hydraulic retention time (HRT). A considerable variation in the COD was observed for organic, toxic, hydraulic, and combined shocks, and the worst values observed were 68.9, 77.1, 70.2, and 57.8%, respectively. Improved control of toxic shock loads of 10 and 20 mg/L of chromium (VI) was identified. The system was adversely affected by the organic shock when a shock load thrice the normal value was used, and this behavior was repeated when the hydraulic shock was 4.8 h HRT. The empirical recovery period was greater than the theoretical period because of the inhibitory effects of phenols, sulfides, high oil, and grease in the PRWW. The system recovery rates from the shocks were in the following order: toxic, organic, hydraulic, and combined shocks. System failure occurred when the combined shocks of organic and hydraulic were applied. The system was resumed by replacing the PRWW with glucose, and the OLR was reduced to half its initial value.

Surfactant-Enhanced Benard Convection on an Evaporating Drop

Science.gov (United States)

Nguyen, Van X.; Stebe, Kathleen J.

2001-11-01

Surfactant effects on an evaporating drop are studied experimentally. Using a fluorescent probe, the distribution and surface phase of the surfactant is directly imaged throughout the evaporation process. From these experiments, we identify conditions in which surfactants promote surface tension-driven Benard instabilities in aqueous systems. The drops under study contain finely divided particles, which act as tracers in the flow, and form well-defined patterns after the drop evaporates. Two flow fields have been reported in this system. The first occurs because the contact line becomes pinned by solid particles at the contact line region. In order for the contact line to remain fixed, an outward flow toward the ring results, driving further accumulation at the contact ring. A ‘coffee ring’ of particles is left as residue after the drop evaporates[1]. The second flow is Benard convection, driven by surface tension gradients on the drop[2,3]. In our experiments, an insoluble monolayer of pentadecanoic acid is spread at the interface of a pendant drop. The surface tension is recorded, and the drop is deposited on a well-defined solid substrate. Fluorescent images of the surface phase of the surfactant are recorded as the drop evaporates. The surfactant monolayer assumes a variety of surface states as a function of the area per molecule at the interface: surface gaseous, surface liquid expanded, and surface liquid condensed phases[4]. Depending upon the surface state of the surfactant as the drop evaporates, transitions of residue patterns left by the particles occur, from the coffee ring pattern to Benard cells to irregular patterns, suggesting a strong resistance to outward flow are observed. The occurrence of Benard cells on a surfactant-rich interface occurs when the interface is in LE-LC coexistence. Prior research concerning surfactant effects on this instability predict that surfactants are strongly stabilizing[5]. The mechanisms for this change in behavior

[Stability of physical state on compound hawthorn dropping pills].

Science.gov (United States)

Zhang, Wei; Chen, Hong-Yan; Jiang, Jian-Lan

2008-11-01

To evaluate the stability of physical state with accelerate test and dropping in process before and after on compound hawthorn dropping pills. Scanning electron microscope, TG-DTA, FT-IR and XRD were used. The active components presented amorphous, tiny crystal and molecular state in dropping pills, and it had no obvious reaction between PEG 4000 and active components. With time prolonging, a little of active components changed from amorphous state to tiny crystal or molecular state. Solid dispersion improved the stability and dissolution of compound hawthorn dropping pills.

A clinical study on "Computer vision syndrome" and its management with Triphala eye drops and Saptamrita Lauha.

Science.gov (United States)

Gangamma, M P; Poonam; Rajagopala, Manjusha

2010-04-01

American Optometric Association (AOA) defines computer vision syndrome (CVS) as "Complex of eye and vision problems related to near work, which are experienced during or related to computer use". Most studies indicate that Video Display Terminal (VDT) operators report more eye related problems than non-VDT office workers. The causes for the inefficiencies and the visual symptoms are a combination of individual visual problems and poor office ergonomics. In this clinical study on "CVS", 151 patients were registered, out of whom 141 completed the treatment. In Group A, 45 patients had been prescribed Triphala eye drops; in Group B, 53 patients had been prescribed the Triphala eye drops and SaptamritaLauha tablets internally, and in Group C, 43 patients had been prescribed the placebo eye drops and placebo tablets. In total, marked improvement was observed in 48.89, 54.71 and 06.98% patients in groups A, B and C, respectively.

Preparation and characterisation of superheated drop detectors

International Nuclear Information System (INIS)

Krishnamoorthy, P.

1989-01-01

Basic mechanism of bubble nucleation in superheated drops with respect to minimum energy of radiation and temperature is discussed. Experimental details and techniques for the preparation of Superheated Drop Detectors (SDDs) is explained. For the sample preparation, homogeneous composition of polymer (Morarfloc) and glycerine was used as the host medium and three different refrigerants Mafron-21, Mafron-12 and Mafron-11/12 (50:50) were chosen as the sensitive liquids. A pressure reactor developed at Health and Safety Laboratory is used for dispersing the sensitive liquid drops in the homogeneous composition under pressure. Some of the imporatant detector characteristics were studied. (author). 26 refs., 9 figs., 1 tab

Underwater sound produced by individual drop impacts and rainfall

DEFF Research Database (Denmark)

Pumphrey, Hugh C.; Crum, L. A.; Jensen, Leif Bjørnø

1989-01-01

An experimental study of the underwater sound produced by water drop impacts on the surface is described. It is found that sound may be produced in two ways: first when the drop strikes the surface and, second, when a bubble is created in the water. The first process occurs for every drop...

Active oil-water interfaces: buckling and deformation of oil drops by bacteria

Science.gov (United States)

Juarez, Gabriel; Stocker, Roman

2014-11-01

Bacteria are unicellular organisms that seek nutrients and energy for growth, division, and self-propulsion. Bacteria are also natural colloidal particles that attach and self-assemble at liquid-liquid interfaces. Here, we present experimental results on active oil-water interfaces that spontaneously form when bacteria accumulate or grow on the interface. Using phase-contrast and fluorescence microscopy, we simultaneously observed the dynamics of adsorbed Alcanivorax bacteria and the oil-water interface within microfluidic devices. We find that, by growing and dividing, adsorbed bacteria form a jammed monolayer of cells that encapsulates the entire oil drop. As bacteria continue to grow at the interface, the drop buckles and the interface undergoes strong deformations. The bacteria act to stabilize non-equilibrium shapes of the oil-phase such wrinkling and tubulation. In addition to presenting a natural example of a living interface, these findings shape our understanding of microbial degradation of oil and may have important repercussions on engineering interventions for oil bioremediation.

From nuclear reactions to liquid-drop collisions

International Nuclear Information System (INIS)

Menchaca R, A.; Huidobro, F.; Martinez D, A.; Michaelian, K.; Perez, A.; Rodriguez, V.; Carjan, N.

1997-01-01

A review of the experimental and theoretical situation in coalescence and fragmentation studies of binary liquid-drop collisions is given, putting in perspective our own contributions, which include experiments with mercury and oil drops and the application of a nuclear reaction model, specifically modified by us for the macroscopic case. (Author)

Drop dynamics on a stretched viscoelastic filament: An experimental study

Science.gov (United States)

Peixinho, Jorge; Renoult, Marie-Charlotte; Crumeyrolle, Olivier; Mutabazi, Innocent

2016-11-01

Capillary pressure can destabilize a thin liquid filament during breakup into a succession of drops. Besides, the addition of a linear, high molecular weight, flexible and soluble polymer is enough to modify the morphology of this instability. In the time period preceding the breakup, the development of beads-on-a-string structures where drops are connected by thin threads is monitored. The drops dynamics involve drop formation, drop migration and drop coalescence. Experiments using a high-speed camera on stretched bridges of viscoelastic polymeric solutions were conducted for a range of viscosities and polymer concentrations. The rheological properties of the solutions are also quantified through conventional shear rheology and normal stress difference. The overall goal of this experimental investigation is to gain more insight into the formation and time evolution of the drops. The project BIOENGINE is co-financed by the European Union with the European regional development fund and by the Normandie Regional Council.

Calculation of drop course of control rod assembly in PWR

International Nuclear Information System (INIS)

Zhou Xiaojia; Mao Fei; Min Peng; Lin Shaoxuan

2013-01-01

The validation of control rod drop performance is an important part of safety analysis of nuclear power plant. Development of computer code for calculating control rod drop course will be useful for validating and improving the design of control rod drive line. Based on structural features of the drive line, the driving force on moving assembly was analyzed and decomposed, the transient value of each component of the driving force was calculated by choosing either theoretical method or numerical method, and the simulation code for calculating rod cluster control assembly (RCCA) drop course by time step increase was achieved. The analysis results of control rod assembly drop course calculated by theoretical model and numerical method were validated by comparing with RCCA drop test data of Qinshan Phase Ⅱ 600 MW PWR. It is shown that the developed RCCA drop course calculation code is suitable for RCCA in PWR and can correctly simulate the drop course and the stress of RCCA. (authors)

Scaling during capillary thinning of particle-laden drops

Science.gov (United States)

Thete, Sumeet; Wagoner, Brayden; Basaran, Osman

2017-11-01

A fundamental understanding of drop formation is crucial in many applications such as ink-jet printing, microfluidic devices, and atomization. During drop formation, the about-to-form drop is connected to the fluid hanging from the nozzle via a thinning filament. Therefore, the physics of capillary thinning of filaments is key to understanding drop formation and has been thoroughly studied for pure Newtonian fluids using theory, simulations, and experiments. In some of the applications however, the forming drop and hence the thinning filament may contain solid particles. The thinning dynamics of such particle-laden filaments differs radically from that of particle-free filaments. Moreover, our understanding of filament thinning in the former case is poor compared to that in the latter case despite the growing interest in pinch-off of particle-laden filaments. In this work, we go beyond similar studies and experimentally explore the impact of solid particles on filament thinning by measuring both the radial and axial scalings in the neck region. The results are summarized in terms of a phase diagram of capillary thinning of particle-laden filaments.

Building micro-soccer-balls with evaporating colloidal fakir drops

Science.gov (United States)

Gelderblom, Hanneke; Marín, Álvaro G.; Susarrey-Arce, Arturo; van Housselt, Arie; Lefferts, Leon; Gardeniers, Han; Lohse, Detlef; Snoeijer, Jacco H.

2013-11-01

Drop evaporation can be used to self-assemble particles into three-dimensional microstructures on a scale where direct manipulation is impossible. We present a unique method to create highly-ordered colloidal microstructures in which we can control the amount of particles and their packing fraction. To this end, we evaporate colloidal dispersion drops from a special type of superhydrophobic microstructured surface, on which the drop remains in Cassie-Baxter state during the entire evaporative process. The remainders of the drop consist of a massive spherical cluster of the microspheres, with diameters ranging from a few tens up to several hundreds of microns. We present scaling arguments to show how the final particle packing fraction of these balls depends on the drop evaporation dynamics, particle size, and number of particles in the system.

Evaporation kinetics in the hanging drop method of protein crystal growth

Science.gov (United States)

Baird, James K.; Frieden, Richard W.; Meehan, E. J., Jr.; Twigg, Pamela J.; Howard, Sandra B.; Fowlis, William A.

1987-01-01

An engineering analysis of the rate of evaporation of solvent in the hanging drop method of protein crystal growth is presented; these results are applied to 18 different drop and well arrangements commonly encountered in the laboratory, taking into account the chemical nature of the salt, the drop size and shape, the drop concentration, the well size, the well concentration, and the temperature. It is found that the rate of evaporation increases with temperature, drop size, and with the salt concentration difference between the drop and the well. The evaporation possesses no unique half-life. Once the salt in the drop achieves about 80 percent of its final concentration, further evaporation suffers from the law of diminishing returns.

Visualization study of film drops produced by bubble bursting

International Nuclear Information System (INIS)

Ma Chao; Bo Hanliang

2012-01-01

The phenomenon that bubble bursting results in drops production is common in the steam generator of the nuclear power plant, and the fine drops generated by this way is one of the most important source of the drop entrainment in the vapor stream. The visualization experiment about the film drops produced by the bursting bubbles at a free water surface was studied using a high-speed video camera. The results show that the bubble cap breaks up in a single point, within the limits of bubble size in the experiment at present. The whole process can be distinguished into four successive stages: A primary inertial drainage, the bubble cap puncture at the foot or on the top, the film rolls-up and the liquid ring appearing with the hole expanding, and fine film drops emission under the effect of destabilization of a Rayleigh-Taylor type. The expression about the bubble radius and the film drops number is obtain by fitting the experiment data at the bubble radius range from 3-25 mm. The result trend agrees well with the previous work. (authors)

Model of organ dose combination

International Nuclear Information System (INIS)

Valley, J.-F.; Lerch, P.

1977-01-01

The ICRP recommendations are based on the limitation of the dose to each organ. In the application and for a unique source the critical organ concept allows to limit the calculation and represents the irradiation status of an individuum. When several sources of radiation are involved the derivation of the dose contribution of each source to each organ is necessary. In order to represent the irradiation status a new parameter is to be defined. Propositions have been made by some authors, in particular by Jacobi introducing at this level biological parameters like the incidence rate of detriment and its severity. The new concept is certainly richer than a simple dose notion. However, in the actual situation of knowledge about radiation effects an intermediate parameter, using only physical concepts and the maximum permissible doses to the organs, seems more appropriate. The model, which is a generalization of the critical organ concept and shall be extended in the future to take the biological effects into account, will be presented [fr

Experimental Setup For Study of Drop Deformation In Air Flow

Directory of Open Access Journals (Sweden)

Basalaev Sergey

2017-01-01

Full Text Available Experimental study for study of deformation of drops in air flow is considered. Experimental setup includes a module for obtaining the drops, an air flow system and measuring system. Module for formation of drops is in the form of vertically arranged dropper with capillary with the possibility of formation of fixed drops. Air flow supply system comprises an air pump coupled conduit through a regulating valve with a cylindrical pipe, installed coaxially with dropper. The measuring system includes the video camera located with possibility of visualization of drop and the Pitot gage for measurement of flow rate of air located in the output section of branch pipe. This experimental setup allows to provide reliable and informative results of the investigation of deformation of drops in the air flow.

Fundamental investigation on electrostatic travelling-wave transport of a liquid drop

International Nuclear Information System (INIS)

Kawamoto, Hiroyuki; Hayashi, Satoshi

2006-01-01

Basic research has been carried out on the transport of a liquid drop and a soft body in an electrostatic travelling field. A conveyer consisting of parallel electrodes was constructed and a four-phase electrostatic travelling wave was applied to the electrodes to transport the drop on the conveyer. The following were clarified by the experiment. (1) Drops and soft bodies can be transported by virtue of the travelling wave in an insulative liquid that is insoluble to the drop, because the drop was charged on the conveyer by friction and driven by the Coulomb force. (2) A drop that covered less than three arrays of the parallel electrode can be transported in the travelling wave field. (3) A threshold voltage exists for the transport. (4) Although the transport was possible not only for insulative but also for conductive drops, the insulative drop can be transported efficiently. (5) The modes of transport can be classified into three categories, namely, a synchronous region where the motion of the liquid drop is in synchrony with the travelling wave, a delayed response regime, and a regime where transport does not occur. (6) Mixing of drops for a chemical reaction was demonstrated on the conveyer with scroll electrodes. A simple model was proposed to simulate the dynamics of the drop in the electrostatic travelling field

Satellite Formation during Coalescence of Unequal Size Drops

KAUST Repository

Zhang, F. H.

2009-03-12

The coalescence of a drop with a flat liquid surface pinches off a satellite from its top, in the well-known coalescence cascade, whereas the coalescence of two equally sized drops does not appear to leave such a satellite. Herein we perform experiments to identify the critical diameter ratio of two drops, above which a satellite is produced during their coalescence. We find that the critical parent ratio is as small as 1.55, but grows monotonically with the Ohnesorge number. The daughter size is typically about 50% of the mother drop. However, we have identified novel pinch-off dynamics close to the critical size ratio, where the satellite does not fully separate, but rather goes directly into a second stage of the coalescence cascade, thus generating a much smaller satellite droplet.

Electrostatic charging and levitation of helium II drops

International Nuclear Information System (INIS)

Niemela, J.J.

1997-01-01

Liquid Helium II drops, of diameter 1 mm or less, are charged with positive helium ions and subsequently levitated by static electric fields. Stable levitation was achieved for drops of order 100-150 micrometers in diameter. The suspended drops could be translated to arbitrary positions within the levitator using additional superimposed DC electric fields, and also could be made to oscillate stably about their average positions by means of an applied time-varying electric field. A weak corona discharge was used to produce the necessary ions for levitation. A novel superfluid film flow device, developed for the controlled deployment of large charged drops, is described. Also discussed is an adjustable electric fountain that requires only a field emission tip operating at modest potentials, and works in both Helium I and Helium II

Satellite Formation during Coalescence of Unequal Size Drops

KAUST Repository

Zhang, F. H.; Li, E. Q.; Thoroddsen, Sigurdur T

2009-01-01

The coalescence of a drop with a flat liquid surface pinches off a satellite from its top, in the well-known coalescence cascade, whereas the coalescence of two equally sized drops does not appear to leave such a satellite. Herein we perform experiments to identify the critical diameter ratio of two drops, above which a satellite is produced during their coalescence. We find that the critical parent ratio is as small as 1.55, but grows monotonically with the Ohnesorge number. The daughter size is typically about 50% of the mother drop. However, we have identified novel pinch-off dynamics close to the critical size ratio, where the satellite does not fully separate, but rather goes directly into a second stage of the coalescence cascade, thus generating a much smaller satellite droplet.

Two secondary drops

Indian Academy of Sciences (India)

Figure shows formation of two secondary drops of unequal size and their merger. The process is same as the earlier process until t= 0.039 Tc with necking occurring at two places, one at the bottom of the column and the other at the middle. The necking at the middle of the liquid column is due to Raleigh instability.

Performance analysis of solar parabolic trough collectors driven combined supercritical CO2 and organic Rankine cycle

Directory of Open Access Journals (Sweden)

Harwinder Singh

2018-06-01

Full Text Available In this paper, attempts have been made on the detailed energy and exergy analysis of solar parabolic trough collectors (SPTCs driven combined power plant. The combination of supercritical CO2 (SCO2 cycle and organic Rankine cycle (ORC integrated with SPTCs has been used to produce power, in which SCO2 cycle and ORC are arranged as a topping and bottoming cycle. Five organic working fluids like R134a, R1234yf, R407c, R1234ze, and R245fa were selected for a low temperature bottoming ORC. Five key exergetic parameters such as exergetic efficiency, exergy destruction rate, fuel depletion ratio, irreversibility ratio, and improvement potential were also examined. It was revealed that exergetic and thermal efficiency of all the combined cycles enhances as the direct normal irradiance increases from 0.5 kW/m2 to 0.95 kW/m2. As can be seen, R407c combined cycle has the maximum exergetic as well as thermal efficiency which is around 78.07% at 0.95 kW/m2 and 43.49% at 0.95 kW/m2, respectively. Alternatively, the R134a and R245fa combined cycle yields less promising results with the marginal difference in their performance. As inferred from the study that SCO2 turbine and evaporator has a certain amount of exergy destruction which is around 9.72% and 8.54% of the inlet exergy, and almost 38.10% of the total exergy destruction in case of R407c combined cycle. Moreover, the maximum amount of exergy destructed by the solar collector field which is more than 25% of the solar inlet exergy and around 54% of the total destructed exergy. Finally, this study concludes that R407c combined cycle has a minimum fuel depletion ratio of 0.2583 for a solar collector and possess the highest power output of 3740 kW. Keywords: Supercritical CO2cycle, Organic Rankine cycle, Exergetic performance, SPTCs, Organic fluids

Morphogenesis of polycrystalline dendritic patterns from evaporation of a reactive nanofluid sessile drop

Science.gov (United States)

Wu, Hua; Briscoe, Wuge H.

2018-04-01

We report polycrystalline residual patterns with dendritic micromorphologies upon fast evaporation of a mixed-solvent sessile drop containing reactive ZnO nanoparticles. The molecular and particulate species generated in situ upon evaporative drying collude with and modify the Marangoni solvent flows and Bénard-Marangoni instabilities, as they undergo self-assembly and self-organization under conditions far from equilibrium, leading to the ultimate hierarchical central cellular patterns surrounded by a peripheral coffee ring upon drying.

Interfacial Instabilities in Evaporating Drops

Science.gov (United States)

Moffat, Ross; Sefiane, Khellil; Matar, Omar

2007-11-01

We study the effect of substrate thermal properties on the evaporation of sessile drops of various liquids. An infra-red imaging technique was used to record the interfacial temperature. This technique illustrates the non-uniformity in interfacial temperature distribution that characterises the evaporation process. Our results also demonstrate that the evaporation of methanol droplets is accompanied by the formation of wave-trains in the interfacial temperature field; similar patterns, however, were not observed in the case of water droplets. More complex patterns are observed for FC-72 refrigerant drops. The effect of substrate thermal conductivity on the structure of the complex pattern formation is also elucidated.

Rain drop size densities over land and over sea

Science.gov (United States)

Bumke, Karl

2010-05-01

A detailed knowledge of rain drop size densities is an essential presumption with respect to remote sensing of precipitation. Since maritime and continental aerosol is significantly different yielding to differences in cloud drop size densities, maritime and continental rain drop size densities may be different, too. In fact only a little is known about differences in rain drop size densities between land and sea due to a lack of suitable data over the sea. To fill in this gap measurements were performed during the recent 10 years at different locations in Germany and on board of research vessels over the Baltic Sea, the North Sea, Atlantic, Indian, and Pacific Ocean. Measurements were done by using an optical disdrometer (ODM 470, Großklaus et al., 1998), which is designed especially to perform precipitation measurements on moving ships and under high wind speeds. Temporal resolution of measurements is generally 1 minute, total number of time series is about 220000. To investigate differences in drop size densities over land and over sea measurements have been divided into four classes on the basis of prevailing continental or maritime influence: land measurements, coastal measurements, measurements in areas of semi-enclosed seas, and open sea measurements. In general differences in drop size densities are small between different areas. A Kolmogoroff Smirnoff test does not give any significant difference between drop size densities over land, coastal areas, semi-enclosed, and open seas at an error rate of 5%. Thus, it can be concluded that there are no systematic differences between maritime and continental drop size densities. The best fit of drop size densities is an exponential decay curve, N(D ) = 6510m -3mm -1mm0.14h- 0.14×R-0.14×exp(- 4.4mm0.25h-0.25×R- 0.25×D mm -1), it is estimated by using the method of least squares. N(D) is the drop size density normalized by the resolution of the optical disdrometer, D the diameter of rain drops in mm, and R the

Analysis of the rod drop accident for Angra-1

International Nuclear Information System (INIS)

Veloso, M.A.; Atayde, P.A.

1989-01-01

The aim of this work is to present a rod drop accident analysis for the third cycle of the Angra-1 nuclear power plant operating in the automatic control mode. In this analysis all possible configurations for dropped rods caused by a single failure in the controller circuits have been considered. The dropped rod worths, power distributions and excore detector tilts were determined by using the Siemens/KWU neutronic code system, in particular the MEDIUM2, PINPOW and DETILT codes. The transient behaviour of the plant during the rod drop event was simulated with the SACI2/MOD0 code, developed at CDTN. Determinations related to the DNBR design limit were conducted by utilizing the CDTN PANTERA-1P subchannel code. The transient analysis indicated that for dropped rod worths greater than about 425 pcm reactor trip from negative neutron flux rate will take place independently of core conditions. In the range from 0 to 425 pcm large power overshoots may occur as a consequence of the automatic control system action. The magnitude of the maximum power peaking during the event increases with the dropped rod worth, as far as the control bank is able to compensate the initial reactivity decrease. Thermal-hydraulic evaluations carried out with the PANTERA-1P code show that for all the relevant dropped rod worths the minimum DNBR will remain above a limit value of 1.365. Even if this conservative limit is met, the calculated nuclear power peaking factors, F N AH , will be at least 6% higher than the allowable F N AH -values. Therefore, the DNBR design margin will be preserved at the event of rod drop. (author)

Vortex-ring-induced large bubble entrainment during drop impact

KAUST Repository

Thoraval, Marie-Jean

2016-03-29

For a limited set of impact conditions, a drop impacting onto a pool can entrap an air bubble as large as its own size. The subsequent rise and rupture of this large bubble plays an important role in aerosol formation and gas transport at the air-sea interface. The large bubble is formed when the impact crater closes up near the pool surface and is known to occur only for drops that are prolate at impact. Herein we use experiments and numerical simulations to show that a concentrated vortex ring, produced in the neck between the drop and the pool, controls the crater deformations and pinchoff. However, it is not the strongest vortex rings that are responsible for the large bubbles, as they interact too strongly with the pool surface and self-destruct. Rather, it is somewhat weaker vortices that can deform the deeper craters, which manage to pinch off the large bubbles. These observations also explain why the strongest and most penetrating vortex rings emerging from drop impacts are not produced by oblate drops but by more prolate drop shapes, as had been observed in previous experiments.

Dispersive liquid-liquid microextraction based on solidification of floating organic drop for simultaneous separation/preconcentration of nickel, cobalt and copper prior to determination by electrothermal atomic absorption spectrometry

Directory of Open Access Journals (Sweden)

Mooud Amirkavei

2013-01-01

Full Text Available A dispersive liquid-liquid microextraction based on solidification of floating organic drop for simultaneous extraction of trace amounts of nickel, cobalt and copper followed by their determination with electrothermal atomic absorption spectrometry was developed. 300 µL of acetone and 1-undecanol was injected into an aqueous sample containing diethyldithiocarbamate complexes of metal ions. For a sample volume of 10 mL, enrichment factors of 277, 270 and 300 and detection limits of 1.2, 1.1 and 1 ng L-1 for nickel, cobalt and copper were obtained, respectively. The method was applied to the extraction and determination of these metals in different water samples.

Ready-made allogeneic ABO-specific serum eye drops

DEFF Research Database (Denmark)

Harritshøj, Lene Holm; Nielsen, Connie; Ullum, Henrik

2014-01-01

serum treatment. CONCLUSION: Ready-made ABO-identical allogeneic serum eye drops were straightforwardly produced, quality-assured and registered as a safe standard blood product for the treatment of certain cases of severe dry eye disease. Therapeutic efficacy was comparable to previous reports......PURPOSE: To overcome problems and delays of the preparation of autologous serum eye drops, a production line of ABO-specific allogeneic serum eye drops from male blood donors was set up in a blood bank. Feasibility, clinical routine, safety and efficacy were evaluated in a cohort of patients...

Headspace Hanging Drop Liquid Phase Microextraction and Gas Chromatography-Mass Spectrometry for the Analysis of Flavors from Clove Buds

Energy Technology Data Exchange (ETDEWEB)

Jung, Mi Jin; Shin, Yeon Jae; Oh, Se Yeon; Kim, Nam Sun; Kim, Kun; Lee, Dong Sun [Seoul Women' s University, Seoul (Korea, Republic of)

2006-02-15

A novel sample pretreatment technique, headspace hanging drop liquid phase microextraction (HS-LPME) was studied and applied to the determination of flavors from solid clove buds by gas chromatography-mass spectrometry (GC-MS). Several parameters affecting on HS-LPME such as organic solvent drop volume, extraction time, extraction temperature and phase ratio were investigated. 1-Octanol was selected as the extracting solvent, drop size was fixed to 0.6 μL. 60 min extraction time at 25 .deg. C was chosen. HS-LPME has the good efficiency demonstrated by the higher partition equilibrium constant (K{sub lh}) values and concentration factor (CF) values. The limits of detection (LOD) were 1.5-3.2 ng. The amounts of eugenol, β-caryophyllene and eugenol acetate from the clove bud sample were 1.90 mg/g, 1.47 mg/g and 7.0 mg/g, respectively. This hanging drop based method is a simple, fast and easy sample enrichment technique using minimal solvent. HSLPME is an alternative sample preparation method for the analysis of volatile aroma compounds by GC-MS.

Dropped Ceiling

OpenAIRE

Tabet, Rayyane

2012-01-01

On December 2nd 1950 the first drop of Saudi oil arrived to Lebanon via the newly constructed Trans-Arabian Pipeline, the world's longest pipeline and the largest American private investment in a foreign land. The 30inch wide structure which spanned 1213 kilometers passing through Saudi Arabia, Jordan, and Syria to end in Lebanon had required 3 years of planning and surveying, 2 years of installation, the fabrication of 256,000 tons of steel tubes, the employment of 30,000 workers, the ratifi...

Eye-Drops for Activation of DREADDs

Directory of Open Access Journals (Sweden)

William T. Keenan

2017-11-01

Full Text Available Designer Receptors Exclusively Activated by Designer Drugs (DREADDs are an important tool for modulating and understanding neural circuits. Depending on the DREADD system used, DREADD-targeted neurons can be activated or repressed in vivo following a dose of the DREADD agonist clozapine-N-oxide (CNO. Because DREADD experiments often involve behavioral assays, the method of CNO delivery is important. Currently, the most common delivery method is intraperitoneal (IP injection. IP injection is both a fast and reliable technique, but it is painful and stressful particularly when many injections are required. We sought an alternative CNO delivery paradigm, which would retain the speed and reliability of IP injections without being as invasive. Here, we show that CNO can be effectively delivered topically via eye-drops. Eye-drops robustly activated DREADD-expressing neurons in the brain and peripheral tissues and does so at the same dosages as IP injection. Eye-drops provide an easier, less invasive and less stressful method for activating DREADDs in vivo.

Numerical study of drop spreading on a flat surface

Science.gov (United States)

Wang, Sheng; Desjardins, Olivier

2017-11-01

In this talk, we perform a numerical study of a droplet on a flat surface with special emphasis on capturing the spreading dynamics. The computational methodology employed is tailored for simulating large-scale two-phase flows within complex geometries. It combines a conservative level-set method to capture the liquid-gas interface, a conservative immersed boundary method to represent the solid-fluid interface, and a sub-grid curvature model at the triple-point to implicitly impose the contact angle of the liquid-gas interface. The performance of the approach is assessed in the inertial droplet spreading regime, the viscous spreading regime of high viscosity drops, and with the capillary oscillation of low viscosity droplets.

Drop test facility available to private industry

International Nuclear Information System (INIS)

Shappert, L.B.; Box, W.D.

1983-01-01

In 1978, a virtually unyielding drop test impact pad was constructed at Oak Ridge National Laboratory's (ORNL's) Tower Shielding Facility (TSF) for the testing of heavy shipping containers designed for transporting radioactive materials. Because of the facility's unique capability for drop-testing large, massive shipping packages, it has been identified as a facility which can be made available for non-DOE users

Measurement of an Evaporating Drop on a Reflective Substrate

Science.gov (United States)

Chao, David F.; Zhang, Nengli

2004-01-01

A figure depicts an apparatus that simultaneously records magnified ordinary top-view video images and laser shadowgraph video images of a sessile drop on a flat, horizontal substrate that can be opaque or translucent and is at least partially specularly reflective. The diameter, contact angle, and rate of evaporation of the drop as functions of time can be calculated from the apparent diameters of the drop in sequences of the images acquired at known time intervals, and the shadowgrams that contain flow patterns indicative of thermocapillary convection (if any) within the drop. These time-dependent parameters and flow patterns are important for understanding the physical processes involved in the spreading and evaporation of drops. The apparatus includes a source of white light and a laser (both omitted from the figure), which are used to form the ordinary image and the shadowgram, respectively. Charge-coupled-device (CCD) camera 1 (with zoom) acquires the ordinary video images, while CCD camera 2 acquires the shadowgrams. With respect to the portion of laser light specularly reflected from the substrate, the drop acts as a plano-convex lens, focusing the laser beam to a shadowgram on the projection screen in front of CCD camera 2. The equations for calculating the diameter, contact angle, and rate of evaporation of the drop are readily derived on the basis of Snell s law of refraction and the geometry of the optics.

A deformable surface model for real-time water drop animation.

Science.gov (United States)

Zhang, Yizhong; Wang, Huamin; Wang, Shuai; Tong, Yiying; Zhou, Kun

2012-08-01

A water drop behaves differently from a large water body because of its strong viscosity and surface tension under the small scale. Surface tension causes the motion of a water drop to be largely determined by its boundary surface. Meanwhile, viscosity makes the interior of a water drop less relevant to its motion, as the smooth velocity field can be well approximated by an interpolation of the velocity on the boundary. Consequently, we propose a fast deformable surface model to realistically animate water drops and their flowing behaviors on solid surfaces. Our system efficiently simulates water drop motions in a Lagrangian fashion, by reducing 3D fluid dynamics over the whole liquid volume to a deformable surface model. In each time step, the model uses an implicit mean curvature flow operator to produce surface tension effects, a contact angle operator to change droplet shapes on solid surfaces, and a set of mesh connectivity updates to handle topological changes and improve mesh quality over time. Our numerical experiments demonstrate a variety of physically plausible water drop phenomena at a real-time rate, including capillary waves when water drops collide, pinch-off of water jets, and droplets flowing over solid materials. The whole system performs orders-of-magnitude faster than existing simulation approaches that generate comparable water drop effects.

Tiller classes on signalgrass pasture according to the cattle droppings position

Directory of Open Access Journals (Sweden)

Manoel Eduardo Rozalino Santos

2010-01-01

Full Text Available The experiment was carried out aiming to investigate the influence of natural deposition of cattle droppings on population density of several classes of tillers on the Brachiaria decumbens Stapf. cv. Basilisk pasture managed under continuous stocking. Two places on the same pasture were evaluated: one near (immediately adjacent and one far, about 1.0 m, from the cattle droppings. Randomized block design with three repetitions was used. Tillers were classified according to the developmental stage, growth origin, defoliation rate and length. The number of vegetative tillers was higher (P<0.05 at the place that was far from the droppings (1.851 perfilhos/ m2 than at the one near them (848 perfilhos/m2. The number of reproductive tillers was higher (P<0.05 at the place near the droppings. Being near or far from the droppings showed no impact on the population density of dead tillers (584 perfilhos/m2 mean. The number of basal tiller and aerial tillers were higher (P<0.05 at the place far from the droppings, when collated to the place near the droppings. The population densities of both defoliated tillers and tillers without shoot meristem, far from the droppings, were higher (P<0.05, while the population density of nondefoliated tillers was higher (P<0.05 at the place found near the droppings. The shortest tillers were common (P<0.05 at the place far from the droppings, while the highest were frequently found (P<0.05 near the droppings. In the B. decumbens pasture under continuous stocking, deposition of droppings by cattle changes the spatial distribution of tillers categories and thus constitutes a factor causing spatial heterogeneity of vegetation.

Investigation of the fragmentation of molten metals dropped into cold water

International Nuclear Information System (INIS)

Shiralkar, G.S.

1976-11-01

The physical mechanism by which small quantities of molten metal fragment extensively when dropped into a pool of cold water was investigated. Since this subject has been the focus of considerable research in the past, some of the more prominent theories are briefly discussed. Experiments were conducted dropping small solid spheres at a high temperature instead of molten metal drops, and indicate a significant difference from the latter. Several hypotheses were proposed based on the hydrodynamics of the molten drop and tested analytically. The theory that the drop fragmentation is caused by the violent release of dissolved gas from within the drop was investigated experimentally and lead to the conclusion that tin fragmentation probably does not occur in this way. It is felt that a calculation of the dynamics of the vapor film that would be expected to surround the hot drop is needed. This calculation was not performed but several suggestions and estimates have been made. It would seem that the possibility of metal fragmentation by rapid vaporization of water entrapped within the metal drop is well worth investigating

Thermodynamic analysis of an integrated gasification solid oxide fuel cell plant combined with an organic Rankine cycle

DEFF Research Database (Denmark)

Pierobon, Leonardo; Rokni, Masoud; Larsen, Ulrik

2013-01-01

into a fixed bed gasification plant to produce syngas which fuels the combined solid oxide fuel cells e organic Rankine cycle system to produce electricity. More than a hundred fluids are considered as possible alternative for the organic cycle using non-ideal equations of state (or state-of-the-art equations......A 100 kWe hybrid plant consisting of gasification system, solid oxide fuel cells and organic Rankine cycle is presented. The nominal power is selected based on cultivation area requirement. For the considered output a land of around 0.5 km2 needs to be utilized. Woodchips are introduced...... achieved by simple and double stage organic Rankine cycle plants and around the same efficiency of a combined gasification, solid oxide fuel cells and micro gas turbine plant. © 2013 Elsevier Ltd. All rights reserved....

Acoustically levitated dancing drops: Self-excited oscillation to chaotic shedding

Science.gov (United States)

Lin, Po-Cheng; I, Lin

2016-02-01

We experimentally demonstrate self-excited oscillation and shedding of millimeter-sized water drops, acoustically levitated in a single-node standing waves cavity, by decreasing the steady acoustic wave intensity below a threshold. The perturbation of the acoustic field by drop motion is a possible source for providing an effective negative damping for sustaining the growing amplitude of the self-excited motion. Its further interplay with surface tension, drop inertia, gravity and acoustic intensities, select various self-excited modes for different size of drops and acoustic intensity. The large drop exhibits quasiperiodic motion from a vertical mode and a zonal mode with growing coupling, as oscillation amplitudes grow, until falling on the floor. For small drops, chaotic oscillations constituted by several broadened sectorial modes and corresponding zonal modes are self-excited. The growing oscillation amplitude leads to droplet shedding from the edges of highly stretched lobes, where surface tension no longer holds the rapid expanding flow.

Efficacy and safety of short-term application of pranoprofen eye drops for senile patients with dry eyes

Directory of Open Access Journals (Sweden)

Yu-Chan Li

2018-06-01

Full Text Available AIM:To investigate the efficacy and safety of short-term application of pranoprofen eye drops in the treatment of dry eyes in senile patients. METHODS: Totally 100 elderly patients with dry eyes treated in our hospital from June 2016 to May 2017 were randomly divided into 2 groups. All cases were bilateral onset, and the right eyes were marked as the observation eyes. The 50 eyes in the observation group were treated with 1g/L pranoprofen eye drops combined with 1g/L sodium hyaluronate eye drops, while 50 in the control group were treated with 1g/L sodium hyaluronate eye drops. The results of Schirmer Ⅰ, ocular surface disease index(OSDI, break-up time(BUT, ocular surface staining(OSS, human leukocyte antigen-DR(HLA-DRand CD11b in conjunctival epithelial cells before and at 2wk after treatment, and adverse reactions in 2 groups were observed. RESULTS: Before treatment, results of Schirmer I, OSDI, BUT, OSS, HLA-DR and CD11b in the two groups were similar, there were no statistically significant differences(P>0.05. After treatment, OSDI, OSS, HLA-DR, CD11b significantly decreased, BUT significantly increased in both groups, the differences were statistically significant(PPPCONCLUSION: Short term application of pranoprofen eye drops can effectively enhance the efficacy in treating elderly patients with dry eyes, release clinical symptoms, and the therapeutic mechanism may be related to the inhibitory effect on HLA-DR.

Drop deformation and breakup in a partially filled horizontal rotating cylinder

Science.gov (United States)

White, Andrew; Pereira, Caroline; Hyacinthe, Hyaquino; Ward, Thomas

2014-11-01

Drop deformation and breakup due to shear flow has been studied extensively in Couette devices as well as in gravity-driven flows. In these cases shear is generated either by the moving wall or the drop's motion. For such flows the drop shape remains unperturbed at low capillary number (Ca), deforms at moderate Ca , and can experience breakup as Ca --> 1 and larger. Here single drops of NaOH(aq) will be placed in a horizontal cylindrical rotating tank partially filled with vegetable oil resulting in 10-2 saponification, can yield lower minimum surface tensions and faster adsorption than non-reactive surfactant systems. Oil films between the wall and drop as well as drop shape will be observed as rotation rates and NaOH(aq) concentration are varied. Results will be presented in the context of previous work on bubble and drop shapes and breakup. NSF CBET #1262718.

Ultrasonic defect sizing using decibel drop methods. III

International Nuclear Information System (INIS)

Mills, C.; Goszczynski, J.; Mitchell, A.B.

1988-03-01

An earlier study on the use of ultrasonic decibel drop sizing methods for determining the length and vertical extent of flaws in welded steel sections was based on the scanning of machined flaws and fabrication flaws. The present study utilized the techniques developed to perform a similar study of the type of flaws expected to develop during service (e.g. fatigue cracks). The general findings are that: a) the use of decibel drops of less than 14 dB generally undersize the length of fatigue cracks; and b) the use of decibel drop methods to determine vertical extent is questionable

Naturally Occurring Egg Drop Syndrome Infection in Turkeys

Directory of Open Access Journals (Sweden)

Z. Biđin

2007-01-01

Full Text Available A decrease in the egg quality, production, fertility and hatchability without serious clinical signs of illness was recorded in turkey fl ocks in Croatia at the beginning of 2002. It was assumed that the egg drop syndrome virus might be one of the etiological agents responsible for the abnormalities in the egg production. The systematic serological monitoring, using a haemagglutination inhibition test, showed that the antibodies to the egg drop syndrome virus existed in 94.4 and 55.1% of the sera analysed in 2002 and 2003, respectively. The haemagglutination inhibition titres ranged from 16 to 128. The sera samples were randomly collected from 11 - to 46-week-old hens from the affected fl ocks. The serological evidence of the egg drop syndrome virus infection was confirmed by detection of the presence of the virus genome in the turkey sera by the polymerase chain reaction. Vaccination of the 18- and 25-week-old turkey hens against the egg drop syndrome virus started in March 2003. After this period, the presence of antibodies to the egg drop syndrome virus (the haemagglutination inhibition titres between 16 and 256 was found in 96.7% of the analysed sera, while the egg production reached normal or higher values for the Nicholas hybrid line of turkeys.

Effective liquid drop description for alpha decay of atomic nuclei

Energy Technology Data Exchange (ETDEWEB)

Tavares, O.A.P.; Duarte, S.B. [Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil); Rodriguez, O.; Guzman, F. [Instituto Superior de Ciencia y Tecnologia Nuclear (ISCTN), La Habana (Cuba); Goncalves, M. [Instituto de Radioprotecao e Dosimetria (IRD), Rio de Janeiro, RJ (Brazil); Garcia, F. [Sao Paulo Univ., SP (Brazil). Inst. de Fisica

1998-06-01

Alpha decay half-lives are presented in the framework of an effective liquid drop model for different combination of mass transfer descriptions and inertia coefficients. Calculated half-life-values for ground-state to ground-state favoured alpha transitions are compared with available, updated experimental data. Results have shown that the present model is very suitable to treat the alpha decay process on equal foot as cluster radioactivity and cold fission processes. Better agreement with the data is found when the sub-set of even-even alpha emitters are considered in the calculation. (author) 44 refs., 5 figs., 3 tabs.; e-mail: telo at ird.gov.br

Combined Turbine and Cycle Optimization for Organic Rankine Cycle Power Systems—Part A

DEFF Research Database (Denmark)

Meroni, Andrea; La Seta, Angelo; Andreasen, Jesper Graa

2016-01-01

Axial-flow turbines represent a well-established technology for a wide variety of power generation systems. Compactness, flexibility, reliability and high efficiency have been key factors for the extensive use of axial turbines in conventional power plants and, in the last decades, in organic...... Rankine cycle power systems. In this two-part paper, an overall cycle model and a model of an axial turbine were combined in order to provide a comprehensive preliminary design of the organic Rankine cycle unit, taking into account both cycle and turbine optimal designs. Part A presents the preliminary...

Superheated drop, open-quotes Bubbleclose quotes, dosimeters

International Nuclear Information System (INIS)

Harper, M.J.; Lindler, K.W.; Nelson, M.E.; Johnson, T.L.; Jones, C.R.; Rabovsky, J.L.; Rao, N.; Kerschner, H.F.; Reil, G.K.; Schwartz, R.B.

1991-01-01

Superheated Drop Dosimeters (SDD) offer a sensitive, immediate measure of the neutron dose equivalent, but their dynamic range is limited and their response varies with temperature, pressure, and vibration. They contain thousands of superheated liquid drops in a stabilizing matrix. High linear energy transfer (LET) radiation triggers vaporization of the drops into visible bubbles. If the matrix is a liquid, the bubbles slowly rise, and the number present indicates the dose rate. Dose may be measured by displacement of the matrix, or by counting the sounds of vaporization. If the matrix is a gel, the bubbles are fixed, and their number is proportional to the dose equivalent. Our research has focused on modeling and elimination of the environmental response, extension of the dynamic range, and tests and evaluations of prototype devices

Fundamentals and applications of fast micro-drop impact

NARCIS (Netherlands)

Visser, C.W.

2014-01-01

3D-printing, biofabrication, diesel engines, and spray cleaning all depend on controlled drop impact. However, surprisingly, these drops have received scarce attention so far. This is mainly due to their small size and high impact velocity, which makes visualizing the impact a challenge. This thesis

Drop-out probabilities of IrisPlex SNP alleles

DEFF Research Database (Denmark)

Andersen, Jeppe Dyrberg; Tvedebrink, Torben; Mogensen, Helle Smidt

2013-01-01

In certain crime cases, information about a perpetrator's phenotype, including eye colour, may be a valuable tool if no DNA profile of any suspect or individual in the DNA database matches the DNA profile found at the crime scene. Often, the available DNA material is sparse and allelic drop-out...... of true alleles is possible. As part of the validation of the IrisPlex assay in our ISO17025 accredited, forensic genetic laboratory, we estimated the probability of drop-out of specific SNP alleles using 29 and 30 PCR cycles and 25, 50 and 100 Single Base Extension (SBE) cycles. We observed no drop-out...... when the amount of DNA was greater than 125 pg for 29 cycles of PCR and greater than 62 pg for 30 cycles of PCR. With the use of a logistic regression model, we estimated the allele specific probability of drop-out in heterozygote systems based on the signal strength of the observed allele...

DropBot: An open-source digital microfluidic control system with precise control of electrostatic driving force and instantaneous drop velocity measurement

International Nuclear Information System (INIS)

Fobel, Ryan; Fobel, Christian; Wheeler, Aaron R.

2013-01-01

We introduce DropBot: an open-source instrument for digital microfluidics (http://microfluidics.utoronto.ca/dropbot). DropBot features two key functionalities for digital microfluidics: (1) real-time monitoring of instantaneous drop velocity (which we propose is a proxy for resistive forces), and (2) application of constant electrostatic driving forces through compensation for amplifier-loading and device capacitance. We anticipate that this system will enhance insight into failure modes and lead to new strategies for improved device reliability, and will be useful for the growing number of users who are adopting digital microfluidics for automated, miniaturized laboratory operation.

Magnetohydrodynamic pressure drop in a quickly changing magnetic field

International Nuclear Information System (INIS)

Xu, Z.Y.; Chen, J.M.; Qian, J.P.; Jiang, W.H.; Pan, C.J.; Li, W.Z.

1995-01-01

The magnetohydrodynamic (MHD) pressure drop of 22 Na 78 K flow in a circular duct was measured under a quickly changing magnetic field. The MHD pressure drop reduced with time as the magnetic field strength decreased. However, the dimensionless pressure drop gradient varied with the interaction parameter and had a higher value in the middle of the range of values of the interaction parameter. Therefore, a quickly changing magnetic field is harmful to the structural material in a liquid metal self-cooled blanket of a fusion reactor, since the greater pressure drop gradient may cause a larger stress in the blanket. This is even more harmful if the magnetic field strength decreases very quickly or its distribution in space is greatly non-uniform. (orig.)

Hydrodynamic shrinkage of liquid CO2 Taylor drops in a straight microchannel

Science.gov (United States)

Qin, Ning; Wen, John Z.; Ren, Carolyn L.

2018-03-01

Hydrodynamic shrinkage of liquid CO2 drops in water under a Taylor flow regime is studied using a straight microchannel (length/width ~100). A general form of a mathematical model of the solvent-side mass transfer coefficient (k s) is developed first. Based on formulations of the surface area (A) and the volume (V) of a general Taylor drop in a rectangular microchannel, a specific form of k s is derived. Drop length and speed are experimentally measured at three specified positions of the straight channel, namely, immediately after drop generation (position 1), the midpoint of the channel (position 2) and the end of the channel (position 3). The reductions of drop length (L x , x  =  1, 2, 3) from position 1 to 2 and down to 3 are used to quantify the drop shrinkage. Using the specific model, k s is calculated mainly based on L x and drop flowing time (t). Results show that smaller CO2 drops produced by lower flow rate ratios ({{Q}LC{{O2}}}/{{Q}{{H2}O}} ) are generally characterized by higher (nearly three times) k s and Sherwood numbers than those produced by higher {{Q}LC{{O2}}}/{{Q}{{H2}O}} , which is essentially attributed to the larger effective portion of the smaller drop contributing in the mass transfer under same levels of the flowing time and the surface-to-volume ratio (~104 m-1) of all drops. Based on calculated pressure drops of the segmented flow in microchannel, the Peng-Robinson equation of state and initial pressures of drops at the T-junction in experiments, overall pressure drop (ΔP t) in the straight channel as well as the resulted drop volume change are quantified. ΔP t from position 1-3 is by average 3.175 kPa with a ~1.6% standard error, which only leads to relative drop volume changes of 0.3‰ to 0.52‰.

Hydrodynamic shrinkage of liquid CO2 Taylor drops in a straight microchannel.

Science.gov (United States)

Qin, Ning; Wen, John; Ren, Carolyn L

2018-01-16

Hydrodynamic shrinkage of liquid CO2 drops in water under a Taylor flow regime is studied using a straight microchannel (length/width ~ 100). A general form of a mathematical model of the solvent-side mass transfer coefficient (ks) is developed first. Based on formulations of the surface area (A) and the volume (V) of a general Taylor drop in a rectangular microchannel, a specific form of ks is derived. Drop length and speed are experimentally measured at three specified positions of the straight channel, namely, immediately after drop generation (position 1), the midpoint of the channel (position 2) and the end of the channel (position 3). The reductions of drop length (Lx, x = 1, 2, 3) from position 1 to 2 and down to 3 are used to quantify the drop shrinkage. Using the specific model, ks is calculated mainly based on Lx and drop flowing time (t). Results show that smaller CO2 drops produced by lower flow rate ratios (QLCO2/QH2O) are generally characterized by higher (nearly three times) ks and Sherwood numbers than those produced by higher QLCO2/QH2O, which is essentially attributed to the larger effective portion of the smaller drop contributing in the mass transfer under same levels of the flowing time and the surface-to-volume ratio (~ 104 m-1) of all drops. Based on calculated pressure drops of the segmented flow in microchannel, the Peng-Robinson equation of state (EOS) and initial pressures of drops at the T-junction in experiments, overall pressure drop (ΔPt) in the straight channel as well as the resulted drop volume change are quantified. ΔPt from position 1 to 3 is by average 3.175 kPa with a ~1.6% standard error, which only leads to relative drop volume changes of 0.3‰ to 0.52‰. © 2018 IOP Publishing Ltd.

Impact of ultra-viscous drops: air-film gliding and extreme wetting

KAUST Repository

Langley, Kenneth

2017-01-23

A drop impacting on a solid surface must push away the intervening gas layer before making contact. This entails a large lubricating air pressure which can deform the bottom of the drop, thus entrapping a bubble under its centre. For a millimetric water drop, the viscous-dominated flow in the thin air layer counteracts the inertia of the drop liquid. For highly viscous drops the viscous stresses within the liquid also affect the interplay between the drop and the gas. Here the drop also forms a central dimple, but its outer edge is surrounded by an extended thin air film, without contacting the solid. This is in sharp contrast with impacts of lower-viscosity drops where a kink in the drop surface forms at the edge of the central disc and makes a circular contact with the solid. Larger drop viscosities make the central air dimple thinner. The thin outer air film subsequently ruptures at numerous random locations around the periphery, when it reaches below 150 nm thickness. This thickness we measure using high-speed two-colour interferometry. The wetted circular contacts expand rapidly, at orders of magnitude larger velocities than would be predicted by a capillary-viscous balance. The spreading velocity of the wetting spots is independent of the liquid viscosity. This may suggest enhanced slip of the contact line, assisted by rarefied-gas effects, or van der Waals forces in what we call extreme wetting. Myriads of micro-bubbles are captured between the local wetting spots.

Pressure drop in flashing flow through obstructions

International Nuclear Information System (INIS)

Weinle, M.E.; Johnston, B.S.

1985-01-01

An experiment was designed to investigate the pressure drop for flashing flow across obstructions of different geometries at various flow rates. Tests were run using two different orifices to determine if the two-phase pressure drop could be characterized by the single phase loss coefficient and the general behavior of the two-phase multiplier. For the geometries studied, it was possible to correlate the multiplier in a geometry-independent fashion

Pressure drop in T's in concentric ducts

International Nuclear Information System (INIS)

Shock, R.A.W.

1983-02-01

A set of experiments has been carried out to measure the pressure drop characteristics of single-phase flow in dividing and joining right-angled T's in a concentric ducting system. These have been compared with measured pressure drops in a simple round tube system. In most tests with the concentric system the number of velocity heads lost is either similar to, or more than, the value for the round tubes. (author)

Falling drops skating on a film of air

Science.gov (United States)

Rubinstein, Shmuel

2012-02-01

When a raindrop hits a window, the surface immediately becomes wet as the water spreads. Indeed, this common observation of a drop impacting a surface is ubiquitous in our everyday experience. I will show that the impact of a drop on a surface is a much richer, more complex phenomenon than our simple experience may suggests: To completely wet the surface the drop must first expel all the air beneath it; however, this does not happened instantaneously. Instead, a very thin film of air, only a few tens of nanometers thick, remains trapped between the falling drop and the surface as the fluid spreads. The thin film of air serves to lubricate the drop enabling the fluid to skate laterally outward at strikingly high velocities. Simultaneously, the wetting fluid spreads inward at a much slower velocity, trapping a bubble of air within the drop. However, these events occur at diminutive length scales and fleeting time scales; therefore, to visualize them we develop new imaging modalities that are sensitive to the behavior right at the surface and that have time resolution superior to even the very fastest cameras. These imaging techniques reveal that the ultimate wetting of the surface occurs through a completely new mechanism, the breakup of the thin film of air through a spinodal like dewetting process that breaks the cylindrical symmetry of the impact and drives an anomalously rapid spreading of a wetting front. These results are in accord with recent theoretical predictions and challenge the prevailing paradigm in which contact between the liquid and solid occurs immediately, and spreading is dominated by the dynamics of a single contact line.

Jetting from impact of a spherical drop with a deep layer

Science.gov (United States)

Zhang, Li; Toole, Jameson; Fazzaa, Kamel; Deegan, Robert; Deegan Group Team; X-Ray Science Division, Advanced Photon Source Collaboration

2011-11-01

We performed an experimental study of jets during the impact of a spherical drop with a deep layer of same liquid. Using high speed optical and X-ray imaging, we observe two types of jets: the so-called ejecta sheet which emerges almost immediately after impact and the lamella which emerges later. For high Reynolds number the two jets are distinct, while for low Reynolds number the two jets combine into a single continuous jet. We also measured the emergence time, speed, and position of the ejecta sheet and found simple scaling relations for these quantities.

Variation of rain intensity and drop size distribution with General Weather Patterns (GWL)

Science.gov (United States)

Ghada, Wael; Buras, Allan; Lüpke, Marvin; Menzel, Annette

2017-04-01

" (HM). "Trough over Central Europe" (TRM) was linked to smaller drops and "High Scandinavia-Iceland, Trough C. Europe" (HNFZ) had fewer drops per time step when compared to other GWL types. We also investigated the intra-event behavior regarding fluctuations in rain intensity, rain drop counts, and drop size distribution with time. When combined with predictions of circulation patterns, our analysis provides a detailed insight into the characteristics of rain events under different future climate scenarios, but definitively an extended measurement period and more measurement locations are needed for validation.

A Simulation Model of Combined Biogas, Bioethanol and Protein Fodder Co-Production in Organic Farming

DEFF Research Database (Denmark)

Oleskowicz-Popiel, Piotr; Thomsen, Mette Hedegaard; Thomsen, Anne Belinda

2009-01-01

In order to evaluate new strategies for the production of renewable energy within sustainable organic agriculture, a process-simulation model for a 100 ha organic farm was developed. Data used for the model was obtained from laboratory trials, literature data, consultancy with experts, and results...... ha organic farm with ethanol or biogas, respectively. This calculation was based on the assumption that the electrical efficiency of CHP (combined heat and power) unit was 38%. A variety of different scenarios can be simulated to mirror the farmer's needs....

Calculation method for control rod dropping time in reactor

International Nuclear Information System (INIS)

Nogami, Takeki; Kato, Yoshifumi; Ishino, Jun-ichi; Doi, Isamu.

1996-01-01

If a control rod starts dropping, the dropping speed is rapidly increased, then settled substantially constant, rapidly decreased when it reaches a dash pot. A second detection signal generated by removing an AC component from a first detection signal is differentiated twice. The time when the maximum value among the twice differentiated values is generated is determined as a time when the control rods starts dropping. The time when minimum value among the twice differentiated values is generated is determined as a time when the control rod reaches the dash pot of the reactor. The measuring time within a range from the time when the control rod starts dropping to the time when the control rod reaches the dash pot of the reactor is determined. As a result, processing for the calculation of the dropping start time and dash pot reaching time of the control rod can be automatized. Further, it is suffice to conduct differentiation twice till the reaching time, which can facilitate the processing thereby enabling to determine a reliable time range. (N.H.)

Drop tests of the Three Mile Island knockout canister

International Nuclear Information System (INIS)

Box, W.D.; Aaron, W.S.; Shappert, L.B.; Childress, P.C.; Quinn, G.J.; Smith, J.V.

1986-09-01

A type of Three Mile Island Unit 2 (TMI-2) defueling canister, called a ''knockout'' canister, was subjected to a series of drop tests at the Oak Ridge National Laboratory's Drop Test Facility. These tests were designed to confirm the structural integrity of internal fixed neutron poisons in support of a request for NRC licensing of this type of canister for the shipment of TMI-2 reactor fuel debris to the Idaho National Engineering Laboratory (INEL) for the Core Examination R and D Program. Work conducted at the Oak Ridge National Laboratory included (1) precise physical measurements of the internal poison rod configuration before assembly, (2) canister assembly and welding, (3) nondestructive examination (an initial hydrostatic pressure test and an x-ray profile of the internals before and after each drop test), (4) addition of a simulated fuel load, (5) instrumentation of the canister for each drop test, (6) fabrication of a cask simulation vessel with a developed and tested foam impact limiter, (7) use of refrigeration facilities to cool the canister to well below freezing prior to three of the drops, (8) recording the drop test with still, high-speed, and normal-speed photography, (9) recording the accelerometer measurements during impact, (10) disassembly and post-test examination with precise physical measurements, and (11) preparation of the final report

Drop detachment and motion on fuel cell electrode materials.

Science.gov (United States)

Gauthier, Eric; Hellstern, Thomas; Kevrekidis, Ioannis G; Benziger, Jay

2012-02-01

Liquid water is pushed through flow channels of fuel cells, where one surface is a porous carbon electrode made up of carbon fibers. Water drops grow on the fibrous carbon surface in the gas flow channel. The drops adhere to the superficial fiber surfaces but exhibit little penetration into the voids between the fibers. The fibrous surfaces are hydrophobic, but there is a substantial threshold force necessary to initiate water drop motion. Once the water drops begin to move, however, the adhesive force decreases and drops move with minimal friction, similar to motion on superhydrophobic materials. We report here studies of water wetting and water drop motion on typical porous carbon materials (carbon paper and carbon cloth) employed in fuel cells. The static coefficient of friction on these textured surfaces is comparable to that for smooth Teflon. But the dynamic coefficient of friction is several orders of magnitude smaller on the textured surfaces than on smooth Teflon. Carbon cloth displays a much smaller static contact angle hysteresis than carbon paper due to its two-scale roughness. The dynamic contact angle hysteresis for carbon paper is greatly reduced compared to the static contact angle hysteresis. Enhanced dynamic hydrophobicity is suggested to result from the extent to which a dynamic contact line can track topological heterogeneities of the liquid/solid interface.

Tracking Drop-out Students in Palestinian Refugee Camps in Lebanon

Science.gov (United States)

Al-Hroub, Anies

2015-01-01

This research paper examines the perceptions of students on the school drop-out problem in Palestinian refugee camps in Lebanon regarding (a) the social and economic causes associated with the phenomenon of school drop-out; (b) the educational policies and practices used in UNRWA schools and their relationship to student drop-out; and (c) the role…

Pressure drops in low pressure local boiling

International Nuclear Information System (INIS)

Courtaud, Michel; Schleisiek, Karl

1969-01-01

For prediction of flow reduction in nuclear research reactors, it was necessary to establish a correlation giving the pressure drop in subcooled boiling for rectangular channels. Measurements of pressure drop on rectangular channel 60 and 90 cm long and with a coolant gap of 1,8 and 3,6 mm were performed in the following range of parameters. -) 3 < pressure at the outlet < 11 bars abs; -) 25 < inlet temperature < 70 deg. C; -) 200 < heat flux < 700 W/cm 2 . It appeared that the usual parameter, relative length in subcooled boiling, was not sufficient to correlate experimental pressure losses on the subcooled boiling length and that there was a supplementary influence of pressure, heat flux and subcooling. With an a dimensional parameter including these terms a correlation was established with an error band of ±10%. With a computer code it was possible to derive the relation giving the overall pressure drop along the channel and to determine the local gradients of pressure drop. These local gradients were then correlated with the above parameter calculated in local conditions. 95 % of the experimental points were computed with an accuracy of ±10% with this correlation of gradients which can be used for non-uniform heated channels. (authors) [fr

Thermal imaging of levitated fresh and salt water drops during laser irradiation

Science.gov (United States)

Brownell, Cody; Biggs, Harrison

2017-11-01

Simulation of high energy laser propagation and scattering in the maritime environment is problematic, due to the high likelihood of turbulence, fog, and rain or sea spray within the beam path. Considering large water drops (diameters of approximately 1-mm), such as those found in a light rain, an incident high energy laser will lead to rapid evaporation of the water drop as it traverses the beam path. In this work we present surface temperature measurements of a water drop obtained using a FLIR IR camera. The drop is acoustically levitated, and subject to a continuous wave laser with a wavelength of 1070-nm and a mean irradiance of approximately 800 W/cm2. These measurements show that the steady-state surface temperature of the drop is well below the saturation temperature, and for pure substances the equilibrium temperature decreases with decreasing drop volume similar to observations with smaller aqueous aerosols. Temperature non-uniformity within the drop is also assessed from statistics of the surface temperature fluctuations. Preliminary results from irradiated salt water drops show notably different behavior from fresh water drops, including temperature spikes as the drop volume decreases and occasional nucleate boiling. Acknowledge support from ONR #N00014-17-WX-00031.

Non-isothermal spreading of liquid drops on horizontal plates

International Nuclear Information System (INIS)

Ehrhard, P.; Davis, S.H.

1990-05-01

A viscous-liquid drop spreads on a smooth horizontal surface, which is uniformly heated or cooled. Lubrication theory is used to study thin drops subject to capillary, thermocapillary and gravity forces, and a variety of contact-angle-versus-speed conditions. It is found for isothermal drops that gravity is very important at large times and determines the power law for unlimited spreading. Predictions compare well with the experimental data on isothermal spreading for both two-dimensional and axisymmetric configurations. It is found that heating (cooling) retards (augments) the spreading process. When the advancing contact angle is zero, heating will cause the drop to spread only finitely far. For positive advancing contact angles, sufficient cooling will cause unlimited spreading. Thus, the heat transfer serves as a sentitive control on the spreading. (orig.) [de

Evaluating Eye Drop Instillation Technique and Its Determinants in Glaucoma Patients

Directory of Open Access Journals (Sweden)

Xinbo Gao

2018-01-01

Full Text Available Aim. To evaluate eye drop instillation technique and to explore its determinants in glaucoma patients. Methods. One hundred and thirteen patients diagnosed with glaucoma and self-administering topical antiglaucoma eye drops for at least 1 month were evaluated. All patients instilled artificial tear solution in one eye as they would do at home. The whole process was evaluated by two study staff. A comprehensive score system associated with eye drop instillation techniques was used to quantify the instillation technique and explore its determinants such as demographic and clinical characteristics. Results. Half of the patients (48.67% finished the administration of eye drop on first attempt.1.7 eye drops were squeezed out on average. 43 patients (37.17% got contact with ocular surface or adnexa. Only 19.7% patients had eye drop instillation techniques being defined as well. 11 patients (9.7% had prior instruction regarding using eye drops, while only 4 patients knew to occlude the tear duct by pressing the dacryocyst area. Older age and worse visual acuity were found to be independent risk factors for worse instillation technique. Conclusions. Eye drop instillation technique in glaucoma patients deserves great attention from eye care practitioners during their lifelong follow-up, especially those aged older and have worse visual acuity.

Tapered Optical Fiber Functionalized with Palladium Nanoparticles by Drop Casting and Laser Radiation for H₂ and Volatile Organic Compounds Sensing Purposes.

Science.gov (United States)

González-Sierra, Nancy Elizabeth; Gómez-Pavón, Luz Del Carmen; Pérez-Sánchez, Gerardo Francisco; Luis-Ramos, Arnulfo; Zaca-Morán, Plácido; Muñoz-Pacheco, Jesús Manuel; Chávez-Ramírez, Francisco

2017-09-06

A comparative study on the sensing properties of a tapered optical fiber pristine and functionalized with the palladium nanoparticles to hydrogen and volatile organic compounds (VOCs), is presented. The sensor response and, response/recovery times were extracted from the measurements of the transient response of the device. The tapered optical fiber sensor was fabricated using a single-mode optical fiber by the flame-brushing technique. Functionalization of the optical fiber was performed using an aqueous solution of palladium chloride by drop-casting technique assisted for laser radiation. The detection principle of the sensor is based on the changes in the optical properties of palladium nanoparticles when exposed to reducing gases, which causes a variation in the absorption of evanescent waves. A continuous wave laser diode operating at 1550 nm is used for the sensor characterization. The sensor functionalized with palladium nanoparticles by this technique is viable for the sensing of hydrogen and VOCs, since it shows an enhancement in sensor response and response time compared to the sensor based on the pristine optical microfiber. The results show that the fabricated sensor is competitive with other fiber optic sensors functionalized with palladium nanoparticles to the hydrogen.

Development of ultrasonically levitated drops as microreactors for study of enzyme kinetics and potential as a universal portable analysis system

Science.gov (United States)

Scheeline, A.; Pierre, Z.; Field, C. R.; Ginsberg, M. D.

2009-05-01

Development of microfluidics has focused on carrying out chemical synthesis and analysis in ever-smaller volumes of solution. In most cases, flow systems are made of either quartz, glass, or an easily moldable polymer such as polydimethylsiloxane (Whitesides 2006). As the system shrinks, the ratio of surface area to volume increases. For studies of either free radical chemistry or protein chemistry, this is undesirable. Proteins stick to surfaces, biofilms grow on surfaces, and radicals annihilate on walls (Lewis et al. 2006). Thus, under those circumstances where small amounts of reactants must be employed, typical microfluidic systems are incompatible with the chemistry one wishes to study. We have developed an alternative approach. We use ultrasonically levitated microliter drops as well mixed microreactors. Depending on whether capillaries (to form the drop) and electrochemical sensors are in contact with the drop or whether there are no contacting solids, the ratio of solid surface area to volume is low or zero. The only interface seen by reactants is a liquid/air interface (or, more generally, liquid/gas, as any gas may be used to support the drop). While drop levitation has been reported since at least the 1940's, we are the second group to carry out enzyme reactions in levitated drops, (Weis; Nardozzi 2005) and have fabricated the lowest power levitator in the literature (Field; Scheeline 2007). The low consumption aspects of ordinary microfluidics combine with a contact-free determination cell (the levitated drop) that ensures against cross-contamination, minimizes the likelihood of biofilm formation, and is robust to changes in temperature and humidity (Lide 1992). We report kinetics measurements in levitated drops and explain how outgrowths of these accomplishments will lead to portable chemistry/biology laboratories well suited to detection of a wide range of chemical and biological agents in the asymmetric battlefield environment.

Student Drop-Out from German Higher Education Institutions

Science.gov (United States)

Heublein, Ulrich

2014-01-01

28% of students of any one year currently give up their studies in bachelor degree programmes at German higher education institutions. Drop-out is to be understood as the definite termination in the higher education system without obtaining an academic degree. The drop-out rate is thereby calculated with the help of statistical estimation…

Spume Drops: Their Potential Role in Air-Sea Gas Exchange

Science.gov (United States)

Monahan, Edward C.; Staniec, Allison; Vlahos, Penny

2017-12-01

After summarizing the time scales defining the change of the physical properties of spume and other droplets cast up from the sea surface, the time scales governing drop-atmosphere gas exchange are compared. Following a broad review of the spume drop production functions described in the literature, a subset of these functions is selected via objective criteria, to represent typical, upper bound, and lower bound production functions. Three complementary mechanisms driving spume-atmosphere gas exchange are described, and one is then used to estimate the relative importance, over a broad range of wind speeds, of this spume drop mechanism compared to the conventional, diffusional, sea surface mechanism in air-sea gas exchange. While remaining uncertainties in the wind dependence of the spume drop production flux, and in the immediate sea surface gas flux, preclude a definitive conclusion, the findings of this study strongly suggest that, at high wind speeds (>20 m s-1 for dimethyl sulfide and >30 m s-1 for gases such a carbon dioxide), spume drops do make a significant contribution to air-sea gas exchange.Plain Language SummaryThis paper evaluates the existing spume drop generation functions available to date and selects a reasonable upper, lower and mid range function that are reasonable for use in air sea exchange models. Based on these the contribution of spume drops to overall air sea gas exchange at different wind speeds is then evaluated to determine the % contribution of spume. Generally below 20ms-1 spume drops contribute <1% of gas exchange but may account for a significant amount of gas exchange at higher wind speeds.

Organic pollution of rivers : Combined threats of urbanization, livestock farming and global climate change

NARCIS (Netherlands)

Wen, Y.; Schoups, G.H.W.; van de Giesen, N.C.

2017-01-01

Organic pollution of rivers by wastewater discharge from human activities negatively impacts people and ecosystems. Without treatment, pollution control relies on a combination of natural degradation and dilution by natural runoff to reduce downstream effects. We quantify here for the first time

Filter aids influence on pressure drop across a filtration system

Science.gov (United States)

Hajar, S.; Rashid, M.; Nurnadia, A.; Ammar, M. R.; Hasfalina, C. M.

2017-06-01

Filter aids is commonly used to reduce pressure drop across air filtration system as it helps to increase the efficiency of filtration of accumulated filter cake. Filtration velocity is one of the main parameters that affect the performance of filter aids material. In this study, a formulated filter aids consisting of PreKot™ and activated carbon mixture (designated as PrekotAC) was tested on PTFE filter media under various filtration velocities of 5, 6, and 8 m/min at a constant material loading of 0.2 mg/mm2. Results showed that pressure drop is highly influenced by filtration velocity where higher filtration velocity leads to a higher pressure drop across the filter cake. It was found that PrekotAC performed better in terms of reducing the pressure drop across the filter cake even at the highest filtration velocity. The diversity in different particle size distribution of non-uniform particle size in the formulated PrekotAC mixture presents a higher permeability causes a lower pressure drop across the accumulated filter cake. The finding suggests that PrekotAC is a promising filter aids material that helps reducing the pressure drop across fabric filtration system.

Experimental analysis of waveform effects on satellite and ligament behavior via in situ measurement of the drop-on-demand drop formation curve and the instantaneous jetting speed curve

International Nuclear Information System (INIS)

Kwon, Kye-Si

2010-01-01

In situ techniques to measure the drop-on-demand (DOD) drop formation curve and the instantaneous jetting speed curve are developed such that ligament behavior and satellite behavior of inkjet droplets can be analyzed effectively. It is known that the droplet jetting behavior differs by ink properties and the driving waveform voltage. In this study, to reduce possible droplet placement errors due to satellite drops or long ligaments during printing, waveform effects on drop formation are investigated based on the measured DOD drop formation curve and the instantaneous jetting speed curve. Experimental results show that a dwell time greater than the so-called efficient dwell time was effective in reducing placement errors due to satellite drops during the printing process

Theory and experiments on electrohydrodynamic enhancement of evaporation from water drops

International Nuclear Information System (INIS)

Barthakur, N.N.

1990-01-01

Space charge produce by a single corona electrode was used to enhance evaporation rates from sessile drops of water. The drying curve was traced and a drop lifetime determined by a beta ray gauge which provided both sensitivity and reproducibility to the measurements. Lifetime was reduced by a factor of 3.5 to 4.7 when subjected to fluxes of 3.02x10 12 positive charges cm -2 s -1 than those from freely evaporating drops in the laboratory. A theoretical model based on mass transfer coefficient was developed to predict the drop lifetime. Calculated lifetime of drops of volume 0.1 to 0.5 ml agreed within 12 percent of the experimental values. Electric wind caused by the ionic drag is proposed to be the principal driving force for the observed enhancement of evaporation from the drops. (author). 24 refs., 2 figs., 1 tab

Physical Watermarking for Securing Cyber-Physical Systems via Packet Drop Injections

Energy Technology Data Exchange (ETDEWEB)

Ozel, Omur [Carnegie Mellon Univ., Pittsburgh, PA (United States); Weekrakkody, Sean [Carnegie Mellon Univ., Pittsburgh, PA (United States); Sinopoli, Bruno [Carnegie Mellon Univ., Pittsburgh, PA (United States)

2017-10-23

Physical watermarking is a well known solution for detecting integrity attacks on Cyber-Physical Systems (CPSs) such as the smart grid. Here, a random control input is injected into the system in order to authenticate physical dynamics and sensors which may have been corrupted by adversaries. Packet drops may naturally occur in a CPS due to network imperfections. To our knowledge, previous work has not considered the role of packet drops in detecting integrity attacks. In this paper, we investigate the merit of injecting Bernoulli packet drops into the control inputs sent to actuators as a new physical watermarking scheme. With the classical linear quadratic objective function and an independent and identically distributed packet drop injection sequence, we study the effect of packet drops on meeting security and control objectives. Our results indicate that the packet drops could act as a potential physical watermark for attack detection in CPSs.

Skating on a Film of Air: Drops Impacting on a Surface

Science.gov (United States)

Kolinski, John M.; Rubinstein, Shmuel M.; Mandre, Shreyas; Brenner, Michael P.; Weitz, David A.; Mahadevan, L.

2012-02-01

The commonly accepted description of drops impacting on a surface typically ignores the essential role of the air that is trapped between the impacting drop and the surface. Here we describe a new imaging modality that is sensitive to the behavior right at the surface. We show that a very thin film of air, only a few tens of nanometers thick, remains trapped between the falling drop and the surface as the drop spreads. The thin film of air serves to lubricate the drop enabling the fluid to skate on the air film laterally outward at surprisingly high velocities, consistent with theoretical predictions. Eventually this thin film of air breaks down as the fluid wets the surface via a spinodal-like mechanism. Our results show that the dynamics of impacting drops are much more complex than previously thought, with a rich array of unexpected phenomena that require rethinking classic paradigms.

Stability of alternating current discharges between water drops on insulation surfaces

International Nuclear Information System (INIS)

Rowland, S M; Lin, F C

2006-01-01

Discharges between water drops are important in the ageing of hydrophobic outdoor insulators. They may also be important in the processes leading up to flashover of these insulators in high pollution conditions. This paper considers discharges between drops when a limited alternating current is available, as experienced by an ageing insulator in service. A phenomenon is identified in which the length of a discharge between two drops is reduced through a particular type of distortion of the drops. This is visually characterized as a liquid protrusion from each of a pair of water drops along the insulator surface. This process is distinct from vibration of the drops, general distortion of their shape and the very fast emission of jet streams seen in very high fields. The process depends upon the discharge current, the resistivity of the moisture and the hydrophobicity of the insulation surface

A review on water fault diagnosis of PEMFC associated with the pressure drop

International Nuclear Information System (INIS)

Pei, Pucheng; Li, Yuehua; Xu, Huachi; Wu, Ziyao

2016-01-01

Highlights: • Reviewed the effect factors and estimations of pressure drop associated with water fault diagnosis. • Reviewed pressure drop-based water fault diagnosis using different indicators. • Deviation of pressure drop is used frequently to diagnose water fault. • Reviewed recovery strategies based on pressure drop used in commercial PEMFC. • Merits, demerits and application prospects of pressure drop-based water fault diagnosis are discussed. - Abstract: The pressure difference between the inlet and outlet of the reactant in fuel cells is called the pressure drop, which is related to the water amount inside the fuel cells. In recent years there have been many studies that used the pressure drop to detect the water content and diagnose water fault of proton exchange membrane fuel cells (PEMFCs). To our knowledge, there has not been a systematic review of these studies. In this paper, the effect variables of pressure drop are reviewed firstly. Then estimations of the theoretical pressure drop are reviewed mainly based on the following four aspects: Bernoulli’s equation, two-phase flow multiplier, Darcy’s law and artificial intelligence. Afterward, the water fault diagnosis based on the pressure drop using the following six indicators are reviewed: indicator of direct pressure drop, its deviation, frequency, multiplier, the ratio of pressure drop to flow rate and the flooding degree. In addition, the strategies of water fault recovery are also summarized. Finally the merits, demerits and application prospects of pressure drop-based water fault diagnosis are presented.

'Cryptogenic Drop Attacks' revisited: evidence of overlap with functional neurological disorder.

Science.gov (United States)

Hoeritzauer, Ingrid; Carson, Alan J; Stone, Jon

2018-02-07

In their 1973 BMJ paper 'Cryptogenic Drop Attacks', Stevens and Matthews described 40, mostly middle-aged, female patients with drop attacks of unknown cause. Although clinically common, there has been little on this topic since. We aimed to determine clinical features, comorbidity and outcome of patients with drop attacks. We carried out a retrospective review of patients with cryptogenic drop attacks seen consecutively by one clinician (JS) between 2006 and 2016. Demographics, phenomenology, duration and frequency of attacks, attack description and comorbid diagnoses were recorded. Patients were followed up with a notes review. 83 patients with cryptogenic drop attacks were predominantly female (89%, n=79), mean age 44  years. The majority (93%, n=77) could not remember the fall itself and almost half (43%, n=36) experienced prodromal dissociative symptoms. Mechanical trips or syncope preceded drop attacks, historically, in 24% (n=20) of cases. Persistent fatigue (73%, n=61), chronic pain (40%, n=33), functional limb weakness (31%,n=26) and dissociative (non-epileptic) attacks 28% (n=23) were common, with the latter usually preceding or emerging from drop attacks. At follow-up (88%, mean 38 months), 28% (n=23) had resolution of their drop attacks. Predisposing (but non-causative) disease comorbidity was found at baseline (n=12) and follow-up (n=5). Cryptogenic drop attacks are associated with high frequency of comorbid functional somatic and functional neurological disorders. Patients commonly have prodromal dissociative symptoms and in some there was a clear relationship with prior or subsequent dissociative (non-epileptic) attacks. Some cryptogenic drop attacks may be best understood as phenomena on the spectrum of dissociative attacks. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Probing the nanoscale with high-speed interferometry of an impacting drop

KAUST Repository

Thoroddsen, Sigurdur T.

2017-02-28

The simple phenomenon of a water drop falling onto a glass plate may seem like a trivial fluid mechanics problem. However, detailed imaging has shown that this process is highly complex and a small air-bubble is always entrapped under the drop when it makes contact with the solid. This bubble can interfere with the uniformity of spray coatings and degrade inkjet fabrication of displays etc. We will describe how we use high-speed interferometry at 5 million frames per second to understand the details of this process. As the impacting drop approaches the solid, the dynamics are characterized by a balance between the lubrication pressure in the thin air layer and the inertia of the bot-tom of the drop. This deforms the drop, forming a dimple at its bottom and making the drop touch the surface along a ring, thereby entrapping the air-layer, which is typically 1-3 mu m thick. This air-layer can be highly compressed and the deceleration of the bottom of the drop can be as large as 300,000 g. We describe how the thicknessevolution of the lubricating air-layer is extracted from following the interference fringes between frames. Two-color interferometry is also used to extract absolute layer thicknesses. Finally, we identify the effects of nanometric surface roughness on the first contact of the drop with the substrate. Here we need to resolve the 100 nm thickness changes occurring during 200 ns intervals, requiring these state of the art high-speed cameras. Surprisingly, we see a ring of micro-bubbles marking the first contact of the drop with the glass, only for microscope slides, which have a typical roughness of 20 nm, while such rings are absent for drop impacts onto molecularly smooth mica surfaces.

Probing the nanoscale with high-speed interferometry of an impacting drop

KAUST Repository

Thoroddsen, Sigurdur T; Li, Erqiang; Vakarelski, Ivan Uriev; Langley, Kenneth

2017-01-01

The simple phenomenon of a water drop falling onto a glass plate may seem like a trivial fluid mechanics problem. However, detailed imaging has shown that this process is highly complex and a small air-bubble is always entrapped under the drop when it makes contact with the solid. This bubble can interfere with the uniformity of spray coatings and degrade inkjet fabrication of displays etc. We will describe how we use high-speed interferometry at 5 million frames per second to understand the details of this process. As the impacting drop approaches the solid, the dynamics are characterized by a balance between the lubrication pressure in the thin air layer and the inertia of the bot-tom of the drop. This deforms the drop, forming a dimple at its bottom and making the drop touch the surface along a ring, thereby entrapping the air-layer, which is typically 1-3 mu m thick. This air-layer can be highly compressed and the deceleration of the bottom of the drop can be as large as 300,000 g. We describe how the thicknessevolution of the lubricating air-layer is extracted from following the interference fringes between frames. Two-color interferometry is also used to extract absolute layer thicknesses. Finally, we identify the effects of nanometric surface roughness on the first contact of the drop with the substrate. Here we need to resolve the 100 nm thickness changes occurring during 200 ns intervals, requiring these state of the art high-speed cameras. Surprisingly, we see a ring of micro-bubbles marking the first contact of the drop with the glass, only for microscope slides, which have a typical roughness of 20 nm, while such rings are absent for drop impacts onto molecularly smooth mica surfaces.

The relationships between the combination of person- and organization-related conditions and patients' perceptions of palliative care quality.

Science.gov (United States)

Sandsdalen, Tuva; Høye, Sevald; Rystedt, Ingrid; Grøndahl, Vigdis Abrahamsen; Hov, Reidun; Wilde-Larsson, Bodil

2017-12-06

Little is known about the combination of person- and organization- related conditions and the relationships with patients' perspectives of care quality. Such a combination could contribute knowledge reflecting the complexity of clinical practice, and enhance individualized care. The aim was to investigate the relationships between the combination of person- and organization-related conditions and patients' perceptions of palliative care quality. A cross-sectional study, including 191 patients in the late palliative phase (73% response rate) admitted to hospice inpatient care (n = 72), hospice day care (n = 51), palliative units in nursing homes (n = 30) and home care (n = 38), was conducted between November 2013 and December 2014, using the instrument Quality from the Patients' Perspective specific to palliative care (QPP-PC). Data were analysed, using analysis of covariance, to explore the amount of the variance in the dependent variables (QPP-PC) that could be explained by combination of the independent variables - Person- and organization-related conditions, - while controlling for differences in covariates. Patients scored the care received and the subjective importance as moderate to high. The combination of person- and organization - related conditions revealed that patients with a high sense of coherence, lower age (person - related conditions) and being in a ward with access to and availability of physicians (organization-related condition) might be associated with significantly higher scores for the quality of care received. Gender (women), daily contact with family and friends, and low health-related quality of life (person-related conditions) might be associated with higher scores for subjective importance of the aspects of care quality. Healthcare personnel, leaders and policy makers need to pay attention to person- and organization-related conditions in order to provide person-centered palliative care of high quality. Further studies from

Critical look at South Africa’s Green Drop Programme

CSIR Research Space (South Africa)

Ntombela, Cebile

2016-10-01

Full Text Available (WSAs) in the controversial wastewater services sector. In particular, we focus on DWS’s incentive-based mechanism, the National Green Drop Certification Programme (Green Drop Programme), and evaluate the achievements and challenges associated with its...

Immediate drop on demand technology (I-DOT) coupled with mass spectrometry via an open port sampling interface.

Science.gov (United States)

Van Berkel, Gary J; Kertesz, Vilmos; Boeltz, Harry

2017-11-01

The aim of this work was to demonstrate and evaluate the analytical performance of coupling the immediate drop on demand technology to a mass spectrometer via the recently introduced open port sampling interface and ESI. Methodology & results: A maximum sample analysis throughput of 5 s per sample was demonstrated. Signal reproducibility was 10% or better as demonstrated by the quantitative analysis of propranolol and its stable isotope-labeled internal standard propranolol-d7. The ability of the system to multiply charge and analyze macromolecules was demonstrated using the protein cytochrome c. This immediate drop on demand technology/open port sampling interface/ESI-MS combination allowed for the quantitative analysis of relatively small mass analytes and was used for the identification of macromolecules like proteins.

Fabrication and Operation of Microfluidic Hanging-Drop Networks.

Science.gov (United States)

Misun, Patrick M; Birchler, Axel K; Lang, Moritz; Hierlemann, Andreas; Frey, Olivier

2018-01-01

The hanging-drop network (HDN) is a technology platform based on a completely open microfluidic network at the bottom of an inverted, surface-patterned substrate. The platform is predominantly used for the formation, culturing, and interaction of self-assembled spherical microtissues (spheroids) under precisely controlled flow conditions. Here, we describe design, fabrication, and operation of microfluidic hanging-drop networks.

On the relation of earthquake stress drop and ground motion variability

Science.gov (United States)

Oth, Adrien; Miyake, Hiroe; Bindi, Dino

2017-07-01

One of the key parameters for earthquake source physics is stress drop since it can be directly linked to the spectral level of ground motion. Stress drop estimates from moment corner frequency analysis have been shown to be extremely variable, and this to a much larger degree than expected from the between-event ground motion variability. This discrepancy raises the question whether classically determined stress drop variability is too large, which would have significant consequences for seismic hazard analysis. We use a large high-quality data set from Japan with well-studied stress drop data to address this issue. Nonparametric and parametric reference ground motion models are derived, and the relation of between-event residuals for Japan Meteorological Agency equivalent seismic intensity and peak ground acceleration with stress drop is analyzed for crustal earthquakes. We find a clear correlation of the between-event residuals with stress drops estimates; however, while the island of Kyushu is characterized by substantially larger stress drops than Honshu, the between-event residuals do not reflect this observation, leading to the appearance of two event families with different stress drop levels yet similar range of between-event residuals. Both the within-family and between-family stress drop variations are larger than expected from the ground motion between-event variability. A systematic common analysis of these parameters holds the potential to provide important constraints on the relative robustness of different groups of data in the different parameter spaces and to improve our understanding on how much of the observed source parameter variability is likely to be true source physics variability.

Drop performance test and evaluation for HANARO shutoff units

International Nuclear Information System (INIS)

Jung, Y. H.; Cho, Y. K.; Lee, J. H.; Choi, Y. S.; Woo, J. S.

2004-01-01

The function of the shutoff units of the HANARO is to rapidly insert the shutoff rod into the reactor core for safe shutdown of reactor. This paper describes drop performance test and evaluation for a shutoff unit for the technical verification of lifetime extension and localization of the HANARO shutoff units. We have performed preliminary drop performance tests for a shutoff unit at 1/2-core test loop and analyzed through the comparison with the test results performed during design verification test and the results of the periodic performance test in HANARO. It shows that the results of the local fabrication, installation and alignment for the shutoff unit meet the basic performance requirements, Furthermore, the performance evaluation method of the periodic drop test of the HANARO shutoff units is a conservative method comparing with the real drop time

An Extensional Characterization of Lambda-Lifting and Lambda-Dropping

DEFF Research Database (Denmark)

Danvy, Olivier

1999-01-01

Lambda-lifting and lambda-dropping respectively transform a block-structured functional program into recursive equations and vice versa. Lambda-lifting was developed in the early 80’s, whereas lambda-dropping is more recent. Both are split into an analysis and a transformation. Published work......, however, has only concentrated on the analysis parts. We focus here on the transformation parts and more precisely on their correctness, which appears never to have been proven. To this end, we define extensional versions of lambda-lifting and lambda-dropping and establish their correctness with respect...

An Extensional Characterization of Lambda-Lifting and Lambda-Dropping

DEFF Research Database (Denmark)

Danvy, Olivier

1998-01-01

Lambda-lifting and lambda-dropping respectively transform a block-structured functional program into recursive equations and vice versa. Lambda-lifting was developed in the early 80’s, whereas lambda-dropping is more recent. Both are split into an analysis and a transformation. Published work......, however, has only concentrated on the analysis parts. We focus here on the transformation parts and more precisely on their correctness, which appears never to have been proven. To this end, we define extensional versions of lambda-lifting and lambda-dropping and establish their correctness with respect...

45-FOOT HIGH DROP TOWER

Data.gov (United States)

Federal Laboratory Consortium — The Drop Tower is used to simulate and measure the impact shocks that are exerted on parachute loads when they hit the ground. It is also used for HSL static lift to...

High-precision drop shape analysis on inclining flat surfaces: introduction and comparison of this special method with commercial contact angle analysis.

Science.gov (United States)

Schmitt, Michael; Heib, Florian

2013-10-07

Drop shape analysis is one of the most important and frequently used methods to characterise surfaces in the scientific and industrial communities. An especially large number of studies, which use contact angle measurements to analyse surfaces, are characterised by incorrect or misdirected conclusions such as the determination of surface energies from poorly performed contact angle determinations. In particular, the characterisation of surfaces, which leads to correlations between the contact angle and other effects, must be critically validated for some publications. A large number of works exist concerning the theoretical and thermodynamic aspects of two- and tri-phase boundaries. The linkage between theory and experiment is generally performed by an axisymmetric drop shape analysis, that is, simulations of the theoretical drop profiles by numerical integration onto a number of points of the drop meniscus (approximately 20). These methods work very well for axisymmetric profiles such as those obtained by pendant drop measurements, but in the case of a sessile drop onto real surfaces, additional unknown and misunderstood effects on the dependence of the surface must be considered. We present a special experimental and practical investigation as another way to transition from experiment to theory. This procedure was developed to be especially sensitive to small variations in the dependence of the dynamic contact angle on the surface; as a result, this procedure will allow the properties of the surface to be monitored with a higher precession and sensitivity. In this context, water drops onto a 111 silicon wafer are dynamically measured by video recording and by inclining the surface, which results in a sequence of non-axisymmetric drops. The drop profiles are analysed by commercial software and by the developed and presented high-precision drop shape analysis. In addition to the enhanced sensitivity for contact angle determination, this analysis technique, in

Combined use of Azolla and loach suppressed paddy weeds and increased organic rice yield: second season results

Directory of Open Access Journals (Sweden)

Weiguo Cheng

2015-01-01

Full Text Available Organic farming uses alternatives to agricultural chemicals such as synthetic fertilizers and pesticides. The primary challenge in organic rice farming is controlling weeds without using herbicides and improving rice yield without chemical fertilizers. In our previous paper entitled as combined use of Azolla and loach suppressed weed Monochoria vaginalis and increased rice yield without agrochemicals, we reported the first year rice growth season results from an in situ container experiment. The experiment was designed with 4 treatments—control (with neither Azolla nor loach, Azolla (Azolla alone, loach (loach alone, and Az+Lo (combined Azolla and loach—with 3 replications each. The first year results showed that combined use of Azolla and loach was successful in weed suppression and increase in rice yield in 2012. In this paper, we report the second year results from the continuous container experiment in 2013. M.vaginalis emergences were very low in second year rice growth season on all treatments. Compared first year, the rice yields decreased in second year on all treatments due to different weather condition and with or without organic soybean oil cake application between two rice growth seasons. The second year results also showed the raising loach had a stronger effect to increase tiller and panicle numbers, and spikelet number per panicle, then improve rice yields to 2.3 times than control. The Azolla residues left from first year have weaker effect on rice growth and yield, but increase soil organic matter accumulation at second year. The two years study indicated that combined use of Azolla and loach can meet two of the greatest challenges in organic rice production: providing effective weed control and improving rice nutrition without agrochemicals.

Complex cooling water systems optimization with pressure drop consideration

CSIR Research Space (South Africa)

Gololo, KV

2012-12-01

Full Text Available Pressure drop consideration has shown to be an essential requirement for the synthesis of a cooling water network where reuse/recycle philosophy is employed. This is due to an increased network pressure drop associated with additional reuse...

Generation of Homogenous Three-Dimensional Pancreatic Cancer Cell Spheroids Using an Improved Hanging Drop Technique.

Science.gov (United States)

Ware, Matthew J; Colbert, Kevin; Keshishian, Vazrik; Ho, Jason; Corr, Stuart J; Curley, Steven A; Godin, Biana

2016-04-01

In vitro characterization of tumor cell biology or of potential anticancer drugs is usually performed using tumor cell lines cultured as a monolayer. However, it has been previously shown that three-dimensional (3D) organization of the tumor cells is important to provide insights on tumor biology and transport of therapeutics. Several methods to create 3D tumors in vitro have been proposed, with hanging drop technique being the most simple and, thus, most frequently used. However, in many cell lines this method has failed to form the desired 3D tumor structures. The aim of this study was to design and test an easy-to-use and highly reproducible modification of the hanging drop method for tumor sphere formation by adding methylcellulose polymer. Most pancreatic cancer cells do not form cohesive and manageable spheres when the original hanging drop method is used, thus we investigated these cell lines for our modified hanging drop method. The spheroids produced by this improved technique were analyzed by histology, light microscopy, immunohistochemistry, and scanning electron microscopy. Results show that using the proposed simple method; we were able to produce uniform spheroids for all five of the tested human pancreatic cancer cell lines; Panc-1, BxPC-3, Capan-1, MiaPaCa-2, and AsPC-1. We believe that this method can be used as a reliable and reproducible technique to make 3D cancer spheroids for use in tumor biology research and evaluation of therapeutic responses, and for the development of bio-artificial tissues.

Vortex-induced buckling of a viscous drop impacting a pool

KAUST Repository

Li, Erqiang

2017-07-20

We study the intricate buckling patterns which can form when a viscous drop impacts a much lower viscosity miscible pool. The drop enters the pool by its impact inertia, flattens, and sinks by its own weight while stretching into a hemispheric bowl. Upward motion along the outer bottom surface of this bowl produces a vortical boundary layer which separates along its top and rolls up into a vortex ring. The vorticity is therefore produced in a fundamentally different way than for a drop impacting a pool of the same liquid. The vortex ring subsequently advects into the bowl, thereby stretching the drop liquid into ever thinner sheets, reaching the micron level. The rotating motion around the vortex pulls in folds to form multiple windings of double-walled toroidal viscous sheets. The axisymmetric velocity field thereby stretches the drop liquid into progressively finer sheets, which are susceptible to both axial and azimuthal compression-induced buckling. The azimuthal buckling of the sheets tends to occur on the inner side of the vortex ring, while their folds can be stretched and straightened on the outside edge. We characterize the total stretching from high-speed video imaging and use particle image velocimetry to track the formation and evolution of the vortex ring. The total interfacial area between the drop and the pool liquid can grow over 40-fold during the first 50 ms after impact. Increasing pool viscosity shows entrapment of a large bubble on top of the drop, while lowering the drop viscosity produces intricate buckled shapes, appearing at the earliest stage and being promoted by the crater motions. We also present an image collage of the most intriguing and convoluted structures observed. Finally, a simple point-vortex model reproduces some features from the experiments and shows variable stretching along the wrapping sheets.

Student Drop-Out Trends at Sultan Qaboos University and Kuwait University: 2000-2011

Science.gov (United States)

Al Ghanboosi, Salim Saleem; Alqahtani, Abdulmuhsen Ayedh

2013-01-01

The current study aims to explore the drop-out trends at Sultan Qaboos. University and Kuwait University. Archival data of the period 2000-2011 were used to achieve this goal. Main findings showed that (a) male drop-out rates are higher than female drop-out rates; (b) drop- out rates at scientific colleges are higher; (c) drop-out rates of…

Effect of rb-bFGF eye drops and hydroxyl indican eye drops on tear film stability and dry eye symptoms after age-related cataract surgery

Directory of Open Access Journals (Sweden)

Jing Chen

2017-10-01

Full Text Available AIM: To compare and analyze the effect of recombinant bovine basic fibroblast growth factor(bFGFeye drops and hydroxyl indican eye drops on the tear film stability and dry eye symptoms after age-related cataract surgery. METHODS: A total of 115 patients(115 affected eyeswith dry eyes after age-related cataract surgery were divided into the bFGF group, the hydroxyl indican group and the blank control group by the random number table method. The blank control group was only given routine anti-inflammatory treatment, and on the basis, the bFGF group and the hydroxyl indican group were treated with bFGF eye drops and hydroxyl indican eye drops respectively. The clinical efficacy, adverse reactions, changes in scores of dry eye symptoms, Schirmer test(SⅠt, tear film break-up time(BUTand corneal fluorescein staining(CFSscores at different time points were compared among the three groups. RESULTS: The total markedly effective rates in the bFGF group(89.5%was higher than that in the hydroxyl indican group(70.3%or the blank control group(47.5%(PPPCONCLUSION: The tear film is unstable in early stage after age-related cataract surgery, and there are dry eye symptoms. The intervention with bFGF eye drops and hydroxyl indican eye drops can effectively restore the tear film stability and significantly relieve dry eye symptoms, and the effect of bFGF eye drops is more significant.

Summary of Skoda JS rod drop measurements analysis

International Nuclear Information System (INIS)

Svarny, J.; Krysl, V.

1999-01-01

A summary is presented of the Skoda JS rod drop reactivity measurements analysis provided during last two years based on control rod worth measurements by the outer ion chambers. Standard analysis based on comparisons of dynamics macrocode MOBY-DICK-SK and experimental data is extended to the 8-th group delayed neutron structure and new features of rod drop process are investigated. (author)

Error-free 320 Gb/s simultaneous add-drop multiplexing

DEFF Research Database (Denmark)

Mulvad, Hans Christian Hansen; Oxenløwe, Leif Katsuo; Clausen, Anders

2007-01-01

We report on the first demonstration of error-free time-division add-drop multiplexing at 320 Gb/s. The add- and drop-operations are performed simultaneously in a non-linear optical loop mirror with only 100 m of highly non-linear fibre....

Chemical-Reaction-Controlled Phase Separated Drops: Formation, Size Selection, and Coarsening

Science.gov (United States)

Wurtz, Jean David; Lee, Chiu Fan

2018-02-01

Phase separation under nonequilibrium conditions is exploited by biological cells to organize their cytoplasm but remains poorly understood as a physical phenomenon. Here, we study a ternary fluid model in which phase-separating molecules can be converted into soluble molecules, and vice versa, via chemical reactions. We elucidate using analytical and simulation methods how drop size, formation, and coarsening can be controlled by the chemical reaction rates, and categorize the qualitative behavior of the system into distinct regimes. Ostwald ripening arrest occurs above critical reaction rates, demonstrating that this transition belongs entirely to the nonequilibrium regime. Our model is a minimal representation of the cell cytoplasm.

Potential drop crack measurement systems for CANDU components

Energy Technology Data Exchange (ETDEWEB)

Sahney, R [Carleton Univ., Ottawa, ON (Canada)

1994-12-31

A project to develop an automated crack measurement system for CANDU pressure tube burst testing is currently underway. The system will utilize either Direct Current Potential Drop (DCPD) or Alternating Current Potential Drop (ACPD) techniques for crack measurement. The preliminary stage of the project involves testing and comparison of both ACPD and DCPD methods on a Zr - 2.5% Nb alloy plate with saw cuts (used to simulate cracks). Preliminary results show that both ACPD and DCPD techniques are capable of detecting cracks; further testing is in progress to determine the ability of each of the two systems to make accurate crack depth measurements. This paper will describe the two potential drop techniques and will present test results from the experimental program. (author). 10 refs., 7 figs.

Dropped fuel damage prediction techniques and the DROPFU code

International Nuclear Information System (INIS)

Mottershead, K.J.; Beardsmore, D.W.; Money, G.

1995-01-01

During refuelling, and fuel handling, at UK Advanced Gas Cooled Reactor (AGR) stations it is recognised that the accidental dropping of fuel is a possibility. This can result in dropping individual fuel elements, a complete fuel stringer, or a whole assembly. The techniques for assessing potential damage have been developed over a number of years. This paper describes how damage prediction techniques have subsequently evolved to meet changing needs. These have been due to later fuel designs and the need to consider drops in facilities outside the reactor. The paper begins by briefly describing AGR fuel and possible dropped fuel scenarios. This is followed by a brief summary of the damage mechanisms and the assessment procedure as it was first developed. The paper then describes the additional test work carried out, followed by the detailed numerical modelling. Finally, the paper describes the extensions to the practical assessment methods. (author)

Contact angle of sessile drops in Lennard-Jones systems.

Science.gov (United States)

Becker, Stefan; Urbassek, Herbert M; Horsch, Martin; Hasse, Hans

2014-11-18

Molecular dynamics simulations are used for studying the contact angle of nanoscale sessile drops on a planar solid wall in a system interacting via the truncated and shifted Lennard-Jones potential. The entire range between total wetting and dewetting is investigated by varying the solid-fluid dispersive interaction energy. The temperature is varied between the triple point and the critical temperature. A correlation is obtained for the contact angle in dependence of the temperature and the dispersive interaction energy. Size effects are studied by varying the number of fluid particles at otherwise constant conditions, using up to 150,000 particles. For particle numbers below 10,000, a decrease of the contact angle is found. This is attributed to a dependence of the solid-liquid surface tension on the droplet size. A convergence to a constant contact angle is observed for larger system sizes. The influence of the wall model is studied by varying the density of the wall. The effective solid-fluid dispersive interaction energy at a contact angle of θ = 90° is found to be independent of temperature and to decrease linearly with the solid density. A correlation is developed that describes the contact angle as a function of the dispersive interaction, the temperature, and the solid density. The density profile of the sessile drop and the surrounding vapor phase is described by a correlation combining a sigmoidal function and an oscillation term.

Volatile fatty acids production from sewage organic matter by combined bioflocculation and anaerobic fermentation

NARCIS (Netherlands)

Khiewwijit, R.; Keesman, K.J.; Rijnaarts, H.H.M.; Temmink, B.G.

2014-01-01

This work aims at exploring the feasibility of a combined process bioflocculation to concentrate sewage organic matter and anaerobic fermentation to produce volatile fatty acids (VFA). Bioflocculation, using a high-loaded aerobic membrane bioreactor (HL-MBR), was operated at an HRT of 1 h and an SRT

Clinical study of 3g/L sodium hyaluronate eye drops with bromhexine hydrochloride tablets for dry eye

Directory of Open Access Journals (Sweden)

Hui-Qun Xu

2018-04-01

Full Text Available AIM:To investigate the clinical efficacy of 3g/L sodium hyaluronate eye drops combined with bromhexine hydrochloride tablets on the treatment of dry eye. METHODS:Totally 200 patients with dry eye were randomly divided into the control group(n=100and observation group(n=100. Patients in two groups were given 3g/L sodium hyaluronate eye drops and physiotherapy. On the basis of this, the observation group were treated with bromhexine hydrochloride tablets. The inflammatory factors(IL-6, IL-10, TNF-α and IL-1βlevels and ocular symptom scores(OSDI, BUT, SⅠt, FLin the two groups were compared between before and after treatment. And the clinical efficacy and adverse reactions were evaluated. RESULTS: After treatment, the IL-6, IL-10, TNF-α, IL-1β, OSDI and FL scores in two groups were significantly lower than those before treatment, and BUT and SⅠt were significantly higher than those before treatment. Moreover, the improvement degree of the above indexes in the observation group were better than those in the control group, showing statistically significant difference(Pχ2=5.531, P=0.019, but there was no significant difference in the incidence of adverse reactions between the two groups(χ2=0.307, P=0.579. CONCLUSION:As for the patients with dry eye, the combination of 3g/L sodium hyaluronate eye drops with bromhexine hydrochloride tablets can significantly decrease the level of inflammatory factors, improve the eye symptoms and the clinical total efficiency, without increasing treatment-related adverse effects.

Capillarity and wetting phenomena drops, bubbles, pearls, waves

CERN Document Server

Gennes, Pierre-Gilles; Quéré, David

2004-01-01

As I glance out my window in the early morning, I can see beads of droplets gracing a spider web. The film of dew that has settled on the threads is unstable and breaks up spontaneously into droplets. This phenomenon has implications for the treatment of textile fibers (the process known as "oiling"), glass, and carbon. It is no less important when applying mascara! I take my morning shower. The moment I step out, I dry off by way of evaporation (which makes me feel cold) and by dewetting (the process by which dry areas form spontaneously and expand on my skin). As I rush into my car under a pelting rain, my attention is caught by small drops stuck on my windshield. I also notice larger drops rolling down and others larger still that, like snails, leave behind them a trail of water. I ask myself what the difference is between these rolling drops and grains of sand tumbling down an incline. I wonder why the smallest drops remain stuck. The answers to such questions do help car manufacturers treat the surface o...

Electromagnetic Drop Scale Scattering Modelling for Dynamic Statistical Rain Fields

OpenAIRE

Hipp, Susanne

2015-01-01

This work simulates the scattering of electromagnetic waves by a rain field. The calculations are performed for the individual drops and accumulate to a time signal dependent on the dynamic properties of the rain field. The simulations are based on the analytical Mie scattering model for spherical rain drops and the simulation software considers the rain characteristics drop size (including their distribution in rain), motion, and frequency and temperature dependent permittivity. The performe...

Drop behavior in acoustic standing waves; Teizaihachu ni okeru ekiteki no kyodo

Energy Technology Data Exchange (ETDEWEB)

Kamimura, H. [National Aerospace Laboratory, Tokyo (Japan); Yamanaka, T. [Yokohama National University, Yokohama (Japan)

1997-10-01

When new materials, such as those for space shuttles, are developed, it is necessary to hold then in a non-contacting manner. Described herein is behavior of drops in a holding device which utilizes acoustic radiation pressure. When an object sufficiently small as compared with wavelength of a sound wave is placed in acoustic standing waves, it is subjected to acoustic radiation pressure. Chandrasekahr developed the theory on the stability of a rotating drop by equating the entire mechanical energy of a drop with its surface energy. This theory, based on the assumption of symmetric surface energy, is incapable of theoretically dealing with multi-lobed waves evolved by surface tension. In this study, multi-lobed waves excited by sound waves in a rotating drop are analytically found without assuming symmetry of drop surface energy. The multi-lobe waves are first found on the assumption that the acoustic radiation pressure around a drop is constant. Then, the effects of the deformed drop on the radiation pressure around the drop are considered. In addition, the equation for the relationship between the radiation pressure and a drop that becomes oblate due to the radiation pressure is obtained. The theoretically derived results by this equation are in good agreement with the observed results by the ground and flight tests. 17 refs., 18 figs.

Pressure Drop Correlations of Single-Phase and Two-Phase Flow in Rolling Tubes

International Nuclear Information System (INIS)

Xia-xin Cao; Chang-qi Yan; Pu-zhen Gao; Zhong-ning Sun

2006-01-01

A series of experimental studies of frictional pressure drop for single phase and two-phase bubble flow in smooth rolling tubes were carried out. The tube inside diameters were 15 mm, 25 mm and 34.5 mm respectively, the rolling angles of tubes could be set as 10 deg. and 20 deg., and the rolling periods could be set as 5 s, 10 s and 15 s. Combining with the analysis of single-phase water motion, it was found that the traditional correlations for calculating single-phase frictional coefficient were not suitable for the rolling condition. Based on the experimental data, a new correlation for calculating single-phase frictional coefficient under rolling condition was presented, and the calculations not only agreed well with the experimental data, but also could display the periodically dynamic characteristics of frictional coefficients. Applying the new correlation to homogeneous flow model, two-phase frictional pressure drop of bubble flow in rolling tubes could be calculated, the results showed that the relative error between calculation and experimental data was less than ± 25%. (authors)

Electrohydrodynamics of suspension of liquid drops in AC fields

Science.gov (United States)

Abdul Halim, Md.; Esmaeeli, Asghar

2012-11-01

Manipulation of liquid drops by an externally applied electric field is currently the focus of increased attention because of its relevance in a broad range of industrial processes. The effect of a uniform DC electric field on a solitary drop is well studied; however, less is know about the impact of electric field on suspension of liquid drops, and very little information is available on the impact of AC field on a single or a suspension of drops. Here we report the results of Direct Numerical Simulations of electrohydrodynamics of suspension of liquid drops. The governing equations are solved using a front tracking/finite difference technique, in conjunction with Taylor's leaky dielectric model. The imposed electric potential comprises of two parts, a time-independent base and a time-dependent part. The goal is to explore the relative importance of these two components in setting the statistically steady state behavior of the suspension. To this end, we report the results of three sets of simulations, where (i) the time-dependent part act as a perturbation on the base potential, (ii) the two components are of the same order, and (iii) the time-dependent part is much larger than the base potential. The problem is studied as a function of the governing nondimensional parameters.

Liquid-drop model description of heavy ion fusion at sub-barrier energies

Energy Technology Data Exchange (ETDEWEB)

Aguiar, C E; Barbosa, V C; Canto, L F; Donangelo, R

1987-10-05

The enhancement of the heavy ion fusion cross section at sub-barrier energies is studied in the liquid-drop model approach. The shape of the system is described by two spheres smoothly connected by a neck, and the kinetic and potential energies are calculated within this parametrization. Underbarrier fusion cross sections for symmetric projectile-target combinations are calculated in the WKB approximation and a comparison with the available data is made. The agreement is quite satisfactory, except for those systems in which the reaction is strongly affected by the details of the nuclear structure of the collision partners.

Active structuring of colloidal armour on liquid drops

OpenAIRE

Dommersnes, Paul; Rozynek, Zbigniew; Mikkelsen, Alexander; Castberg, Rene; Kjerstad, Knut; Hersvik, Kjetil; Fossum, Jon Otto

2013-01-01

Adsorption and assembly of colloidal particles at the surface of liquid droplets are at the base of particle-stabilized emulsions and templating. Here we report that electrohydrodynamic and electro-rheological effects in leaky-dielectric liquid drops can be used to structure and dynamically control colloidal particle assemblies at drop surfaces, including electric-fieldassisted convective assembly of jammed colloidal ‘ribbons’, electro-rheological colloidal chains confined to a...

LTPS-TFT Pixel Circuit Compensating for TFT Threshold Voltage Shift and IR-Drop on the Power Line for AMOLED Displays

Directory of Open Access Journals (Sweden)

Ching-Lin Fan

2012-01-01

Full Text Available We propose a new pixel design for the active matrix organic light-emitting diode (AMOLED using low-temperature polycrystalline silicon thin-film transistors (LTPS-TFTs. The proposed pixel is composed of four switching TFTs, one driving TFT (DTFT, and one capacitor. The simulation results are performed by AIM-SPICE software. The error rate of OLED output current with (threshold voltage variation (0.3 V and power line drop by 1 V are improved to about 1.67% and 15%, respectively. Thus, the proposed pixel circuit can successfully overcome drawbacks suffered from DTFT threshold voltage deviation and IR-drop on power line.

Origin and dynamics of vortex rings in drop splashing.

Science.gov (United States)

Lee, Ji San; Park, Su Ji; Lee, Jun Ho; Weon, Byung Mook; Fezzaa, Kamel; Je, Jung Ho

2015-09-04

A vortex is a flow phenomenon that is very commonly observed in nature. More than a century, a vortex ring that forms during drop splashing has caught the attention of many scientists due to its importance in understanding fluid mixing and mass transport processes. However, the origin of the vortices and their dynamics remain unclear, mostly due to the lack of appropriate visualization methods. Here, with ultrafast X-ray phase-contrast imaging, we show that the formation of vortex rings originates from the energy transfer by capillary waves generated at the moment of the drop impact. Interestingly, we find a row of vortex rings along the drop wall, as demonstrated by a phase diagram established here, with different power-law dependencies of the angular velocities on the Reynolds number. These results provide important insight that allows understanding and modelling any type of vortex rings in nature, beyond just vortex rings during drop splashing.

Two-phase flow boiling pressure drop in small channels

International Nuclear Information System (INIS)

Sardeshpande, Madhavi V.; Shastri, Parikshit; Ranade, Vivek V.

2016-01-01

Highlights: • Study of typical 19 mm steam generator tube has been undertaken in detail. • Study of two phase flow boiling pressure drop, flow instability and identification of flow regimes using pressure fluctuations is the main focus of present work. • Effect of heat and mass flux on pressure drop and void fraction was studied. • Flow regimes identified from pressure fluctuations data using FFT plots. • Homogeneous model predicted pressure drop well in agreement. - Abstract: Two-phase flow boiling in small channels finds a variety of applications in power and process industries. Heat transfer, boiling flow regimes, flow instabilities, pressure drop and dry out are some of the key issues related to two-phase flow boiling in channels. In this work, the focus is on pressure drop in two-phase flow boiling in tubes of 19 mm diameter. These tubes are typically used in steam generators. Relatively limited experimental database is available on 19 mm ID tube. Therefore, in the present work, the experimental set-up is designed for studying flow boiling in 19 mm ID tube in such a way that any of the different flow regimes occurring in a steam generator tube (from pre-heating of sub-cooled water to dry-out) can be investigated by varying inlet conditions. The reported results cover a reasonable range of heat and mass flux conditions such as 9–27 kW/m 2 and 2.9–5.9 kg/m 2 s respectively. In this paper, various existing correlations are assessed against experimental data for the pressure drop in a single, vertical channel during flow boiling of water at near-atmospheric pressure. A special feature of these experiments is that time-dependent pressures are measured at four locations along the channel. The steady-state pressure drop is estimated and the identification of boiling flow regimes is done with transient characteristics using time series analysis. Experimental data and corresponding results are compared with the reported correlations. The results will be

The millennium water vapour drop in chemistry–climate model simulations

Directory of Open Access Journals (Sweden)

S. Brinkop

2016-07-01

. Our free-running simulations do not capture the drop as observed, because a the cold point temperature has a low bias and thus the water vapour variability is reduced and b because they do not simulate the appropriate dynamical state. Large negative water vapour declines are also found in other years and seem to be a feature which can be found after strong combined El Niño/La Niña events if the QBO west phase during La Niña changes to the east phase.

Analysis of DCI cask drop test onto reinforced concrete pad

International Nuclear Information System (INIS)

Ito, C.; Kato, Y.; Hattori, S.; Shirai, K.; Misumi, M.; Ozaki, S.

1993-01-01

In a cask-storage facility, a cask may be subjected to an impact load as a result of a free drop onto the floor because of cask mishandling. We performed drop tests of casks onto a reinforced concrete (RC) slab representing the floor of a facility as well as simulation analysis [Kato et al]. This paper describes the details of the FEM analysis and calculated results and compares them with the drop test results. (J.P.N.)

牛黄解毒滴丸联合溃疡散治疗口腔溃疡106例疗效观察%Treatment of dental ulcer by Calculus Bovis Detoxication dropping pill combined with sucralfate

Institute of Scientific and Technical Information of China (English)

尹晓飞; 王书杰; 王文森; 蔡大伟

2013-01-01

Objective To study the curative effects of Calculus Bovis Detoxication dropping pill combined with sucralfate on dental ulcer. Methods 220 patients with dental ulcer were randomly divided into two groups, and they all took compound vitamin B tablets. The treatment group also buccally took Calculus Bovis Detoxication dropping pill combined with sucralfate, and 7 days were a course of treatment. The clinical curative effects of the two groups were observed. Results The total effective rate of the treatment group was 90. 57% . That of the control group was 68. 93% . The curative effects of the treatment group was significantly better than those of the control group( P <0. 05 ). Conclusion Treatment of dental ulcer by buccally taking Calculus Bovis Detoxication drilling pill combined with sucralfate is safe, effective, and cheap, which should be promoted.%目的 研究牛黄解毒滴丸联合溃疡散治疗口腔溃疡的临床疗效.方法 将220例患者随机分为2组,两组均给予复合维生素B片,治疗组另含服牛黄解毒滴丸联合溃疡散外敷治疗,疗程7 d.观察两组治疗后临床疗效.结果 治疗组的总有效率为90.57%,对照组的总有效率为68.93%,治疗组疗效明显优于对照组(P＜0.05).结论 含服牛黄解毒滴丸联合溃疡散治疗口腔溃疡疗效安全高效、价格低廉,有临床推广价值.

Electrohydrodynamics of drops in strong electric fields: Simulations and theory

Science.gov (United States)

Saintillan, David; Das, Debasish

2016-11-01

Weakly conducting dielectric liquid drops suspended in another dielectric liquid exhibit a wide range of dynamical behaviors when subject to an applied uniform electric field contingent on field strength and material properties. These phenomena are best described by the much celebrated Maylor-Taylor leaky dielectric model that hypothesizes charge accumulation on the drop-fluid interface and prescribes a balance between charge relaxation, the jump in Ohmic currents and charge convection by the interfacial fluid flow. Most previous numerical simulations based on this model have either neglected interfacial charge convection or restricted themselves to axisymmetric drops. In this work, we develop a three-dimensional boundary element method for the complete leaky dielectric model to systematically study the deformation and dynamics of liquid drops in electric fields. The inclusion of charge convection in our simulation permits us to investigate drops in the Quincke regime, in which experiments have demonstrated symmetry-breaking bifurcations leading to steady electrorotation. Our simulation results show excellent agreement with existing experimental data and small deformation theories. ACSPRF Grant 53240-ND9.

Shuttlecock Velocity of a Badminton Drop Shot

Directory of Open Access Journals (Sweden)

Ampharin Ongvises

2013-01-01

Full Text Available In a badminton ‘drop shot’, the shuttlecock is struck by a non-rotating racquet at low speed. In this investigation, a shuttlecock was hit by a badminton racquet in a linear collision, simulating a drop shot. The collision was recorded with high-speed video and the velocities of the racquet and shuttlecock determined. The relationship between the impact velocity of the racquet and the velocity of the shuttlecock as it leaves the badminton racquet after collision was found to be proportional over the range tested.

Shuttlecock Velocity of a Badminton Drop Shot

Directory of Open Access Journals (Sweden)

Ampharin Ongvises

2013-12-01

Full Text Available In a badminton ‘drop shot’, the shuttlecock is struck by a non-rotating racquet at low speed. In this investigation, a shuttlecock was hit by a badminton racquet in a linear collision, simulating a drop shot. The collision was recorded with high-speed video and the velocities of the racquet and shuttlecock determined. The relationship between the impact velocity of the racquet and the velocity of the shuttlecock as it leaves the badminton racquet after collision was found to be proportional over the range tested.

High-Speed Interferometry Under Impacting Drops

KAUST Repository

Langley, Kenneth R.; Li, Erqiang; Thoroddsen, Sigurdur T

2017-01-01

Over the last decade the rapid advances in high-speed video technology, have opened up to study many multi-phase fluid phenomena, which tend to occur most rapidly on the smallest length-scales. One of these is the entrapment of a small bubble under a drop impacting onto a solid surface. Here we have gone from simply observing the presence of the bubble to detailed imaging of the formation of a lubricating air-disc under the drop center and its subsequent contraction into the bubble. Imaging the full shape-evolution of the air-disc has required μm and sub-μs space and time resolutions. Time-resolved 200 ns interferometry with monochromatic light, has allowed us to follow individual fringes to obtain absolute air-layer thicknesses, based on the eventual contact with the solid. We can follow the evolution of the dimple shape as well as the compression of the gas. The improved imaging has also revealed new levels of detail, like the nature of the first contact which produces a ring of micro-bubbles, highlighting the influence of nanometric surface roughness. Finally, for impacts of ultra-viscous drops we see gliding on ~100 nm thick rarified gas layers, followed by extreme wetting at numerous random spots.

High-Speed Interferometry Under Impacting Drops

KAUST Repository

Langley, Kenneth R.

2017-08-31

Over the last decade the rapid advances in high-speed video technology, have opened up to study many multi-phase fluid phenomena, which tend to occur most rapidly on the smallest length-scales. One of these is the entrapment of a small bubble under a drop impacting onto a solid surface. Here we have gone from simply observing the presence of the bubble to detailed imaging of the formation of a lubricating air-disc under the drop center and its subsequent contraction into the bubble. Imaging the full shape-evolution of the air-disc has required μm and sub-μs space and time resolutions. Time-resolved 200 ns interferometry with monochromatic light, has allowed us to follow individual fringes to obtain absolute air-layer thicknesses, based on the eventual contact with the solid. We can follow the evolution of the dimple shape as well as the compression of the gas. The improved imaging has also revealed new levels of detail, like the nature of the first contact which produces a ring of micro-bubbles, highlighting the influence of nanometric surface roughness. Finally, for impacts of ultra-viscous drops we see gliding on ~100 nm thick rarified gas layers, followed by extreme wetting at numerous random spots.

Combining essential oils and olive extract for control of multi-drug resistant Salmonella enterica on organic leafy greens

Science.gov (United States)

We investigated the combined antimicrobial effects of plant essential oils and olive extract against antibiotic resistant Salmonella enterica serovar Newport on organic leafy greens. Organic baby spinach, mature spinach, romaine lettuce, and iceberg lettuce were inoculated with S. Newport and dip-t...

Flow rate-pressure drop relation for deformable shallow microfluidic channels

Science.gov (United States)

Christov, Ivan C.; Cognet, Vincent; Shidhore, Tanmay C.; Stone, Howard A.

2018-04-01

Laminar flow in devices fabricated from soft materials causes deformation of the passage geometry, which affects the flow rate--pressure drop relation. For a given pressure drop, in channels with narrow rectangular cross-section, the flow rate varies as the cube of the channel height, so deformation can produce significant quantitative effects, including nonlinear dependence on the pressure drop [{Gervais, T., El-Ali, J., G\\"unther, A. \\& Jensen, K.\\ F.}\\ 2006 Flow-induced deformation of shallow microfluidic channels.\\ \\textit{Lab Chip} \\textbf{6}, 500--507]. Gervais et. al. proposed a successful model of the deformation-induced change in the flow rate by heuristically coupling a Hookean elastic response with the lubrication approximation for Stokes flow. However, their model contains a fitting parameter that must be found for each channel shape by performing an experiment. We present a perturbation approach for the flow rate--pressure drop relation in a shallow deformable microchannel using the theory of isotropic quasi-static plate bending and the Stokes equations under a lubrication approximation (specifically, the ratio of the channel's height to its width and of the channel's height to its length are both assumed small). Our result contains no free parameters and confirms Gervais et. al.'s observation that the flow rate is a quartic polynomial of the pressure drop. The derived flow rate--pressure drop relation compares favorably with experimental measurements.

Develoment of pressure drop calculation modules for a wire-wrapped LMR subassembly

International Nuclear Information System (INIS)

Kim, Young Gyun; Lim, Hyun Jin; Kim, Won Seok; Kim, Young Il

2000-06-01

Pressure drop calculation modules for a wire-wrapped LMR subassembly was been developed. This report summarizes present information on pressure drop calculation modules for inlet hole, lower part and upper part of a wire-wrapped LMR subassembly which was developed using simple formulas of sudden expansion and sudden contraction. A case calculation study was done using design data of a KALIMER driver fuel subassembly. And the total pressure drop in the driver fuel subassembly, except for the bundle part, was calculated as 0.13 MPa, which is in the reasonable pressure drop range. The developed modules will be integrated in the total subassembly pressure drop calculation code with further improvements

Analysis of an Electrostatic MEMS Squeeze-film Drop Ejector

Directory of Open Access Journals (Sweden)

Edward P. Furlani

2009-10-01

Full Text Available We present an analysis of an electrostatic drop-on-demand MEMS fluid ejector. The ejector consists of a microfluidic chamber with a piston that is suspended a few microns beneath a nozzle plate. A drop is ejected when a voltage is applied between the orifice plate and the piston. This produces an electrostatic force that moves the piston towards the nozzle. The moving piston generates a squeeze-film pressure distribution that causes drop ejection. We discuss the operating physics of the ejector and present a lumped-element model for predicting its performance. We calibrate the model using coupled structural-fluidic CFD analysis.

Internal flow of acoustically levitated drops undergoing sectorial oscillations

International Nuclear Information System (INIS)

Shen, C.L.; Xie, W.J.; Yan, Z.L.; Wei, B.

2010-01-01

We present the experimental observation and theoretical analysis of fluid flow in acoustically levitated water drop undergoing sectorial oscillations. The fluid always flows between the extended sections and the compressed sections. The magnitude of fluid velocity decreases from the equatorial fringe to the centre of levitated drop. The maximum fluid velocity is 60-160 mm/s and the Reynolds number of the oscillations is estimated to be 137-367. The internal flow of the drop is analyzed as potential flow, and the fluid velocity is found to be horizontal. In the equatorial plane, the calculated stream lines and velocity profiles agree well with the experimental observations.

Primary and secondary organic aerosol origin by combined gas-particle phase source apportionment

Directory of Open Access Journals (Sweden)

M. Crippa

2013-08-01

Full Text Available Secondary organic aerosol (SOA, a prominent fraction of particulate organic mass (OA, remains poorly constrained. Its formation involves several unknown precursors, formation and evolution pathways and multiple natural and anthropogenic sources. Here a combined gas-particle phase source apportionment is applied to wintertime and summertime data collected in the megacity of Paris in order to investigate SOA origin during both seasons. This was possible by combining the information provided by an aerosol mass spectrometer (AMS and a proton transfer reaction mass spectrometer (PTR-MS. A better constrained apportionment of primary OA (POA sources is also achieved using this methodology, making use of gas-phase tracers. These tracers made possible the discrimination between biogenic and continental/anthropogenic sources of SOA. We found that continental SOA was dominant during both seasons (24–50% of total OA, while contributions from photochemistry-driven SOA (9% of total OA and marine emissions (13% of total OA were also observed during summertime. A semi-volatile nighttime component was also identified (up to 18% of total OA during wintertime. This approach was successfully applied here and implemented in a new source apportionment toolkit.

Evaluation of Sodium Sulphacetamide drops in the Treatment of ...

African Journals Online (AJOL)

Sodium sulphacetamide eye drops had been used successfully in the past in the treatment of ophthalmia neonatorium (ON) but its use has decreased remarkably in recent time. The efficacy of 10 percent sodium sulphacetamide eye drops in the treatment of ON was prospectively evaluated in 68 neonates seen in our ...

Assessment of the Sustainability of the Mediterranean Diet Combined with Organic Food Consumption: An Individual Behaviour Approach.

Science.gov (United States)

Seconda, Louise; Baudry, Julia; Allès, Benjamin; Hamza, Oualid; Boizot-Szantai, Christine; Soler, Louis-Georges; Galan, Pilar; Hercberg, Serge; Lairon, Denis; Kesse-Guyot, Emmanuelle

2017-01-12

Mediterranean diets are promising sustainable food models and the organic food system may provide health and environmental benefits. Combining the two models could therefore be a favourable approach for food sustainability. The aim of this study was to draw up a comparative description of four diets differing in the level of organic foods consumption and the adherence to the Mediterranean diet, using multidisciplinary indicators to assess the sustainability of these diets. Four groups of participants were defined and compared, combining the proportion of organic food in their diet (Org versus Conv) and the adherence to the Mediterranean diet (Med versus NoMed). Conv-NoMed: Conventional consumers and non-Mediterranean diet followers; Conv-Med: Conventional consumers and Mediterranean diet followers; Org-NoMed: Organic consumers and non-Mediterranean diet followers; Org-Med: Organic consumers and Mediterranean diet followers. The adherence to nutritional recommendations was higher among the Org-Med and Conv-Med groups compared to the Conv-NoMed group (using the mPNNS-GS (modified-Programme National nutrition santé guidelines score/13.5 points): 9.29 (95% confidence intervals (CI) = 9.23-9.36) and 9.30 (95% CI = 9.24-9.35) versus 8.19 (95% CI = 8.17-8.22)) respectively. The mean plant/animal protein intake ratio was 1.38 (95% CI = 1.01-1.74) for the Org-Med group versus 0.44 (95% CI = 0.28-0.60) for the Conv-NoMed group. The average cost of the diet of Org-Med participants was the highest: 11.43 €/day (95% CI = 11.34-11.52). This study highlighted the importance of promoting the Mediterranean diet combined with organic food consumption for individual health and environmental aspects but challenges with regard to the cost remain.

Efficacy and Tolerability of Fixed-Combination Brinzolamide/Timolol in Latin American Patients with Open-Angle Glaucoma or Ocular Hypertension Previously on Brimonidine/Timolol Fixed Combination

OpenAIRE

Alezzandrini, Arturo; Hubatsch, Douglas; Alfaro, Rene

2014-01-01

Introduction Fixed-combination glaucoma medications are commonly used to achieve target intraocular pressure (IOP) reduction in patients uncontrolled with monotherapy; however, ocular discomfort associated with eye drops can decrease adherence. This study assessed the efficacy and tolerability of twice-daily fixed-combination brinzolamide 1%/timolol 0.5% (BRINZ/TIM-FC) in Latin American patients transitioned from fixed-combination brimonidine 0.2%/timolol 0.5% (BRIM/TIM-FC) because of insuffi...

Log-normal spray drop distribution...analyzed by two new computer programs

Science.gov (United States)

Gerald S. Walton

1968-01-01

Results of U.S. Forest Service research on chemical insecticides suggest that large drops are not as effective as small drops in carrying insecticides to target insects. Two new computer programs have been written to analyze size distribution properties of drops from spray nozzles. Coded in Fortran IV, the programs have been tested on both the CDC 6400 and the IBM 7094...

Controlling a nuclear reactor with dropped control rods

International Nuclear Information System (INIS)

Mc Atee, K.R.; Alsop, B.H.

1987-01-01

A control system is described for a nuclear power plant including a reactor with a core having an upper portion and a lower portion and control rods which are inserted into and withdrawn from the core of the reactor vertically to control reactivity in the core. The system comprises: means to measure neutron flux separately in the upper portion and the lower portion of the reactor and to generate from such measurements a signal representative of axial distribution of power between the upper and lower portions of the reactor core; means to detect a dropped control rod in the reactor and to generate a dropped rod signal in response thereto; means to generate an axial power distribution limit signal representative of a critical axial power distribution for a dropped rod condition; means to compare the axial power distribution signal to the axial power distribution limit signal and to generate an axial power distribution out of limits signal when the axial power distribution signal exceeds the axial power distribution limit signal; and means responsive only to the presence of both the dropped rod signal and the axial power distribution out of limits signal to generate a signal for shutting the reactor down

Sodium-fuel interaction: dropping experiments and subassembly test

International Nuclear Information System (INIS)

Holtbecker, H.; Schins, H.; Jorzik, E.; Klein, K.

1978-01-01

Nine dropping tests, which bring together 2 to 4 kg of molten UO 2 with 150 l sodium, showed the incoherency and non-violence of these thermal interactions. The pressures can be described by sodium incipient boiling and bubble collapse; the UO 2 fragmentation by thermal stress and bubble collapse impact forces. The mildness of the interaction is principally due to the slowness and incoherency of UO 2 fragmentation. This means that parametric models which assume instantaneous mixing and fragmentation are of no use for the interpretation of dropping experiments. One parametric model, the Caldarola Fuel Coolant Interaction Variable Mass model, is being coupled to the two dimensional time dependent hydrodynamic REXCO-H code. In a first step the coupling is applicated to a monodimensional geometry. A subassembly test is proposed to validate the model. In this test rapid mixing between UO 2 and sodium has to be obtained. Dispersed molten UO 2 fuel is obtained by flashing injected sodium drops inside a UO 2 melt. This flashing is theoretically explained and modelled as a superheat limited explosion. The measured sodium drop dwell times of two experiments are compared to results obtained from the mentioned theory, which is the basis of the Press 2 Code

Structure formation in soft nanocolloids: liquid-drop model.

Science.gov (United States)

Doukas, A-K; Likos, C N; Ziherl, P

2018-04-25

Using a model where soft nanocolloids such as spherical polymer brushes and star polymers are viewed as compressible liquid drops, we theoretically explore contact interactions between such particles. By numerically minimizing the phenomenological free energy consisting of bulk and surface terms, we find that at small deformations the drop-drop interaction is pairwise additive and described by a power law. We also propose a theory to describe the small-deformation regime, and the agreement is very good at all drop compressibilities. The large-deformation regime, which is dominated by many-body interactions, is marked by a rich phase diagram which includes the face- and body-centered-cubic, σ, A15, and simple hexagonal lattice as well as isostructural and re-entrant transitions. Most of these features are directly related to the non-convex deformation free energy emerging from many-body effects in the partial-faceting regime. The phase diagram, which depends on just two model parameters, contains many of the condensed phases observed in experiments. We also provide statistical-mechanical arguments that relate the two model parameters to the molecular architecture of the polymeric nanocolloids, chain rigidity, and solvent quality. The model represents a generic framework for the overarching features of the phase behavior of polymeric nanocolloids at high compressions.

Foamed emulsion drainage: flow and trapping of drops.

Science.gov (United States)

Schneider, Maxime; Zou, Ziqiang; Langevin, Dominique; Salonen, Anniina

2017-06-07

Foamed emulsions are ubiquitous in our daily life but the ageing of such systems is still poorly understood. In this study we investigate foam drainage and measure the evolution of the gas, liquid and oil volume fractions inside the foam. We evidence three regimes of ageing. During an initial period of fast drainage, both bubbles and drops are very mobile. As the foam stabilises drainage proceeds leading to a gradual decrease of the liquid fraction and slowing down of drainage. Clusters of oil drops are less sheared, their dynamic viscosity increases and drainage slows down even further, until the drops become blocked. At this point the oil fraction starts to increase in the continuous phase. The foam ageing leads to an increase of the capillary pressure until the oil acts as an antifoaming agent and the foam collapses.

Preventive and therapeutic effects of SkQ1-containing Visomitin eye drops against light-induced retinal degeneration.

Science.gov (United States)

Novikova, Yu P; Gancharova, O S; Eichler, O V; Philippov, P P; Grigoryan, E N

2014-10-01

The human retina is constantly affected by light of varying intensity, this being especially true for photoreceptor cells and retinal pigment epithelium. Traditionally, photoinduced damages of the retina are induced by visible light of high intensity in albino rats using the LIRD (light-induced retinal degeneration) model. This model allows study of pathological processes in the retina and the search for retinoprotectors preventing retinal photodamage. In addition, the etiology and mechanisms of retina damage in the LIRD model have much in common with the mechanisms of the development of age-related retinal disorders, in particular, with age-related macular degeneration (AMD). We have studied preventive and therapeutic effects of Visomitin eye drops (based on the mitochondria-targeted antioxidant SkQ1) on albino rat retinas damaged by bright light. In the first series of experiments, rats receiving Visomitin for two weeks prior to illumination demonstrated significantly less expressed atrophic and degenerative changes in the retina compared to animals receiving similar drops with no SkQ1. In the second series, the illuminated rats were treated for two weeks with Visomitin or similar drops without SkQ1. The damaged retinas of the experimental animals were repaired much more effectively than those of the control animals. Therefore, we conclude that Visomitin SkQ1-containing eye drops have pronounced preventive and therapeutic effects on the photodamaged retina and might be recommended as a photoprotector and a pharmaceutical preparation for the treatment of AMD in combination with conventional medicines.

Experimental research of pressure drop in packed beds of monosized spheres a novel correlation for pressure drop calculation

Directory of Open Access Journals (Sweden)

Stamenić Mirjana S.

2017-01-01

Full Text Available Flow through packed beds of spheres is a complex phenomenon and it has been extensively studied. Although, there is many different correlations there is still no reliable universal equation for prediction of pressure drop. The paper presents the results of experimental research of pressure drop in packed bed of monosized spheres of three different diameters, 8, 11, and 13 mm set within cylindrical vessel of diameter dk = 74 mm, and two different heights of packed bed, hs = 300 and 400 mm. It has been proposed modification of widely used Ergun’s equation in the form of fp = [150+1.3•(Rep/(1-ε]•(1-ε2/(ε3×Rep and new correlation fp = 1/[(27.4-25700•dh/Rep+0.545+6.85•dh] for pressure drop calculation in simple and convenient form for hand and computer calculations. For total number of 362 experimental runs the correlation ratio of the modified Ergun’s relation was CR = 99.3%, and standard deviation SD = 12.2%, while novel relation has CR = 93.7% and SD = 5.4%. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. 33049

Motion of Drops on Surfaces with Wettability Gradients

Science.gov (United States)

Subramanian, R. Shankar; McLaughlin, John B.; Moumen, Nadjoua; Qian, Dongying

2002-11-01

A liquid drop present on a solid surface can move because of a gradient in wettability along the surface, as manifested by a gradient in the contact angle. The contact angle at a given point on the contact line between a solid and a liquid in a gaseous medium is the angle between the tangent planes to the liquid and the solid surfaces at that point and is measured within the liquid side, by convention. The motion of the drop occurs in the direction of increasing wettability. The cause of the motion is the net force exerted on the drop by the solid surface because of the variation of the contact angle around the periphery. This force causes acceleration of an initially stationary drop, and leads to its motion in the direction of decreasing contact angle. The nature of the motion is determined by the balance between the motivating force and the resisting hydrodynamic force from the solid surface and the surrounding gaseous medium. A wettability gradient can be chemically induced as shown by Chaudhury and Whitesides who provided unambiguous experimental evidence that drops can move in such gradients. The phenomenon can be important in heat transfer applications in low gravity, such as when condensation occurs on a surface. Daniel et al have demonstrated that the velocity of a drop on a surface due to a wettability gradient in the presence of condensation can be more than two orders of magnitude larger than that observed in the absence of condensation. In the present research program, we have begun to study the motion of a drop in a wettability gradient systematically using a model system. Our initial efforts will be restricted to a system in which no condensation occurs. The experiments are performed as follows. First, a rectangular strip of approximate dimensions 10 x 20 mm is cut out of a silicon wafer. The strip is cleaned thoroughly and its surface is exposed to the vapor from an alkylchlorosilane for a period lasting between one and two minutes inside a

Surfactant effect on drop coalescence and film drainage hydrodynamics

Science.gov (United States)

Weheliye, Weheliye; Chinaud, Maxime; Voulgaropoulos, Victor; Angeli, Panagiota

2015-11-01

Coalescence of a drop on an aqueous-organic interface is studied in two test geometries A rectangular acrylic vessel and a Hele-Shaw cell (two parallel plates placed 2mm apart) are investigated for the experiments. Time resolved Particle Image Velocimetry (PIV) measurements provide information on the hydrodynamics during the bouncing stage of the droplet and on the vortices generated at the bulk fluid after the droplet has coalesced. The velocity field inside the droplet during its coalescence is presented. By localizing the rupture point of the coalescence in the quasi two dimensional cell, the film drainage dynamics are discussed by acquiring its flow velocity by PIV measurements with a straddling camera. The effect of surface tension forces in the coalescence of the droplet is investigated by introducing surface active agents at various concentrations extending on both sides of the critical micelle concentration.

Organic pollution of rivers: Combined threats of urbanization, livestock farming and global climate change.

Science.gov (United States)

Wen, Yingrong; Schoups, Gerrit; van de Giesen, Nick

2017-02-23

Organic pollution of rivers by wastewater discharge from human activities negatively impacts people and ecosystems. Without treatment, pollution control relies on a combination of natural degradation and dilution by natural runoff to reduce downstream effects. We quantify here for the first time the global sanitation crisis through its impact on organic river pollution from the threats of (1) increasing wastewater discharge due to urbanization and intensification of livestock farming, and (2) reductions in river dilution capacity due to climate change and water extractions. Using in-stream Biochemical Oxygen Demand (BOD) as an overall indicator of organic river pollution, we calculate historical (2000) and future (2050) BOD concentrations in global river networks. Despite significant self-cleaning capacities of rivers, the number of people affected by organic pollution (BOD >5 mg/l) is projected to increase from 1.1 billion in 2000 to 2.5 billion in 2050. With developing countries disproportionately affected, our results point to a growing need for affordable wastewater solutions.

Organic pollution of rivers: Combined threats of urbanization, livestock farming and global climate change

Science.gov (United States)

Wen, Yingrong; Schoups, Gerrit; van de Giesen, Nick

2017-02-01

Organic pollution of rivers by wastewater discharge from human activities negatively impacts people and ecosystems. Without treatment, pollution control relies on a combination of natural degradation and dilution by natural runoff to reduce downstream effects. We quantify here for the first time the global sanitation crisis through its impact on organic river pollution from the threats of (1) increasing wastewater discharge due to urbanization and intensification of livestock farming, and (2) reductions in river dilution capacity due to climate change and water extractions. Using in-stream Biochemical Oxygen Demand (BOD) as an overall indicator of organic river pollution, we calculate historical (2000) and future (2050) BOD concentrations in global river networks. Despite significant self-cleaning capacities of rivers, the number of people affected by organic pollution (BOD >5 mg/l) is projected to increase from 1.1 billion in 2000 to 2.5 billion in 2050. With developing countries disproportionately affected, our results point to a growing need for affordable wastewater solutions.

Drop-out from a drug treatment clinic and associated reasons.

Science.gov (United States)

Hoseinie, Leila; Gholami, Zhaleh; Shadloo, Behrang; Mokri, Azarakhsh; Amin-Esmaeili, Masoumeh; Rahimi-Movaghar, Afarin

2017-05-01

The aim of this study was to assess drop-out rates and associated reasons among patients at the Iranian National Center for Addiction Studies (INCAS) clinic. In a one-year period (April 2014 to March 2015), all patients with drug dependence who had been referred for treatment and attended for a first assessment were included in this study (N=242). Those who received treatment were followed until March 2016. Survival analysis showed that 70.2% had dropped out from treatment. Log rank test showed that treatment drop-out rates differed between the different approaches used (P < 0.001), with the lowest slope inbuprenorphine maintenance treatment and the highest in the detoxification programme. Drop-out rates within the first three months was 62% (SE= 0.05) and 82.4% (SE=0.03) for opioids and stimulants dependence, respectively. Analyses were performed using SPSS (Version 21.0) and STATA software, (version 13.0). From the patients' perspective, motivational inconsistencies were considered as the main reason for not starting or leaving treatment. The findings of this study could give service providers a better grasp of drop-out rates and the associated reasons.

Bacterial and fungal flora of seagull droppings in Jersey

Science.gov (United States)

Cragg, John; Clayton, Yvonne M.

1971-01-01

In Jersey 166 fresh and 122 dried seagull droppings were obtained and studied locally and in London for the presence of bacteria and fungi of potentially pathogenic nature. There were no salmonella or shigella bacteria isolated from the two groups but there was a high proportion of Candida albicans obtained from the fresh material (21·7%) and only 1·6% from the dry faeces. Cryptococcus neoformans and Histoplasma capsulatum were not found in either the dry or fresh droppings. The normal bacterial and fungal flora of the seagull was established and it is considered that the C. albicans in fresh gull droppings would not materially increase albicans infections in man. PMID:5104846

Polymer Surface Textured with Nanowire Bundles to Repel High-Speed Water Drops.

Science.gov (United States)

Li, Y P; Li, X Y; Zhu, X P; Lei, M K; Lakhtakia, A

2018-05-11

Water drops impacting windshields of high-speed trains and aircraft as well as blades in steam turbine power generators obliquely and at high speeds are difficult to repel. Impacting drops penetrate the void regions of nanotextured and microtextured superhydrophobic coatings, with this pinning resulting in the loss of drop mobility. In order to repel high-speed water drops, we nanotextured polymer surfaces with nanowire bundles separated from their neighbors by microscale void regions, with the nanowires in a bundle separated from their neighbors by nanoscale void regions. Water drops with speeds below a critical speed rebound completely. Water drops with speeds exceeding a critical speed rebound partially, but residual droplets that begin to be pinned undergo a spontaneous dewetting process and slide off. The natural oscillations of residual droplets drive this dewetting process in the interbundle void regions, resulting in a transition from the sticky Wenzel state to the slippery Cassie state without external stimuli.

On the Impact of Particulate Matter Distribution on Pressure Drop of Wall-Flow Particulate Filters

Directory of Open Access Journals (Sweden)

Vicente Bermúdez

2017-03-01

Full Text Available Wall-flow particulate filters are a required exhaust aftertreatment system to abate particulate matter emissions and meet current and incoming regulations applying worldwide to new generations of diesel and gasoline internal combustion engines. Despite the high filtration efficiency covering the whole range of emitted particle sizes, the porous substrate constitutes a flow restriction especially relevant as particulate matter, both soot and ash, is collected. The dependence of the resulting pressure drop, and hence the fuel consumption penalty, on the particulate matter distribution along the inlet channels is discussed in this paper taking as reference experimental data obtained in water injection tests before the particulate filter. This technique is demonstrated to reduce the particulate filter pressure drop without negative effects on filtration performance. In order to justify these experimental data, the characteristics of the particulate layer are diagnosed applying modeling techniques. Different soot mass distributions along the inlet channels are analyzed combined with porosity change to assess the new properties after water injection. Their influence on the subsequent soot loading process and regeneration is assessed. The results evidence the main mechanisms of the water injection at the filter inlet to reduce pressure drop and boost the interest for control strategies able to force the re-entrainment of most of the particulate matter towards the inlet channels’ end.

No-shows, drop-outs and completers in psychotherapeutic treatment

DEFF Research Database (Denmark)

Fenger, Morten Munthe; Mortensen, Erik Lykke; Poulsen, Stig Bernt

2011-01-01

A primary challenge in mental health services is a high rate of non-attendance (i.e. no-show and drop-out) for patients referred to treatment for psychiatric disorders.......A primary challenge in mental health services is a high rate of non-attendance (i.e. no-show and drop-out) for patients referred to treatment for psychiatric disorders....

Combined discrete nebulization and microextraction process for molybdenum determination by flame atomic absorption spectrometry (FAAS)

International Nuclear Information System (INIS)

Oviedo, Jenny A.; Jesus, Amanda M.D. de; Fialho, Lucimar L.; Pereira-Filho, Edenir R.

2014-01-01

Simple and sensitive procedures for the extraction/preconcentration of molybdenum based on vortex-assisted solidified floating organic drop microextraction (VA-SFODME) and cloud point combined with flame absorption atomic spectrometry (FAAS) and discrete nebulization were developed. The influence of the discrete nebulization on the sensitivity of the molybdenum preconcentration processes was studied. An injection volume of 200 μ resulted in a lower relative standard deviation with both preconcentration procedures. Enrichment factors of 31 and 67 and limits of detection of 25 and 5 μ L -1 were obtained for cloud point and VA-SFODME, respectively. The developed procedures were applied to the determination of Mo in mineral water and multivitamin samples. (author)

Effect of rb-bFGF eye drops and hydroxyl indican eye drops on tear film stability and dry eye symptoms after age-related cataract surgery

Directory of Open Access Journals (Sweden)

Yu Ling

2018-01-01

Full Text Available AIM: To investigate the effect of recombinant bovine basic fibroblast growth factor(rb-bFGFeye drops and hydroxyl indican eye drops on tear film stability and dry eye symptoms after age-related cataract surgery. METHODS: Totally 80 patients with 80 affected eyes undergoing age-related cataract surgery in our hospital from January 2015 to October 2016 were selected as study subjects, and they were randomly divided into control group and experimental group with 40 patients(40 affected eyesin each group. The two groups were treated with hydroxyl indican eye drops and rb-bFGF eye drops, respectively. The clinical curative effect, inflammation related factors \\〖interleukin 6(IL-6, tumor necrosis factor α(TNF-α\\〗, Schirmer test(SⅠt, break-up time(BUTof tear film, corneal sodium fluorescein staining(FLand scores of dry eye symptoms in the two groups were observed. RESULTS: The total treatment effective rate of experimental group after treatment was significantly higher than that of the control group(90.0% vs 72.5%; χ2=4.021, PP>0.05. After treatment, IL-6, TNF-α, SⅠt, FL score and scores of dry eye symptoms in two groups significantly decreased while BUT significantly increased(PPCONCLUSION: In the treatment of patients after age-related cataract after surgery, rb-bFGF eye drops has more advantages over hydroxyl indican eye drops in regulating the expression of inflammatory factors, improving the tear film stability and relieving dry eye symptoms.

Pressure drop in contraction flow

DEFF Research Database (Denmark)

Rasmussen, Henrik Koblitz

This note is a supplement to Dynamic of Polymeric Liquids (DPL) page 178. DPL gives an equation for the pressure drop in a tapered (and circular) contraction, valid only at low angles. Here the general definition of contraction flow (the Bagley correction) and a more general method to find...

Spreading Dynamics of an Ellipsoidal Drop Impacting on a Heated Substrate

Energy Technology Data Exchange (ETDEWEB)

Yun, Sungchan [Korea Nat’l. Univ. of Transportation, Chungju (Korea, Republic of)

2017-03-15

Unlike spherical drop impact, ellipsoidal drop impact can control the bouncing height on a heated surface by significantly altering impact behavior. To scrutinize the effect of the aspect ratio (AR) of the drop on the bounce suppression, in this study, non-axisymmetric spreading behaviors are observed from two side views and characterized based on the spreading width of the drop for horizontal principal axes. In addition, the maximum spreading width is investigated for various ARs. The results show that as the AR increases, the maximum spreading width of the minor axis increases, whereas that of the major axis shows no significant variation. In the regime of high AR and high impact velocity, liquid fragmentations by three parts are observed during bouncing. These fragmentations are discussed in this work. The hydrodynamic features of ellipsoidal drop impact will help understand bouncing control on non-wetting surfaces for several applications, such as self-cleaning and spray cooling.

Evidence of fast non-linear feedback in EBR-II rod-drop measurements

International Nuclear Information System (INIS)

Grimm, K.N.; Meneghetti, D.

1987-06-01

Feedback reactivities determine the time dependence of a reactor during and after a transient initiating event. Recent analysis of control-rod drops in the Experimental Breeder Reactor II (EBR-II) Reactor has indicated that some relatively fast feedback may exist which cannot be accounted for by the linear feedback mechanisms. The linear and deduced non-linear feedback reactivities from a control-rod drop in EBR-II run 93A using detailed temperature coefficients of reactivity in the EROS kinetics code have been reported. The transient analyses have now been examined in more detail for times close to the drop to ascertain if additional positive reactivity is being built-in early in the drop which could be gradually released later in the drop

New Method Developed to Measure Contact Angles of a Sessile Drop

Science.gov (United States)

Chao, David F.; Zhang, Nengli

2002-01-01

The spreading of an evaporating liquid on a solid surface occurs in many practical processes and is of importance in a number of practical situations such as painting, textile dyeing, coating, gluing, and thermal engineering. Typical processes involving heat transfer where the contact angle plays an important role are film cooling, boiling, and the heat transfer through heat pipes. The biological phenomenon of cell spreading also is analogous to a drop spreading (ref. 1). In the study of spreading, the dynamic contact angle describes the interfacial properties on solid substrates and, therefore, has been studied by physicists and fluid mechanics investigators. The dynamic contact angle of a spreading nonvolatile liquid drop provides a simple tool in the study of the free-boundary problem, but the study of the spreading of a volatile liquid drop is of more practical interest because the evaporation of common liquids is inevitable in practical processes. The most common method to measure the contact angle, the contact radius, and the height of a sessile drop on a solid surface is to view the drop from its edge through an optical microscope. However, this method gives only local information in the view direction. Zhang and Yang (ref. 2) developed a laser shadowgraphy method to investigate the evaporation of sessile drop on a glass plate. As described here, Zhang and Chao (refs. 3 and 4) improved the method and suggested a new optical arrangement to measure the dynamic contact angle and the instant evaporation rate of a sessile drop with much higher accuracy (less than 1 percent). With this method, any fluid motion in the evaporating drop can be visualized through shadowgraphy without using a tracer, which often affects the field under investigation.

Dropping out of outpatient psychiatric treatment: a preliminary report of a 2-year follow-up of 1500 psychiatric outpatients in Kermanshah, Iran.

Science.gov (United States)

Khazaie, Habibolah; Rezaie, Leeba; de Jong, Desiree M

2013-01-01

Outpatient psychiatric treatment provides both psychotherapy and pharmacotherapy for a large portion of psychiatric patients. Dropping out, or early termination of treatment, may be considered a common barrier to outpatient's psychiatric treatment. There are limited studies on this issue in Iran. The current study aimed to examine rates, predictors and reasons of dropping out of an outpatient psychiatric treatment. In this 6-month cohort study, 1500 outpatients who visited 10 psychiatrist's offices in the Iranian city of Kermanshah were recruited and followed for 2 years (2009-2011) for recommended treatments including admission to hospital, pharmacotherapy, psychotherapy and a combination of both psychotherapy and pharmacotherapy. Characteristics of patients who dropped out of the current study were collected, and reasons for dropping out were collected via phone or in person interview. Dropouts were prevalent in prescribed treatments. Pretreatment (primary) dropout rates in psychotherapy treatment were 4 times greater than dropout rates in pharmacotherapy treatment (80% and 20%, respectively). There were significance differences between dropouts and non-dropouts of pharmacotherapy with respect to patient characteristics; younger age, male gender, low level of education, unemployment, lack of insurance, new cases and divorce were more prevalent among dropouts (Preasons for dropping out included overslept and too ill to attend treatment and fear of becoming addicted to prescribed psychotropic medication (30% and 18%, respectively). Lack of confidence in therapist ability and lack of confidence in the efficacy of the treatment were more prevalent in patients who dropped out of psychotherapy (Preasons for dropping out and strategies to reduce rates of dropouts is recommended. Copyright © 2013 Elsevier Inc. All rights reserved.

Flexible organic tandem solar modules with 6% efficiency: combining roll-to-roll compatible processing with high geometric fill factors

DEFF Research Database (Denmark)

Spyropoulos, G. D.; Kubis, P.; Li, Na

2014-01-01

Organic solar cell technology bears the potential for high photovoltaic performance combined with truly low-cost, high-volume processing. Here we demonstrate organic tandem solar modules on flexible substrates fabricated by fully roll-to-roll compatible processing at temperatures...

Preconcentration of valsartan by dispersive liquid-liquid microextraction based on solidification of floating organic drop and its determination in urine sample: Central composite design.

Science.gov (United States)

Pebdani, Arezou Amiri; Shabani, Ali Mohammad Haji; Dadfarnia, Shayesteh; Talebianpoor, Mohammad Sharif; Khodadoust, Saeid

2016-05-01

In this work, a fast, easy, and efficient dispersive liquid-liquid microextraction method based on solidification of floating organic drop followed by high-performance liquid chromatography with UV detection was developed for the separation/preconcentration and determination of the drug valsartan. Experimental design was applied for the optimization of the effective variables (such as volume of extracting and dispersing solvents, ionic strength, and pH) on the extraction efficiency of valsartan from urine samples. The optimized values were 250.0 μL ethanol, 65.0 μL 1-dodecanol, 4.0% w/v NaCl, pH 3.8, 1.0 min extraction time, and 4.0 min centrifugation at 4000 rpm min(-1) . The linear response (r(2) = 0.997) was obtained in the range of 0.013-10.0 μg mL(-1) with a limit of detection of 4.0 ng mL(-1) and relative standard deviations of less than 5.0 % (n = 6). © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Effects of Evaporation/Condensation on Spreading and Contact Angle of a Volatile Liquid Drop

Science.gov (United States)

Zhang, Nengli; Chao, David F.; Singh, Bhim S. (Technical Monitor)

2000-01-01

Effects of evaporation/condensation on spreading and contact angle were experimentally studied. A sessile drop of R-113 was tested at different vapor environments to determine the effects of evaporation/condensation on the evolution of contact diameter and contact angle of the drop. Condensation on the drop surface occurs at both the saturated and a nonsaturated vapor environments and promotes the spreading. When the drop is placed in the saturated vapor environment it tends to completely wetting and spreads rapidly. In a nonsaturated vapor environment, the evolution of the sessile drop is divided three stages: condensation-spreading stage, evaporation-retracting stage and rapid contracting stage. In the first stage the drop behaves as in the saturated environment. In the evaporation -retracting stage, the competition between spreading and evaporation of the drop determines the evolution characteristics of the contact diameter and the contact angle. A lower evaporation rate struggles against the spreading power to turn the drop from spreading to retracting with a continuous increase of the contact angle. The drop placed in open air has a much higher evaporation rate. The strong evaporation suppresses the spreading and accelerates the retraction of the drop with a linear decrease of the contact diameter. The contraction of the evaporating drops is gradually accelerated when the contact diameter decreases to 3 min and less till drying up, though the evaporation rate is gradually slowing down.

Effectiveness of eye drops protective against ultraviolet radiation.

Science.gov (United States)

Daxer, A; Blumthaler, M; Schreder, J; Ettl, A

1998-01-01

To test the effectiveness of commercially available ultraviolet (UV)-protective eye drops (8-hydroxy-1-methylchinolinium methylsulphate) which are recommended for protection against both solar and artificial UV radiation. The spectral transmission in the wavelength range from 250 to 500 nm was investigated in 1-nm steps using a high-resolution double monochromator with holographic gratings of 2,400 lines/mm and a 1,000-watt halogen lamp as light source. The transmission spectrum was measured for different values of the layer thickness. The transmission of a liquid layer of about 10 microns, which corresponds to the thickness of the human tear film, shows a cut-off at 290 nm with a transmission of about 25-50% at shorter wavelengths. For wavelengths longer than 290 nm the transmission is higher than 90%. The threshold time ratio for keratitis formation with and without eye drops is above 0.93 considering solar radiation on the earth's surface and above 0.65 considering radiation from arc-welding, respectively. The transmission spectrum of the eye drops under realistic conditions does not show a protective effect against solar UV radiation. However, there exists reduction of UVC radiation in the spectral range typical of artificial UV sources such as arc-welding. We cannot recommend the application of these eye drops as an UV-protective aid against eye damage by solar UV radiation.

Predictors of postoperative hemoglobin drop after laparoscopic myomectomy.

Science.gov (United States)

Watrowski, Rafał; Jäger, Christoph; Forster, Johannes

2017-01-01

Laparoscopic myomectomy (LM) can be associated with significant bleeding. To identify factors influencing the postoperative hemoglobin (Hb) drop after LM. This is a retrospective, single-center study. We evaluated data of 150 consecutive patients undergoing LM due to intramural myomas between 2010 and 2015. The median age of the patients was 37 (23-53) years. The mean diameter of the largest myoma was 5.7 ±2.3 (1.5-12) cm. The mean surgical time was 83 ±38 (35-299) min. The median number of sutures was 3 (1-11). The mean postoperative Hb drop was 1.6 ±1.2 (0-6) g/dl, and the mean estimated blood loss was 261 ±159 (50-1700) ml. In the univariate analysis, the postoperative Hb drop correlated with the duration of surgery (p < 0.001), diameter of the largest myoma (p < 0.001), cumulative myoma weight (p < 0.001), and number of sutures (p < 0.001), but not with patients' age or number of intramural myomas. In the multivariable analysis, the surgical time ( β = 0.395, p < 0.001), diameter of the largest myoma ( β = 0.292, p = 0.03) and preoperative Hb concentration ( β = 0.299, p < 0.001) predicted the postoperative Hb change. Surgical time and dominant myoma diameter are independent predictors of the postoperative Hb drop after LM.

Shifting problems and shifting policies to reduce student drop-out

DEFF Research Database (Denmark)

Jørgensen, Christian Helms

2016-01-01

, as well as the policies that have been implemented in pursuit of improving student retention. The review identifies two pervasive ways in which the drop-out problem has been framed in both policy and research. The first locates the drop-out problem with individual students, while the second locates...... finds that the rate of student drop-out has been a cause for ongoing concern among policy makers for more than a century, and that the framing of the problem has shifted considerably over time. The problem has variously been placed with the individual apprentice, the basic structure of vocational......Education policy generally places a premium on raising the level of education attained by the young generation ultimately heading towards the labour market. While the rate of enrolment in post-compulsory education has risen in most countries, so too has the rate of drop-out, in particular from...

Drop evaporation and triple line dynamics

Science.gov (United States)

Sobac, Benjamin; Brutin, David; Gavillet, Jerome; Université de Provence Team; Cea Liten Team

2011-03-01

Sessile drop evaporation is a phenomenon commonly came across in nature or in industry with cooling, paintings or DNA mapping. However, the evaporation of a drop deposited on a substrate is not completely understood due to the complexity of the problem. Here we investigate, with several nano-coating of the substrate (PTFE, SiOx, SiOc and CF), the influence of the dynamic of the triple line on the evaporation process. The experiment consists in analyzing simultaneously the motion of the triple line, the kinetics of evaporation, the internal thermal motion and the heat and mass transfer. Measurements of temperature, heat-flux and visualizations with visible and infrared cameras are performed. The dynamics of the evaporative heat flux appears clearly different depending of the motion of the triple line

Coupling slots without shunt impedance drop

International Nuclear Information System (INIS)

Balleyguier, P.

1996-01-01

It is well known that coupling slots between adjacent cells in a π-mode structure reduce shunt impedance per unit length with respect to single cell cavities. To design optimized coupling slots, one has to answer the following question: for a given coupling factor, what shape, dimension, position and number of slots lead to the lowest shunt impedance drop? A numerical study using the 3D code MAFIA has been carried out. The aim was to design the 352 MHz cavities for the high intensity proton accelerator of the TRISPAL project. The result is an unexpected set of four 'petal' slots. Such slots should lead to a quasi-negligible drop in shunt impedance: about -1% on average, for particle velocity from 0.4 c to 0.8 c. (author)

Semisupervised Community Detection by Voltage Drops

Directory of Open Access Journals (Sweden)

Min Ji

2016-01-01

Full Text Available Many applications show that semisupervised community detection is one of the important topics and has attracted considerable attention in the study of complex network. In this paper, based on notion of voltage drops and discrete potential theory, a simple and fast semisupervised community detection algorithm is proposed. The label propagation through discrete potential transmission is accomplished by using voltage drops. The complexity of the proposal is OV+E for the sparse network with V vertices and E edges. The obtained voltage value of a vertex can be reflected clearly in the relationship between the vertex and community. The experimental results on four real networks and three benchmarks indicate that the proposed algorithm is effective and flexible. Furthermore, this algorithm is easily applied to graph-based machine learning methods.

Anomalous interfacial tension temperature dependence of condensed phase drops in magnetic fluids

Science.gov (United States)

Ivanov, Aleksey S.

2018-05-01

Interfacial tension temperature dependence σ(T) of the condensed phase (drop-like aggregates) in magnetic fluids undergoing field induced phase transition of the "gas-liquid" type was studied experimentally. Numerical analysis of the experimental data has revealed the anomalous (if compared to ordinary one-component fluids) behavior of the σ(T) function for all tested magnetic colloid samples: the condensed phase drops at high T ≈ 75 C exhibit higher σ(T) than the drops condensed at low T ≈ 20 C. The σ(T) behavior is explained by the polydispersity of magnetic colloids: at high T, only the largest colloidal particles are able to take part in the field induced condensation; thus, the increase of T causes the growth of the average particle diameters inside the drop-like aggregates, what in its turn results in the growth of σ(T). The result is confirmed by qualitative theoretical estimations and qualitative experimental observation of the condensed phase "evaporation" process after the applied magnetic field is removed: the drops that are formed due to capillary instability of the drop-like aggregates retract by one order of magnitude faster at high T, and the evaporation of the drops slows down at high T.

Evaluation of X-band polarimetric radar estimation of rainfall and rain drop size distribution parameters in West Africa

Science.gov (United States)

Koffi, A. K.; Gosset, M.; Zahiri, E.-P.; Ochou, A. D.; Kacou, M.; Cazenave, F.; Assamoi, P.

2014-06-01

As part of the African Monsoon Multidisciplinary Analysis (AMMA) field campaign an X-band dual-polarization Doppler radar was deployed in Benin, West-Africa, in 2006 and 2007, together with a reinforced rain gauge network and several optical disdrometers. Based on this data set, a comparative study of several rainfall estimators that use X-band polarimetric radar data is presented. In tropical convective systems as encountered in Benin, microwave attenuation by rain is significant and quantitative precipitation estimation (QPE) at X-band is a challenge. Here, several algorithms based on the combined use of reflectivity, differential reflectivity and differential phase shift are evaluated against rain gauges and disdrometers. Four rainfall estimators were tested on twelve rainy events: the use of attenuation corrected reflectivity only (estimator R(ZH)), the use of the specific phase shift only R(KDP), the combination of specific phase shift and differential reflectivity R(KDP,ZDR) and an estimator that uses three radar parameters R(ZH,ZDR,KDP). The coefficients of the power law relationships between rain rate and radar variables were adjusted either based on disdrometer data and simulation, or on radar-gauges observations. The three polarimetric based algorithms with coefficients predetermined on observations outperform the R(ZH) estimator for rain rates above 10 mm/h which explain most of the rainfall in the studied region. For the highest rain rates (above 30 mm/h) R(KDP) shows even better scores, and given its performances and its simplicity of implementation, is recommended. The radar based retrieval of two parameters of the rain drop size distribution, the normalized intercept parameter NW and the volumetric median diameter Dm was evaluated on four rainy days thanks to disdrometers. The frequency distributions of the two parameters retrieved by the radar are very close to those observed with the disdrometer. NW retrieval based on a combination of ZH

A method for the combined measurement of volatile and condensable organic AMC in semiconductor applications

Science.gov (United States)

Miller, Charles M.; Zaloga, Emily C.; Lobert, Jürgen M.

2014-04-01

traps, but were fully retained on the multi-layered adsorbent trap. This demonstrates that the standard trap used in the industry will result in significantly underreporting actual AMC concentrations for volatile organic compounds, including some siloxanes (TMS, HMDSO, D3). Performance of the proposed trap was excellent at both zero and 50% relative humidity, an important metric, as the trap is used for AMC detection in dry supply gases and humidified environments. Retention of all organic compounds was quantitative for more than 30 liters of air, sufficient for ppq-level detection limits. Desorption efficiency was 94% for C26 compounds. Pressure drop through the new trap was comparable to that of polymer-based traps and much lower than other, commercially available carbonaceous traps. Precision of repeated analyses was 5%, a very good result. Resolution of IPA and acetone was complete and that of a mix of halogenated refrigerants was much improved over existing methods. We propose to adopt this methodology as a new industry standard to overcome widespread inaccuracy in the reporting of volatile organic AMC and false positive condensable AMC.

Neuromuscular function during drop jumps in young and elderly males.

Science.gov (United States)

Piirainen, Jarmo M; Linnamo, Vesa; Sippola, Niina; Avela, Janne

2012-12-01

The Hoffman reflex (H-reflex), indicating alpha-motoneuron pool activity, has been shown to be task - and in resting conditions - age dependent. How aging affects H-reflex activity during explosive movements is not clear at present. The purpose of this study was to examine the effects of aging on H-reflexes during drop jumps, and its possible role in drop jump performance. Ten young (26.8 ± 2.7 years) and twenty elderly (64.2 ± 2.7 years) subjects participated in the study. Maximal drop jump performance and soleus H-reflex response (H/M jump) 20 ms after ground contact were measured in a sledge ergometer. Maximal H-reflex, maximal M-wave, Hmax/Mmax-ratio and H-reflex excitability curves were measured during standing rest. Although in young the H-reflex response (Hmax/Mmax) was 6.5% higher during relaxed standing and 19.7% higher during drop jumps (H jump/M jump) than in the elderly group, these differences were not statistically significant. In drop jumps, the elderly subjects had lower jumping height (30.4%, p push-off force (18.0%, p push-off time (31.0% p push-off force (r = 0.833, p push-off time (r = -0.857, p < 0.01) in young but not in the elderly. Correlations between H-reflex response and jumping parameters in young may indicate different jumping and activation strategies in drop jumps. However, it does not fully explain age related differences in jumping performance, since age related differences in H-reflex activity were non-significant. Copyright © 2012 Elsevier Ltd. All rights reserved.

Cranberry juice and combinations of its organic acids are effective against experimental urinary tract infection

DEFF Research Database (Denmark)

Jensen, Heidi Dorthe; Struve, Carsten; Christensen, Søren Brøgger

2017-01-01

The antibacterial effect of cranberry juice and the organic acids therein on infection by uro28 pathogenic Escherichia coli was studied in an experimental mouse model of urinary tract infection (UTI). Reduced bacterial counts were found in the bladder (P ... administered singly, did not have any effect in the UTI model. Apparently, the antibacterial effect of the organic acids from cranberry juice on UTI can be obtained by administering a combination of malic acid and either citric or quinic acid. This study show for the first time that cranberry juice reduce E...

Impact of water drops on small targets

Science.gov (United States)

Rozhkov, A.; Prunet-Foch, B.; Vignes-Adler, M.

2002-10-01

The collision of water drops against small targets was studied experimentally by means of a high-speed photography technique. The drop impact velocity was about 3.5 m/s. Drop diameters were in the range of 2.8-4.0 mm. The target was a stainless steel disk of 3.9 mm diameter. The drop spread beyond the target like a central cap surrounded by a thin, slightly conical lamella bounded by a thicker rim. By mounting a small obstacle near the target, surface-tension driven Mach waves in the flowing lamella were generated, which are formally equivalent to the familiar compressibility driven Mach waves in gas dynamics. From the measurement of the Mach angle, the values of some flow parameters could be obtained as functions of time, which provided insight into the flow structure. The liquid flowed from the central cap to the liquid rim through the thin lamella at constant momentum flux. At a certain stage of the process, most of the liquid accumulated in the rim and the internal part of the lamella became metastable. In this situation, a rupture wave propagating through the metastable internal part of the lamella caused the rim to retract while forming outwardly directed secondary jets. The jets disintegrated into secondary droplets due to the Savart-Plateau-Rayleigh instability. Prior to the end of the retraction, an internal circular wave of rupture was formed. It originated at the target and then it propagated to meet the retracting rim. Their meeting resulted in a crown of tiny droplets. A theoretical analysis of the ejection process is proposed.

Leidenfrost drops cooling surfaces: theory and interferometric measurement

OpenAIRE

Van Limbeek, Michiel A. J.; Klein Schaarsberg, Martin H.; Sobac, Benjamin; Rednikov, Alexey; Sun, Chao; Colinet, Pierre; Lohse, Detlef

2017-01-01

When a liquid drop is placed on a highly superheated surface, it can be levitated by its own vapour. This remarkable phenomenon is referred to as the Leidenfrost effect. The thermally insulating vapour film results in a severe reduction of the heat transfer rate compared to experiments at lower surface temperatures, where the drop is in direct contact with the solid surface. A commonly made assumption is that this solid surface is isothermal, which is at least questionable for materials of lo...

Current organ allocation disadvantages kidney alone recipients over combined organ recipients.

Science.gov (United States)

Martin, Michael S; Hagan, Michael E; Granger, Darla K

2016-03-01

The United Network for Organ Sharing began including the Kidney Donor Profile Index (KDPI) March 26, 2012 and began a new allocation scheme December 1, 2014. Kidney donors from our organ procurement organization from March 2012 to December 2014 were reviewed. The KDPIs of all 919 kidney only transplants were compared with all 102 kidney/extrarenal transplants. The average KDPI for kidney alone allografts was 47 (range 1 to 100) (standard deviation = 25.83) vs 27 for kidney/extrarenal kidneys (range 1 to 82) (standard deviation = 20.16) (P disadvantages those waiting for a kidney alone. Attention to the outcomes of kidneys transplanted with extrarenal organs is needed. Copyright © 2016 Elsevier Inc. All rights reserved.

An analysis of pipe degradation shape using potential drop method

International Nuclear Information System (INIS)

Jegal, S.; Lee, S. H.

1999-01-01

The Potential Drop (PD) method, one of NDE (Non-Destructive Evaluation) method is used to analyze the thickness distribution of pipes degraded by FAC (Flow Accelerated Corrosion). A DCPD (Direct Current Potential Drop) system which can measure PD for direct current was made, and the specimens with line defects and cylinder type defects have been used for experiments to prove the theory of Potential Drop method and to find out the effects of each factors. The experiment to find out defect distributions has been performed and it is found that PD method can analyze almost correct position of defects

Prediction of drop time and impact velocity of rod cluster control assembly

International Nuclear Information System (INIS)

Choi, Kee Sung; Yim, Jeong Sik; Kim, Il Kon; Kim, Kyu Tae

1992-01-01

This paper deals with the drop modelling of rod cluster control assembly(RCCA) and the prediction of drop time and impact velocity of RCCA at scram event. On the scram, RCCA, dropping into the guide thimble of fuel assembly by the gravity, is subject to retarding forces such as hydraulic resistance, mechanical friction and buoyancy. Considering these retarding forces RCCA dynamic equation is derived and computerized it to solve the equation in conjunction with fluid equation which is coupled with the motion of the RCCA. Because the equation is nonlinear, coupled with fluid equations, the program is written in FORTRAN using numerical method in order to calculate the drop distance and velocity with time increment. To verify the program, its results are compared with those of other fuel vendors. Predicting identical tendency as other fuel vendors and the deviation is insignificant in values this program is expected to be used for predicting the drop time and impact velocity of RCCA when the parameters affecting the control rod drop time and impact velocity changes are occurred

Laser Control of Self-Organization Process in Microscopic Region and Fabrication of Fine Microporous Structure

OpenAIRE

Matsumura, Yukimasa; Inami, Wataru; Kawata, Yoshimasa

2012-01-01

We present a controlling technique of microporous structure by laser irradiation during self-organization process. Self-organization process is fabrication method of microstructure. Polymer solution was dropped on the substrate at high humid condition. Water in air appears dropping air temperature below the dew point. The honeycomb structure with regularly aligned pores on the film was fabricated by attaching water droplets onto the solution surface. We demonstrate that it was possible to pre...

Using acoustics to study and stimulate the coalescence of oil drops surrounded by water

Energy Technology Data Exchange (ETDEWEB)

Gardner, E.A.; Apfel, R.E. (Yale Univ., New Haven, CT (United States). Dept. of Mechanical Engineering)

1993-08-01

The coalescence of oil drops in water is studied using acoustic levitation and stimulated with acoustic cavitation. Unlike most earlier studies, which investigate the coalescence of a single drop with an initially planar interface, the use of acoustic radiation forces allows two drops to be brought into contact and allowed to coalesce. The acoustic technique has the advantage over other drop-drop coalescence systems in that the drops remain in contact until they coalesce without the use of solid supports to control them. Additionally, acoustic cavitation is observed to deposit sufficient energy in the oil-water interface to trigger the coalescence of a pair of 2-mm-diameter drops. This stimulation mechanism could have application to emulsion breaking. Some of the factors that affect spontaneous and stimulated coalescence are investigated.

A Mathematical Scheme for Calculating Flows and Pressure Drops in Lit and Unlit Cigarettes

Directory of Open Access Journals (Sweden)

Dwyer RW

2014-12-01

Full Text Available A computational methodology is presented for evaluating the flows and pressure drops in both lit and unlit cigarettes. The flows and pressure drops across rows of tipping-paper perforations are considered explicitly, as are the locations and relative sizes of the ventilation holes. The flows and pressure drops across air-permeable cigarette papers are included. The influence of plugwrappermeabilities on filter ventilation is developed. Lit cigarettes are mimicked by adding a “coal” pressure drop to the upstream end of the cigarette. The computational scheme is used to predict the effects of tobacco-rod length, puff volume, and vent blocking on cigarette ventilation and pressure drop. A derivation of the pressure-drop and flow equations for a cigarette with an upstream pressure drop is included in an appendix.

Particle scavenging in a cylindrical ultrasonic standing wave field using levitated drops

Science.gov (United States)

Merrell, Tyler; Saylor, J. R.

2015-11-01

A cylindrical ultrasonic standing wave field was generated in a tube containing a flow of particles and fog. Both the particles and fog drops were concentrated in the nodes of the standing wave field where they combined and then grew large enough to fall out of the system. In this way particles were scavenged from the system, cleaning the air. While this approach has been attempted using a standing wave field established between disc-shaped transducers, a cylindrical resonator has not been used for this purpose heretofore. The resonator was constructed by bolting three Langevin transducers to an aluminum tube. The benefit of the cylindrical geometry is that the acoustic energy is focused. Furthermore, the residence time of the particle in the field can be increased by increasing the length of the resonator. An additional benefit of this approach is that tubes located downstream of the resonator were acoustically excited, acting as passive resonators that enhanced the scavenging process. The performance of this system on scavenging particles is presented as a function of particle diameter and volumetric flow rate. It is noted that, when operated without particles, the setup can be used to remove drops and shows promise for liquid aerosol retention from systems where these losses can be financially disadvantageous and/or hazardous.

Effects of sodium hyaluronate on ocular inflammatory response and dry eye after phacoemulsification combined with IOL implantation for cataract

Directory of Open Access Journals (Sweden)

Xing-Guang He

2018-04-01

Full Text Available AIM: To investigate the effect of sodium hyaluronate eye drops on ocular inflammatory response and dry eye after phacoemulsification combined with intraocular lenses(IOLimplantation for age-related cataract. METHODS: The clinical data of age-related cataract patients treated with phacoemulsification combined with IOL implantation in 200 cases(200 eyesof our hospital from June 2016 to July 2017 were retrospectively analyzed. According to the different postoperative application of eye drops they were divided into observation group and control group(100 cases each. The observation group was given sodium hyaluronate eye drops and the control group was given tobramycin dexamethasone eye drops. The results of BUT, FL, proteins concentration in aqueous and ocular surface disease index(OSDIscore were compared before and at the first day, the seventh day and the fourteenth day after the operation. And the incidence of conjunctival hyperemia and ciliary hyperemia was compared between 1d after surgery and 14d after surgery. RESULTS: There was no significant difference in OSDI scores between the two groups before and at 1d after surgery(P>0.05. The OSDI score of the two groups was higher than that before the operation on the first, the seventh and the fourteenth day after surgery(PPPP>0.05. The levels of BUT in the two groups were lower than those before operation on the first, the seventh and the fourteenth day after surgery(PPPP>0.05. The levels of FL in the two groups were different from those before operation(PPPPP>0.05; the incidence of conjunctival hyperemia and ciliary hyperemia in the two groups on the fourteenth day after surgery was lower than that on the first day after surgery(PPPPPCONCLUSION: The effect of sodium hyaluronate eye drops on improving dry eye after age-related cataract phacoemulsification combined with IOL implantation is greater than that of tobramycin dexamethasone eye drops, but it is less effective for eye inflammation than

Fluid flow in drying drops

NARCIS (Netherlands)

Gelderblom, Hanneke

2013-01-01

When a suspension drop evaporates, it leaves behind a drying stain. Examples of these drying stains encountered in daily life are coffee or tea stains on a table top, mineral rings on glassware that comes out of the dishwasher, or the salt deposits on the streets in winter. Drying stains are also

Comparison of novel lipid-based eye drops with aqueous eye drops for dry eye: a multicenter, randomized controlled trial

Directory of Open Access Journals (Sweden)

Simmons PA

2015-04-01

Full Text Available Peter A Simmons, Cindy Carlisle-Wilcox, Joseph G Vehige Ophthalmology Research and Development, Allergan, Inc., Irvine, CA, USA Background: Dry eye may be caused or exacerbated by deficient lipid secretion. Recently, lipid-containing artificial tears have been developed to alleviate this deficiency. Our study compared the efficacy, safety, and acceptability of lipid-containing eye drops with that of aqueous eye drops.Methods: A non-inferiority, randomized, parallel-group, investigator-masked multicenter trial was conducted. Subjects with signs and symptoms of dry eye were randomized to use one of two lipid-containing artificial tears, or one of two aqueous artificial tears. Subjects instilled assigned drops in each eye at least twice daily for 30 days. The primary efficacy analysis tested non-inferiority of a preservative-free lipid tear formulation (LT UD to a preservative-free aqueous tear formulation (AqT UD for change in Ocular Surface Disease Index (OSDI score from baseline at day 30. Secondary measures included OSDI at day 7, tear break-up time (TBUT, corneal and conjunctival staining, Schirmer’s test, acceptability and usage questionnaires, and safety assessments.Results: A total of 315 subjects were randomized and included in the analyses. Subjects reported instilling a median of three doses of study eye drops per day in all groups. At days 7 and 30, all groups showed statistically significant improvements from baseline in OSDI (P<0.001 and TBUT (P≤0.005. LT UD was non-inferior to AqT UD for mean change from baseline in OSDI score at day 30. No consistent or clinically relevant differences for the other efficacy variables were observed. Acceptability was generally similar across the groups and there was a low incidence of adverse events.Conclusion: In this heterogeneous population of dry eye subjects, there were no clinically significant differences in safety, effectiveness, and acceptability between lipid-containing artificial tears

Effects of combined application of organic and inorganic fertilizers plus nitrification inhibitor DMPP on nitrogen runoff loss in vegetable soils.

Science.gov (United States)

Yu, Qiaogang; Ma, Junwei; Zou, Ping; Lin, Hui; Sun, Wanchun; Yin, Jianzhen; Fu, Jianrong

2015-01-01

The application of nitrogen fertilizers leads to various ecological problems such as large amounts of nitrogen runoff loss causing water body eutrophication. The proposal that nitrification inhibitors could be used as nitrogen runoff loss retardants has been suggested in many countries. In this study, simulated artificial rainfall was used to illustrate the effect of the nitrification inhibitor DMPP (3,4-dimethyl pyrazole phosphate) on nitrogen loss from vegetable fields under combined organic and inorganic nitrogen fertilizer application. The results showed that during the three-time simulated artificial rainfall period, the ammonium nitrogen content in the surface runoff water collected from the DMPP application treatment increased by 1.05, 1.13, and 1.10 times compared to regular organic and inorganic combined fertilization treatment, respectively. In the organic and inorganic combined fertilization with DMPP addition treatment, the nitrate nitrogen content decreased by 38.8, 43.0, and 30.1% in the three simulated artificial rainfall runoff water, respectively. Besides, the nitrite nitrogen content decreased by 95.4, 96.7, and 94.1% in the three-time simulated artificial rainfall runoff water, respectively. A robust decline in the nitrate and nitrite nitrogen surface runoff loss could be observed in the treatments after the DMPP addition. The nitrite nitrogen in DMPP addition treatment exhibited a significant low level, which is near to the no fertilizer application treatment. Compared to only organic and inorganic combined fertilizer treatment, the total inorganic nitrogen runoff loss declined by 22.0 to 45.3% in the organic and inorganic combined fertilizers with DMPP addition treatment. Therefore, DMPP could be used as an effective nitrification inhibitor to control the soil ammonium oxidation in agriculture and decline the nitrogen runoff loss, minimizing the nitrogen transformation risk to the water body and being beneficial for the ecological environment.

The drop of flowers and fruits in apple, with special reference to the June drop of Cox's orange pippin and its control with growth regulators

NARCIS (Netherlands)

Wertheim, S.J.

1971-01-01

To study possibilities for increases of yield of the apple cultivar Cox's Orange Pippin, relevant information was gathered about fruit set and fruit drop, in particular about June drop. The information concerned pollination intensity, amount of fruit set, seed content of the fruit, number

Determination of trihalomethanes in waters by ionic liquid-based single drop microextraction/gas chromatographic/mass spectrometry.

Science.gov (United States)

Aguilera-Herrador, Eva; Lucena, Rafael; Cárdenas, Soledad; Valcárcel, Miguel

2008-10-31

A simple, rapid, solventless method for the determination of trihalomethanes (THMs) (chloroform, bromodichloromethane, dibromochloromethane and bromoform) in water samples is presented. The analytes are extracted from the headspace of the aqueous matrix into a 2 microL drop of the ionic liquid 1-octyl-3-methyl-imidazolium hexafluorophosphate working at 30 degrees C for 30 min. The separation and detection of the target compounds is accomplished by gas chromatography/mass spectrometry owing to the use of an interface that efficiently transfers the analytes extracted in the ionic liquid drop to the gas chromatograph while preventing the ionic liquid from entering the column. The detection limits obtained are below the values compelled by the legislation, ranging from 0.5 microg L(-1) for chloroform and bromodichloromethane to 0.9 microg L(-1) for dibromochloromethane. The use of ionic liquid in the extraction procedure avoids the use of organic solvents and leads to relative standard deviations that range from 3.1% to 4.8%.

Investigation of water and saline solution drops evaporation on a solid substrate

Directory of Open Access Journals (Sweden)

Orlova Evgenija G.

2014-01-01

Full Text Available Experimental investigation water and saline solution drops evaporation on a solid substrate made of anodized aluminum is presented in the paper. Parameters characterizing drop profile have been obtained (contact angle, contact diameter, height. The specific evaporation rate has been calculated from obtained values. It was found that water and saline solution drops with concentration up to 9.1% evaporate in the pinning mode. However, with increasing the salt concentration in the solution up to 16.7% spreading mode was observed. Two stages of drop evaporation depending on change of the evaporation rate have been separated.

Increased medial foot loading during drop jump in subjects with patellofemoral pain

DEFF Research Database (Denmark)

Rathleff, Michael S; Richter, Camilla; Brushøj, Christoffer

2014-01-01

PURPOSE: To compare medial-to-lateral plantar forces during drop jump and single leg squat in individuals with and without patellofemoral pain. METHODS: This cross-sectional study compared 23 young adults with patellofemoral pain to 20 age- and sex-matched controls without knee pain. The plantar...... pressure distribution was collected during drop jump and single leg squat using pressure-sensitive Pedar insoles, inserted into a standard flat shoe. The primary outcome was the medial-to-lateral force, quantified as the peak force under the medial forefoot as the percentage of force under the total...... forefoot during drop jump. Secondary outcomes included peak medial-to-lateral force during single leg squat and mean forces during drop jump and single leg squat. RESULTS: The primary outcome showed that individuals with patellofemoral pain had a 22 % higher medial-to-lateral peak force during drop jump...

Speciation of As(III) and As(V) in water samples by graphite furnace atomic absorption spectrometry after solid phase extraction combined with dispersive liquid-liquid microextraction based on the solidification of floating organic drop.

Science.gov (United States)

Shamsipur, Mojtaba; Fattahi, Nazir; Assadi, Yaghoub; Sadeghi, Marzieh; Sharafi, Kiomars

2014-12-01

A solid phase extraction (SPE) coupled with dispersive liquid-liquid microextraction based on the solidification of floating organic drop (DLLME-SFO) method, using diethyldithiphosphate (DDTP) as a proper chelating agent, has been developed as an ultra preconcentration technique for the determination of inorganic arsenic in water samples prior to graphite furnace atomic absorption spectrometry (GFAAS). Variables affecting the performance of both steps were thoroughly investigated. Under optimized conditions, 100mL of As(ΙΙΙ) solution was first concentrated using a solid phase sorbent. The extract was collected in 2.0 mL of acetone and 60.0 µL of 1-undecanol was added into the collecting solvent. The mixture was then injected rapidly into 5.0 mL of pure water for further DLLME-SFO. Total inorganic As(III, V) was extracted similarly after reduction of As(V) to As(III) with potassium iodide and sodium thiosulfate and As(V) concentration was calculated by difference. A mixture of Pd(NO3)2 and Mg(NO3)2 was used as a chemical modifier in GFAAS. The analytical characteristics of the method were determined. The calibration graph was linear in the rage of 10-100 ng L(-1) with detection limit of 2.5 ng L(-1). Repeatability (intra-day) and reproducibility (inter-day) of method based on seven replicate measurements of 80 ng L(-1) of As(ΙΙΙ) were 6.8% and 7.5%, respectively. The method was successfully applied to speciation of As(III), As(V) and determination of the total amount of As in water samples and in a certified reference material (NIST RSM 1643e). Copyright © 2014 Elsevier B.V. All rights reserved.

Liquid-metal pin-fin pressure drop by correlation in cross flow

International Nuclear Information System (INIS)

Wang, Zhibi; Kuzay, T.M.; Assoufid, L.

1994-01-01

The pin-fin configuration is widely used as a heat transfer enhancement method in high-heat-flux applications. Recently, the pin-fin design with liquid-metal coolant was also applied to synchrotron-radiation beamline devices. This paper investigates the pressure drop in a pin-post design beamline mirror with liquid gallium as the coolant. Because the pin-post configuration is a relatively new concept, information in literature about pin-post mirrors or crystals is rare, and information about the pressure drop in pin-post mirrors with liquid metal as the coolant is even more sparse. Due to this the authors considered the cross flow in cylinder-array geometry, which is very similar to that of the pin-post, to examine the pressure drop correlation with liquid metals over pin fins. The cross flow of fluid with various fluid characteristics or properties through a tube bank was studied so that the results can be scaled to the pin-fin geometry with liquid metal as the coolant. Study lead to two major variables to influence the pressure drop: fluid properties, viscosity and density, and the relative length of the posts. Correlation of the pressure drop between long and short posts and the prediction of the pressure drop of liquid metal in the pin-post mirror and comparison with an existing experiment are addressed

Estimation of pressure drop in gasket plate heat exchangers

Directory of Open Access Journals (Sweden)

Neagu Anisoara Arleziana

2016-06-01

Full Text Available In this paper, we present comparatively different methods of pressure drop calculation in the gasket plate heat exchangers (PHEs, using correlations recommended in literature on industrial data collected from a vegetable oil refinery. The goal of this study was to compare the results obtained with these correlations, in order to choose one or two for practical purpose of pumping power calculations. We concluded that pressure drop values calculated with Mulley relationship and Buonopane & Troupe correlation were close and also Bond’s equation gave results pretty close to these but the pressure drop is slightly underestimated. Kumar correlation gave results far from all the others and its application will lead to oversize. In conclusion, for further calculations we will chose either the Mulley relationship or the Buonopane & Troupe correlation.

Emulsion Design. Analysis of Drop Deformations in Mixed Flows

DEFF Research Database (Denmark)

Egholm, Runi Ditlev

2008-01-01

. Furthermore wall effects are also investigated by varying the size of the computational domain which consists of a box with variable mesh size. In the center of the domain, where the drop resides, the mesh consists of a fine region whereas closer to the walls the elements gradually increase in size. Tests...... by the drop in the rotor-stator device is emulated in the computational box used for carrying out drop shape simulations. Comparison of simulated and experimentally obtained deformations show that in general the agreement is acceptable on a qualitative level. However, the simulations predict deformations...... there is a relaxation in the flow field. Furthermore we observe that for small viscosity ratios (A ~ 0.1) tip streaming is predominant while for larger viscosity ratios either binary or capillary break-up is predominant....

Model for determining vapor equilibrium rates in the hanging drop method for protein crystal growth

Science.gov (United States)

Baird, James K.; Frieden, Richard W.; Meehan, E. J., Jr.; Twigg, Pamela J.; Howard, Sandra B.; Fowlis, William A.

1987-01-01

An engineering analysis of the rate of evaporation of solvent in the hanging drop method of protein crystal growth is presented. Results are applied to 18 drop and well arrangements commonly encountered in the laboratory. The chemical nature of the salt, drop size and shape, drop concentration, well size, well concentration, and temperature are taken into account. The rate of evaporation increases with temperature, drop size, and the salt concentration difference between the drop and the well. The evaporation in this model possesses no unique half-life. Once the salt in the drop achieves 80 percent of its final concentration, further evaporation suffers from the law of diminishing returns.

Four-point potential drop measurements for materials characterization

International Nuclear Information System (INIS)

Bowler, Nicola

2011-01-01

The technique of measuring the voltage difference (potential drop) between two of the four electrodes of a four-point probe, in order to determine conductivity or surface resistivity of a test piece, is well established in the direct-current (dc) or quasi-dc regime. The technique finds wide usage in the semiconductor industry for the purpose of measuring surface resistivity of semiconductors, and also in the measurement of conductivity of metals, particularly of ferromagnetic metals for which conductivity cannot be easily measured using eddy-current nondestructive evaluation (NDE). In these applications, the conductivity of the test piece is deduced from an analytic formula that depends on the geometry of the probe and test piece. Such a formula requires, as an input, the measured value of the potential drop. Several analytical expressions exist for a variety of test-piece geometries and probe arrangements. Recently, it has been shown that broadband measurements of the potential drop, known as 'alternating current potential drop' (ac PD) measurements, can be used not only to obtain the conductivity of a test piece, but also its linear permeability μ. The beauty of this measurement is that the two parameters are completely decoupled in the quasi-static regime. In fact, μ does not appear in the quasi-static expression for σ. Hence, σ may be obtained from low-frequency ac PD measurements and then μ may be deduced as the frequency increases beyond the quasi-static regime, once σ is known. In this review, both dc and ac solutions that are useful in determining the conductivity of metals and semiconductors, and the permeability of ferromagnetic conductors, are summarized. In particular, flat test pieces with arbitrary thickness are considered. At the next level of complexity, a solution for a half-space coated with a surface layer is given, along with a discussion of the use of the four-point potential drop method for determining thickness of a surface layer, such

CONSTOR registered V/TC drop tests. Pre-test analysis by finite element method

International Nuclear Information System (INIS)

Voelzer, W.; Koenig, S.; Klein, K.; Tso, C.F.; Owen, S.; Monk, C.

2004-01-01

The CONSTOR registered family of steel-concrete-steel sandwich cask designs have been developed to fulfil both the internationally valid IAEA criteria for transportation and the requirements for long-term intermediate storage in the US and various European countries. A comprehensive drop testing programme using a full-scale prototype test cask (CONSTOR registered V/TC) has been developed as part of the application for a transport license in both Germany and the US. The drop tests using the full-scale cask will be performed by BAM at test facilities in Horstwalde. The tests will include five different 9m drops onto flat unyielding targets and seven different 1m drops onto a punch. The first drop test, a 9m side drop, will be performed during PATRAM 2004. The other drop tests will take place during the following year. The development of the cask design and the formulation of the drop test programme has been supported by an extensive series of finite element analyses. The objectives of the finite element analyses were; to provide an intermediate step in demonstrating the performance of the CONSTOR registered in fulfilling the requirements of 10 CFR 71 and the IAEA transport regulations. To justify the selection of drop tests. To predict the performance of V/TC during the drop tests. To estimate the strain and acceleration time histories at measuring points on the test cask and to aid in the setting up of the test instrumentation. To develop an analysis model that can be used in future safety analyses for transport and storage license applications and which can confidently be used to demonstrate the performance of the package. This paper presents an overview of the analyses performed, including a summary of all the different drop orientations that were considered. The major assumptions employed during the analyses are also discussed, as are the specifics of the modelling techniques that were employed. At the end of the paper, the key results obtained from the analyses

The hydrodynamics of segmented two-phase flow in a circular tube with rapidly dissolving drops.

Science.gov (United States)

Leary, Thomas F; Ramachandran, Arun

2017-05-03

This article discusses boundary integral simulations of dissolving drops flowing through a cylindrical tube for large aspect ratio drops. The dynamics of drop dissolution is determined by three dimensionless parameters: λ, the viscosity of the drop fluid relative to the suspending fluid; Ca, the capillary number defining the ratio of the hydrodynamic force to the interfacial tension force; and k, a dissolution constant based on the velocity of dissolution. For a single dissolving drop, the velocity in the upstream region is greater than the downstream region, and for sufficiently large k, the downstream velocity can be completely reversed, particularly at low Ca. The upstream end of the drop travels faster and experiences greater deformation than the downstream end. The film thickness, δ, between the drop and the tube wall is governed by a delicate balance between dissolution and changes in the outer fluid velocity resulting from a fixed pressure drop across the tube and mass continuity. Therefore, δ, and consequently, the drop average velocity, can increase, decrease or be relatively invariant in time. For two drops flowing in succession, while low Ca drops maintain a nearly constant separation distance during dissolution, at sufficiently large Ca, for all values of k, dissolution increases the separation distance between drops. Under these conditions, the liquid segments between two adjacent drops can no longer be considered as constant volume stirred tanks. These results will guide the choices of geometry and operating parameters that will facilitate the characterization of fast gas-liquid reactions via two-phase segmented flows.

Measurements of subchannel velocity and pressure drop for HANARO fuel assembly

International Nuclear Information System (INIS)

Yang, Sun Kyu; Jeong, Heung Jun; Cho, Suk; Min, Kyung Ho; Jeong, Moon Ki

1996-07-01

This report presents the hydraulic test results for HANARO fuel assemblies, which are performed to obtain the axial velocity and pressure drop data to be used to validate the code calculation model. For both 18 and 36-element fuel assemblies axial velocities of the entrance and exit regions are obtained, and developing axial velocity profiles along the flow direction for the fuel region of 18-element fuel assembly are also obtained. Varying the pressure tap locations, pressure drop data for each component of fuel assembly are obtained for various flow conditions. From the pressure drop test results it is noted that the pressure drops across the fuel assembly are 214 kPa and 205 kPa for the 18-element and 36-element fuel assembly respectively. 39 tabs., 12 figs., 5 refs. (Author)

Physical test report to drop test of a 9975 radioactive material shipping packaging

International Nuclear Information System (INIS)

Blanton, P.S.

1997-01-01

This report presents the drop test results for the 9975 radioactive material shipping package being dropped 30 feet onto a unyielding surface followed by a 40-inch puncture pin drop. The purpose of these drops was to show that the package lid would remain attached to the drum. The 30-foot drop was designed to weaken the lid closure lug while still maintaining maximum extension of the lugs from the drum surface. This was accomplished by angling the drum approximately 30 degrees from horizontal in an inverted position. In this position, the drum was rotated slightly so as not to embed the closure lugs into the drum as a result of the 30-foot drop. It was determined that this orientation would maximize deformation to the closure ring around the closure lug while still maintaining the extension of the lugs from the package surface. The second drop was from 40 inches above a 40-inch tall 6-inch diameter puncture pin. The package was angled 10 degrees from vertical and aligned over the puncture pin to solidly hit the drum lug(s) in an attempt to disengage the lid when dropped.Tests were performed in response to DOE EM-76 review Q5 inquires that questioned the capability of the 9975 drum lid to remain in place under this test sequence. Two packages were dropped utilizing this sequence, a 9974 and 9975. Test results for the 9974 package are reported in WSRC-RP-97-00945. A series of 40-inch puncture pin tests were also performed on undamaged 9975 and 9974 packages

Combined effects of microplastics and chemical contaminants on the organ toxicity of zebrafish (Danio rerio).

Science.gov (United States)

Rainieri, Sandra; Conlledo, Nadia; Larsen, Bodil K; Granby, Kit; Barranco, Alejandro

2018-04-01

Microplastics contamination of the aquatic environment is considered a growing problem. The ingestion of microplastics has been documented for a variety of aquatic animals. Studies have shown the potential of microplastics to affect the bioavailability and uptake route of sorbed co-contaminants of different nature in living organisms. Persistent organic pollutants and metals have been the co-contaminants majorly investigated in this field. The combined effect of microplastics and sorbed co-contaminants in aquatic organisms still needs to be properly understood. To address this, we have subjected zebrafish to four different feeds: A) untreated feed; B) feed supplemented with microplastics (LD-PE 125-250µm of diameter); C) feed supplemented with 2% microplastics to which a mixture of PCBs, BFRs, PFCs and methylmercury were sorbed; and D) feed supplemented with the mixture of contaminants only. After 3 weeks of exposure fish were dissected and liver, intestine, muscular tissue and brain were extracted. After visual observation, evaluation of differential gene expression of some selected biomarker genes in liver, intestine and brain were carried out. Additionally, quantification of perfluorinated compounds in liver, brain, muscular tissue and intestine of some selected samples were performed. The feed supplemented with microplastics with sorbed contaminants produced the most evident effects especially on the liver. The results indicate that microplastics alone does not produce relevant effects on zebrafish in the experimental conditions tested; on the contrary, the combined effect of microplastics and sorbed contaminants altered significantly their organs homeostasis in a greater manner than the contaminants alone. Copyright © 2017 Elsevier Inc. All rights reserved.

Strategies toward High Performance Organic Photovoltaic Cell: Material and Process

Science.gov (United States)

Kim, Bong Gi

The power conversion efficiency of organic photovoltaic (OPV) cells has been rapidly improved during the last few years and currently reaches around 10 %. The performance is evenly governed by absorption, exciton diffusion, exciton dissociation, carrier transfer, and collection efficiencies. Establishing a better understanding of OPV device physics combined with the development of new materials for each executive step contributes to this dramatic improvement. This dissertation focuses mainly on material design and development to correlate the intrinsic properties of organic semiconductors and the OPV performance. The introductory Chapter 1 briefly reviews the motivation of OPV research, its working mechanism, and representative organic materials for OPV application. Chapter 2 discusses the modulation of conjugated polymer's (CP's) absorption behavior and an efficient semi-empirical approach to predict CP's energy levels from its constituent monomers' HOMO/LUMO values. A strong acceptor lowered both the HOMO and LUMO levels of the CP, but the LUMO dropped more rapidly which ultimately produced a narrowed band-gap in the electron donating/accepting alternating copolymer system. In addition, the energy level difference between the CP and the constituent monomers converged to a constant value, providing an energy level prediction tool. Chapter 3 illustrates the systematic investigation on the relationship between the molecular structure of an energy harvesting organic dye and the exciton dissociation efficiency. The study showed that the quantum yield decreased as the exciton binding energy increases, and dipole moment direction should be properly oriented in the dye framework in order to improve photo-current generation when used in a dye sensitized photovoltaic device. Chapter 4 demonstrates the ultrasonic-assisted self-assembly of CPs in solution, rapidly and efficiently. Ultrasonication combined with dipolar media accelerated CP's aggregation, and the effect of CP

Fault roughness and strength heterogeneity control earthquake size and stress drop

KAUST Repository

Zielke, Olaf; Galis, Martin; Mai, Paul Martin

2017-01-01

An earthquake's stress drop is related to the frictional breakdown during sliding and constitutes a fundamental quantity of the rupture process. High-speed laboratory friction experiments that emulate the rupture process imply stress drop values

Growth factors mediated differentiation of mesenchymal stem cells to cardiac polymicrotissue using hanging drop and bioreactor.

Science.gov (United States)

Konstantinou, Dimitrios; Lei, Ming; Xia, Zhidao; Kanamarlapudi, Venkateswarlu

2015-04-01

Heart disease is the major leading cause of death worldwide and the use of stem cells promises new ways for its treatment. The relatively easy and quick acquisition of human umbilical cord matrix mesenchymal stem cells (HUMSCs) and their properties make them useful for the treatment of cardiac diseases. Therefore, the main aim of this investigation was to create cardiac polymicrotissue from HUMSCs using a combination of growth factors [sphingosine-1-phosphate (S1P) and suramin] and techniques (hanging drop and bioreactor). Using designated culture conditions of the growth factors (100 nM S1P and 500 µM suramin), cardiomyocyte differentiation medium (CDM), hanging drop, bioreactor and differentiation for 7 days, a potential specific cardiac polymicrotissue was derived from HUMSCs. The effectiveness of growth factors alone or in combination in differentiation of HUMSCs to cardiac polymicrotissue was analysed by assessing the presence of cardiac markers by immunocytochemistry. This analysis demonstrated the importance of those growth factors for the differentiation. This study for the first time demonstrated the formation of a cardiac polymicrotissue under specific culture conditions. The polymicrotissue thus obtained may be used in future as a 'patch' to cover the injured cardiac region and would thereby be useful for the treatment of heart diseases. © 2014 International Federation for Cell Biology.

Drops and bubbles in contact with solid surfaces

CERN Document Server

Ferrari, Michele

2012-01-01

The third volume in a series dedicated to colloids and interfaces, Drops and Bubbles in Contact with Solid Surfaces presents an up-to-date overview of the fundamentals and applications of drops and bubbles and their interaction with solid surfaces. The chapters cover the theoretical and experimental aspects of wetting and wettability, liquid-solid interfacial properties, and spreading dynamics on different surfaces, including a special section on polymers. The book examines issues related to interpretation of contact angle from nano to macro systems. Expert contributors discuss interesting pec

Modeling merging behavior at lane drops.

Science.gov (United States)

2015-02-01

In work-zone configurations where lane drops are present, merging of traffic at the taper presents an operational concern. In : addition, as flow through the work zone is reduced, the relative traffic safety of the work zone is also reduced. Improvin...

Drop impact entrapment of bubble rings

KAUST Repository

Thoraval, M.-J.; Takehara, K.; Etoh, T.G.; Thoroddsen, Sigurdur T

2013-01-01

We use ultra-high-speed video imaging to look at the initial contact of a drop impacting on a liquid layer. We observe experimentally the vortex street and the bubble-ring entrapments predicted numerically, for high impact velocities, by Thoraval et

Simplified analytical solutions for free drops during NCT for radioactive material packagings

International Nuclear Information System (INIS)

Gupta, N.K.

1997-01-01

To ensure structural integrity during normal conditions of transport (NCT), Federal regulations in 10CFR71.71 require that the nuclear material package designs be evaluated for the effects of free drops. The vessel stress acceptance criteria for these drops are given in Regulatory Guide 7.6 and ASME Section III Code. During initial phases of the package design, the effects of the NCT free drops can be evaluated by simplified analytical solutions which will ensure that the safety margins specified in R. G. 7.6 are met. These safety margins can be verified during the final stages of the package design with dynamic analyses using finite element methods. This paper calculates the maximum impact open-quotes gclose quotes loading on the vessels using single degree of freedom models for different drop orientations. Only end, bottom, and corner drops are analyzed for cylindrical packages or packages with cylindrical ends

A pressure drop model for PWR grids

Energy Technology Data Exchange (ETDEWEB)

Oh, Dong Seok; In, Wang Ki; Bang, Je Geon; Jung, Youn Ho; Chun, Tae Hyun [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

1999-12-31

A pressure drop model for the PWR grids with and without mixing device is proposed at single phase based on the fluid mechanistic approach. Total pressure loss is expressed in additive way for form and frictional losses. The general friction factor correlations and form drag coefficients available in the open literatures are used to the model. As the results, the model shows better predictions than the existing ones for the non-mixing grids, and reasonable agreements with the available experimental data for mixing grids. Therefore it is concluded that the proposed model for pressure drop can provide sufficiently good approximation for grid optimization and design calculation in advanced grid development. 7 refs., 3 figs., 3 tabs. (Author)

A pressure drop model for PWR grids

Energy Technology Data Exchange (ETDEWEB)

Oh, Dong Seok; In, Wang Ki; Bang, Je Geon; Jung, Youn Ho; Chun, Tae Hyun [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

1998-12-31

A pressure drop model for the PWR grids with and without mixing device is proposed at single phase based on the fluid mechanistic approach. Total pressure loss is expressed in additive way for form and frictional losses. The general friction factor correlations and form drag coefficients available in the open literatures are used to the model. As the results, the model shows better predictions than the existing ones for the non-mixing grids, and reasonable agreements with the available experimental data for mixing grids. Therefore it is concluded that the proposed model for pressure drop can provide sufficiently good approximation for grid optimization and design calculation in advanced grid development. 7 refs., 3 figs., 3 tabs. (Author)

Operative time, blood loss, hemoglobin drop, blood transfusion, and hospital stay in orthognathic surgery.

Science.gov (United States)

Salma, Ra'ed Ghaleb; Al-Shammari, Fahad Mohammed; Al-Garni, Bishi Abdullah; Al-Qarzaee, Mohammed Abdullah

2017-06-01

This study was conducted to evaluate the operative time, blood loss, hemoglobin drop, blood transfusion, and length of hospital stay in orthognathic surgery. A 10-year retrospective analysis was performed on patients who underwent bilateral sagittal split osteotomy (with or without genioplasty), Le Fort I osteotomy (with or without genioplasty), or any combination of these procedures. A total of 271 patients were included. The age range was 17 to 49 years, with a mean age of 24.13 ± 4.51 years. Approximately 62% of patients underwent double-jaw surgery. The most common procedure was bilateral sagittal split with Le Fort I (37%). The average operative time was 3.96 ± 1.25 h. The mean estimated blood loss was 345.2 ± 149.74 mL. Approximately 9% of patients received intraoperative blood transfusion. The mean hemoglobin drop in the non-transfusion cases was 2.38 ± 0.89 g/dL. The mean postoperative hospital stay was 1.85 ± 0.83 days. Only one patient was admitted to the ICU for one night. In orthognathic surgery, blood loss is relatively minor, blood transfusion is frequent, and ICU admission is unlikely. Operative time, blood loss, blood transfusion, and the complexity of the surgical procedure can significantly increase the length of hospital stay. Males may bleed more than females in orthognathic surgery. Hemoglobin drop can be overestimated due to hemodilution in orthognathic surgery, which may influence the decision to use blood transfusion.

Mimicking the stenocara beetle--dewetting of drops from a patterned superhydrophobic surface.

Science.gov (United States)

Dorrer, Christian; Rühe, Jürgen

2008-06-17

This paper describes the preparation of superhydrophobic surfaces that have been selectively patterned with circular hydrophilic domains. These materials mimicked the back of the stenocara beetle and collected drops of water if exposed to mist or fog. Under the effect of gravity, the drops dewetted from the hydrophilic regions once a critical volume had been reached. The surface energy in the hydrophilic regions was carefully controlled and assumed various values, allowing us to study the behavior of drops as a function of the superhydrophobic/hydrophilic contrast. We have investigated the development of drops and quantitatively analyzed the critical volumes as a function of several parameters.

Exergoeconomic assessment and parametric study of a Gas Turbine-Modular Helium Reactor combined with two Organic Rankine Cycles

International Nuclear Information System (INIS)

Mohammadkhani, F.; Shokati, N.; Mahmoudi, S.M.S.; Yari, M.; Rosen, M.A.

2014-01-01

An exergoeconomic analysis is reported for a combined system with a net electrical output of 299 MW in which waste heat from a Gas Turbine-Modular Helium Reactor (GT-MHR) is utilized by two Organic Rankine Cycles (ORCs). A parametric study is also done to reveal the effects on the exergoeconomic performance of the combined system of such significant parameters as compressor pressure ratio, turbine inlet temperature, temperatures of evaporators, pinch point temperature difference in the evaporators and degree of superheat at the ORC (Organic Rankine Cycle) turbines inlet. Finally the combined cycle performance is optimized from the viewpoint of exergoeconomics. The results show that the precooler, the intercooler and the ORC condensers exhibit the worst exergoeconomic performance. For the overall system, the exergoeconomic factor, the capital cost rate and the exergy destruction cost rate are determined to be 37.95%, 6876 $/h and 11,242 $/h, respectively. Also, it is observed that the unit cost of electricity produced by the GT-MHR turbine increases with increasing GT-MHR turbine inlet temperature but decreases as the other above mentioned parameters increase. - Highlights: • An exergoeconomic analysis is performed for the GT-MHR/ORC (Organic Rankine Cycle) combined cycle. • The effects of decision parameters on the exergoeconomic performance are studied. • The highest exergy destructions occur in the precooler, intercooler and condenser. • Superheating the working fluid at the ORC turbine inlet is not necessary. • Thermodynamic and exergoeconomic optimal conditions differ from each other

Drop Dynamics and Speciation in Isolation of Metals from Liquid Wastes by Reactive Scavenging

Energy Technology Data Exchange (ETDEWEB)

Arne J. Pearlstein; Alexander Scheeline

2002-08-30

Computational and experimental studies of the motion and dynamics of liquid drops in gas flows were conducted with relevance to reactive scavenging of metals from atomized liquid waste. Navier-Stoke's computations of deformable drops revealed a range of conditions from which prolate drops are expected, and showed how frajectiones of deformable drops undergoing deceleration can be computed. Experimental work focused on development of emission fluorescence, and scattering diagnostics. The instrument developed was used to image drop shapes, soot, and nonaxisymmetric departures from steady flow in a 22kw combustor

Sporadic frame dropping impact on quality perception

Science.gov (United States)

Pastrana-Vidal, Ricardo R.; Gicquel, Jean Charles; Colomes, Catherine; Cherifi, Hocine

2004-06-01

Over the past few years there has been an increasing interest in real time video services over packet networks. When considering quality, it is essential to quantify user perception of the received sequence. Severe motion discontinuities are one of the most common degradations in video streaming. The end-user perceives a jerky motion when the discontinuities are uniformly distributed over time and an instantaneous fluidity break is perceived when the motion loss is isolated or irregularly distributed. Bit rate adaptation techniques, transmission errors in the packet networks or restitution strategy could be the origin of this perceived jerkiness. In this paper we present a psychovisual experiment performed to quantify the effect of sporadically dropped pictures on the overall perceived quality. First, the perceptual detection thresholds of generated temporal discontinuities were measured. Then, the quality function was estimated in relation to a single frame dropping for different durations. Finally, a set of tests was performed to quantify the effect of several impairments distributed over time. We have found that the detection thresholds are content, duration and motion dependent. The assessment results show how quality is impaired by a single burst of dropped frames in a 10 sec sequence. The effect of several bursts of discarded frames, irregularly distributed over the time is also discussed.

Silicon-Based Asymmetric Add-Drop Microring Resonators with Ultra-Large Through-Port Extinctions

International Nuclear Information System (INIS)

Xi, Xiao; Yun-Tao, Li; Yu-De, Yu; Jin-Zhong, Yu

2010-01-01

We theoretically simulate and experimentally demonstrate ultra-large through-port extinctions in silicon-based asymmetrically-coupled add-drop microring resonators (MRs). Through-port responses in an add-drop MR are analyzed by simulations and large extinctions are found when the MR is near-critically coupled. Accurate fabrication techniques are applied in producing a series of 20 μm-radii add-drop microrings with drop-side gap-widths in slight differences. A through-port extinction of about 42.7 dB is measured in an MR with through- and drop-side gap-width to be respectively 280nm and 295nm. The large extinction suggests about a 20.5 dB improvement from the symmetrical add-drop MR of the same size and the through-side gap-width. The experimental results are finally compared with the post-fabrication simulations, which show a gap-width tolerance of > 30 am for the through-port extinction enhancement

Separation/preconcentration and determination of vanadium with dispersive liquid-liquid microextraction based on solidification of floating organic drop (DLLME-SFO) and electrothermal atomic absorption spectrometry.

Science.gov (United States)

Asadollahi, Tahereh; Dadfarnia, Shayessteh; Shabani, Ali Mohammad Haji

2010-06-30

A novel dispersive liquid-liquid microextraction based on solidification of floating organic drop (DLLME-SFO) for separation/preconcentration of ultra trace amount of vanadium and its determination with the electrothermal atomic absorption spectrometry (ETAAS) was developed. The DLLME-SFO behavior of vanadium (V) using N-benzoyl-N-phenylhydroxylamine (BPHA) as complexing agent was systematically investigated. The factors influencing the complex formation and extraction by DLLME-SFO method were optimized. Under the optimized conditions: 100 microL, 200 microL and 25 mL of extraction solvent (1-undecanol), disperser solvent (acetone) and sample volume, respectively, an enrichment factor of 184, a detection limit (based on 3S(b)/m) of 7 ng L(-1) and a relative standard deviation of 4.6% (at 500 ng L(-1)) were obtained. The calibration graph using the preconcentration system for vanadium was linear from 20 to 1000 ng L(-1) with a correlation coefficient of 0.9996. The method was successfully applied for the determination of vanadium in water and parsley. Copyright 2010 Elsevier B.V. All rights reserved.

Organic Food "Made in China"

OpenAIRE

Sternfeld, Eva

2009-01-01

China joined the international organic movement comparatively late. Challenged by the scarcity of arable land and a large population to feed, the Chinese Ministry of Agriculture (MoA) for many years has been reluctant to support organic farming that might result in a drop of agricultural output. On the contrary, China’s “Green Revolution” catapulted the country to a leading producer and user of agrochemicals in the world. This development came at a high cost for the country’s environmental qu...

Combined effects of microplastics and chemical contaminants on the organ toxicity of zebrafish ( Danio rerio )

DEFF Research Database (Denmark)

Rainieri, Sandra; Conlledo, Nadia; Larsen, Bodil Katrine

2018-01-01

3 weeks of exposure fish were dissected and liver, intestine, muscular tissue and brain were extracted. After visual observation, evaluation of differential gene expression of some selected biomarker genes in liver, intestine and brain were carried out. Additionally, quantification of perfluorinated...... compounds in liver, brain, muscular tissue and intestine of some selected samples were performed. The feed supplemented with microplastics with sorbed contaminants produced the most evident effects especially on the liver. The results indicate that microplastics alone does not produce relevant effects......-contaminants of different nature in living organisms. Persistent organic pollutants and metals have been the co-contaminants majorly investigated in this field. The combined effect of microplastics and sorbed co-contaminants in aquatic organisms still needs to be properly understood. To address this, we have subjected...

High-Efficiency Small-Scale Combined Heat and Power Organic Binary Rankine Cycles

Directory of Open Access Journals (Sweden)

Costante Mario Invernizzi

2018-04-01

Full Text Available Small-CHP (Combined Heat and Power systems are generally considered a valuable technological option to the conventional boilers, in a technology developed context. If small-CHP systems are associated with the use of renewable energies (biomass, for example they could play an important role in distributed generation even in developing countries or, in any case, where there are no extensive electricity networks. Traditionally the considered heat engines for micro- or mini-CHP are: the gas engine, the gas turbine (with internal combustion, the steam engine, engine working according to the Stirling and to the Rankine cycles, the last with organic fluids. In principle, also fuel cells could be used. In this paper, we focus on small size Rankine cycles (10–15 k W with organic working fluids. The assumed heat source is hot combustion gases at high temperature (900–950 ∘ C and we assume to use only single stages axial turbines. The need to work at high temperatures, limits the choice of the right organic working fluids. The calculation results show the limitation in the performances of simple cycles and suggest the opportunity to resort to complex (binary cycle configurations to achieve high net conversion efficiencies (15–16%.