DURABILITY AND TRIBOLOGICAL PROPERTIES OF THERMALLY SPRAYED WC CERMET COATING IN LUBRICATED ROLLING WITH SLIDING CONTACT

Directory of Open Access Journals (Sweden)

Mohammad Ali

2010-09-01

Full Text Available Durability and tribological properties of thermally sprayed WC-Cr-Ni cermet coating were investigated experimentally in lubricated rolling with sliding contact conditions. By means of the high energy type flame spraying (Hi-HVOF method, the coating was formed onto the axially ground and circumferentially ground roller specimens made of a thermally refined carbon steel. In the experiments, the WC cermet coated steel roller was mated with the carburized hardened steel roller without coating in line contact condition. The coated roller was mated with the smooth non-coated roller under a contact pressure of 1.0 or 1.2 GPa, and it was mated with the rough non-coated roller under a contact pressure of 0.6 or 0.8 GPa. As a result, it was found that in general, the coating on the circumferentially ground substrate shows a lower durability compared with that on the axially ground substrate and this difference appears more distinctly for the higher contact pressure for both smooth mating surface and rough mating surface. It was also found that there are significant differences in the tribological properties of WC cermet coating depending on the contact pressure. In addition, depending on the smooth or rough mating surface, remarkable differences in the tribological properties were found.

Self-Mobilization Using a Foam Roller Versus a Roller Massager: Which Is More Effective for Increasing Hamstrings Flexibility?

Science.gov (United States)

DeBruyne, Danielle M; Dewhurst, Marina M; Fischer, Katelyn M; Wojtanowski, Michael S; Durall, Chris

2017-01-01

Clinical Scenario: Increasing the length of the muscle-tendon unit may prevent musculotendinous injury. Various methods have been proposed to increase muscle-tendon flexibility, including self-mobilization using foam rollers or roller massagers, although the effectiveness of these devices is uncertain. This review was conducted to determine if the use of foam rollers or roller massagers to improve hamstrings flexibility is supported by moderate- to high-quality evidence. Are foam rollers or roller massagers effective for increasing hamstrings flexibility in asymptomatic physically active adults? Summary of Key Findings: The literature was searched for studies on the effects of using foam rollers or roller massagers to increase hamstrings flexibility in asymptomatic physically active adults. Four randomized controlled trials were included; 2 studies provided level 2 or 3 evidence regarding foam rollers and 2 studies provided level 2 or 3 evidence regarding roller massagers. Both roller-massager studies reported increases in hamstrings flexibility after treatment. Data from the foam-roller studies did not demonstrate a statistically significant increase in hamstrings flexibility, but 1 study did demonstrate a strong effect size. Clinical Bottom Line: The reviewed moderate-quality studies support the use of roller massagers but provide limited evidence on the effectiveness of foam rolling to increase hamstrings flexibility in asymptomatic physically active adults. Flexibility gains may be improved by a longer duration of treatment and administration by a trained therapist. Gains appear to decline rapidly postrolling. Neither device has been shown to confer a therapeutic benefit superior to static stretching, and the effectiveness of these devices for preventing injury is unknown. Strength of Recommendation: Grade B evidence supports the use of roller massagers to increase hamstrings flexibility in asymptomatic physically active adults.

On Calculation Methods and Results for Straight Cylindrical Roller Bearing Deflection, Stiffness, and Stress

Science.gov (United States)

Krantz, Timothy L.

2011-01-01

The purpose of this study was to assess some calculation methods for quantifying the relationships of bearing geometry, material properties, load, deflection, stiffness, and stress. The scope of the work was limited to two-dimensional modeling of straight cylindrical roller bearings. Preparations for studies of dynamic response of bearings with damaged surfaces motivated this work. Studies were selected to exercise and build confidence in the numerical tools. Three calculation methods were used in this work. Two of the methods were numerical solutions of the Hertz contact approach. The third method used was a combined finite element surface integral method. Example calculations were done for a single roller loaded between an inner and outer raceway for code verification. Next, a bearing with 13 rollers and all-steel construction was used as an example to do additional code verification, including an assessment of the leading order of accuracy of the finite element and surface integral method. Results from that study show that the method is at least first-order accurate. Those results also show that the contact grid refinement has a more significant influence on precision as compared to the finite element grid refinement. To explore the influence of material properties, the 13-roller bearing was modeled as made from Nitinol 60, a material with very different properties from steel and showing some potential for bearing applications. The codes were exercised to compare contact areas and stress levels for steel and Nitinol 60 bearings operating at equivalent power density. As a step toward modeling the dynamic response of bearings having surface damage, static analyses were completed to simulate a bearing with a spall or similar damage.

Screw-released roller brake

Science.gov (United States)

Vranish, John M. (Inventor)

1999-01-01

A screw-released roller brake including an input drive assembly, an output drive assembly, a plurality of locking sprags, a mechanical tripper nut for unlocking the sprags, and a casing therefor. The sprags consist of three dimensional (3-D) sprag members having pairs of contact surface regions which engage respective pairs of contact surface regions included in angular grooves or slots formed in the casing and the output drive assembly. The sprags operate to lock the output drive assembly to the casing to prevent rotation thereof in an idle mode of operation. In a drive mode of operation, the tripper is either self actuated or motor driven and is translated linearly up and down against a spline and at the limit of its travel rotates the sprags which unlock while coupling the input drive assembly to the output drive assembly so as to impart a turning motion thereto in either a clockwise or counterclockwise direction.

Problematics of Reliability of Road Rollers

Science.gov (United States)

Stawowiak, Michał; Kuczaj, Mariusz

2018-06-01

This article refers to the reliability of road rollers used in a selected roadworks company. Information on the method of road rollers service and how the service affects the reliability of these rollers is presented. Attention was paid to the process of the implemented maintenance plan with regard to the machine's operational time. The reliability of road rollers was analyzed by determining and interpreting readiness coefficients.

Roller-compacted concrete pavements.

Science.gov (United States)

2010-09-01

Roller-compacted concrete (RCC) gets its name from the heavy vibratory steel drum and rubber-tired rollers used to help compact it into its final form. RCC has similar strength properties and consists of the same basic ingredients as conventional con...

Pervasive liquid metal based direct writing electronics with roller-ball pen

Directory of Open Access Journals (Sweden)

Yi Zheng

2013-11-01

Full Text Available A roller-ball pen enabled direct writing electronics via room temperature liquid metal ink was proposed. With the rolling to print mechanism, the metallic inks were smoothly written on flexible polymer substrate to form conductive tracks and electronic devices. The contact angle analyzer and scanning electron microscope were implemented to disclose several unique inner properties of the obtained electronics. An ever high writing resolution with line width and thickness as 200 μm and 80 μm, respectively was realized. Further, with the administration of external writing pressure, GaIn24.5 droplets embody increasing wettability on polymer which demonstrates the pervasive adaptability of the roller-ball pen electronics.

Development of roller type side slip tester; Roller shiki side slip tester no kaihatsu

Energy Technology Data Exchange (ETDEWEB)

Nishiyama, S [Hiroshima City Industrial Technology Institute, Hiroshima (Japan); Harada, S; Harada, K

1997-10-01

This paper presents a new development of roller type side slip tester (RTSSI). The test equipment consists of four parts, which are developed in this research. These are a roller part, a control part, a remote control part and a CRT part. In this study, we especially investigated the mechanism and performance between tire and roller. We analyzed the amount of side slip with various toe angles. The developed tester is examined under the conditions that is considered in industrial applications. We investigated the influences of toe angle, size of tire, pressure of tire, coefficient of friction between tire and roller, pushing force of tire, revolution velocity of roller, axle load and so on. The validity of the developed RTSST is confirmed under these conditions. It was found that the RTSST can be used in practical use. Some measurement results are presented in the form of parametric plots. And we also compared measurements data between the RTSST and that of flat type using several automobiles. 4 refs., 8 figs., 4 tabs.

Profiled Roller Stress/Fatigue Life Analysis Methodology and Establishment of an Appropriate Stress/Life Exponent

Science.gov (United States)

1997-01-01

The objective of this work was to determine the three dimensional volumetric stress field, surface pressure distribution and actual contact area between a 0.50" square roller with different crown profiles and a flat raceway surface using Finite Element Analysis. The 3-dimensional stress field data was used in conjunction with several bearing fatigue life theories to extract appropriate values for stress-life exponents. Also, results of the FEA runs were used to evaluate the laminated roller model presently used for stress and life prediction.

Analytical evaluation of the roller bearing service life

Directory of Open Access Journals (Sweden)

Antsupov Aleksey

2017-01-01

Full Text Available An analytical method has been developed for the design evaluation of the service life of roller bearings by the criterion of contact endurance of elements that does not require carrying out the experimental studies. It is based on the kinetic approach to the description of the solids destruction process and the theory of parametric reliability of machine parts. In contradistinction to the standard empirical dependence, which is currently used, the method allows one to take into account the effect of the material properties, and basic design and operational parameters on the service life. The results of the theoretical studies of the service life of roller bearing No. 212 (DIN 5412 T1 are presented for the quantitative assessment of this effect. They showed that the temperature-force loading conditions or material properties that were not taken into account might result in the prediction error of 1.5 or more times.

Analysis of bearing steel exposed to rolling contact fatigue

DEFF Research Database (Denmark)

Hansen, K. T.; Fæster, Søren; Natarajan, Anand

2017-01-01

The objective of this work is to characterize fatigue damage in roller bearings under conditions of high load and slippage. A test rig constructed for rolling contact fatigue tests of rings is described, and test results are presented for rings taken from two spherical roller bearings. The prepar...

The 1982 epidemic--roller skating injuries.

Science.gov (United States)

Bunker, T. D.

1983-01-01

A series of 100 roller skating injuries is presented. Roller skating injuries have been occurring at a higher rate than the previously reported skateboarding epidemic of 1977. The severity of injury has been lower, 32% fractures and dislocations occurring whilst roller skating, compared to 60% whilst skateboarding. In particular a striking reduction is seen in ankle fractures. Fifty questionnaires detailing method of injury were analysed. Images p205-a Fig. 1 Fig. 2 PMID:6652406

Development of ceramic roller bush for diesel fuel injection pump; Nenryo funsha pump yo ceramics sei roller bush no kaihatsu

Energy Technology Data Exchange (ETDEWEB)

Noda, K; Kamiya, S; Fujimura, M; Tsuzuki, M [Toyota Motor Corp., Aichi (Japan); Taniguchi, K [Denso Corp., Aichi (Japan)

1997-10-01

Silicon nitride ceramics have been applied to roller bush for diesel fuel injection pump in order to improve the seizure resistance. It was found that ceramic roller bush made it possible to improve the seizure load by more than three times as compared to conventional metal roller bush when the kerosene was used as lubricant The ceramic roller bush proved to be durable under engine operating conditions. 6 refs., 13 figs., 1 tab.

49 CFR 215.115 - Defective roller bearing.

Science.gov (United States)

2010-10-01

... 49 Transportation 4 2010-10-01 2010-10-01 false Defective roller bearing. 215.115 Section 215.115... § 215.115 Defective roller bearing. (a) A railroad may not place or continue in service a car, if the car has— (1) A roller bearing that shows signs of having been overheated as evidenced by— (i...

Depreciation of bearing blocks of rollers of roller conveyers of rolling mills

Science.gov (United States)

Artiukh, Viktor; Belyaev, Michael; Ignatovich, Igor; Miloradova, Nadezda

2017-10-01

Essential increase in functional durability of a node of a roller of the roller conveyer of the rolling mill by the rational choice of parameters of the small-size shock-absorber (buffer adapter) is shown. At the same time dimensions of a node don’t change, costs of reconstruction are small. The possibility of management of loadings in a bearing node without change of technology parameters of the process which is carried out by the rolling mill is confirmed.

Pressure and temperature measurements of cam follower and roller tappet in tribological contact. Final report; Druck- und Temperaturmessungen im Tribokontakt Nocken-Rollenstoessel. Schlussbericht

Energy Technology Data Exchange (ETDEWEB)

Noronha, A.P.; Glasser, S.; Sadeghi, F.

2002-12-20

Tribocontact between cam follower and roller tappet involves mixing and limiting friction states, which causes wear in the form of adhesive corrosion and pitting of surfaces. In cooperation with Purdue University, the influence of microgeometry (surface roughness) and macrogeometry (surface shape) was investigated in order to optimize lubrication for EHD lubrication conditions in contact, thus preventing wear and failure. This component project involves pressure and temperature measurements of cam follower and roller tappet tribocontact using flash-deposited thin film probes. The results are to provide information on design optimization. [German] Im Tribokontakt Nocken-Rollenstoessel herrschen vorwiegend Misch- und Grenzreibungszustaende. Dies fuehrt zu erheblichem Verschleiss in Form von adhaesiv bedingtem Fressen und Pittingbildung durch Oberflaechenzerruettung. Ziel dieses Forschungsvorhabens ist es, in Kooperation mit der Partnerhochschule ''Purdue University'' in den USA, den Einfluss der Mikrogeometrie (Oberflaechenrauheiten) und Makrogeometrie (Oberflaechenform) des Tribokontaktes Nocken-Rollenstoessel hinsichtlich des Betriebsverhaltens zu untersuchen, um Kenntnisse zur Verbesserung der Schmierbedingungen zu gewinnen, so dass im Kontakt elastohydrodynamische (EHD) Schmierungsverhaeltnisse realisiert werden und dadurch ein Ausfall aufgrund von Verschleiss ausgeschlossen wird. Im Rahmen dieses Teilvorhabens sollten Druck- und Temperaturmessungen mittels aufgedampfter Duennschichtaufnehmer im Tribokontakt, Nocken-Rollenstoessel, durchgefuehrt werden, um die theoretischen Forschungsarbeiten, welche in der Purdue University erarbeitet werden, zu untermauern. Beide Arbeiten werden somit neue Erkenntnisse zur konstruktiven Auslegung von verschleissfreien Nocken-Stoessel-Paarungen liefern. (orig.)

ROLLER RIG TESTING AT THE CZECH TECHNICAL UNIVERSITY

Directory of Open Access Journals (Sweden)

J. Kalivoda

2016-08-01

Full Text Available Purpose. Although the advancements in computer simulation technology have paved way to provide very reliable simulation results, track tests still play an essential role during the process of development and homologation of any railway vehicle. On the other hand, track tests depend on weather conditions, are difficult to organize and are not suitable for testing vehicles in critical situations. On a roller rig, the tested vehicle is longitudinally fixed and a track is replaced by rotating rollers. Such device offer testing of railway vehicle running dynamics in safe and stable laboratory environment. The purpose of an article is to investigate and describe roller rig testing at the Czech technical university in Prague (CTU. Methodology. In the paper it is shown the history of development of the scaled CTU roller rig from the earlier stages until the current projects for which the CTU roller rig is utilized for. The current design of the experimental bogie, roller rig, sensors instrumentation and types of experiments conducted at the CTU roller rig are described in more detail. Findings. Although the differences in vehicle behaviour on a track and a scaled model on a roller rig are not negligible, scaled roller rig experiments are found as a relatively inexpensive way for verification and demonstration of computer simulations results. They are especially useful for verification of multibody system simulations (MBS of entirely new running gear concepts. Originality. The CTU roller rig is currently used for the experiments with active controlled wheelset guidance. According to simulations results published in many papers such systems offer, in principle, better performance compared to conventional passive vehicles. However, utilization and testing of active controlled wheelset guidance on vehicles is still rare. CTU roller rig serves as a tool to verify computer simulations and demonstrate benefits of active wheelset guidance. Practical value

Ice-skating and roller disco injuries in Dublin.

OpenAIRE

Horner, C.; McCabe, M. J.

1984-01-01

A comparative study was carried out on a series of 72 ice-skating and 57 roller skating injuries over a sixteen month period. The average patient age was 20.5 years in the ice-skating group and 16.5 years in the roller skating group. Females predominated in both groups accounting for 72% of ice-skaters injured and 77% of roller skaters injured. Ice-skaters sustained more serious injuries than roller skaters as was evident from the significant difference in fracture numbers in the two groups. ...

Rolling contact fatigue testing of peek based composites

Directory of Open Access Journals (Sweden)

Petrogalli C.

2010-06-01

Full Text Available Rolling contact fatigue phenomenon was investigated on unfilled PEEK and on three different PEEK composites: 10% carbon micro-fiber, graphite and PTFE filled matrix, 30% carbon micro-fiber filled matrix, 30% glass micro-fiber filled matrix. For this aim, roller-shaped specimens were machined from extruded bars of these materials and subjected to rolling contact tests at different contact pressure levels by means of a four roller machine. Contact pressure-life diagrams and wear rates were so obtained and compared, highlighting a relationship with monotonic and hardness materials properties. Microscopic observations of contact surfaces and transversal section of the specimens also allowed observing the damage mechanisms occurred in the materials tested and the effects of the filler. In particular way, deep radial cracks appeared on unfilled PEEK, while spalling and delamination phenomena where found on composites. Diffuse microcracks were found at the filler-matrix interface of the composites specimens, confirming that the fatigue life of these materials is essentially determined by the crack propagation phase, also under rolling contact loading.

Ice-skating and roller disco injuries in Dublin.

Science.gov (United States)

Horner, C.; McCabe, M. J.

1984-01-01

A comparative study was carried out on a series of 72 ice-skating and 57 roller skating injuries over a sixteen month period. The average patient age was 20.5 years in the ice-skating group and 16.5 years in the roller skating group. Females predominated in both groups accounting for 72% of ice-skaters injured and 77% of roller skaters injured. Ice-skaters sustained more serious injuries than roller skaters as was evident from the significant difference in fracture numbers in the two groups. Ice-skating fractures accounted for 40% of all injuries while roller skating fractures were only 14% of their total injuries. The majority of ice-skating fractures occurred in females. As a result of our study we recommended several preventative measures. Images p207-a p207-b PMID:6487948

21 CFR 870.4370 - Roller-type cardiopulmonary bypass blood pump.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Roller-type cardiopulmonary bypass blood pump. 870... Roller-type cardiopulmonary bypass blood pump. (a) Identification. A roller-type cardiopulmonary bypass blood pump is a device that uses a revolving roller mechanism to pump the blood through the...

49 CFR 215.117 - Defective roller bearing adapter.

Science.gov (United States)

2010-10-01

... 49 Transportation 4 2010-10-01 2010-10-01 false Defective roller bearing adapter. 215.117 Section... Suspension System § 215.117 Defective roller bearing adapter. A railroad may not place or continue in service a car, if the car has a roller bearing adapter that is— (a) Cracked or broken; (b) Not in its design...

DETERMINATION OF ADHESIVE STRENGTH LAYER’S ROLLER COMPACTED CONCRETE THE METHOD AXIAL EXTENSION

Directory of Open Access Journals (Sweden)

Tang Van Lam

2017-07-01

Full Text Available Roller compacted concrete for the construction of hydraulic and hydroelectric buildings is a composite material, which consists of a binder, fine aggregate (sand, coarse aggregate (gravel or crushed stone, water and special additives that provide the desired concrete workability and impart the required concrete performance properties. Concrete mixture is prepared at from concrete mixing plants strictly metered quantities of cement, water, additives and graded aggregates, whereupon they are delivered to the site laying Mixer Truck and sealing layers with each stack layer. The advantages of roller compaction technology should include the reduction of construction time, which allows fast commissioning construction projects, as well as reduce the amount of investment required. One of the main problems encountered in the process of roller compaction of the concrete mix is the need to provide the required adhesion strength between layers of concrete. This paper presents a method for determining the strength of adhesion between the concrete layers of different ages roller compacted concrete using axial tension. This method makes it possible to obtain objective and accurate results with a total thickness of layers of compacted concrete of up to 300…400 mm. Results from this method, studies have shown that the value of strength between the concrete layers in addition to the composition of the concrete and adhesion depends on the quality and the parallel end surfaces of the cylinder-models, which are mounted steel plates for axial tension, as well as the state of the contact surfaces of the concrete layer. The method can be used to determine the strength of interlayer adhesion in roller compacted concrete, which are used in the construction of dams and other hydraulic structures.

Engine testing of ceramic cam-roller followers

Energy Technology Data Exchange (ETDEWEB)

Kalish, Y. (Detroit Diesel Corp., MI (United States))

1992-04-01

For several years, DDC has been developing monolithic ceramic heat engine components. One of the components, developed for an application in our state-of-the-art on-highway, heavy-duty diesel engine, the Series 60, is a silicon nitride cam-roller follower. Prior to starting this program, each valve train component in the Series 60 was considered for conversion to a ceramic material. Many advantages and disadvantages (benefits and risks) were considered. From this effort, one component was selected, the cam-roller follower. Using a system design approach, a ceramic cam-roller follower offered functional improvement at a reasonable cost. The purpose of the project was to inspect and test 100 domestically produced silicon nitride cam-roller followers built to the requirements of the DDC series 60 engine.

49 CFR 230.103 - Tender roller bearing journal boxes.

Science.gov (United States)

2010-10-01

... 49 Transportation 4 2010-10-01 2010-10-01 false Tender roller bearing journal boxes. 230.103... Locomotives and Tenders Running Gear § 230.103 Tender roller bearing journal boxes. Tender roller bearing journal boxes shall be maintained in a safe and suitable condition. ...

Numerically Analysed Thermal Condition of Hearth Rollers with the Water-Cooled Shaft

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A. V. Ivanov

2016-01-01

Full Text Available Continuous furnaces with roller hearth have wide application in the steel industry. Typically, furnaces with roller hearth belong to the class of medium-temperature heat treatment furnaces, but can be used to heat the billets for rolling. In this case, the furnaces belong to the class of high temperature heating furnaces, and their efficiency depends significantly on the reliability of the roller hearth furnace. In the high temperature heating furnaces are used three types of watercooled shaft rollers, namely rollers without insulation, rollers with insulating screens placed between the barrel and the shaft, and rollers with bulk insulation. The definition of the operating conditions of rollers with water-cooled shaft greatly facilitates the choice of their design parameters when designing. In this regard, at the design stage of the furnace with roller hearth, it is important to have information about the temperature distribution in the body of the rollers at various operating conditions. The article presents the research results of the temperature field of the hearth rollers of metallurgical heating furnaces. Modeling of stationary heat exchange between the oven atmosphere and a surface of rollers, and between the cooling water and shaft was executed by finite elements method. Temperature fields in the water-cooled shaft rollers of various designs are explored. The water-cooled shaft rollers without isolation, rollers with screen and rollers with bulk insulation, placed between the barrel and the water-cooled shaft were investigated. Determined the change of the thermo-physic parameters of the coolant, the temperature change of water when flowing in a pipe and shaft, as well as the desired pressure to supply water with a specified flow rate. Heat transfer coefficients between the cooling water and the shaft were determined directly during the solution based on the specified boundary conditions. Found that the greatest heat losses occur in the

Kinematics and Dynamics of Roller Chain Drives

DEFF Research Database (Denmark)

Fuglede, Niels

There are two main subjects of this work: Kinematic and dynamic modeling and analysis of roller chain drives. In the kinematic analysis we contribute first with a complete treatment of the roller chain drive modeled as a four-bar mechanism. This includes a general, exact and approximate analysis...... which is useful for predicting the characteristic loading of the roller chain drive. As a completely novel contribution, a kinematic model and analysis is presented which includes both spans and sprockets in a simple chain drive system. A general procedure for determination of the total wrapping length...... is presented, which also allows for exact sprocket center positions for a chain with a given number of links. Results show that the total chain wrapping length varies periodically with the tooth frequency. These results are of practical importance to both the design, installation and operation of roller chain...

Roller-chain Drives Mechanics using Multibody Dynamics Tools

DEFF Research Database (Denmark)

Ambrosio, Jorge A. C.; Hansen, John Michael

1999-01-01

An integrated model for the simulation of roller-chain drives based on a multibody dynamics methodology is presented here in order to describeits complex dynamic behavior. The chain is modeled by masses lumped at the roller locations and connected by translational spring-damper elements in order ...... engagement on the sprockets responsible for the polygonal effect is thoroughly analyzed and the induced impulsive forces developed during that action are treated by a strategy where kinematic constraints between sprockets and rollers are added and deleted....

A FILTRATION METHOD AND APPARATUS INCLUDING A ROLLER WITH PORES

DEFF Research Database (Denmark)

2008-01-01

The present invention offers a method for separating dry matter from a medium. A separation chamber is at least partly defined by a plurality of rollers (2,7) and is capable of being pressure regulated. At least one of the rollers is a pore roller (7) having a surface with pores allowing permeabi...

Roller compaction of moist pharmaceutical powders.

Science.gov (United States)

Wu, C-Y; Hung, W-L; Miguélez-Morán, A M; Gururajan, B; Seville, J P K

2010-05-31

The compression behaviour of powders during roller compaction is dominated by a number of factors, such as process conditions (roll speed, roll gap, feeding mechanisms and feeding speed) and powder properties (particle size, shape, moisture content). The moisture content affects the powder properties, such as the flowability and cohesion, but it is not clear how the moisture content will influence the powder compression behaviour during roller compaction. In this study, the effect of moisture contents on roller compaction behaviour of microcrystalline cellulose (MCC, Avicel PH102) was investigated experimentally. MCC samples of different moisture contents were prepared by mixing as-received MCC powder with different amount of water that was sprayed onto the powder bed being agitated in a rotary mixer. The flowability of these samples were evaluated in terms of the poured angle of repose and flow functions. The moist powders were then compacted using the instrumented roller compactor developed at the University of Birmingham. The flow and compression behaviour during roller compaction and the properties of produced ribbons were examined. It has been found that, as the moisture content increases, the flowability of moist MCC powders decreases and the powder becomes more cohesive. As a consequence of non-uniform flow of powder into the compaction zone induced by the friction between powder and side cheek plates, all produced ribbons have a higher density in the middle and lower densities at the edges. For the ribbons made of powders with high moisture contents, different hydration states across the ribbon width were also identified from SEM images. Moreover, it was interesting to find that these ribbons were split into two halves. This is attributed to the reduction in the mechanical strength of moist powder compacts with high moisture contents produced at high compression pressures. Copyright (c) 2010 Elsevier B.V. All rights reserved.

Assesment on Reproductive Performance and Hormonal Studies in Rural Women Beedi Rollers in Jagitial District of Telangana State

Directory of Open Access Journals (Sweden)

Vanitha Baluka

2017-10-01

Full Text Available Beedi manufacturing is the second largest industry in India. It provides employment to millions of women mostly from the poor socioeconomic class. In North region of Telangana, beedi rolling is a major occupation for illiterate women in many villages. It may affect due to the inhalation of unfiltered tobacco dust and volatile and toxic components of tobacco. Biomonitoring of women beedi rollers and their reproductive performance assessment is necessary to take prevention/control the reproduction failure and carcinogen effect on cervical system. Continuous exposed to unfiltered tobacco dust may have systemic effect and lead to many disorders including hormone defects and reproductive health problems. Although studies have been carried out on beedi industry workers and tobacco smoke exposed people at national and international level, no such studies were carried out on women beedi rollers living in rural areas in Telangana State. Hence, this investigation is attempted to understand the study is find to association with hormonal levels and reproductive outcome in rural women beedi rollers of reproductive age in North Telangana. Statistical analysis was done for the obtained results to find the significance between the two groups for the reproductive outcome and Hormonal Studies. Total 50 women (married who are exposed minimum 6-10 years to the unfiltered tobacco dust beedi rollers in the age group of 25 to 45 years from villages of Jagitial district were enrolled for this study. 50 equal numbers of women in the same age group belonging to the same socio economic status and not exposed occupationally to chemical and physical agents was selected for comparison (control group. Estroidal, Progesterone the T3, T4 and TSH levels were measured found significantly T3, T4 levels were low in the beedi rollers, compared the controls. TSH levels were found to be higher in the beedi rollers. Estroidal and progesterone levels were obtained non

Salmonella transfer during pilot plant scale washing and roller conveying of tomatoes.

Science.gov (United States)

Wang, Haiqiang; Ryser, Elliot T

2014-03-01

Salmonella transfer during washing and roller conveying of inoculated tomatoes was quantified using a pilot scale tomato packing line equipped with plastic, foam, or brush rollers. Red round tomatoes (2.3 kg) were dip inoculated with Salmonella enterica serovar Typhimurium LT2 (avirulent) (4 log CFU/g), air dried for 2 h, and then washed in sanitizer-free water for 2 min. Inoculated tomatoes were then passed single file over a 1.5-m conveyor equipped with plastic, foam, or brush rollers followed by 25 previously washed uninoculated tomatoes. Tomato samples were collected after 2 min of both washing and roller conveying, with all 25 uninoculated tomatoes collected individually after conveying. Roller surface samples were collected before and after conveying the uninoculated tomatoes. Both tomato and surface samples were quantitatively examined for Salmonella by direct plating or membrane filtration using xylose lysine Tergitol 4 agar. Regardless of the roller type, Salmonella populations on inoculated tomatoes did not significantly (P conveyors. After conveying uninoculated tomatoes over contaminated foam rollers, 96% of the 25 tomatoes were cross-contaminated with Salmonella at >100 CFU per tomato. With plastic rollers, 24 and 76% of tomatoes were cross-contaminated with Salmonella at 10 to 100 and 1 to 10 CFU per tomato, respectively. In contrast, only 8% of 25 tomatoes were cross-contaminated with brush rollers with Salmonella populations of 1 to 10 CFU per tomato. Overall, cross-contamination was greatest with foam, followed by plastic and brush rollers (P < 0.05). Adding peroxyacetic acid or chlorine to the wash water significantly decreased cross-contamination during tomato conveying, with chlorine less effective in controlling Salmonella on foam compared with plastic and brush rollers.

A General Case to Determine Dimensions and Their Tolerance Zones for the Thread Parts of Epicyclic Roller-Screw Mechanisms

Directory of Open Access Journals (Sweden)

D. S. Blinov

2017-01-01

Full Text Available The most important trend in the development of aerospace industry is to increase load capacity of mechanisms, assemblies, and parts without increasing their size and weight. The above is also true for widely used in aircrafts and the most promising up to date Epicyclic Roller-Screw Mechanisms (ERSM that convert rotational movement into translational one. Previously (in the article, it was proposed to increase the load capacity (approximately by 15% through reduction of included angle of ERSM threaded parts from 90° to 70°.However, such improvement of ERSM will change dimensions of the mechanism parts and its parameters and characteristics (efficiency factor, position of initial point of contact of the conjugated thread turns and parameters of their contact interaction, as well as kinematic parameters, which will require additional studies. If we take into account the priority of these studies, then surely we must begin with development of technique to determine dimensions of the ERSM main parts and their tolerance zones because we need drawings to manufacture and test the upgraded ERSM. We have developed a technique to calculate dimensions of the main parts of ERSM and associated tolerance zones that takes in to account the change of included angle of threaded parts of the mechanism and radius of circular arc according to which roller thread profile has been fulfilled. So the proposed technique is the general one in comparison with the previous ones.This technique uses various conditions and equations to determine dimensions of parts and associated tolerance zones. For example, a nut encircles a screw with rollers, and their dimensions form a closed dimension chain, in which the dimensions and associated tolerances must be such as to ensure ERSM assembling, on the one hand, and, on the other hand the backlash of the mechanism should be minimal to ensure high load capacity, kinematic accuracy, and rigidity of ERSM. We used the following

Variability of sediment-contact tests in freshwater sediments with low-level anthropogenic contamination - Determination of toxicity thresholds

International Nuclear Information System (INIS)

Hoess, S.; Ahlf, W.; Fahnenstich, C.; Gilberg, D.; Hollert, H.; Melbye, K.; Meller, M.; Hammers-Wirtz, M.; Heininger, P.; Neumann-Hensel, H.; Ottermanns, R.; Ratte, H.-T.

2010-01-01

Freshwater sediments with low levels of anthropogenic contamination and a broad range of geochemical properties were investigated using various sediment-contact tests in order to study the natural variability and to define toxicity thresholds for the various toxicity endpoints. Tests were performed with bacteria (Arthrobacter globiformis), yeast (Saccharomyces cerevisiae), nematodes (Caenorhabditis elegans), oligochaetes (Lumbriculus variegatus), higher plants (Myriophyllum aquaticum), and the eggs of zebrafish (Danio rerio). The variability in the response of some of the contact tests could be explained by particle size distribution and organic content. Only for two native sediments could a pollution effect not be excluded. Based on the minimal detectable difference (MDD) and the maximal tolerable inhibition (MTI), toxicity thresholds (% inhibition compared to the control) were derived for each toxicity parameter: >20% for plant growth and fish-egg survival, >25% for nematode growth and oligochaete reproduction, >50% for nematode reproduction and >60% for bacterial enzyme activity. - Sediment-contact tests require toxicity thresholds based on their variability in native sediments with low-level contamination.

Variability of sediment-contact tests in freshwater sediments with low-level anthropogenic contamination - Determination of toxicity thresholds

Energy Technology Data Exchange (ETDEWEB)

Hoess, S., E-mail: hoess@ecossa.d [Ecossa, Giselastr. 6, 82319 Starnberg (Germany); Institute of Biodiversity - Network (IBN), Dreikronengasse 2, 93047 Regensburg (Germany); Ahlf, W., E-mail: ahlf@tu-harburg.d [Institute of Environmental Technology and Energy Economics, Technical University Hamburg-Harburg, Eissendorfer Str. 40, 21071 Hamburg (Germany); Fahnenstich, C. [Institute of Environmental Technology and Energy Economics, Technical University Hamburg-Harburg, Eissendorfer Str. 40, 21071 Hamburg (Germany); Gilberg, D., E-mail: d-gilberg@ect.d [ECT Oekotoxikologie, Boettgerstr. 2-14, 65439 Floersheim (Germany); Hollert, H., E-mail: henner.hollert@bio5.rwth-aachen.d [Department of Ecosystem Analysis, Institute for Environmental Research (Biology 5), RWTH Aachen University, Worringerweg 1, 52074 Aachen (Germany); Melbye, K. [Dr. Fintelmann and Dr. Meyer, Mendelssohnstr. 15D, 22761 Hamburg (Germany); Meller, M., E-mail: m-meller@ecotox-consult.d [ECT Oekotoxikologie, Boettgerstr. 2-14, 65439 Floersheim (Germany); Hammers-Wirtz, M., E-mail: hammers-wirtz@gaiac.rwth-aachen.d [Research Institute for Ecosystem Analysis and Assessment (gaiac), RWTH Aachen University, Worringerweg 1, 52056 Aachen (Germany); Heininger, P., E-mail: heininger@bafg.d [Federal Institute of Hydrology (BfG), Am Mainzer Tor 1, 56070 Koblenz (Germany); Neumann-Hensel, H., E-mail: hensel@fintelmann-meyer.d [Dr. Fintelmann and Dr. Meyer, Mendelssohnstr. 15D, 22761 Hamburg (Germany); Ottermanns, R., E-mail: ottermanns@bio5.rwth-aachen.d [Chair for Environmental Biology and Chemodynamics, Institute for Environmental Research (Biology 5), RWTH Aachen University, Worringerweg 1, 52074 Aachen (Germany); Ratte, H.-T., E-mail: toni.ratte@bio5.rwth-aachen.d [Chair for Environmental Biology and Chemodynamics, Institute for Environmental Research (Biology 5), RWTH Aachen University, Worringerweg 1, 52074 Aachen (Germany)

2010-09-15

Freshwater sediments with low levels of anthropogenic contamination and a broad range of geochemical properties were investigated using various sediment-contact tests in order to study the natural variability and to define toxicity thresholds for the various toxicity endpoints. Tests were performed with bacteria (Arthrobacter globiformis), yeast (Saccharomyces cerevisiae), nematodes (Caenorhabditis elegans), oligochaetes (Lumbriculus variegatus), higher plants (Myriophyllum aquaticum), and the eggs of zebrafish (Danio rerio). The variability in the response of some of the contact tests could be explained by particle size distribution and organic content. Only for two native sediments could a pollution effect not be excluded. Based on the minimal detectable difference (MDD) and the maximal tolerable inhibition (MTI), toxicity thresholds (% inhibition compared to the control) were derived for each toxicity parameter: >20% for plant growth and fish-egg survival, >25% for nematode growth and oligochaete reproduction, >50% for nematode reproduction and >60% for bacterial enzyme activity. - Sediment-contact tests require toxicity thresholds based on their variability in native sediments with low-level contamination.

Errors of car wheels rotation rate measurement using roller follower on test benches

Science.gov (United States)

Potapov, A. S.; Svirbutovich, O. A.; Krivtsov, S. N.

2018-03-01

The article deals with rotation rate measurement errors, which depend on the motor vehicle rate, on the roller, test benches. Monitoring of the vehicle performance under operating conditions is performed on roller test benches. Roller test benches are not flawless. They have some drawbacks affecting the accuracy of vehicle performance monitoring. Increase in basic velocity of the vehicle requires increase in accuracy of wheel rotation rate monitoring. It determines the degree of accuracy of mode identification for a wheel of the tested vehicle. To ensure measurement accuracy for rotation velocity of rollers is not an issue. The problem arises when measuring rotation velocity of a car wheel. The higher the rotation velocity of the wheel is, the lower the accuracy of measurement is. At present, wheel rotation frequency monitoring on roller test benches is carried out by following-up systems. Their sensors are rollers following wheel rotation. The rollers of the system are not kinematically linked to supporting rollers of the test bench. The roller follower is forced against the wheels of the tested vehicle by means of a spring-lever mechanism. Experience of the test bench equipment operation has shown that measurement accuracy is satisfactory at small rates of vehicles diagnosed on roller test benches. With a rising diagnostics rate, rotation velocity measurement errors occur in both braking and pulling modes because a roller spins about a tire tread. The paper shows oscillograms of changes in wheel rotation velocity and rotation velocity measurement system’s signals when testing a vehicle on roller test benches at specified rates.

Engine testing of ceramic cam-roller followers. Final report

Energy Technology Data Exchange (ETDEWEB)

Kalish, Y. [Detroit Diesel Corp., MI (United States)

1992-04-01

For several years, DDC has been developing monolithic ceramic heat engine components. One of the components, developed for an application in our state-of-the-art on-highway, heavy-duty diesel engine, the Series 60, is a silicon nitride cam-roller follower. Prior to starting this program, each valve train component in the Series 60 was considered for conversion to a ceramic material. Many advantages and disadvantages (benefits and risks) were considered. From this effort, one component was selected, the cam-roller follower. Using a system design approach, a ceramic cam-roller follower offered functional improvement at a reasonable cost. The purpose of the project was to inspect and test 100 domestically produced silicon nitride cam-roller followers built to the requirements of the DDC series 60 engine.

EVALUATION OF A LOW FRICTION - HIGH EFFICIENCY ROLLER BEARING ENGINE

Energy Technology Data Exchange (ETDEWEB)

Kolarik, Robert V. II; Shattuck, Charles W.; Copper, Anthony P.

2009-06-30

This Low Friction (High Efficiency Roller Bearing) Engine (LFE) report presents the work done by The Timken Company to conduct a technology demonstration of the benefits of replacing hydrodynamic bearings with roller bearings in the crankshaft and camshaft assemblies of an internal combustion engine for the purpose of collecting data sufficient to prove merit. The engines in the present study have been more extensively converted to roller bearings than any previous studies (40 needle roller bearings per engine) to gain understanding of the full potential of application of bearing technology. The project plan called for comparative testing of a production vehicle which was already respected for having demonstrated low engine friction levels with a rollerized version of that engine. Testing was to include industry standard tests for friction, emissions and fuel efficiency conducted on instrumented dynamometers. Additional tests for fuel efficiency, cold start resistance and other measures of performance were to be made in the actual vehicle. Comparative measurements of noise, vibration and harshness (NVH), were planned, although any work to mitigate the suspected higher NVH level in the rollerized engine was beyond the scope of this project. Timken selected the Toyota Avalon with a 3.5L V-6 engine as the test vehicle. In an attempt to minimize cost and fabrication time, a ‘made-from’ approach was proposed in which as many parts as possible would be used or modified from production parts to create the rollerized engine. Timken commissioned its test partner, FEV Engine Technology, to do a feasibility study in which they confirmed that using such an approach was possible to meet the required dimensional restrictions and tolerances. In designing the roller bearing systems for the crank and cam trains, Timken utilized as many production engine parts as possible. The crankshafts were produced from production line forgings, which use Timken steel, modified with special

Direct fabrication of rigid microstructures on a metallic roller using a dry film resist

International Nuclear Information System (INIS)

Jiang, Liang-Ting; Huang, Tzu-Chien; Chang, Chih-Yuan; Ciou, Jian-Ren; Yang, Sen-Yeu; Huang, Po-Hsun

2008-01-01

This paper presents a novel method to fabricate a metallic roller mold with microstructures on its surface using a dry film resist (DFR). The DFR is laminated uniformly onto the curvy surface of a copper roller. After that, the micro-scale photoresist on the surface of the roller can be patterned by non-planar lithography using a flexible film photomask, followed by ferric chloride wet etching to obtain the desired microstructures. This method overcomes the uniformity issue of photoresist coating on rollers, and solves the molds sliding problem during the embossing process because the microstructures are fabricated directly on the roller surface. Furthermore, the rigid metallic roller mold has excellent strength durability and temperature endurance, which can be used in roller hot embossing with a high embossing pressure. The fabricated microstructure roller mold is used as a mold in the hybrid extrusion roller embossing process and successfully fabricates uniform micro-scale prominent line arrays on PC films. This result proves that the roller fabricated by this method can be successfully used in roller embossing for microstructure mass production. The excellent flatness of dry film resist laminating is the key in this fabrication process. The flexible film photomask can be easily designed using CAD software; this roller fabrication method enhances the design flexibility and reduces the cost and time

Roller Locking Brake

Science.gov (United States)

Vranish, John M.

1993-01-01

Roller locking brake is normally braking rotary mechanism allowing free rotation when electromagnet in mechanism energized. Well suited to robots and other machinery which automatic braking upon removal of electrical power required. More compact and reliable. Requires little electrical power to maintain free rotation and exhibits minimal buildup of heat.

A study on rheological characteristics of roller milled fenugreek fractions.

Science.gov (United States)

Sakhare, Suresh D; Inamdar, Aashitosh A; Prabhasankar, P

2016-01-01

Fenugreek seeds were fractionated by roller milling to get various fractions. The roller milled fractions and whole fenugreek flour (WFF) were evaluated for the flow behavior and time-dependent flow properties using a rotational viscometer at the temperatures of 10-60 (0)C. The samples subjected to a programmed shear rate increase linearly from 0 to 300 s(-1) in 3 min and successive decrease linearly shear rate from 300 s(-1) to 0 in 3 min. The roller milled fractions and WFF paste exhibited non-Newtonian pseudoplastic behavior. Difference in hysteresis loop area was observed among the roller milled fractions and WFF, being more noticeable at lower temperatures. Power law and Casson models were used to predict flow properties of samples. The power law model described well the flow behavior of the roller milled fractions and WFF at temperatures tested. Except flour (FL) fraction, consistency coefficient, m, increased with the temperature both in the forward and backward measurements. The roller milled fractions and WFF exhibited rheopectic behavior that increased viscosity with increasing the shear speed and the temperature. For all the sample tested, initial shear stress increased with increase in shear rate and temperature.

Armed rollers: does nestling's vomit function as a defence against predators?

Directory of Open Access Journals (Sweden)

Deseada Parejo

Full Text Available Chemical defences against predators are widespread in the animal kingdom although have been seldom reported in birds. Here, we investigate the possibility that the orange liquid that nestlings of an insectivorous bird, the Eurasian roller (Coracias garrulus, expel when scared at their nests acts as a chemical defence against predators. We studied the diet of nestling rollers and vomit origin, its chemical composition and deterrent effect on a mammal generalist predator. We also hypothesized that nestling rollers, as their main prey (i.e. grasshoppers do from plants, could sequester chemicals from their prey for their use. Grasshoppers, that also regurgitate when facing to a threat, store the harmful substances used by plants to defend themselves against herbivores. We found that nestling rollers only vomit after being grasped and moved. The production of vomit depended on food consumption and the vomit contained two deterrent chemicals (hydroxycinnamic and hydroxybenzoic acids stored by grasshoppers and used by plants to diminish herbivory, suggesting that they originate from the rollers' prey. Finally, we showed for the first time that the oral secretion of a vertebrate had a deterrent effect on a model predator because vomit of nestling rollers made meat distasteful to dogs. These results support the idea that the vomit of nestling rollers is a chemical defence against predators.

48 CFR 225.7009 - Restriction on ball and roller bearings.

Science.gov (United States)

2010-10-01

... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false Restriction on ball and roller bearings. 225.7009 Section 225.7009 Federal Acquisition Regulations System DEFENSE ACQUISITION... roller bearings. ...

Effects of water chemistry and surface contact on the toxicity of silver nanoparticles to Bacillus subtilis.

Science.gov (United States)

Yi, Jun; Cheng, Jinping

2017-07-01

The growing use of silver nanoparticles (AgNPs) has created concerns about its potential impacts on natural microbial communities. In this study, the physicochemical properties of AgNPs and its toxicity on natural bacteria Bacillus subtilis (B. subtilis) were investigated in aqueous conditions. The characterization data showed that AgNPs highly aggregated in aqueous conditions, and the hydrodynamic diameter of AgNPs in aqueous conditions was larger than its primary size. The studied AgNPs was less toxic to B. subtilis in estuarine water as compared to that in Milli-Q water and artificial seawater, which might be due to the observed enhanced aggregation of AgNPs in estuarine water. The toxicity of AgNPs to B. subtilis was greatly reduced when their surface contact was blocked by a dialysis membrane. Scanning electron microscope images showed that exposure contact to AgNPs resulted in damage of the microbial cell wall and enhanced formation of fibrillar structures. These results suggest that particle-cell contact is largely responsible for the observed toxicity of AgNPs in B. subtilis. This study can help to understand the potential impacts of AgNPs to natural microbes, especially in the complex aquatic environments.

A Methodology of Designing the Teeth Conjugation in a Planetary Roller Screw

Directory of Open Access Journals (Sweden)

Lisowski Filip

2016-12-01

Full Text Available The paper presents the methodology for designing the teeth conjunction of planetary gears in the planetary roller screw mechanism. A function of the planetary gears is to synchronize an operation of rollers in order to avoid axial displacements. A condition of the correct operation is no axial movement of rollers in relation to the nut. The planetary gears are integral parts of rollers and therefore an operation of the gear transmissions has a direct impact on cooperation of the screw, rollers and the nut. The proper design of gear engagements is essential for reducing slippage on surfaces of the cooperating threaded elements. For this purpose, in a designing method, both the limitations of operation and kinematic conditions of rollers’ operation have to be taken into account.

Skateboarding: more dangerous than roller skating or in-line skating.

Science.gov (United States)

Osberg, J S; Schneps, S E; Di Scala, C; Li, G

1998-10-01

To describe the circumstances, severity, and outcomes of skating-related injuries among children admitted to trauma centers. A cross-sectional comparison of roller skaters (n = 154), in-line skaters (n = 190), and skateboarders (n = 254) aged 5 to 19 years who were hospitalized with injuries. Seventy-nine hospitals and pediatric trauma centers participating in the National Pediatric Trauma Registry between October 1988 and April 1997. Three quarters (75.8%) of the study sample were male, nearly half (47.8%) were injured on roads, and more than one third (37.1%) had head injuries. Among skateboarders, 50.8% had head injuries compared with 33.7% of in-line skaters and 18.8% of roller skaters (Pskateboarders were 8 times more likely to be severe or critical compared with roller skaters' injuries and more than 2 times as likely to be severe or critical compared with in-line skaters' injuries. Mean hospital length of stay was 6.0 days for skateboarders, 3.4 days for in-line skaters, and 2.4 days for roller skaters (PSkateboarders were more likely to be male and to be injured on roads than were in-line skaters or roller skaters. Skateboarding-related injuries are more severe and have more serious consequences than roller skating or in-line skating injuries. Research is needed to identify ergonomic and behavioral factors responsible for higher head injury risk to skateboarders, and interventions are needed to reduce the risk.

Impact Analysis of Roller System Stability for Four-High Mill Horizontal Vibration

Directory of Open Access Journals (Sweden)

Xiao-bin Fan

2016-01-01

Full Text Available In order to study the hot Compact Strip Production (CSP, four-high mill vibration characteristics, and vibration suppression method, the roller system structure stability was analyzed and calculated at first in the paper. And then, the mill stand gap was measured at field and its influence on roll transverse vibration was analyzed. The drum gear coupling effect on the roller system stability and the automatic balance conditions of the coupling transmission torque were studied; the influence of axial force caused by the roller cross on the system stability was analyzed. Finally, the roller transverse friction chatter vibration mechanics model was established; the simulation analysis was carried out with eliminating mill house-bearing clearance and adding floating support for coupling, respectively. And the characteristics of the roller “jump vibration” were studied. We applied copper gaskets to eliminate or reduce mill house-bearing clearance for suppressing the rolling mill vibration on the spot; the test results show that the roller transverse vibration was suppressed after eliminating clearance.

Three-dimensional frictionless contact between layered elastic bodies and incorporating sharp edges

Science.gov (United States)

Tordesillas, A. A.; Hill, J. M.

1991-07-01

The roller coating system used in industry to apply paint to sheet metal involves two contacting rolling cylinders, one of which is rubber covered and through which the sheet metal travels. Of particular concern in the industry is the effect of high pressures upon the flow of paint at the ends of the rollers. In an elastohydrodynamic-lubrication analysis of the paint flow, it is the corresponding “dry-contact pressure” which is of major concern. In this paper we present a numerical solution to the three-dimensional contact problem for both smooth profiled layered bodies and those which involve sharp edges but in both cases ignoring the effects of curvature. The procedure adopted is based on one previously developed by a number of authors for homogeneous bodies. An understanding of the consequences of changing the operating variables is of prime importance in an industrial scenario. The numerical scheme described here provides complete measurements of both the deformation and the contact pressure distribution for given operating variables, which are the elastic properties and dimensions of both rolls and the total applied force.

Pediatric fractures during skateboarding, roller skating, and scooter riding.

Science.gov (United States)

Zalavras, Charalampos; Nikolopoulou, Georgia; Essin, Daniel; Manjra, Nahid; Zionts, Lewis E

2005-04-01

Skateboarding, roller skating, and scooter riding are popular recreational and sporting activities for children and adolescents but can be associated with skeletal injury. The purpose of this study is to describe the frequency and characteristics of fractures resulting from these activities. Fractures from skateboarding, roller skating, and scooter riding compose a considerable proportion of pediatric musculoskeletal injuries. Case series; Level of evidence, 4. Demographic data and injury characteristics were analyzed for all patients who presented to the pediatric fracture clinic of the level I trauma center from January 2001 to May 2002 after sustaining fractures due to skateboarding, roller skating, and scooter riding. Among a total of 2371 fractures, the authors identified 325 fractures (13.7%) that occurred during one of these activities. There were 187 patients (mean age, 13 years; 95% male) who sustained 191 skateboard-related fractures, 64 patients (mean age, 10.8 years; 54% male) who sustained 65 fractures while roller skating, and 66 patients (mean age, 9.7 years; 64% male) who sustained 69 fractures while riding a scooter. The forearm was fractured most often, composing 48.2% of skate-boarding fractures, 63.1% of roller-skating fractures, and 50.7% of fractures due to scooter riding. Of the forearm fractures, 94% were located in the distal third. In the skateboarding group, 10 of 191 (5.2%) fractures were open injuries of the forearm, compared to 6 of 2046 (0.3%) fractures caused by other mechanisms of injury (significant odds ratio, 18.8). Skateboarding, roller-skating, and scooter-riding accidents result in a large proportion of pediatric fractures. An open fracture, especially of the forearm, was more likely to be caused by skateboarding than by other mechanisms of injury. Use of wrist and forearm protective equipment should be considered in all children who ride a skateboard.

Standard test method for measurement of web/roller friction characteristics

CERN Document Server

American Society for Testing and Materials. Philadelphia

2003-01-01

1.1 This test method covers the simulation of a roller/web transport tribosystem and the measurement of the static and kinetic coefficient of friction of the web/roller couple when sliding occurs between the two. The objective of this test method is to provide users with web/roller friction information that can be used for process control, design calculations, and for any other function where web/roller friction needs to be known. 1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

Improvement of Railroad Roller Bearing Test Procedures & Development of Roller Bearing Diagnostic Techniques. Volume 2.

Science.gov (United States)

1982-04-01

A comprehensive review of existing basic diagnostic techniques applicable to the railcar roller bearing defect and failure problem was made. Of the potentially feasible diagnostic techniques identified, high frequency vibration was selected for exper...

48 CFR 252.225-7016 - Restriction on acquisition of ball and roller bearings.

Science.gov (United States)

2010-10-01

... of ball and roller bearings. 252.225-7016 Section 252.225-7016 Federal Acquisition Regulations System... and roller bearings. As prescribed in 225.7009-5, use the following clause: Restriction on Acquisition of Ball and Roller Bearings (MAR 2006) (a) Definitions. As used in this clause' (1) Bearing...

Improving feeding powder distribution to the compaction zone in the roller compaction.

Science.gov (United States)

Yu, Mingzhe; Omar, Chalak; Schmidt, Alexander; Litster, James D; Salman, Agba D

2018-07-01

In the roller compaction process, powder flow properties have a significant influence on the uniformity of the ribbon properties. The objective of this work was to improve the powder flow in the feeding zone by developing novel feeding guiders which are located in the feeding zone close to the rollers in the roller compactor (side sealing system). Three novel feeding guiders were designed by 3D printing and used in the roller compactor, aiming to control the amount of powder passing across the roller width. The new feeding guiders were used to guide more powder to the sides between the rollers and less powder to the centre comparing to the original feeding elements. Temperature profile and porosity across the ribbon width indicated the uniformity of the ribbon properties. Using the novel feeding guiders resulted in producing ribbons with uniform temperature profile and porosity distribution across the ribbon width. The design of the feeding guiders contributed to improving the tensile strength of the ribbons produced from the compaction stage as well as reducing the fines produced from the crushing stage. Copyright © 2018 Elsevier B.V. All rights reserved.

Micromechanical study of the effect of inclusions on fatigue failure in a roller bearing

DEFF Research Database (Denmark)

Cerullo, Michele; Tvergaard, Viggo

2015-01-01

model containing a single inclusion, using the approximation of a 2D plane strain numerical analysis. The Dang Van multiaxial fatigue criterion is used for the local stresses in the matrix material, to ensure that the stresses remain within the fatigue limit. The matrix material is taken to be one...... of the most commonly used bearing steels, AISI 52100, and two different types of inclusions are considered. The macroscopic stress histories applied correspond to either a Hertzian or an elastohydrodynamic (EHL) contact pressure distribution under the rollers. Findings - The paper shows that sub...

Chaotic Dynamics of Cage Behavior in a High-Speed Cylindrical Roller Bearing

Directory of Open Access Journals (Sweden)

Long Chen

2016-01-01

Full Text Available This paper presents a mathematical model to investigate the nonlinear dynamic behavior of cage in high-speed cylindrical bearing. Variations of cage behavior due to varying cage eccentricity and cage guidance gap are observed. Hydrodynamic behavior in cage contacts is taken into consideration for a more realistic calculation of acting forces owing to high working speed. Analysis of real-time cage dynamic behavior on radial plane is carried out using chaos theory based on the theoretical and mathematical model established in the paper. The analytical results of this paper provide a solid foundation for designing and manufacturing of high-speed cylindrical roller bearing.

Phylogenetic relationships of rollers (Coraciidae) based on complete mitochondrial genomes and fifteen nuclear genes.

Science.gov (United States)

Johansson, Ulf S; Irestedt, Martin; Qu, Yanhua; Ericson, Per G P

2018-04-06

The rollers (Coraciidae) constitute a relative small avian family with ca. 12 species distributed in Africa, western and southern Eurasia, and eastern Australia. In this study we examine the phylogenetic relationships of all species currently recognized in the family, including two taxa whose taxonomic status is currently contested. By using shotgun sequencing on degraded DNA from museum study skins we have been able to recover complete mitochondrial genomes as well as 15 nuclear genes for in total 16 taxa. The gene sequences were analyzed both concatenated in a maximum likelihood framework as well in a species tree approach using MP-EST. The different analytical approaches yield similar, highly supported trees and support the current division of the rollers into two genera, Coracias and Eurystomus. The only conflict relates to the placement of the Blue-bellied Roller (C. cyanogaster), where the mitochondrial, and the concatenated nuclear and mitochondrial data set, place this taxon as sister to the other Coracias species, whereas nuclear data and the species tree analysis place it as the sister taxon of C. naevia and C. spatulatus. All analyses place the Eurasian roller (C. garrulus) with the two African species, Abyssinian Roller (C. abyssinica) and Liliac-breasted Roller (C. caudatus), and place this clade as the sister group to the Asian Coracias rollers. In addition, our results support a sister group relationship between the morphologically rather dissimilar Purple Roller (C. naevia) and Racquet-tailed Roller (C. spatulatus) and also support the division of Eurystomus in an African and an Asian clade. However, within the Asian clade the Azure Roller (E. azureus) from Halmahera appears to be nested within the Dollarbird (E. orientalis), indicating that that this taxon is a morphological divergent, but a rather recent offshoot, of the widespread Dollarbird. Similarly, the Purple-winged Roller (C. temminickii) from Sulawesi group together with C. benghalensis

Contact toxicities of anuran skin alkaloids against the fire ant ( Solenopsis invicta)

Science.gov (United States)

Weldon, Paul J.; Cardoza, Yasmin J.; Vander Meer, Robert K.; Hoffmann, W. Clint; Daly, John W.; Spande, Thomas F.

2013-02-01

Nearly 500 alkaloids, representing over 20 structural classes, have been identified from the skin of neotropical poison frogs (Dendrobatidae). These cutaneous compounds, which are derived from arthropod prey of the frogs, generally are believed to deter predators. We tested the red imported fire ant ( Solenopsis invicta) for toxicosis following contact with 20 alkaloids (12 structural classes) identified from dendrobatids or other anurans. Individual ants forced to contact the dried residues of 13 compounds exhibited convulsions and/or reduced ambulation. We estimated the cutaneous concentrations of several compounds based on their reported recoveries from skin extracts of free-ranging frogs and our measurements of the skin surface areas of museum specimens. Pumiliotoxin 251D exhibited contact toxicity below its estimated cutaneous concentration in the Ecuadorian frog, Epipedobates anthonyi, an observation consistent with the hypothesized role of this compound in anuran chemical defense. Our results and those of a previous study of mosquitoes indicate that some anuran skin compounds function defensively as contact toxins against arthropods, permeating their exoskeleton.

Nanocrystalline, superhard, ductile ceramic coatings for roller-cone bit bearings

Energy Technology Data Exchange (ETDEWEB)

Namavar, F.; Colter, P.; Karimy, H. [Spire Corp., Bedford, MA (United States)] [and others

1997-12-31

The established method for construction of roller bits utilizes carburized steel, frequently with inserted metal bearing surfaces. This construction provides the necessary surface hardness while maintaining other desirable properties in the core. Protective coatings are a logical development where enhanced hardness, wear resistance, corrosion resistance, and surface properties are required. The wear properties of geothermal roller-cone bit bearings could be further improved by application of protective ceramic hard coatings consisting of nanometer-sized crystallites. Nanocrystalline protective coatings provide the required combination of hardness and toughness which has not been available thus far using traditional ceramics having larger grains. Increased durability of roller-cone bit bearings will ultimately reduce the cost of drilling geothermal wells through increased durability.

On Working Capacity Criteria for Screw-Roller Mechanisms

Directory of Open Access Journals (Sweden)

D. S. Blinov

2015-01-01

Full Text Available Today roller-screw mechanisms (RSM are the most prospective motion converters from rotary to linear type. RSM manufacturers have suggested their design in the way, similar to the rolling bearings, in static and dynamic load ratings. The latter means that during long operations the main criterion of the RSM working capacity is fatigue spalling. However, this approach does not permit to consider temporal changes of the most critical performance parameters of the RSM (such as the axial play, the efficiency factor, the axial stiffness, the accuracy, the starting torque force for zero lash RSMs, etc. through calculations. The abovementioned method was not perfect, because the choice of the main criterion of RSM working capacity was wrong. The article proves that wear-resistance is the main criterion of RSM working capacity. The proof is the RSM efficiency factor equal to 80-88% on the average. The power loss occurs because of overcoming a sliding friction between multiple (from 300 to 1000 interfacing turns of thread on the screw and the rollers as well as on the rollers and the nut. That is why the RSMs are the screwtype rolling mechanisms with an essential portion of sliding friction. High-accuracy measurements taken using the device called a form-tracer for threaded pieces permitted to determine the essential changes on the profiles of turns of threads on the rollers (a straight-line portion appeared on the radial profile; these changes could emerge only from wear. Besides, the length of this portion increased with the increasing RSM operation time. The JSC “Moskvich” has examined the RSMs, which have been put out of operation after completing their service life as parts of robot welding machines. There were no traces of fatigue spalling found on the threaded surfaces of the RSM parts, while the sizes of the straight-line portions on the turns of the roller threads were much bigger than they were during the measurements after the initial

Fast EEMD Based AM-Correntropy Matrix and Its Application on Roller Bearing Fault Diagnosis

Directory of Open Access Journals (Sweden)

Yunxiao Fu

2016-06-01

Full Text Available Roller bearing plays a significant role in industrial sectors. To improve the ability of roller bearing fault diagnosis under multi-rotating situation, this paper proposes a novel roller bearing fault characteristic: the Amplitude Modulation (AM based correntropy extracted from the Intrinsic Mode Functions (IMFs, which are decomposed by Fast Ensemble Empirical mode decomposition (FEEMD and employ Least Square Support Vector Machine (LSSVM to implement intelligent fault identification. Firstly, the roller bearing vibration acceleration signal is decomposed by FEEMD to extract IMFs. Secondly, IMF correntropy matrix (IMFCM as the fault feature matrix is calculated from the AM-correntropy model of the primary vibration signal and IMFs. Furthermore, depending on LSSVM, the fault identification results of the roller bearing are obtained. Through the bearing identification experiments in stationary rotating conditions, it was verified that IMFCM generates more stable and higher diagnosis accuracy than conventional fault features such as energy moment, fuzzy entropy, and spectral kurtosis. Additionally, it proves that IMFCM has more diagnosis robustness than conventional fault features under cross-mixed roller bearing operating conditions. The diagnosis accuracy was more than 84% for the cross-mixed operating condition, which is much higher than the traditional features. In conclusion, it was proven that FEEMD-IMFCM-LSSVM is a reliable technology for roller bearing fault diagnosis under the constant or multi-positioned operating conditions, and as such, it possesses potential prospects for a broad application of uses.

Edgewise vibration control of wind turbine blades using roller and liquid dampers

DEFF Research Database (Denmark)

Zhang, Zili; Nielsen, Søren R.K.

2014-01-01

suppressing edgewise vibrations. The roller dampers are more volumetrically efficient due to the higher mass density of the steel comparing with the liquid. On the other hand, TLCDs have their advantage that it is easier to specify the optimum damping of the damper by changing the opening ratio of the orifice......This paper deals with the passive vibration control of edgewise vibrations by means of roller dampers and tuned liquid column dampers (TLCDs). For a rotating blade, the large centrifugal acceleration makes it possible to use roller dampers or TLCDs with rather small masses for effectively...

Edgewise vibration control of wind turbine blades using roller and liquid dampers

International Nuclear Information System (INIS)

Zhang, Z L; Nielsen, S R K

2014-01-01

This paper deals with the passive vibration control of edgewise vibrations by means of roller dampers and tuned liquid column dampers (TLCDs). For a rotating blade, the large centrifugal acceleration makes it possible to use roller dampers or TLCDs with rather small masses for effectively suppressing edgewise vibrations. The roller dampers are more volumetrically efficient due to the higher mass density of the steel comparing with the liquid. On the other hand, TLCDs have their advantage that it is easier to specify the optimum damping of the damper by changing the opening ratio of the orifice. In this paper, 2-DOF nonlinear models are suggested for tuning a roller damper or a TLCD attached to a rotating wind turbine blade, ignoring the coupling between the blade and the tower. The decoupled optimization is verified by incorporating the optimized damper into a more sophisticated 13- DOF wind turbine model with due consideration of the coupled blade-tower-drivetrain vibrations, quasi-static aeroelasticity as well as a collective pitch controller. Performances of the dampers are compared in terms of the control efficiency and the practical applications. The results indicate that roller dampers and TLCDs at optimal tuning can effectively suppress the dynamic response of wind turbine blades

Daylighting performance evaluation of a bottom-up motorized roller shade

Energy Technology Data Exchange (ETDEWEB)

Kapsis, K.; Athienitis, A.K.; Zmeureanu, R.G. [Department of Building, Civil and Environmental Engineering, Concordia University, Montreal, QC (Canada); Tzempelikos, A. [School of Civil Engineering, Purdue University, West Lafayette, IN (United States)

2010-12-15

This paper presents an experimental and simulation study for quantifying the daylighting performance of bottom-up roller shades installed in office spaces. The bottom-up shade is a motorized roller shade that opens from top to bottom operating in the opposite direction of a conventional roller shade, so as to cover the bottom part of the window, while allowing daylight to enter from the top part of the window, reaching deeper into the room. A daylighting simulation model, validated with full-scale experiments, was developed in order to establish correlations between the shade position, outdoor illuminance and work plane illuminance for different outdoor conditions. Then, a shading control algorithm was developed for application in any location and orientation. The validated model was employed for a sensitivity analysis of the impact of shade optical properties and control on the potential energy savings due to the use of daylighting. The results showed that Daylight Autonomy for the bottom-up shade is 8-58% higher compared to a conventional roller shade, with a difference of 46% further away from the facade, where the use of electric lighting is needed most of the time. The potential reduction in energy consumption for lighting is 21-41%. (author)

INFLUENCE CONSTRUCTION OF THE ROLLER ON THE POWER OF THE DRIVE SYSTEM OF THE BELT CONVEYOR

Directory of Open Access Journals (Sweden)

Tadeusz OPASIAK

2014-09-01

Full Text Available The paper presents a study of new design of rollers. The study focused on the measurement of static and dynamic resistance of rotating rollers and the impact of new construction on the power consumption of the belt conveyor. Rollers have been modified through the use of class C4 bearing seals and labyrinth seal U4Exp 62/65 with a cover 2LU4 of runner construction. Measurements of static and dynamic resistance of rotating rollers were made on a universal rollers stand and power measurements were carried out on a belt conveyor power supply system Gwarek 1200 No. TW in mine KWK Mysłowice–Wesoła.

Edge coating apparatus with movable roller applicator for solar cell substrates

Science.gov (United States)

Pavani, Luca; Abas, Emmanuel

2012-12-04

A non-contact edge coating apparatus includes an applicator for applying a coating material on an edge of a solar cell substrate and a control system configured to drive the applicator. The control system may drive the applicator along an axis to maintain a distance with an edge of the substrate as the substrate is rotated to have the edge coated with a coating material. The applicator may include a recessed portion into which the edge of the substrate is received for edge coating. For example, the applicator may be a roller with a groove. Coating material may be introduced into the groove for application onto the edge of the substrate. A variety of coating materials may be employed with the apparatus including hot melt ink and UV curable plating resist.

Toxicity assessment of sediments from three European river basins using a sediment contact test battery

NARCIS (Netherlands)

Tuikka, A.I.; Schmitt, C.; Hoess, S.; Bandow, N; von der Ohe, P.; de Zwart, D.; de Deckere, E.; Streck, G.; Mothes, S.; van Hattum, A.G.M.; Kocan, A.; Brix, R.; Brack, W.; Barcelo, D.; Sormunen, A.; Kukkonen, J.V.K.

2011-01-01

The toxicity of four polluted sediments and their corresponding reference sediments from three European river basins were investigated using a battery of six sediment contact tests representing three different trophic levels. The tests included were chronic tests with the oligochaete Lumbriculus

Roller compaction: Effect of relative humidity of lactose powder.

Science.gov (United States)

Omar, Chalak S; Dhenge, Ranjit M; Palzer, Stefan; Hounslow, Michael J; Salman, Agba D

2016-09-01

The effect of storage at different relative humidity conditions, for various types of lactose, on roller compaction behaviour was investigated. Three types of lactose were used in this study: anhydrous lactose (SuperTab21AN), spray dried lactose (SuperTab11SD) and α-lactose monohydrate 200M. These powders differ in their amorphous contents, due to different manufacturing processes. The powders were stored in a climatic chamber at different relative humidity values ranging from 10% to 80% RH. It was found that the roller compaction behaviour and ribbon properties were different for powders conditioned to different relative humidities. The amount of fines produced, which is undesirable in roller compaction, was found to be different at different relative humidity. The minimum amount of fines produced was found to be for powders conditioned at 20-40% RH. The maximum amount of fines was produced for powders conditioned at 80% RH. This was attributed to the decrease in powder flowability, as indicated by the flow function coefficient ffc and the angle of repose. Particle Image Velocimetry (PIV) was also applied to determine the velocity of primary particles during ribbon production, and it was found that the velocity of the powder during the roller compaction decreased with powders stored at high RH. This resulted in less powder being present in the compaction zone at the edges of the rollers, which resulted in ribbons with a smaller overall width. The relative humidity for the storage of powders has shown to have minimal effect on the ribbon tensile strength at low RH conditions (10-20%). The lowest tensile strength of ribbons produced from lactose 200M and SD was for powders conditioned at 80% RH, whereas, ribbons produced from lactose 21AN at the same condition of 80% RH showed the highest tensile strength. The storage RH range 20-40% was found to be an optimum condition for roll compacting three lactose powders, as it resulted in a minimum amount of fines in the

The System of Simulation and Multi-objective Optimization for the Roller Kiln

Science.gov (United States)

Huang, He; Chen, Xishen; Li, Wugang; Li, Zhuoqiu

It is somewhat a difficult researching problem, to get the building parameters of the ceramic roller kiln simulation model. A system integrated of evolutionary algorithms (PSO, DE and DEPSO) and computational fluid dynamics (CFD), is proposed to solve the problem. And the temperature field uniformity and the environment disruption are studied in this paper. With the help of the efficient parallel calculation, the ceramic roller kiln temperature field uniformity and the NOx emissions field have been researched in the system at the same time. A multi-objective optimization example of the industrial roller kiln proves that the system is of excellent parameter exploration capability.

Design, development and evaluation of a divergent roller sizer for almond kernels

Directory of Open Access Journals (Sweden)

D Ghanbarian

2015-09-01

Full Text Available Introduction: Iran is one of the major producers of almonds. According to the statistics released by FAO (2011, Iran with more than 110000 tons of almonds is the third in rank throughout the world. However, most Iranian almonds are presented as an unsorted and unpackaged product. Some producers sort their products by hand which is very time-consuming and labor-intensive. So, there is an essential need for suitable grading and packaging machines especially for the export of almond kernels.Grading, which is sometimes called sorting, is basically separating the material in different homogenous groups according to its specific characteristics like size, shape, color and on the basis of quality. Weighing is one of the best methods for grading agricultural products based on size, but due to its high cost and complexity of operations, usage of weigh size sorting machines is practically limited. So, sizing of most agricultural products is accomplished based on their dimensional attributes such as diameter, length, thickness or a combination of them. Field study shows that recently vibrating sizing machines are used for grading almond kernels. This type of sizing machine is huge, expensive, noisy and it consumes a lot of energy. Thus, the main objective of the present study was the design, development and evaluation of a new prototype of an almond kernel sizing machine. Materials and methods: It is important that the machine could resolve defects of existing vibrating machines. It should provide efficient and cost effective sizing for a wide range of kernel sizes and shapes. Furthermore, it should be of simple construction and be able to accept manual feeding. Previously conducted experiments showed that the thickness of the kernel is the most appropriate dimension for its sizing. Among the different types of dimensional sizing machines, the divergent roller grader which grades the products based on their thickness is considered to be one of the simplest

Effects of glovebox gloves on grip and key pinch strength and contact forces for simulated manual operations with three commonly used hand tools.

Science.gov (United States)

Sung, Peng-Cheng

2014-01-01

This study examined the effects of glovebox gloves for 11 females on maximum grip and key pinch strength and on contact forces generated from simulated tasks of a roller, a pair of tweezers and a crescent wrench. The independent variables were gloves fabricated of butyl, CSM/hypalon and neoprene materials; two glove thicknesses; and layers of gloves worn including single, double and triple gloving. CSM/hypalon and butyl gloves produced greater grip strength than the neoprene gloves. CSM/hypalon gloves also lowered contact forces for roller and wrench tasks. Single gloving and thin gloves improved hand strength performances. However, triple layers lowered contact forces for all tasks. Based on the evaluating results, selection and design recommendations of gloves for three hand tools were provided to minimise the effects on hand strength and optimise protection of the palmar hand in glovebox environments. To improve safety and health in the glovebox environments where gloves usage is a necessity, this study provides recommendations for selection and design of glovebox gloves for three hand tools including a roller, a pair of tweezers and a crescent wrench based on the results discovered in the experiments.

Roller Skating; Physical Education: 9.8414.

Science.gov (United States)

Amacker, Kathy; Mikell, Lenora

GRADES OR AGES: Grades 7-12. SUBJECT MATTER: Methods and procedures of roller skating. ORGANIZATION AND PHYSICAL APPEARANCE: The contents are divided into six areas, which are Course Guidelines, Course Description and Accreditation Standard Broad Goal, Course of Study Behavioral Objectives, Course Content, Learning Activities and Teaching…

Knee joint position sense of roller hockey players: a comparative study.

Science.gov (United States)

Venâncio, João; Lopes, Diogo; Lourenço, Joaquim; Ribeiro, Fernando

2016-06-01

This study aimed to compare knee joint position sense of roller hockey players with an age-matched group of non-athletes. Forty-three male participants voluntarily participated in this cross-sectional study: 21 roller hockey players (mean age: 23.2 ± 4.2 years old, mean weight: 81.8 ± 9.8 kg, mean height: 180.5 ± 4.1 cm) and 22 age-matched non-athletes (mean age: 23.7 ± 3.9 years old, mean weight: 85.0 ± 6.2 kg, mean height: 181.5 ± 5.0 cm). Knee joint position sense of the dominant limb was evaluated using a technique of open-kinetic chain and active knee positioning. Joint position sense was reported using absolute, relative and variable angular errors. The main results indicated that the group of roller hockey players showed significantly lower absolute (2.4 ± 1.2º vs. 6.5 ± 3.2º, p ≤ 0.001) and relative (1.7 ± 2.1º vs. 5.8 ± 4.4º, p ≤ 0.001) angular errors in comparison with the non-athletes group. In conclusion, the results from this present study suggest that proprioceptive acuity, assessed by measuring joint position sense, is increased in roller hockey players. The enhanced proprioception of the roller hockey players could contribute to injury prevention and improved performance during sporting activities.

Modelling of a mecanum wheel taking into account the geometry of road rollers

Science.gov (United States)

Hryniewicz, P.; Gwiazda, A.; Banaś, W.; Sękala, A.; Foit, K.

2017-08-01

During the process planning in a company one of the basic factors associated with the production costs is the operation time for particular technological jobs. The operation time consists of time units associated with the machining tasks of a workpiece as well as the time associated with loading and unloading and the transport operations of this workpiece between machining stands. Full automation of manufacturing in industry companies tends to a maximal reduction in machine downtimes, thereby the fixed costs simultaneously decreasing. The new construction of wheeled vehicles, using Mecanum wheels, reduces the transport time of materials and workpieces between machining stands. These vehicles have the ability to simultaneously move in two axes and thus more rapid positioning of the vehicle relative to the machining stand. The Mecanum wheel construction implies placing, around the wheel free rollers that are mounted at an angle 450, which allow the movement of the vehicle not only in its axis but also perpendicular thereto. The improper selection of the rollers can cause unwanted vertical movement of the vehicle, which may cause difficulty in positioning of the vehicle in relation to the machining stand and the need for stabilisation. Hence the proper design of the free rollers is essential in designing the whole Mecanum wheel construction. It allows avoiding the disadvantageous and unwanted vertical vibrations of a whole vehicle with these wheels. In the article the process of modelling the free rollers, in order to obtain the desired shape of unchanging, horizontal trajectory of the vehicle is presented. This shape depends on the desired diameter of the whole Mecanum wheel, together with the road rollers, and the width of the drive wheel. Another factor related with the curvature of the trajectory shape is the length of the road roller and its diameter decreases depending on the position with respect to its centre. The additional factor, limiting construction of

Case histories of roller cone core bit application in crystalline rock

International Nuclear Information System (INIS)

Dahlem, J.S.

1988-01-01

The increased interest in deep crystalline rock drilling projects has resulted in a requirement for premium coring bits which are effective in such a harsh and abrasive environment. Hard formation roller cone insert bits have traditionally and constantly performed well in crystalline rock. As a result, the application of state of the art roller cone rock bit technology to the design and development of core bits has made crystalline coring projects more viable than ever before. This paper follows the development of roller cone core bits by examining their use on project such as HDR (Hot Dry Rock, Los Alamos); NAGRA (Nuclear Waste Disposal Wells in Switzerland); Camborne School of Mines Geothermal Project in Cornwall, UK; Deep Gas Project in Sweden; and the KTB Deep Drilling Project in West Germany

Dropping a particle out of a roller coaster

International Nuclear Information System (INIS)

Mungan, Carl E; Lipscombe, Trevor C

2014-01-01

A rider in a roller coaster lets go of a particle such as a small marble. How far does the marble travel horizontally from the point of release before hitting the ground, assuming the speed of the roller coaster is determined by conservation of mechanical energy starting from the highest hill up which it was pulled? Where should the marble be released along the track if one wishes to maximize the range of the marble? These questions constitute interesting variations on conventional problems in two-dimensional kinematics, appropriate for an undergraduate course in classical mechanics. Exploration of various shapes of tracks could form interesting student projects for numerical or experimental investigation. (paper)

3000-HP Roller Gear Transmission Development Program. Volume 3. Roller Gear Manufacture

Science.gov (United States)

1975-07-01

power is fed through the ramp roller clutch type free- wheel units to spur gears which mesh with the combining spur gear whose centerline is common...when the engine tends to turn faster than the main rotor shaft. It is in the free- wheel mode when the main rotor shaft tends to turn faster than the...gears are cut progrind at this time. Check face runout on each end of largo gears. Not to exceed .002" TIR 30 EBW one end 40 EBW opposite end

Contact and fumigant toxicity of Armoracia rusticana essential oil, allyl isothiocyanate and related compounds to Dermatophagoides farinae.

Science.gov (United States)

Yun, Yeon-Kyeong; Kim, Hyun-Kyung; Kim, Jun-Ran; Hwang, Kumnara; Ahn, Young-Joon

2012-05-01

The toxicity to adult Dermatophagoides farinae of allyl isothiocyanate identified in horseradish, Armoracia rusticana, oil and another 27 organic isothiocyanates was evaluated using contact + fumigant and vapour-phase mortality bioassays. Results were compared with those of two conventional acaricides, benzyl benzoate and dibutyl phthalate. Horseradish oil (24 h LC(50), 1.54 µg cm(-2)) and allyl isothiocyanate (2.52 µg cm(-2)) were highly toxic. Benzyl isothiocyanate (LC(50) , 0.62 µg cm(-2)) was the most toxic compound, followed by 4-chlorophenyl, 3-bromophenyl, 3,5-bis(trifluoromethyl)phenyl, cyclohexyl, 2-chlorophenyl, 4-bromophenyl and 2-bromophenyl isothiocyanates (0.93-1.41 µg cm(-2)). All were more effective than either benzyl benzoate (LC(50) , 4.58 µg cm(-2)) or dibutyl phthalate (24.49 µg cm(-2)). The structure-activity relationship indicates that types of functional group and chemical structure appear to play a role in determining the isothiocyanate toxicities to adult D. farinae. In the vapour-phase mortality bioassay, these isothiocyanates were consistently more toxic in closed versus open containers, indicating that their mode of delivery was, in part, a result of vapour action. In the light of global efforts to reduce the level of highly toxic synthetic acaricides in indoor environments, the horseradish oil-derived compounds and the isothiocyanates described herein merit further study as potential acaricides for the control of house dust mite populations as fumigants with contact action. Copyright © 2011 Society of Chemical Industry.

Temperature and Thermal Expansion Analysis of the Cooling Roller Based on the Variable Heat Flux Boundary Condition

Science.gov (United States)

Li, Yongkang; Yang, Yang; He, Changyan

2018-06-01

Planar flow casting (PFC) is a primary method for preparing an amorphous ribbon. The qualities of the amorphous ribbon are significantly influenced by the temperature and thermal expansion of the cooling roller. This study proposes a new approach to analyze the three-dimensional temperature and thermal expansion of the cooling roller using variable heat flux that acted on the cooling roller as a boundary condition. First, a simplified two-dimensional model of the PFC is developed to simulate the distribution of the heat flux in the circumferential direction with the software FLUENT. The resulting heat flux is extended to be three-dimensional in the ribbon's width direction. Then, the extended heat flux is imported as the boundary condition by the CFX Expression Language, and the transient temperature of the cooling roller is analyzed in the CFX software. Next, the transient thermal expansion of the cooling roller is simulated through the thermal-structural coupling method. Simulation results show that the roller's temperature and expansion are unevenly distributed, reach the peak value in the middle width direction, and the quasi-steady state of the maximum temperature and thermal expansion are achieved after approximately 50 s and 150 s of casting, respectively. The minimum values of the temperature and expansion are achieved when the roller has a thickness of 45 mm. Finally, the reliability of the approach proposed is verified by measuring the roller's thermal expansion on the spot. This study provides theoretical guidance for the roller's thermal expansion prediction and the gap adjustment in the PFC.

ANALYSIS OF MOVEMENT RESISTANCE OF CONVEYOR BELT AND ROLLERS IN THE COAL MINE MYSŁOWICE-WESOŁA

Directory of Open Access Journals (Sweden)

Tadeusz OPASIAK

2014-03-01

Full Text Available The paper presents a study of new design of SAG rollers. The study focused on the measurement of static and dynamic resistance of rotating rollers and the impact of new construction on the power consumption of the conveyor. Rollers have been modified through the use of class C4 bearing seals and labyrinth seal U4Exp 62/65 with a cover 2LU4 of runner construction. Measurements of static and dynamic resistance of rotating rollers were made on a universal rollers test bench, and power measurements were carried out on a belt conveyor power supply system Gwarek 1200 No. TW in KWK Mysłowice-Wesoła

Rock 'n roller coaster : an explorative study on the evolution of the European steel roller coaster industry

NARCIS (Netherlands)

Timmermans, B.; Bekkers, R.N.A.; Bordoli, L.

2012-01-01

This article investigates the 50 years evolution of the European steel roller coaster industry, which can be classified as a complex products systems (CoPS) industry. This industry is characterized as a non-shake out industry where entry can be divided in three waves, i.e. early diversifiers, new

Cost of a roller skating rink to the local accident and emergency department.

Science.gov (United States)

Nayeem, N; Shires, S E; Porter, J E

1990-01-01

A 14 month retrospective study was undertaken to determine the cost implications of the opening of a roller skating rink to the local hospital accident and emergency department (A and E). A total of 398 patients attended following injury at the roller skating rink, of whom 384 were included in the study. The estimated cost of their injuries was determined by the hospital accounts department. The average cost per patient attending the A and E department following roller skating injury was about 100 pounds. The total cost to the A and E department of all injuries sustained at the rink over this period was 38,412 pounds. The cost implications of opening a roller skating rink for the A and E department are considerable. If proposals for self-budgeting are applied, A and E departments will have to seek additional funding if such leisure facilities are opened in their vicinity. PMID:2097020

Influence of Surface-profile and Movement-path of Roller on Thickness Thinning during Multi-pass Deep Drawing Spinning

Directory of Open Access Journals (Sweden)

Xia Qinxiang

2016-01-01

Full Text Available Over thinning is a serious defect influencing the forming quality of spun workpiece during multi-pass deep drawing spinning. Surface-profile and movement-path of roller are the key factors influencing the thinning ratio of wall thickness of spun workpiece. The influence of surface-profile and movement-path of roller on thickness thinning were studied based on numerical simulation and experimental research, four groups of forming experiments were carried out under the combination of the different surface-profile of roller (R12 and R25-12 and movement-path of roller (spinning from the bottom of the blank and spinning from the middle of the blank. The results show that both the surface-profile and movement-path of roller have great influence on wall thickness thinning during multi-pass deep drawing spinning; and compared with the movement-path of roller, the influence of surface-profile of roller is more significant. The experimental results conform well to the simulation ones. It indicates that the FEA model established is reasonable and reliable.

Oriented Onion Sowing by a Forked-Roller Sowing Unit

Directory of Open Access Journals (Sweden)

Aleksandr G.

2018-03-01

Full Text Available Introduction: The existing sowing machines do not provide a single feeding of the bulbs with a planting (sowing unit that leads to a violation of the agrotechnical requirements of planting bulbs. It is necessary to search new solutions to preserve the position of the bulbs in the furrow with the bottom down and their regularly spaced distribution. Materials and Methods: The article presents the design for a prototype for a planting machine equipped with a forked-roller sowing unit for orienting the onion-sowing into a furrow. Testing the forked-roller sowing unit were carried out on a flat area where the physical and mechanical properties of the soil were determined on the days of sowing, and the indices of the quality of the onion-sowing were determined. The study of the effect of the sowing machine speed on the quality of the onion-seed bulb landing was determined by the change in the translational speed of the sowing unit in the range of 0.8 m/s to 1.2 m/s with a variation interval of 0.1 m/s. The indicators of the quality of the planting of the bulbs were determined by the opening of the closed furrow. The results of laboratory-field studies of the planting machine prototype are presented. Results: The results of laboratory-field studies of a planting machine equipped with a forked-roller sowing unit for planting onion bulbs are presented. The optimal technological parameters are determined experimentally. It was determined the number of bulbs that are for up is 51 % and the regularity of planting by the forked-roller sowing unit – 79 %. These figures are provided at the forward speed of the planting machine VM = 0.9–1.0 m/s, the height of the fall of the bulb HA = 0.12 m, and the rotation frequency of the landing drum nБ = 0.47 c-1. Discussion and Conclusions: The use of a forked-roller sowing unit makes it possible to increase the proportion of onions planted by bottom down by 200 %, and the uniformity of planting bulbs by 19 %, in

Improvement of Roller Bearing Diagnosis with Unlabeled Data Using Cut Edge Weight Confidence Based Tritraining

Directory of Open Access Journals (Sweden)

Wei-Li Qin

2016-01-01

Full Text Available Roller bearings are one of the most commonly used components in rotational machines. The fault diagnosis of roller bearings thus plays an important role in ensuring the safe functioning of the mechanical systems. However, in most cases of bearing fault diagnosis, there are limited number of labeled data to achieve a proper fault diagnosis. Therefore, exploiting unlabeled data plus few labeled data, this paper proposed a roller bearing fault diagnosis method based on tritraining to improve roller bearing diagnosis performance. To overcome the noise brought by wrong labeling into the classifiers training process, the cut edge weight confidence is introduced into the diagnosis framework. Besides a small trick called suspect principle is adopted to avoid overfitting problem. The proposed method is validated in two independent roller bearing fault experiment vibrational signals that both include three types of faults: inner-ring fault, outer-ring fault, and rolling element fault. The results demonstrate the desirable diagnostic performance improvement by the proposed method in the extreme situation where there is only limited number of labeled data.

Verkkokaupan kansainvälistäminen Facebook-mainonnalla : Case HighRoller

OpenAIRE

Heikkinen, Tiia

2016-01-01

Verkkokauppa toimii HighRoller Suomi Oy:n HighRoller-lihashuoltolaiteen pääasiallisena myyntikanavana ja Facebook-markkinointikanavana. Tähän mennessä tuotetta on markkinoitu Facebookissa ilman varsinaista strategiaa. Nyt tuotetta viedään Ruotsiin ja uusia markkinoita varten suunniteltiin ja toteutettiin Facebook-mainoskampanja. Teoreettisessä viitekehyksessä käydään läpi aluksi digimarkkinointia, minkä jälkeen pohditaan sosiaalisen median merkitystä verkkokaupalle. Seuraavaksi keskitytää...

An investigation into the impact of magnesium stearate on powder feeding during roller compaction.

Science.gov (United States)

Dawes, Jason; Gamble, John F; Greenwood, Richard; Robbins, Phil; Tobyn, Mike

2012-01-01

A systematic evaluation on the effect of magnesium stearate on the transmission of a placebo formulation from the hopper to the rolls during screw fed roller compaction has been carried out. It is demonstrated that, for a system with two 'knurled' rollers, addition of 0.5% w/w magnesium stearate can lead to a significant increase in ribbon mass throughput, with a consequential increase in roll gap, compared to an unlubricated formulation (manufactured at equivalent process conditions). However, this effect is reduced if one of the rollers is smooth. Roller compaction of a lubricated formulation using two smooth rollers was found to be ineffective due to a reduction in friction at the powder/roll interface, i.e. powder was not drawn through the rollers leading to a blockage in the feeding system. An increase in ribbon mass throughput could also be achieved if the equipment surfaces were pre-lubricated. However this increase was found to be temporary suggesting that the residual magnesium stearate layer was removed from the equipment surfaces. Powder sticking to the equipment surfaces, which is common during pharmaceutical manufacturing, was prevented if magnesium stearate was present either in the blend, or at the roll surface. It is further demonstrated that the influence of the hopper stirrer, which is primarily used to prevent bridge formation in the hopper and help draw powder more evenly into the auger chamber, can lead to further mixing of the formulation, and could therefore affect a change in the lubricity of the carefully blended input material.

Design rules for out-of-plane stability of roller bent steel arches with FEM

NARCIS (Netherlands)

Spoorenberg, R.C.; Snijder, H.H.; Hoenderkamp, J.C.D.; Beg, D.

2012-01-01

This paper describes a numerical investigation into the out-of-plane buckling behavior of freestanding roller bent steel arches. As roller bent arches have structural imperfections which differ considerably from those of hot-rolled or welded sections, specific attention is paid to their inclusion in

Application research of ferrous matrix composites in roller ring used in high-speed wire/bar rolling mill

International Nuclear Information System (INIS)

Song Yanpei; Li Xiuqing; Bi Shuangxu

2010-01-01

Research highlights: → A composite structure roller rings was fabricated by centrifugal casting. → The roller rings consisted of outer WCP/Fe-C composites layer and inner Fe-C alloy matrix. → Hardness attained to HRA80-85 in the composites layer, and HRA73-76 in inner Fe-C alloy matrix where the toughness was over 8 J/cm 2 . → The wear resistance of the roller rings excelled that of high-speed steel, and approached to that of the WC hard alloy roll. → The production cost of the WCP/Fe-C composites roller ring decreased by 50%. - Abstract: Tungsten carbide particle (WC P ) reinforced ferrous matrix composites roller rings were fabricated by centrifugal casting. The microstructures, properties and application effect of the composites roller rings were investigated by SEM, TEM and various property testers. The experimental results show that the WC P were uniformly distributed in outer reinforced-layer (working-layer) of 20-50 mm in thickness and their volume fraction reached 60-80 vol.%; there was a good interface bonding between WC P and Fe-C alloy without any reaction products; hardness attained to HRA80-85 in working-layer, and HRA73-76 in inner ferrous matrix where the toughness was over 8 J/cm 2 ; the wear resistance of the composites roller rings excels that of high-speed steel; service life of the composites parts approached to that of the WC hard alloy roll when the same WC P -volume-fraction in working-layer were obtained for both of them, but the production cost of the WC P /Fe-C composites roller ring decreased by 50%.

Roller pressure algometry as a new tool for assessing dynamic pressure sensitivity in migraine

DEFF Research Database (Denmark)

Guerrero-Peral, Ángel L.; Ruíz, Marina; Barón, Johanna

2018-01-01

from 500 to 5300 g. Each roller was moved at a speed of 0.5 cm/sec over a 60 mm horizontal line covering the temporalis muscle. The dynamic pain threshold (the pressure level of the first painful roller) and pain elicited during the pain threshold (roller evoked pain) were determined. Static pressure...... pain thresholds were assessed over the temporalis muscle, C5/C6 joint, second metacarpal, and tibialis anterior. Results Side-to-side consistency between dynamic pain threshold (rs = 0.769, p ... was slightly stronger in chronic migraine. Pain during dynamic pain threshold was negatively associated with widespread pressure pain thresholds (-0.336 

Effect of Using Porcelanite as Partial Replacement of Fine Aggregate on Roller Compacted Concrete with Different Curing Methods

Directory of Open Access Journals (Sweden)

Abeer Abdulqader Salih

2016-09-01

Full Text Available Roller-Compacted Concrete is a no-slump concrete, with no reinforcing steel, no forms, no finishing and wet enough to support compaction by vibratory rollers. Due to the effect of curing on properties and durability of concrete, the main purpose of this research is to study the effect of various curing methods (air curing, 7 days water curing, and permanent water curing and porcelanite (local material used as an Internal Curing agent with different replacement percentages of fine aggregate (volumetric replacement on some properties of Roller-Compacted Concrete and to explore the possibility of introducing practical Roller-Compacted Concrete for road pavement with minimum requirement of curing. Specimens were sawed from slabs of (380*380*100 mm for determination of Ultrasonic Pulse Velocity (UPV and Voids volume. Results show that using (5 % porcelanite improved the results of UPV and Voids volume of Roller-Compacted Concrete (with air curing as compared with reference Roller-Compacted Concrete (with permanent water curing by percentages ranging from(3.6 to 28.9% and (-8 to -15.5% respectively.

Evaluation of wheel/rail contact mechanics : roller rig concept design review.

Science.gov (United States)

2014-07-01

A need exists for a new test rig design with advanced sensing technologies that will allow the railroad industry and regulatory : agencies to better understand the wheel-rail contact dynamics and mechanics, especially as it pertains to high-speed rai...

Biomechanical pole and leg characteristics during uphill diagonal roller skiing.

Science.gov (United States)

Lindinger, Stefan Josef; Göpfert, Caroline; Stöggl, Thomas; Müller, Erich; Holmberg, Hans-Christer

2009-11-01

Diagonal skiing as a major classical technique has hardly been investigated over the last two decades, although technique and racing velocities have developed substantially. The aims of the present study were to 1) analyse pole and leg kinetics and kinematics during submaximal uphill diagonal roller skiing and 2) identify biomechanical factors related to performance. Twelve elite skiers performed a time to exhaustion (performance) test on a treadmill. Joint kinematics and pole/plantar forces were recorded separately during diagonal roller skiing (9 degrees; 11 km/h). Performance was correlated to cycle length (r = 0.77; P Push-off demonstrated performance correlations for impulse of leg force (r = 0.84), relative duration (r= -0.76) and knee flexion (r = 0.73) and extension ROM (r = 0.74). Relative time to peak pole force was associated with performance (r = 0.73). In summary, diagonal roller skiing performance was linked to 1) longer cycle length, 2) greater impulse of force during a shorter push-off with larger flexion/extension ROMs in leg joints, 3) longer leg swing, and 4) later peak pole force, demonstrating the major key characteristics to be emphasised in training.

Kinematics and Path Following Control of an Articulated Drum Roller

Science.gov (United States)

BIAN, Yongming; YANG, Meng; FANG, Xiaojun; WANG, Xiahui

2017-07-01

Automatic navigation of an articulated drum roller, which is an articulated steering type vehicle widely used in the construction industry, is highly expected for operation cost reduction and improvement of work efficiency. In order to achieve the path following control, considering that its steering system is articulated steering and two frames are articulated by an active revolute joint, a kinematic model and an error dynamic state-space equation of an articulated drum roller are proposed. Besides, a state-feedback control law based on Lyapunov stability theory is also designed, which can be proved to achieve the purpose of control by the analysis of stability. What's more, to evaluate the performance of the proposed method, simulation under the MATLAB/Simulink and experiments using positioning algorithm and errors correction at the uneven construction site are performed, with initial displacement error (-1.5 m), heading error (-0.11 rad) and steering angle (-0.19 rad). Finally, simulation and experimental results show that the errors and steering angle can decrease gradually, and converge to zero with time. Meanwhile, the control input is not saturated. An articulated drum roller can lock into a desired path with the proposed method in uneven fields.

77 FR 50716 - Tapered Roller Bearings From China

Science.gov (United States)

2012-08-22

... INTERNATIONAL TRADE COMMISSION [Investigation No. 731-TA-344 (Third Review)] Tapered Roller..., the United States International Trade Commission (Commission) determines, pursuant to section 751(c... notice in the Office of the Secretary, U.S. International Trade Commission, Washington, DC, and by...

A Roller Bearing Fault Diagnosis Method Based on LCD Energy Entropy and ACROA-SVM

Directory of Open Access Journals (Sweden)

HungLinh Ao

2014-01-01

Full Text Available This study investigates a novel method for roller bearing fault diagnosis based on local characteristic-scale decomposition (LCD energy entropy, together with a support vector machine designed using an Artificial Chemical Reaction Optimisation Algorithm, referred to as an ACROA-SVM. First, the original acceleration vibration signals are decomposed into intrinsic scale components (ISCs. Second, the concept of LCD energy entropy is introduced. Third, the energy features extracted from a number of ISCs that contain the most dominant fault information serve as input vectors for the support vector machine classifier. Finally, the ACROA-SVM classifier is proposed to recognize the faulty roller bearing pattern. The analysis of roller bearing signals with inner-race and outer-race faults shows that the diagnostic approach based on the ACROA-SVM and using LCD to extract the energy levels of the various frequency bands as features can identify roller bearing fault patterns accurately and effectively. The proposed method is superior to approaches based on Empirical Mode Decomposition method and requires less time.

Synaptic contacts impaired by styrene-7,8-oxide toxicity

International Nuclear Information System (INIS)

Corsi, P.; D'Aprile, A.; Nico, B.; Costa, G.L.; Assennato, G.

2007-01-01

Styrene-7,8-oxide (SO), a chemical compound widely used in industrial applications, is a potential hazard for humans, particularly in occupational settings. Neurobehavioral changes are consistently observed in occupationally exposed individuals and alterations of neurotransmitters associated with neuronal loss have been reported in animal models. Although the toxic effects of styrene have been extensively documented, the molecular mechanisms responsible for SO-induced neurotoxicity are still unclear. A possible dopamine-mediated effect of styrene neurotoxicity has been previously demonstrated, since styrene oxide alters dopamine neurotransmission in the brain. Thus, the present study hypothesizes that styrene neurotoxicity may involve synaptic contacts. Primary striatal neurons were exposed to styrene oxide at different concentrations (0.1-1 mM) for different time periods (8, 16, and 24 h) to evaluate the dose able to induce synaptic impairments. The expression of proteins crucial for synaptic transmission such as Synapsin, Synaptophysin, and RAC-1 were considered. The levels of Synaptophysin and RAC-1 decreased in a dose-dependent manner. Accordingly, morphological alterations, observed at the ultrastructural level, primarily involved the pre-synaptic compartment. In SO-exposed cultures, the biochemical cascade of caspases was activated affecting the cytoskeleton components as their target. Thus the impairments in synaptic contacts observed in SO-exposed cultures might reflect a primarily morphological alteration of neuronal cytoskeleton. In addition, our data support the hypothesis developed by previous authors of reactive oxygen species (ROS) initiating events of SO cytotoxicity

Simulation and Analysis of Roller Chain Drive Systems

DEFF Research Database (Denmark)

Pedersen, Sine Leergaard

The subject of this thesis is simulation and analysis of large roller chain drive systems, such as e.g. used in marine diesel engines. The aim of developing a chain drive simulation program is to analyse dynamic phenomena of chain drive systems and investigate different design changes to the syst......The subject of this thesis is simulation and analysis of large roller chain drive systems, such as e.g. used in marine diesel engines. The aim of developing a chain drive simulation program is to analyse dynamic phenomena of chain drive systems and investigate different design changes...... mathematical models, and compare to the prior done research. Even though the model is developed at first for the use of analysing chain drive systems in marine engines, the methods can with small changes be used in general, as for e.g. chain drives in industrial machines, car engines and motorbikes. A novel...

A method of increasing the depth of the plastically deformed layer in the roller burnishing process

Science.gov (United States)

Kowalik, Marek; Trzepiecinski, Tomasz

2018-05-01

The subject of this paper is an analysis of the determination of the depth of the plastically deformed layer in the process of roller burnishing a shaft using a newly developed method in which a braking moment is applied to the roller. It is possible to increase the depth of the plastically deformed layer by applying the braking moment to the roller during the burnishing process. The theoretical considerations presented are based on the Hertz-Bielayev and Huber-Mises theories and permit the calculation of the depth of plastic deformation of the top layer of the burnished shaft. The theoretical analysis has been verified experimentally and using numerical calculations based on the finite element method using the Msc.MARC program. Experimental tests were carried out on ring-shaped samples made of C45 carbon steel. The samples were burnished at different values of roller force and different values of braking moment. A significant increase was found in the depth of the plastically deformed surface layer of roller burnished shafts. Usage of the phenomenon of strain hardening of steel allows the technology presented here to increase the fatigue life of the shafts.

Assessment of solid microneedle rollers to enhance transmembrane delivery of doxycycline and inhibition of MMP activity.

Science.gov (United States)

Omolu, Abbie; Bailly, Maryse; Day, Richard M

2017-11-01

Many chronic wounds exhibit high matrix metalloproteinase (MMP) activity that impedes the normal wound healing process. Intradermal delivery (IDD) of sub-antimicrobial concentrations of doxycycline, as an MMP inhibitor, could target early stages of chronic wound development and inhibit further wound progression. To deliver doxycycline intradermally, the skin barrier must be disrupted. Microneedle rollers offer a minimally invasive technique to penetrate the skin by creating multiple microchannels that act as temporary conduits for drugs to diffuse through. In this study, an innovative and facile approach for delivery of doxycycline across Strat-M TM membrane was investigated using microneedle rollers. The quantity and rate of doxycycline diffusing through the micropores directly correlated with increasing microneedle lengths (250, 500 and 750 μm). Treatment of Strat-M TM with microneedle rollers resulted in a reduction in fibroblast-mediated collagen gel contraction and MMP activity compared with untreated Strat-M TM . Our results show that treatment of an epidermal mimetic with microneedle rollers provides sufficient permeabilization for doxycycline diffusion and inhibition of MMP activity. We conclude that microneedle rollers are a promising, clinically ready tool suitable for delivery of doxycycline intradermally to treat chronic wounds.

Brown coal derived humate inhibits contact hypersensitivity; An efficacy, toxicity and teratogenicity study in rats

Energy Technology Data Exchange (ETDEWEB)

Van Rensburg, C.E.J.; Snyman, J.R.; Mokoele, T.; Cromarty, A.D. [University of Pretoria, Pretoria (South Africa). Faculty of Health Science

2007-10-15

The effects of two humate products were compared to that of prednisolone on a contact hypersensitivity rat model. Rats, sensitized with dinitrofluorobenzene (DNFB), were placed on a daily oral treatment of 61 mg/kg BW of humate derived from either leonardite or bituminous coal or on prednisolone at one mg/kg BW and challenged 6 days later with a topical application of DNFB to the right ear. The inflamed ears were measured daily. In a toxicity study rats were exposed to daily oral treatment of leonardite humate at 1,000 mg/kg BW for 1 month. A teratogenicity study was done where pregnant rats were treated with 500 mg/kg BW on days 5 to 17 of pregnancy. Only the leonardite humate compared favourably with prednisolone in suppressing contact hypersensitivity. No signs of toxicity were observed and weight gain was normal during the 6-day and 1 month treatments and during the teratogenicity study with the leonardite humate. However, the rats on the other two products experienced slower weight gain. The identification of a naturally occurring nontoxic compound with anti-inflammatory activity is exciting and merits further evaluation in the treatment of patients suffering from inflammatory conditions.

Roller-massager application to the quadriceps and knee-joint range of motion and neuromuscular efficiency during a lunge.

Science.gov (United States)

Bradbury-Squires, David J; Noftall, Jennifer C; Sullivan, Kathleen M; Behm, David G; Power, Kevin E; Button, Duane C

2015-02-01

Roller massagers are used as a recovery and rehabilitative tool to initiate muscle relaxation and improve range of motion (ROM) and muscular performance. However, research demonstrating such effects is lacking. To determine the effects of applying a roller massager for 20 and 60 seconds on knee-joint ROM and dynamic muscular performance. Randomized controlled clinical trial. University laboratory. Ten recreationally active men (age = 26.6 ± 5.2 years, height = 175.3 ± 4.3 cm, mass = 84.4 ± 8.8 kg). Participants performed 3 randomized experimental conditions separated by 24 to 48 hours. In condition 1 (5 repetitions of 20 seconds) and condition 2 (5 repetitions of 60 seconds), they applied a roller massager to the quadriceps muscles. Condition 3 served as a control condition in which participants sat quietly. Visual analog pain scale, electromyography (EMG) of the vastus lateralis (VL) and biceps femoris during roller massage and lunge, and knee-joint ROM. We found no differences in pain between the 20-second and 60-second roller-massager conditions. During 60 seconds of roller massage, pain was 13.5% (5.7 ± 0.70) and 20.6% (6.2 ± 0.70) greater at 40 seconds and 60 seconds, respectively, than at 20 seconds (P joint ROM was 10% and 16% greater in the 20-second and 60-second roller-massager conditions, respectively, than the control condition (P joint ROM and neuromuscular efficiency during a lunge.

Toxicity testing and chemical analyses of recycled fibre-based paper for food contact

DEFF Research Database (Denmark)

Binderup, Mona-Lise; Pedersen, Gitte Alsing; Vinggaard, Anne

2002-01-01

of different qualities as food-contact materials and to Perform a preliminary evaluation of their suitability from a safety point of view, and, second, to evaluate the use of different in vitro toxicity tests for screening of paper and board. Paper produced from three different categories of recycled fibres (B...... of the paper products were extracted with either 99% ethanol or water. Potential migrants in the extracts were identified and semiquantified by GC-1R-MS or GC-HRMS. In parallel to the chemical analyses, a battery of four different in vitro toxicity tests with different endpoints were applied to the same...... was less cytotoxic than the extracts prepared from paper made from recycled fibres, and extracts prepared from C was the most cytotoxic. None of the extracts showed mutagenic activity No conclusion about the oestrogenic activity could be made, because all extracts were cytotoxic to the test organism (yeast...

Simulation of accelerated strip cooling on the hot rolling mill run-out roller table

International Nuclear Information System (INIS)

Muhin, U.; Belskij, S.; Makarov, E.; Koinov, T.

2013-01-01

Full text: A mathematical model of the thermal state of the metal on the run-out roller table of a continuous wide hot-strip mill is presented. The mathematical model takes into account the heat generation during the polymorphic γ → α transformation of super cooled austenite phase and the influence of chemical composition on the physical properties of the steel. The model allows the calculation of modes of accelerated cooling of strips on the run-out roller table of a continuous wide hot strip mill. Winding temperature calculation error does not exceed 20 °C for 98.5 % of the strips from low-carbon and low-alloyed steels. key words: hot rolled, wide-strip, accelerated cooling, run-out roller table, polymorphic transformation, mathematical modeling

Increasing the Energy Efficiency of the Cyclic Action Mechanisms in Rolling for a Roller Bed Used as an Example

Science.gov (United States)

andreev, A. N.; Kolesnichenko, D. A.

2017-12-01

The possibility of increasing the energy efficiency of the production cycle in a roller bed is briefly reviewed and justified. The sequence diagram of operation of the electrical drive in a roller bed is analyzed, and the possible increase in the energy efficiency is calculated. A method for energy saving is described for the application of a frequency-controlled asynchronous electrical drive of drive rollers in a roller bed with an increased capacitor capacity in a dc link. A fine mathematical model is developed to describe the behavior of the electrical drive during the deceleration of a roller bed. An experimental setup is created and computer simulation and physical modeling are performed. The basic information flows of the general hierarchical automatic control system of an enterprise are described and determined with allowance for the proposed method of increasing the energy efficiency.

Do Maximal Roller Skiing Speed and Double Poling Performance Predict Youth Cross-Country Skiing Performance?

Directory of Open Access Journals (Sweden)

Roland Stöggl, Erich Müller, Thomas Stöggl

2017-09-01

Full Text Available The aims of the current study were to analyze whether specific roller skiing tests and cycle length are determinants of youth cross-country (XC skiing performance, and to evaluate sex specific differences by applying non-invasive diagnostics. Forty-nine young XC skiers (33 boys; 13.8 ± 0.6 yrs and 16 girls; 13.4 ± 0.9 yrs performed roller skiing tests consisting of both shorter (50 m and longer durations (575 m. Test results were correlated with on snow XC skiing performance (PXC based on 3 skating and 3 classical distance competitions (3 to 6 km. The main findings of the current study were: 1 Anthropometrics and maturity status were related to boys’, but not to girls’ PXC; 2 Significant moderate to acceptable correlations between girls’ and boys’ short duration maximal roller skiing speed (double poling, V2 skating, leg skating and PXC were found; 3 Boys’ PXC was best predicted by double poling test performance on flat and uphill, while girls’ performance was mainly predicted by uphill double poling test performance; 4 When controlling for maturity offset, boys’ PXC was still highly associated with the roller skiing tests. The use of simple non-invasive roller skiing tests for determination of PXC represents practicable support for ski clubs, schools or skiing federations in the guidance and evaluation of young talent.

Visualization and prediction of porosity in roller compacted ribbonswith near infrared chemical imaging (NIR-CI)

DEFF Research Database (Denmark)

Khorasani, Milad Rouhi; Amigo Rubio, Jose Manuel; Sonnergaard, Jørn

2015-01-01

The porosity of roller compacted ribbon is recognized as an important critical quality attribute which has a huge impact on the final product quality. The purpose of this study was to investigate the use of near-infrared chemical imaging (NIR-CI) for porosity estimation of ribbons produced...... and control of continuously operating roller compaction line....

Neuromuscular Responses of Elite Skaters During Different Roller Figure Skating Jumps

Directory of Open Access Journals (Sweden)

Pantoja Patrícia Dias

2014-07-01

Full Text Available This study aimed to describe the neuromuscular activity of elite athletes who performed various roller figure skating jumps, to determine whether the muscle activation is greater during jumps with more rotations and in which phase the muscles are more active. This study also aimed to analyze if there is any difference in the muscle activity pattern between female and male skaters. Four elite skaters were evaluated, and each participated in two experimental sessions. During the first session, anthropometric data were collected, and the consent forms were signed. For the second session, neuromuscular data were collected during jumps, which were performed with skates at a rink. The following four roller figure skating jumps were evaluated: single Axel, double Axel, double Mapes and triple Mapes. The neuromuscular activity of the following seven muscles was obtained with an electromyograph which was fixed to the waist of each skater with a strap: biceps femoris, lateral gastrocnemius, tibialis anterior, rectus femoris, vastus lateralis, vastus medialis and gluteus maximus. The signal was transmitted wirelessly to a laptop. During the roller figure skating jumps, the lateral gastrocnemius, rectus femoris, vastus lateralis, biceps femoris and gluteus maximus, showed more activation during the jumps with more rotations, and the activation mainly occurred during the propulsion and flight phases. Female skaters demonstrated higher muscle activities in tibialis anterior, vastus lateralis, vastus medialis and gluteus maximus during the landing phase of the triple Mapes, when compared to their male counterparts. The results obtained in this study should be considered when planning training programs with specific exercises that closely resemble the roller figure skating jumps. This may be important for the success of elite skaters in competitions.

Neuromuscular Responses of Elite Skaters During Different Roller Figure Skating Jumps

Science.gov (United States)

Pantoja, Patrícia Dias; Mello, André; Liedtke, Giane Veiga; Kanitz, Ana Carolina; Cadore, Eduardo Lusa; Pinto, Stephanie Santana; Alberton, Cristine Lima; Kruel, Luiz Fernando Martins

2014-01-01

This study aimed to describe the neuromuscular activity of elite athletes who performed various roller figure skating jumps, to determine whether the muscle activation is greater during jumps with more rotations and in which phase the muscles are more active. This study also aimed to analyze if there is any difference in the muscle activity pattern between female and male skaters. Four elite skaters were evaluated, and each participated in two experimental sessions. During the first session, anthropometric data were collected, and the consent forms were signed. For the second session, neuromuscular data were collected during jumps, which were performed with skates at a rink. The following four roller figure skating jumps were evaluated: single Axel, double Axel, double Mapes and triple Mapes. The neuromuscular activity of the following seven muscles was obtained with an electromyograph which was fixed to the waist of each skater with a strap: biceps femoris, lateral gastrocnemius, tibialis anterior, rectus femoris, vastus lateralis, vastus medialis and gluteus maximus. The signal was transmitted wirelessly to a laptop. During the roller figure skating jumps, the lateral gastrocnemius, rectus femoris, vastus lateralis, biceps femoris and gluteus maximus, showed more activation during the jumps with more rotations, and the activation mainly occurred during the propulsion and flight phases. Female skaters demonstrated higher muscle activities in tibialis anterior, vastus lateralis, vastus medialis and gluteus maximus during the landing phase of the triple Mapes, when compared to their male counterparts. The results obtained in this study should be considered when planning training programs with specific exercises that closely resemble the roller figure skating jumps. This may be important for the success of elite skaters in competitions. PMID:25114728

Modeling of Comparative Performance of Asphalt Concrete under Hammer, Gyratory, and Roller Compaction

Directory of Open Access Journals (Sweden)

Saad I. Sarsam

2016-11-01

Full Text Available The main objective of this study is to develop predictive models using SPSS software (version 18 for Marshall Test results of asphalt mixtures compacted by Hammer, Gyratory, and Roller compaction. Bulk density of (2.351 gm/cc, at OAC of (4.7 % was obtained as a benchmark after using Marshall Compactor as laboratory compactive effort with 75-blows. Same density was achieved by Roller and Gyratory Compactors using its mix designed methods. A total of (75 specimens, for Marshall, Gyratory, and Roller Compactors have been prepared, based on OAC of (4.7 % with an additional asphalt contents of more and less than (0.5 % from the optimum value. All specimens have been subjected to Marshall Test. Mathematical models obtained indicated that variation of Marshall Stiffness is based on the variation of air voids. All of these models depend on asphalt cement content too.

To Enhance the Fire Resistance Performance of High-Speed Steel Roller Door with Water Film System

Directory of Open Access Journals (Sweden)

De-Hua Chung

2015-01-01

Full Text Available The structure of high-speed roller door with water film has improved in this study. The flameproof water film system is equipped with a water circulating device to reduce the water consumption of water film system. The water film is generated at the roller box of the high-speed roller door in this study. The heating test is done with the full-scale heating furnace. Both cases of the water film on unexposed surface and water film on exposed surface passed the fire resistance test based on ISO 834, proving that the high-speed roller door with water film system has 120A fire resistance period. The main findings indicate that the water film on exposed surface shows that as the amount of water film evaporated by high temperature inside the furnace must be greater than the evaporation capacity of water film on unexposed surface, the required water supply is 660 L more than the water film on unexposed surface.

Solid-Phase Contact Assay That Uses a lux-Marked Nitrosomonas europaea Reporter Strain To Estimate Toxicity of Bioavailable Linear Alkylbenzene Sulfonate in Soil

OpenAIRE

Brandt, Kristian K.; Pedersen, Anders; Sørensen, Jan

2002-01-01

Information about in situ toxicity of the bioavailable pools of adsorptive soil pollutants is a prerequisite for proper ecological risk assessment in contaminated soils. Such toxicity data may be obtained by assays allowing for direct exposure of introduced test microorganisms to the toxicants, as they appear in solid solution equilibria in the natural soil. We describe a novel sensitive solid-phase contact assay for in situ toxicity testing of soil pollutants based on a recombinant biolumine...

Compressed sensing of roller bearing fault based on multiple down-sampling strategy

Science.gov (United States)

Wang, Huaqing; Ke, Yanliang; Luo, Ganggang; Tang, Gang

2016-02-01

Roller bearings are essential components of rotating machinery and are often exposed to complex operating conditions, which can easily lead to their failures. Thus, to ensure normal production and the safety of machine operators, it is essential to detect the failures as soon as possible. However, it is a major challenge to maintain a balance between detection efficiency and big data acquisition given the limitations of sampling theory. To overcome these limitations, we try to preserve the information pertaining to roller bearing failures using a sampling rate far below the Nyquist sampling rate, which can ease the pressure generated by the large-scale data. The big data of a faulty roller bearing’s vibration signals is firstly reduced by a down-sample strategy while preserving the fault features by selecting peaks to represent the data segments in time domain. However, a problem arises in that the fault features may be weaker than before, since the noise may be mistaken for the peaks when the noise is stronger than the vibration signals, which makes the fault features unable to be extracted by commonly-used envelope analysis. Here we employ compressive sensing theory to overcome this problem, which can make a signal enhancement and reduce the sample sizes further. Moreover, it is capable of detecting fault features from a small number of samples based on orthogonal matching pursuit approach, which can overcome the shortcomings of the multiple down-sample algorithm. Experimental results validate the effectiveness of the proposed technique in detecting roller bearing faults.

Compressed sensing of roller bearing fault based on multiple down-sampling strategy

International Nuclear Information System (INIS)

Wang, Huaqing; Ke, Yanliang; Luo, Ganggang; Tang, Gang

2016-01-01

Roller bearings are essential components of rotating machinery and are often exposed to complex operating conditions, which can easily lead to their failures. Thus, to ensure normal production and the safety of machine operators, it is essential to detect the failures as soon as possible. However, it is a major challenge to maintain a balance between detection efficiency and big data acquisition given the limitations of sampling theory. To overcome these limitations, we try to preserve the information pertaining to roller bearing failures using a sampling rate far below the Nyquist sampling rate, which can ease the pressure generated by the large-scale data. The big data of a faulty roller bearing’s vibration signals is firstly reduced by a down-sample strategy while preserving the fault features by selecting peaks to represent the data segments in time domain. However, a problem arises in that the fault features may be weaker than before, since the noise may be mistaken for the peaks when the noise is stronger than the vibration signals, which makes the fault features unable to be extracted by commonly-used envelope analysis. Here we employ compressive sensing theory to overcome this problem, which can make a signal enhancement and reduce the sample sizes further. Moreover, it is capable of detecting fault features from a small number of samples based on orthogonal matching pursuit approach, which can overcome the shortcomings of the multiple down-sample algorithm. Experimental results validate the effectiveness of the proposed technique in detecting roller bearing faults. (paper)

Validation of a Functional Pyelocalyceal Renal Model for the Evaluation of Renal Calculi Passage While Riding a Roller Coaster.

Science.gov (United States)

Mitchell, Marc A; Wartinger, David D

2016-10-01

The identification and evaluation of activities capable of dislodging calyceal renal calculi require a patient surrogate or validated functional pyelocalyceal renal model. To evaluate roller coaster facilitation of calyceal renal calculi passage using a functional pyelocalyceal renal model. A previously described adult ureteroscopy and renoscopy simulator (Ideal Anatomic) was modified and remolded to function as a patient surrogate. Three renal calculi of different sizes from the patient who provided the original computed tomographic urograph on which the simulator was based were used. The renal calculi were suspended in urine in the model and taken for 20 rides on the Big Thunder Mountain Railroad roller coaster at Walt Disney World in Orlando, Florida. The roller coaster rides were analyzed using variables of renal calculi volume, calyceal location, model position on the roller coaster, and renal calculi passage. Sixty renal calculi rides were analyzed. Independent of renal calculi volume and calyceal location, front seating on the roller coaster resulted in a passage rate of 4 of 24. Independent of renal calculi volume and calyceal location, rear seating on the roller coaster resulted in a passage rate of 23 of 36. Independent of renal calculi volume in rear seating, calyceal location differed in passage rates, with an upper calyceal calculi passage rate of 100%; a middle calyceal passage rate of 55.6%; and a lower calyceal passage rate of 40.0%. The functional pyelocalyceal renal model serves as a functional patient surrogate to evaluate activities that facilitate calyceal renal calculi passage. The rear seating position on the roller coaster led to the most renal calculi passages.

High-energy roller injuries to the upper extremity.

Science.gov (United States)

Askins, G; Finley, R; Parenti, J; Bush, D; Brotman, S

1986-12-01

Eleven cases of high-energy industrial roller injuries treated between 1980 and 1984 were retrospectively reviewed. The dominant extremity was affected in nine. Six patients sustained fractures and/or dislocations, and three of these patients required fasciotomies for clinical signs of impending compartment syndromes. All fracture/dislocations, with the exception of a scapula fracture, anterior dislocation of a thumb interphalangeal joint, and a fractured coronoid process of the ulna, required open reduction with internal fixation. Three patients required split-thickness skin grafting for extensive skin degloving. Two patients required immediate amputation. Late sequelae included prolonged edema, nutritional depletion, neuroma formation of the superficial branch of the radial nerve, late carpal tunnel syndrome, and partial brachial plexus palsy. Industrial roller injuries continue to be an occupational hazard associated with more severe crushing trauma than the low-energy wringer washer injuries first described by MacCollum (11). Attention must be paid to the treatment of crushed skin, muscle, and nerves, fracture stabilization, nutritional support, and occupational therapy. Concurrent monitoring for signs of a developing compartment syndrome and complications of rhabdomyolysis is essential.

Scale up of diesel oil biodegradation in a baffled roller bioreactor.

Science.gov (United States)

Nikakhtari, Hossein; Song, Wanning; Kumar, Pardeep; Nemati, Mehdi; Hill, Gordon A

2010-05-01

Diesel oil is a suitable substance to represent petroleum contamination from accidental spills in operating and transportation facilities. Using a microbial culture enriched from a petroleum contaminated soil, biodegradation of diesel oil was carried out in 2.2, 55, and 220 L roller baffled bioreactors. The effects of bioreactor rotation speed (from 5 to 45 rpm) and liquid loading (from 18% to 73% of total volume) on the biodegradation of diesel oil were studied. In the small scale bioreactor (2.2L), the maximum rotation speed of 45 rpm resulted in the highest biodegradation rate with a first order biodegradation kinetic constant of 0.095 d(-1). In the larger scale bioreactors, rotation speed did not affect the biodegradation rate. Liquid loadings higher than 64% resulted in reduced biodegradation rates in the small scale bioreactor; however, in the larger roller bioreactors liquid loading did not affect the biodegradation rate. Biodegradation of diesel oil at 5 rpm and 73% loading is recommended for operating large scale roller baffled bioreactors. Under these conditions, high diesel oil concentrations up to 50 gL(-1) can be bioremediated at a rate of 1.61 gL(-1)d(-1). Copyright 2010 Elsevier Ltd. All rights reserved.

The dynamic analysis of drum roll lathe for machining of rollers

Science.gov (United States)

Qiao, Zheng; Wu, Dongxu; Wang, Bo; Li, Guo; Wang, Huiming; Ding, Fei

2014-08-01

An ultra-precision machine tool for machining of the roller has been designed and assembled, and due to the obvious impact which dynamic characteristic of machine tool has on the quality of microstructures on the roller surface, the dynamic characteristic of the existing machine tool is analyzed in this paper, so is the influence of circumstance that a large scale and slender roller is fixed in the machine on dynamic characteristic of the machine tool. At first, finite element model of the machine tool is built and simplified, and based on that, the paper carries on with the finite element mode analysis and gets the natural frequency and shaking type of four steps of the machine tool. According to the above model analysis results, the weak stiffness systems of machine tool can be further improved and the reasonable bandwidth of control system of the machine tool can be designed. In the end, considering the shock which is caused by Z axis as a result of fast positioning frequently to feeding system and cutting tool, transient analysis is conducted by means of ANSYS analysis in this paper. Based on the results of transient analysis, the vibration regularity of key components of machine tool and its impact on cutting process are explored respectively.

Visualization in mechanics: the dynamics of an unbalanced roller

Science.gov (United States)

Cumber, Peter S.

2017-04-01

It is well known that mechanical engineering students often find mechanics a difficult area to grasp. This article describes a system of equations describing the motion of a balanced and an unbalanced roller constrained by a pivot arm. A wide range of dynamics can be simulated with the model. The equations of motion are embedded in a graphical user interface for its numerical solution in MATLAB. This allows a student's focus to be on the influence of different parameters on the system dynamics. The simulation tool can be used as a dynamics demonstrator in a lecture or as an educational tool driven by the imagination of the student. By way of demonstration the simulation tool has been applied to a range of roller-pivot arm configurations. In addition, approximations to the equations of motion are explored and a second-order model is shown to be accurate for a limited range of parameters.

Effects of frequency on gross efficiency and performance in roller ski skating.

Science.gov (United States)

Leirdal, S; Sandbakk, O; Ettema, G

2013-06-01

The purpose of the present study was to examine the effect of frequency on efficiency and performance during G3 roller ski skating. Eight well-trained male cross-country skiers performed three submaximal 5-min speeds (10, 13, and 16 km/h) and a time-to-exhaustion (TTE) performance (at 20 km/h) using the G3 skating technique using freely chosen, high, and low frequency at all four speeds. All tests were done using roller skis on a large treadmill at 5% incline. Gross efficiency (GE) was calculated as power divided by metabolic rate. Power was calculated as the sum of power against frictional forces and power against gravity. Metabolic rate was calculated from oxygen consumption and blood lactate concentration. Freely chosen frequency increased from 60 to 70 strokes/min as speed increased from 10 to 20 km/h. GE increased with power. At high power (20 km/h performance test), both efficiency and performance were significantly reduced by high frequency. In regard to choice of frequency during G3 roller ski skating, cross-country skiers seems to be self-optimized both in relation to energy saving (efficiency) and performance (TTE). © 2011 John Wiley & Sons A/S.

Three-dimensional earthquake analysis of roller-compacted concrete dams

Directory of Open Access Journals (Sweden)

M. E. Kartal

2012-07-01

Full Text Available Ground motion effect on a roller-compacted concrete (RCC dams in the earthquake zone should be taken into account for the most critical conditions. This study presents three-dimensional earthquake response of a RCC dam considering geometrical non-linearity. Besides, material and connection non-linearity are also taken into consideration in the time-history analyses. Bilinear and multilinear kinematic hardening material models are utilized in the materially non-linear analyses for concrete and foundation rock respectively. The contraction joints inside the dam blocks and dam–foundation–reservoir interaction are modeled by the contact elements. The hydrostatic and hydrodynamic pressures of the reservoir water are modeled with the fluid finite elements based on the Lagrangian approach. The gravity and hydrostatic pressure effects are employed as initial condition before the strong ground motion. In the earthquake analyses, viscous dampers are defined in the finite element model to represent infinite boundary conditions. According to numerical solutions, horizontal displacements increase under hydrodynamic pressure. Besides, those also increase in the materially non-linear analyses of the dam. In addition, while the principle stress components by the hydrodynamic pressure effect the reservoir water, those decrease in the materially non-linear time-history analyses.

Corrective action plan for CAU No. 404: Roller Coaster Sewage Lagoons and North Disposal Trench, Tonopah Test Range

Energy Technology Data Exchange (ETDEWEB)

NONE

1997-07-01

This Corrective Action Plan (CAP) provides the selected corrective action alternative and proposes the closure implementation methodology for the Roller Coaster Sewage Lagoons and North Disposal Trench Corrective Action Unit (CAU) No. 404. The site is located on the Tonopah Test Range. CAU 404 consists of two Corrective Action Sites (CAS): the Roller Coaster Lagoons (CAS No TA-03-001-TA-RC) and the North Disposal Trench (CAS No TA-21-001-TA-RC). A site map of the lagoons and trench is provided. The Roller Coaster Sewage Lagoons are comprised of two unlined lagoons that received liquid sanitary waste in 1963 from the Operation Roller Coaster Man Camp and debris from subsequent construction and range cleanup activities. The North Disposal Trench was excavated in approximately 1963 and received solid waste and debris from the man camp and subsequent construction and range cleanup activities. A small hydrocarbon spill occurred during the 1995 Voluntary Corrective Action (VCA) activities in an area associated with the North Disposal Trench CAS.

Corrective action plan for CAU No. 404: Roller Coaster Sewage Lagoons and North Disposal Trench, Tonopah Test Range

International Nuclear Information System (INIS)

1997-07-01

This Corrective Action Plan (CAP) provides the selected corrective action alternative and proposes the closure implementation methodology for the Roller Coaster Sewage Lagoons and North Disposal Trench Corrective Action Unit (CAU) No. 404. The site is located on the Tonopah Test Range. CAU 404 consists of two Corrective Action Sites (CAS): the Roller Coaster Lagoons (CAS No TA-03-001-TA-RC) and the North Disposal Trench (CAS No TA-21-001-TA-RC). A site map of the lagoons and trench is provided. The Roller Coaster Sewage Lagoons are comprised of two unlined lagoons that received liquid sanitary waste in 1963 from the Operation Roller Coaster Man Camp and debris from subsequent construction and range cleanup activities. The North Disposal Trench was excavated in approximately 1963 and received solid waste and debris from the man camp and subsequent construction and range cleanup activities. A small hydrocarbon spill occurred during the 1995 Voluntary Corrective Action (VCA) activities in an area associated with the North Disposal Trench CAS

Vibratory synchronization transmission of a cylindrical roller in a vibrating mechanical system excited by two exciters

Science.gov (United States)

Zhang, Xueliang; Wen, Bangchun; Zhao, Chunyu

2017-11-01

In present work vibratory synchronization transmission (VST) of a cylindrical roller with dry friction in a vibrating mechanical system excited by two exciters, is studied. Using the average method, the criterion of implementing synchronization of two exciters and that of ensuring VST of a roller, are achieved. The criterion of stability of the synchronous states satisfies the Routh-Hurwitz principle. The influences of the structural parameters of the system to synchronization and stability, are discussed numerically, which can be served as the theoretical foundation for engineering designs. An experiment is carried out, which approximately verify the validity of the theoretical and numerical results, as well as the feasibility of the method used. Utilizing the VST theory of a roller, some types of vibrating crushing or grinding equipments, etc., can be designed.

Granule fraction inhomogeneity of calcium carbonate/sorbitol in roller compacted granules

DEFF Research Database (Denmark)

Bacher, Charlotte; Olsen, P.M.; Bertelsen, P.

2008-01-01

The granule fraction inhomogeneity of roller compacted granules was examined on mixtures of three different morphologic forms of calcium carbonate and three particle sizes of sorbitol. The granule fraction inhomogeneity was determined by the distribution of the calcium carbonate in each of the 10...... size fractions between 0 and 2000 µm and by calculating the demixing potential. Significant inhomogeneous occurrence of calcium carbonate in the size fractions was demonstrated, depending mostly on the particles sizes of sorbitol but also on the morphological forms of calcium carbonate......, the ability of the powder to agglomerate in the roller compactor was demonstrated to be related to the ability of the powder to be compacted into a tablet, thus the most compactable calcium carbonate and the smallest sized sorbitol improved the homogeneity by decreasing the demixing potential....

Influence of quartz particles on wear in vertical roller mills

DEFF Research Database (Denmark)

Jensen, Lucas R.D.; Friis, Henrik; Fundal, Erling

2010-01-01

The standard closed circuit comminution process commonly employed in industrial vertical roller mills has been analyzed to determine the influence of typical abrasive minerals on wear rates. With the main focus on raw mixes used in cement plants, synthetic mixtures imitating were prepared. Using...

Prevention of Roller Bearing-Initiated Burnoffs in Railroad Freight Car Journals

Science.gov (United States)

1979-01-01

The objective of this program was to determine the technical feasibility and cost effectiveness of constructing three separate devices for the prevention of catastrophic roller bearing-initiated, railroad journal failure. 1. Construction of a low cos...

Computational stress and damage modelling for rolling contact fatigue

DEFF Research Database (Denmark)

Cerullo, Michele

Rolling contact fatigue in radial roller bearings is studied by means of a 2D plane strain nite element program. The Dang Van multiaxial fatigue criterion is firstly used, in a macroscopic study modeling the bearing raceway, to investigate the region where fatigue cracks are more likely to nucleate...... and of compressive residual stresses are also analyzed. The stress history of a material point at the depth where the maximum Dang Van damage factor is reached is then recorded and used in a subsequent micro-mechanical analysis. The stress history is applied as periodic boundary conditions in a representative volume...

Yellow phosphorus process to convert toxic chemicals to non-toxic products

Science.gov (United States)

Chang, S.G.

1994-07-26

The present invention relates to a process for generating reactive species for destroying toxic chemicals. This process first contacts air or oxygen with aqueous emulsions of molten yellow phosphorus. This contact results in rapid production of abundant reactive species such as O, O[sub 3], PO, PO[sub 2], etc. A gaseous or liquid aqueous solution organic or inorganic chemicals is next contacted by these reactive species to reduce the concentration of toxic chemical and result in a non-toxic product. The final oxidation product of yellow phosphorus is phosphoric acid of a quality which can be recovered for commercial use. A process is developed such that the byproduct, phosphoric acid, is obtained without contamination of toxic species in liquids treated. A gas stream containing ozone without contamination of phosphorus containing species is also obtained in a simple and cost-effective manner. This process is demonstrated to be effective for destroying many types of toxic organic, or inorganic, compounds, including polychlorinated biphenyls (PCB), aromatic chlorides, amines, alcohols, acids, nitro aromatics, aliphatic chlorides, polynuclear aromatic compounds (PAH), dyes, pesticides, sulfides, hydroxyamines, ureas, dithionates and the like. 20 figs.

Physical and mechanical behaviour of a roller compacted concrete ...

African Journals Online (AJOL)

In order to study the behaviour of a roller compacted concrete (RCC) reinforced with polypropylene fiber, six types of RCC were made with different content of fibers (0, 0.5, 1, 1.5, 2 and 2.5 Kg/m3). The physical parameters are the density, the workability, the shrinkage and the water absorption. For the mechanical ...

Experimental performance investigation of glazing system combined with internal roller blinds

DEFF Research Database (Denmark)

Larsen, Olena Kalyanova; Jensen, Rasmus Lund; Iversen, Tore Dahl

2016-01-01

Modern low-energy buildings are often associated with efficient shading devices, as an inevitable component to reduce the peak heat gain in the building and to improve visual comfort. Internal shading devices may have inferior performance compared to external shading, but these are still the most...... used in practice due to lower cost, simplicity and better acceptance between architects and users. The interplay between glazing systems and internal shading devices has been studied and in everyday practice this interplay is described by the solar shading coefficient and the total g......-value of the system (window + roller blind). Solar shading coefficient in such practice is assumed to be independent of the window properties and solar incidence angle. This paper is aimed to illustrate the deviation between the actual and assumed performance of the window system with internal roller blind. This task...

A Optimal Dimension Parameters Design of Needle Roller Bearings Considering Multi Factors Affecting Life

Science.gov (United States)

Bai, XiaoBo; Li, Bo

2017-12-01

Taking into many influencing factors, a Needle Roller Bearings life calculation model was established using the Influence coefficient method and ISO formula. Take this model as the optimization objective function, some optimization variables were determined, and these variables were added constraint conditions. Using dynamic nonlinear strategy to improve the inertia weight, the arccosine strategy to adjust the learning factor, function constraints was solved by the methods of ensure particle legitimacy. Nonlinear optimization design of cylindrical roller bearings was realized by Improved Particle Swarm Algorithm. The proposed method of bearing design was verified effective by test of the optimization results.

Intelligence diagnosis method for roller bearings using features of AE signal

International Nuclear Information System (INIS)

Pan, J; Wang, H Q; Wang, F; Yang, J F; Liu, W B

2012-01-01

Rolling bearings are important components in rotating machines, which are wildly used in industrial production. The fault diagnosis technology plays a very important role for quality and life of machines. Based on symptom parameters of acoustic emission (AE) signals, this paper presents an intelligent diagnosis method for roller bearings using the principal component analysis, rough sets, and BP neural network to detect faults and distinguish fault types. The principal component analysis and the rough sets algorithm are used to reduce details of time-domain symptom parameters for training the BP neural network. The BP neural network, which is used for condition diagnosis of roller bearings, can obtain good convergence using the symptom parameters acquired by the principal component analysis and the rough sets during learning, and automatically distinguish fault types during diagnosing. Practical examples are provided to verify the efficiency of the proposed method.

A roller-like bird (Coracii) from the Early Eocene of Denmark.

Science.gov (United States)

Bourdon, Estelle; Kristoffersen, Anette V; Bonde, Niels

2016-09-27

The fossil record of crown group birds (Neornithes) prior to the Cretaceous-Paleogene boundary is scarce and fragmentary. Early Cenozoic bird fossils are more abundant, but are typically disarticulated and/or flattened. Here we report the oldest roller (Coracii), Septencoracias morsensis gen. et sp. nov. (Primobucconidae), based on a new specimen from the Early Eocene (about 54 million years ago) Fur Formation of Denmark. The new fossil is a nearly complete, three-dimensionally preserved and articulated skeleton. It lies at the lower end of the size range for extant rollers. Salient diagnostic features of Septencoracias relative to other Coracii include the proportionally larger skull and the small, ovoid and dorsally positioned narial openings. Our discovery adds to the evidence that the Coracii had a widespread northern hemisphere distribution in the Eocene. Septencoracias is the oldest substantial record of the Picocoraciae and provides a reliable calibration point for molecular phylogenetic studies.

Roller-coaster Ride to, Relief From TMJ | NIH MedlinePlus the Magazine

Science.gov (United States)

... on a roller coaster ride, seeking relief from temporomandibular joint (TMJ) disorder, which causes pain and, sometimes, dysfunction in the jaw joint and muscles of the neck, head, and face. She has endured: excruciating pain ...

Fire ants protect mealybugs against their natural enemies by utilizing the leaf shelters constructed by the leaf roller Sylepta derogata.

Directory of Open Access Journals (Sweden)

Aiming Zhou

Full Text Available The importance of mutualism is receiving more attention in community ecology. In this study, the fire ant Solenopsis invicta was found to take advantage of the shelters constructed by the leaf roller Sylepta derogata to protect mealybugs (Phenacoccus solenopsis against their natural enemies. This protective effect of fire ant tending on the survival of mealybugs in shelters was observed when enemies and leaf rollers were simultaneously present. Specifically, fire ants moved the mealybugs inside the shelters produced by S. derogata on enemy-infested plants. Compared with that in plants without ants, the survival of mealybugs in shelters in the presence of natural enemies in plants with ants markedly improved. Both the protection of ants and the shelters provided by leaf rollers did not affect the survival of mealybugs in the absence of enemies in plants. Ants and leaf rollers significantly improved the survival of mealybugs in predator-infested plants, whereas no such improvement was observed in parasitoid-infested ones.

Roller skating--is it a dangerous sport?

Science.gov (United States)

Tse, P Y; Shen, W Y; Chan, K M; Leung, P C

1987-01-01

A prospective survey of 111 cases of roller skating injuries within one year are reported. Males were more commonly injured than females. There was a high incidence (86%) of serious injuries, 28% of which required surgical treatment. The wrist (23%) was the commonest region involved, followed by the shoulder (20%), the elbow (15%) and the ankle (12%). Collision with other skaters and loss of control were the main factors leading to injury. Better rink discipline, instruction classes and safety publicity should be helpful in minimising accidents. Images Fig. 2 & Fig. 3 PMID:3676638

Intermittent stick-slip dynamics during the peeling of an adhesive tape from a roller.

Science.gov (United States)

Cortet, Pierre-Philippe; Dalbe, Marie-Julie; Guerra, Claudia; Cohen, Caroline; Ciccotti, Matteo; Santucci, Stéphane; Vanel, Loïc

2013-02-01

We study experimentally the fracture dynamics during the peeling at a constant velocity of a roller adhesive tape mounted on a freely rotating pulley. Thanks to a high speed camera, we measure, in an intermediate range of peeling velocities, high frequency oscillations between phases of slow and rapid propagation of the peeling fracture. This so-called stick-slip regime is well known as the consequence of a decreasing fracture energy of the adhesive in a certain range of peeling velocity coupled to the elasticity of the peeled tape. Simultaneously with stick slip, we observe low frequency oscillations of the adhesive roller angular velocity which are the consequence of a pendular instability of the roller submitted to the peeling force. The stick-slip dynamics is shown to become intermittent due to these slow pendular oscillations which produce a quasistatic oscillation of the peeling angle while keeping constant the peeling fracture velocity (averaged over each stick-slip cycle). The observed correlation between the mean peeling angle and the stick-slip amplitude questions the validity of the usually admitted independence with the peeling angle of the fracture energy of adhesives.

Simulation of accelerated strip cooling on the hot rolling mill run-out roller table

Directory of Open Access Journals (Sweden)

E.Makarov

2016-07-01

Full Text Available A mathematical model of the thermal state of the metal in the run-out roller table continuous wide hot strip mill. The mathematical model takes into account heat generation due to the polymorphic γ → α transformation of supercooled austenite phase state and the influence of the chemical composition of the steel on the physical properties of the metal. The model allows calculation of modes of accelerated cooling strips on run-out roller table continuous wide hot strip mill. Winding temperature calculation error does not exceed 20°C for 98.5 % of strips of low-carbon and low-alloy steels

Roller kiln with very low fluoride emission. The Ecokiln

Energy Technology Data Exchange (ETDEWEB)

Reymer, P.S.; Denissen, A.M. [TNO TPD Materials Research and Technology, Eindhoven (Netherlands)

2001-09-01

In most European countries the limit for fluoride emission in ceramic kiln flue gases is set at 5 mg HF/m{sup 3} flue gas. In cooperation with Royal Mosa, Royal Sphinx, Gasunie in the Netherlands and Sacmi, Italy, a roller kiln has been developed which can operate below the fore-mentioned limit. Also, a flue gas cleaning device is not necessary. 4 refs.

Simulation modeling of wheeled vehicle dynamics on the stand "Roller"

Directory of Open Access Journals (Sweden)

G. O. Kotiev

2014-01-01

Full Text Available The tests are an integral part of the wheeled vehicle design, manufacturing, and operation. The need for their conducting arises from the research and experimental activities to assess the qualitative and quantitative characteristics of the vehicles in general, as well as the individual components and assemblies. It is obvious that a variety of design features of wheeled vehicles request a development of methods both for experimental studies and for creating the original bench equipment for these purposes.The main positive feature of bench tests of automotive engineering is a broad capability to control the combinations of traction loads, speed rates, and external input conditions. Here, the steady state conditions can be used for a long time, allowing all the necessary measurements to be made, including those with video and photo recording experiment.It is known that the benefits of test "M" type (using a roller dynamometer include a wide range of test modes, which do not depend on the climatic conditions, as well as a capability to use a computer-aided testing programs. At the same time, it is known that the main drawback of bench tests of full-size vehicle is that the tire rolling conditions on the drum mismatch to the real road pavements, which are difficult to simulate on the drum surface. This problem can be solved owing to wheeled vehicle tests at the benches "Roller" to be, in efficiency, the most preferable research method. The article gives a detailed presentation of developed at BMSTU approach to its solving.Problem of simulation mathematical modeling has been solved for the vehicle with the wheel formula 8 × 8, and individual wheel-drive.The simulation results have led to the conclusion that the proposed principle to simulate a vehicle rolling on a smooth non-deformable support base using a bench " Roller " by simulation modeling is efficient.

Contact toxicity and residual effects of selected insecticides against the adult Paederus fuscipes (Coleoptera: Staphylinidae).

Science.gov (United States)

Bong, Lee-Jin; Neoh, Kok-Boon; Jaal, Zairi; Lee, Chow-Yang

2013-12-01

The contact toxicity of four insecticide formulations (deltamethrin, fipronil, fenitrothion, and imidacloprid) applied on three different substrates (tile, plywood, and concrete) against the adult rove beetle, Paederus fuscipes Curtis, was evaluated. The relative order of speed of killing effects was as follows: deltamethrin > imidacloprid > fipronil > fenitrothion. Although deltamethrin showed the fastest action against P. fuscipes, the recovery rate of rove beetles at 48 h posttreatment was moderate (approximately 25%) on the tile surface to high (approximately 80%) on the plywood surface. Thus, it is likely that the insects did not pick up the lethal dose especially on porous surfaces. In contrast, fipronil demonstrated delayed toxicity that might promote maximal uptake by the insects. More than 80% mortality was registered for tile and plywood surfaces up to 4 wk after exposure. High mortality (almost 100%) was recorded for imidacloprid-exposed P. fuscipes at 48 h posttreatment, but only on the tile surface. Among the four insecticides tested, fenitrothion was the least effective against P. fuscipes because low percentage to no mortality was recorded in the fenitrothion treatment.

Usefulness of extracorporeal membrane oxygenation using double roller pumps in a low body weight newborn: A novel strategy for mechanical circulatory support in an infant

Directory of Open Access Journals (Sweden)

Keisuke Nakanishi

2016-01-01

Full Text Available Extracorporeal membrane oxygenation (ECMO with a centrifugal pump requires a certain flow rate; therefore, its application for low body weight infants is frequently accompanied by oxygenator membrane malfunction and/or inadequate perfusion. To prevent low-flow associated complications, we report a case in which a novel system of dual roller pumps was used. A baby girl with a body mass index 0.25 m 2 , who experienced difficulty weaning from cardiopulmonary bypass after a Norwood-like operation, required an ECMO. Concerns for the tube lifespan reduction due to roller pump friction led to the use of a double roller pump circulation. The termination of ECMO during tube exchange is not needed, because circulation is maintained by another roller pump. The novel strategy of ECMO with double roller pumps will allow low perfusion rate to provide adequate circulatory support for low body weight patients.

Avoiding Electroerosion in roller bearings; Elektroerosion in Waelzlagern vermeiden

Energy Technology Data Exchange (ETDEWEB)

Preisinger, G.; Groeschl, M. [Inst. fuer Allgemeine Physik der TU Wien (Austria); Koettritsch, H. [SKF Oesterreich AG, Steyr (Austria)

2001-12-17

Roller bearings in electric motors and generators can be exposed to passage of current, which failes not only components, but also changes lubricants. The erosion can be avoided by isolation layers and optimized frequency converters. [German] Waelzlager in Elektromotoren und Generatoren koennen Stromdurchgang ausgesetzt sein, der nicht nur die Teile schaedigt, sondern auch den Schmierstoff veraendert. Die Schaeden sind nicht nur auf Metallteile begrenzt. Abhilfe bieten Isolationsschichten und optimierte Frequenzumrichter. (orig.)

Liikluseksperimendis edestas roller tsiklit ja teisi osalejaid : “2 vs 4″

Index Scriptorium Estoniae

2010-01-01

12. mail toimus Tallinnas keskkonnasõbraliku motonäituse MoMa raames eksperiment, milles osalesid jalgratas, elektriroller, roller, mootorratas ja auto. Marsruudil Miidurand-Nõmme üritati hommikuses liikluses välja selgitada, milline neist sõiduvahendest kõige edukamalt toime tuleb

Roller and Centrifugal Pumps: A Retrospective Comparison of Bleeding Complications in Extracorporeal Membrane Oxygenation.

Science.gov (United States)

Halaweish, Ihab; Cole, Adam; Cooley, Elaine; Lynch, William R; Haft, Jonathan W

2015-01-01

Centrifugal pumps are increasingly used for extracorporeal membrane oxygenation (ECMO) rather than roller pumps. However, shear forces induced by these types of continuousflow pumps are associated with acquired von Willebrand factor deficiency and bleeding complications. This study was undertaken to compare adverse bleeding complications with the use of centrifugal and roller pumps in patients on prolonged ECMO support. The records of all adult ECMO patients from June 2002 to 2013 were retrospectively reviewed using the University of Michigan Health System database and the Extracorporeal Life Support Organization registry, focusing on patients supported for at least 5 days. Ninety-five ECMO patients met criteria for inclusion (48 roller vs. 47 centrifugal pump). Indications included pulmonary (79%), cardiac (15%), and extracorporeal cardiopulmonary resuscitation (6%), without significant difference between the two groups. Despite lower heparin anticoagulation (10.9 vs. 13.7 IU/kg/hr) with centrifugal pumps, there was a higher incidence of nonsurgical bleeding (gastrointestinal, pulmonary, and neurological) in centrifugal pump patients (26.1 vs. 9.0 events/1,000 patient-days, p = 0.024). In conclusion, in our historical comparison, despite reduced anticoagulation, ECMO support using centrifugal pumps was associated with a higher incidence of nonsurgical bleeding. The mechanisms behind this are multifactorial and require further investigation.

Visualizing asphalt roller trajectories in context: acquiring, processing, and representing sensor readings

NARCIS (Netherlands)

Vasenev, Alexandr

2015-01-01

The asphalt compaction process relies heavily on the skills and knowledge of roller operators who act alongside other stakeholders involved in asphalt paving. It is essential that these construction specialists: (1) are adequately informed about the initial temperature distribution of the asphalt

High Capacity cylinder roller bearing; High Capacity Zylinderrollenlager. Ein vollrolliges Lager mit Kaefig

Energy Technology Data Exchange (ETDEWEB)

Reichert, J.; Baum, J. [SKF, Schweinfurt (Germany)

2007-07-15

The high capacity cylinder roller bearing is an example for continuous development of SKF products and does an effective contribution to increase operational safety and offers the possibility to reduce weight and compact design. (GL)

Kinematics of roller chain drives - Exact and approximate analysis

DEFF Research Database (Denmark)

Fuglede, Niels; Thomsen, Jon Juel

2016-01-01

An exact and approximate kinematic analysis of a roller chain drive modeled as a four-bar mechanism is presented. The span connects the sprockets such that they rotate in the same direction, and the sprocket size, number of teeth, and shaft center distance can be arbitrary. The driven sprocket...... to be very good agreement. All together this gives new insights into the characteristics of chain drive kinematics and the influence of main design parameters....

Roller Testing to Mimic Damage of the ISS SARJ Ring and Durability Test to Simulate Fifteen Years of SARJ Operation Using the Damaged Surface

Science.gov (United States)

Krantz, Timothy L.; Elchert, Justin P.; DellaCorte, Christopher; Dube, Michael J.

2016-01-01

The International Space Station's starboard Solar Alpha Rotary Joint (SARJ) experienced a breakdown of the joint's race ring surface. The starboard SARJ mechanism was cleaned and lubricated with grease. To provide some guidance on the expected behavior of the damaged SARJ ring with continued operations, experiments were conducted using rollers and a vacuum roller test rig. The approach of the experimental work involved three main steps: (1) initiate damage using conditions representative of the SARJ with inadequate lubrication; (2) propagate the damage by operating the test rollers without lubrication; and (3) assess the durability of the roller by testing to simulate the equivalent of 15 years of SARJ operation on the damaged surface assuming adequate grease lubrication. During the rig testing, additional and/or replacement grease was introduced at regular intervals to maintain good lubrication in the rig. The damage to the nitride layer continued even after application of grease. The grease lubrication proved to be effective for limiting the value of the axial force that can be developed. Limiting the axial force on the SARJ mechanism is important since the larger the axial force the more concentrated the load pressure becomes on the blend-radius location on the SARJ roller. After the testing simulating 15 years of SARJ operations, the wear depths were the order of 0.2 mm for the nitrided 15-5 roller and the order of 0.06 mm for the mating 440C roller. Metallographic inspections were done to search for indications of impending fatigue or other fracture indications that might eventually propagate and cause structural failure. There were no indications or features found that could eventually compromise structural integrity.

Lake Robertson hydroelectric project. Construction of a roller compacted concrete dam

Energy Technology Data Exchange (ETDEWEB)

Labelle, M.; Robitaille, F. [Hydro-Quebec, Montreal, PQ (Canada)

1995-12-31

Construction of the Lake Robertson hydroelectric project on Quebec`s Lower North Shore was discussed in detail. The dam and powerhouse, located on the HaHa River, consists of a 134 m long concrete gravity dam, and a 21 MW powerhouse with two 69 kV transmission lines and four substations. The climate, terrain, and geography of the region, all of them characterized as severe, and the logistics of construction of the dam and power lines, aggravated by the isolation and severe conditions at the site, were described. The roller compacted concrete design and construction were noted, and justification for a concrete dam over an earth-fill dam was provided. Economics, properties, and composition of the roller compacted concrete (RCC) were examined, and control test results for the RCC concrete were provided. The use of RCC for the Lake Robertson development was described as successful in terms of the quality, watertightness, and completion time. The experience gained by the participants will make it possible to offer RCC as an alternative on various other projects. 2 figs.

The two-dimensional cutting stock problem within the roller blind production process

NARCIS (Netherlands)

E.R. de Gelder; A.P.M. Wagelmans (Albert)

2007-01-01

textabstractIn this paper we consider a two-dimensional cutting stock problem encountered at a large manufacturer of window covering products. The problem occurs in the production process of made-to-measure roller blinds. We develop a solution method that takes into account the characteristics of

Preliminary evaluation of steel-roller round baler for woody biomass baling

Science.gov (United States)

B. J. Stokes; D. L. Sirois; S. L. Woodfin

1987-01-01

A round hay baler with little modification was used to bale small-diameter, crushed trees. The trees had been crushed using a series of compression rollers. Bale cores had to be developed by hand before the baler became self-feeding. Windrowed material was packed off the ground by the baler system after a core had been developed.

Acceleration in One, Two, and Three Dimensions in Launched Roller Coasters

Science.gov (United States)

Pendrill, Ann-Marie

2008-01-01

During a roller coaster ride, the body experiences acceleration in three dimensions. An accelerometer can measure and provide a graph of the forces on the body during different parts of a ride. To couple the experience of the body to pictures of the ride and an analysis of data can contribute to a deeper understanding of Newton's laws. This…

Corrective action decision document for the Roller Coaster Lagoons and North Disposal Trench (Corrective Action Unit Number 404)

International Nuclear Information System (INIS)

1997-01-01

The North Disposal Trench, located north of the eastern most lagoon, was installed in 1963 to receive solid waste and construction debris from the Operation Roller Coaster man camp. Subsequent to Operation Roller Coaster, the trench continued to receive construction debris and range cleanup debris (including ordnance) from Sandia National Laboratories and other operators. A small hydrocarbon spill occurred during Voluntary Corrective Action (VCA) activities (VCA Spill Area) at an area associated with the North Disposal Trench Corrective Action Site (CAS). Remediation activities at this site were conducted in 1995. A corrective action investigation was conducted in September of 1996 following the Corrective Action Investigation Plan (CAIP); the detailed results of that investigation are presented in Appendix A. The Roller Coaster Lagoons and North Disposal Trench are located at the Tonopah Test Range (TTR), a part of the Nellis Air Force Range, which is approximately 225 kilometers (140 miles) northwest of Las Vegas, Nevada, by air

The influence of increased distal loading on metabolic cost, efficiency, and kinematics of roller ski skating.

Science.gov (United States)

Bolger, Conor M; Bessone, Veronica; Federolf, Peter; Ettema, Gertjan; Sandbakk, Øyvind

2018-01-01

The purpose of the present study was to examine the influence of increased loading of the roller ski on metabolic cost, gross efficiency, and kinematics of roller ski skating in steep and moderate terrain, while employing two incline-specific techniques. Ten nationally ranked male cross-country skiers were subjected to four 7-minute submaximal intervals, with 0, 0.5, 1.0, and 1.5 kg added beneath the roller-ski in a randomized order. This was done on two separate days, with the G2 skating at 12% incline and 7 km/h speed and G3 skating at 5% incline and 14 km/h speed, respectively. At 12% incline, there was a significant increase in metabolic rate and a decrease in gross efficiency with added weight (P0.05). No changes in cycle characteristics were observed between the different ski loadings at either incline, although the lateral and vertical displacements of the foot/skis were slightly altered at 12% incline with added weight. In conclusion, the present study demonstrates that increased loading of the ski increases the metabolic cost and reduces gross efficiency during steep uphill roller skiing in G2 skating, whereas no significant effect was revealed when skating on relatively flat terrain in G3. Cycle characteristics remained unchanged across conditions at both inclines, whereas small adjustments in the displacement of the foot coincided with the efficiency changes in uphill terrain. The increased RPE values with added ski-weight at both inclines indicates that other factors than those measured here could have influenced effort and/or fatigue when lifting a heavier ski.

An optimum design on rollers containing the groove with changeable inner diameter based on response surface methodology

Directory of Open Access Journals (Sweden)

Xi Zhao

2016-05-01

Full Text Available In order to realize the precision plastic forming of the revolving body component with changeable wall thickness, a kind of roller containing grooves with changeable inner diameter is put forward, as the forming mould of the technology of rolling-extrusion. Specifically, first, the arc length of the groove in the roller is designed according to the prediction on the forward slip value during the process of forming, to make accurate control of the actual length of the forming segments; then, to obtain better parameters of the roller structure, a second-order response surface model combining finite element numerical simulation and response surface methodology was put forward, taking the factor of forming uniformity as evaluation index. The result of the experiment shows that, for the formed component, not only the size can meet the needs but also each mechanical property index can be greatly improved, which verify the rationality of the forward slip model and the structural parameter of the optimum model based on the response surface methodology.

Experimental studies in Ultrasonic Pulse Velocity of roller compacted concrete pavement containing fly ash and M-sand

Directory of Open Access Journals (Sweden)

S. Krishna Rao

2016-07-01

Full Text Available This paper presents the experimental investigation results of Ultrasonic Pulse Velocity (UPV tests conducted on roller compacted concrete pavement (RCCP material containing Class F fly ash of as mineral admixture. River sand, M-sand and combination of M-sand and River sand are used as fine aggregate in this experimental work. Three types of fly ash roller compacted concrete mixes are prepared using above three types of fine aggregates and they are designated as Series A (River sand, Series B (manufactured sand and Series C (combination of River sand and M-sand. In each series the fly ash content in place of cement is varied from 0% to 60%. In each series and for different ages of curing (i.e 3, 7, 28 and 90 days forty two cube specimens are cast and tested for compressive strength and UPV. The UPV results of fly ash containing roller compacted concrete pavement (FRCCP show lower values at all ages from 3 days to 90 days in comparison with control mix concrete (0% fly ash in all mixes. However, it is also observed that Series B and C mixes containing fly ash show better results in UPV values, compressive strength and Dynamic Elastic Modulus in comparison to Series A mixes with fly ash. Relationships between compressive strength of FRCCP and UPV and Dynamic Elastic Modulus are proposed for all series mixes. A new empirical equation is proposed to determine the Dynamic Elastic Modulus of FRCCP. Keywords: Compressive strength, Dynamic Elastic Modulus, Fly ash, Roller compacted concrete pavement, Ultrasonic Pulse Velocity

Fatigue and Wear in Rolling and Sliding Contacts

DEFF Research Database (Denmark)

Janakiraman, Shravan

bearing supports the main shaft, which connects the rotor to thegearbox. The main bearing is a rolling element bearing containing sphericalrolling elements. The loads on a main bearings are very high, which leads toa lubrication regime called elastohydrodynamic lubrication (EHL). Under theEHL regime...... to increase the film thickness, so as to ensure there is no contactbetween the roller and the raceway. Under lower loads (loads less than EHLloads) it has been observed that axial grooves help to increase the film thicknessat certain optimum operating conditions. It is believed that these groovesact...... the filmthickness. They might improve the film thickness at certain optimum runningconditions, but it is tough to ascertain what those conditions are.The main bearings also undergo rolling contact fatigue failure. The main bearingsexperience premature fatigue failure in both onshore and offshore windturbines...

Study on the Effect of Steel Wheel and Ground on Single Steel Vibratory Roller

Science.gov (United States)

Li, Jiabo; You, Guanghui; Qiao, Jiabin; Ye, Min; Guo, Jin; Zhang, Hongyang

2018-03-01

In the compacting operation of single drum vibratory roller, the forces acting on the foundation of drum include the weight of the drum, the weight of the frame, the exciting force and so on. Based on the theoretical study of ground mechanics, this paper analyzes and calculates the forces acting on the steel wheel and the ground, and obtains the distribution of the laminar stress in the ground when the working plane vibrates. Derive the formula of dynamic compressive stress and static compressive stress in the foundation during vibration compaction. Through the compaction test of the soil trough of 20T single drum roller, the compressive stress data of the soil hydraulic field are obtained. The data of the dynamic compressive stress and the static compressive stress of each layer during the third compaction are obtained, and the theoretical research is verified.

Investigating possible use of roller bearings made of plastic in belt conveyor idlers

Energy Technology Data Exchange (ETDEWEB)

Grzeszek, A

1979-05-01

This paper presents results of laboratory and operational tests of roller bearings made of polyamide in belt conveyor idlers. During operational tests the conveyor was inclined to one side so the load on individual bearings varied and the bearings were also covered with dust and dirt. The tests show that the first failures of the plastic bearings took place after 3 months but some of the bearings were in operation one year without failures. All the failures were caused by wear of the bearing due to dust and dirt on their sliding surface. Increased friction resulted in higher temperatures which deformed the bearings. The tests showed that the bearings which were not dirty operated without failure. It is concluded that the plastic-made roller bearings cannot be used under conditions of brown coal surface mines as these mines are characterized by intense dustfall and by dirt which would increase friction in the bearings. (In Polish)

Rereading "The Jack-Roller:" Hidden Histories in Sociology and Social Work

Science.gov (United States)

Shaw, Ian

2009-01-01

I revisit one of the iconic Chicago School studies, Clifford Shaw's "The Jack-Roller". A naive reading of Shaw's book leaves the reader with a sense of having been inducted into a melange of what we now know as "sociology" and "social work," but which to Shaw seems a coherent stance. I suggest that this is close to the heart of how things were,…

Out-of-plane stability of roller bent steel arches – an experimental investigation

NARCIS (Netherlands)

La Poutre, D.B.; Spoorenberg, R.C.; Snijder, H.H.; Hoenderkamp, J.C.D.

2013-01-01

This paper presents an experimental investigation of the elastic-plastic out-of-plane buckling response of roller bent circular steel arches subjected to a single force applied to the crown. The experiments are used to validate a finite element model described in a related paper. A series of 15

Long-Life, Oil-Free Polymeric, Multi-Roller Traction Drives for Planetary Vehicle Surface Exploration, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — Multi-roller traction drives have several advantages relative to geared units for aerospace and commercial drive applications. Among these are zero backlash, low...

The selection of flying roller as an effort to increase the power of scooter-matic as the main power of centrifugal pump for fire fighter motor cycle

Science.gov (United States)

Hadi Sutrisno, Himawan

2018-03-01

In densely populated settlements, fires often occur and cause losses. In some instances, the process of the occurrence of fires takes place so quickly that to reduce and avoid the occurrence of a fire disaster effort is required in accordance with the existing environmental condition. Fire fighter motorcycle by using motorcycle scooter-matic is considered suitable as one alternative to combating fire hazard in densely populated residential settlements. The use of motorcycle engines as the driving force of the pump often leads to unstable and not optimum power. Thus, the water spray on the centrifugal pump also becomes not maximum. To increase the engine power at scooter-matic engine idle rotation (700-2000 rpm), then the flying roller replacement with certain mass weight becomes an option. By selecting a 10 to 14 gram flying roller mass, the power analysis using a dynotest engine produces several variations. Of the calculation, the mass of a 14 gram flying roller provides a significant increase in motor power on the upper rotation. Meanwhile, on the lower power rotation using a flying roller with a mass of 10 grams provides an increase in power compared to a standard flying roller on a scooter matic motor engine. As a reference to the use of scooter-matic motor power as the pump power, the result of use of the flying roller with a mass of 10 grams becomes the best option.

An Analysis of US Emergency Department Visits From Falls From Skiing, Snowboarding, Skateboarding, Roller-Skating, and Using Nonmotorized Scooters.

Science.gov (United States)

Nathanson, Brian H; Ribeiro, Kara; Henneman, Philip L

2016-07-01

We analyzed the US incidence of emergency department (ED) visits and hospitalizations for falls from skiing, snowboarding, skateboarding, roller-skating, and nonmotorized scooters in 2011. The outcome was hospital admission from the ED. The primary analysis compared pediatric patients aged 1 to 17 years to adults aged 18 to 44 years. The analysis used ICD-9 E-codes E885.0 to E885.4 using discharge data from the Nationwide Emergency Department Sample, Healthcare Cost and Utilization Project, Agency for Healthcare Research and Quality. Approximately 214 000 ED visits met study criteria. Skiing injuries had the highest percentage of hospitalizations (3.30% in pediatric patients and 6.65% in adults 18-44 years old). Skateboard and snowboard injuries were more likely to require hospitalization than roller skating injuries in pediatric patients (odds ratio = 2.42; 95% CI = 2.14-2.75 and odds ratio = 1.83; 95% CI =1.55-2.15, respectively). In contrast, skateboard and snowboard injuries were less severe than roller-skating injuries in adults. © The Author(s) 2015.

Radiometric and ultrasonic testing of vibrating roller compacting effects

International Nuclear Information System (INIS)

Prikryl, F.; Habarta, J.; Kovarikova, E.

1977-01-01

A hole was filled with two layers of concrete mixture. Each layer was compacted using a Dynapac CA 25 vibrating roller 10,000 kg in weight, operating with a frequency of 30 Hz. A concrete block thus produced had dimensions of 11.0x2.5 m and a height of 1.6 m. After the concrete block hardening (roughly 120 days) drill cores were bored and bulk density was determined using nondestructive methods. Bulk density determination of the concrete between the drill cores was conducted using a 137 Cs emitter of an activity of 89 GBq, a FHZ-88b Geiger-Mueller counter was used as the detector. The emitter and detector were placed to touch the bore wall and were lowered to different depths in 10 cm increments. 10 count rate values were measured in each depth. The measurement time was chosen such that the decay statistical error did not exceed 1;. Bulk density of the individual segments of the drill cores was determined using 60 Co of an activitBy of 55 Mq as the radiation source and a TESLA 20/100 GWl GM counter as the detector. The detector operating voltage was 1240 V. Ultrasonic measurements were conducted using the USME-5 instrument. The measured bulk density values show that the compacting of a concrete layer 80 cm in thickness using a vibrating roller is sufficiently efficient. Both nondestructive methods were well proven, the results show that bulk density values in different depths differ due to concrete moisture content. (J.P.)

Hot Ductility Behavior of an 8 Pct Cr Roller Steel

Science.gov (United States)

Wang, Zhenhua; Sun, Shuhua; Shi, Zhongping; Wang, Bo; Fu, Wantang

2015-04-01

The hot ductility of an 8 pct Cr roller steel was determined between 1173 K and 1473 K (900 °C and 1200 °C) at strain rates of 0.01 to 10 s-1 through tensile testing. The fracture morphology was observed using scanning electron microscopy, and the microstructure was examined through optical microscopy and transmission electron microscopy. The dependence of the hot ductility behavior on the deformation conditions, grain size, and precipitation was analyzed. The relationship between the reduction in area and the natural logarithm of the Zener-Hollomon parameter (ln Z) was found to be a second-order polynomial. When ln Z was greater than 40 s-1, the hot ductility was poor and fracture was mainly caused by incompatible deformation between the grains. When ln Z was between 32 and 40 s-1, the hot ductility was excellent and the main fracture mechanism was void linking. When ln Z was below 32 s-1, the hot ductility was poor and fracture was mainly caused by grain boundary sliding. A fine grain structure is beneficial for homogenous deformation and dynamic recrystallization, which induces better hot ductility. The effect of M7C3 carbide particles dispersed in the matrix on the hot ductility was small. The grain growth kinetics in the 8 pct Cr steel were obtained between 1373 K and 1473 K (1100 °C and 1200 °C). Finally, optimized preheating and forging procedures for 8 pct Cr steel rollers are provided.

Control rod upper pin and roller removal and replacement

International Nuclear Information System (INIS)

Giordano, B.

1995-01-01

There has been increasing utility interest in removing cobalt sources as a means to minimize dose rates and shipping costs associated with operations, maintenance, shipping and radioactive waste disposal. This activation product accounts for approximately 80% of the dose rates at a plant. Estimates suggest that older (original equipment) control rod blades (CRBs) using stellite rollers and Haynes Alloy 25 pins can contribute as much as 43% of the cobalt in the plant. Since CRBs are the most concentrated source of cobalt in the reactor vessel, pin and roller (P ampersand R) replacement will provide significant reductions in cobalt-60 levels. The reductions will be measurable within 2 years, and should plateau within 5 to 6 years. This paper described a new, simple, cost effective, field proven in-situ method to replace these high source term contributing components and return the CRB to the reactor core for continued service. The paper also briefly describes a methodology that has been developed to estimate the labor and material costs along with a man-rem dollar savings for removal of the upper P ampersand Rs from in-service CRBs purchased prior to 1982. This method permits comparison to the cost of early replacement of CRBs. The result of this study is an EXCEL spreadsheet cost/benefit analysis that can be made plant specific by incorporation of plant data. The Analysis shows that the removal of P ampersand Rs can be beneficial for a Co-60 contribution as low as 5-10%. Recent interest by non-utility radioactive material users in obtaining the removed P ampersand Rs may further increase the benefit and reduce the cost associated with in-situ removal

A Sparsity-Promoted Decomposition for Compressed Fault Diagnosis of Roller Bearings

Directory of Open Access Journals (Sweden)

Huaqing Wang

2016-09-01

Full Text Available The traditional approaches for condition monitoring of roller bearings are almost always achieved under Shannon sampling theorem conditions, leading to a big-data problem. The compressed sensing (CS theory provides a new solution to the big-data problem. However, the vibration signals are insufficiently sparse and it is difficult to achieve sparsity using the conventional techniques, which impedes the application of CS theory. Therefore, it is of great significance to promote the sparsity when applying the CS theory to fault diagnosis of roller bearings. To increase the sparsity of vibration signals, a sparsity-promoted method called the tunable Q-factor wavelet transform based on decomposing the analyzed signals into transient impact components and high oscillation components is utilized in this work. The former become sparser than the raw signals with noise eliminated, whereas the latter include noise. Thus, the decomposed transient impact components replace the original signals for analysis. The CS theory is applied to extract the fault features without complete reconstruction, which means that the reconstruction can be completed when the components with interested frequencies are detected and the fault diagnosis can be achieved during the reconstruction procedure. The application cases prove that the CS theory assisted by the tunable Q-factor wavelet transform can successfully extract the fault features from the compressed samples.

Acute, fatal Sarcocystis calchasi-associated hepatitis in Roller pigeons (Columbia livia f. dom.) at Philadelphia Zoo

Science.gov (United States)

Four Roller pigeons (Columba livia f. dom.) at the Philadelphia Zoo died suddenly. Necropsy examination revealed macroscopic hepatitis. Microscopically, the predominant lesions were in liver, characterized with necrosis and mixed cell inflammatory response. Sarcocystis calchasi-like schizonts and fr...

Roller Bearing Monitoring by New Subspace-Based Damage Indicator

Directory of Open Access Journals (Sweden)

G. Gautier

2015-01-01

Full Text Available A frequency-band subspace-based damage identification method for fault diagnosis in roller bearings is presented. Subspace-based damage indicators are obtained by filtering the vibration data in the frequency range where damage is likely to occur, that is, around the bearing characteristic frequencies. The proposed method is validated by considering simulated data of a damaged bearing. Also, an experimental case is considered which focuses on collecting the vibration data issued from a run-to-failure test. It is shown that the proposed method can detect bearing defects and, as such, it appears to be an efficient tool for diagnosis purpose.

Investigation of Thermostressed State of Coating Formation at Electric Contact Surfacing of “Shaft” Type Parts

Directory of Open Access Journals (Sweden)

Olena V. Berezshnaya

2016-01-01

Full Text Available The forming of coating at electric contact surfacing is considered. The mathematical model of the coating formation is developed. The method of numerical recurrent solution of the finite-difference form of static equilibrium conditions of the selected elementary volume of coating is used. This model considers distribution of thermal properties and geometric parameters along the thermal deformation zone during the process of electric contact surfacing by compact material. It is found that the change of value of speed asymmetry factor leads to increasing of the friction coefficient in zone of surfacing. This provides the forming of the coating of higher quality. The limitation of the technological capabilities of equipment for electric contact surfacing is related to the size of recoverable parts and application of high electromechanical powers. The regulation of the speed asymmetry factor allows for expanding the technological capabilities of equipment for electric contact surfacing. The nomograms for determination of the stress on the roller electrode and the finite thickness of the coating as the function of the initial thickness of the compact material and the deformation degree are shown.

The effect of extrusion and drying on roller techniques concerning the rheological characteristics of rice-, corn-, sweet potato-, bean- and cassava root- and leaf- based composite flour

Directory of Open Access Journals (Sweden)

Johanna Aristizábal Galvis

2013-01-01

Full Text Available Promoting food security in Latin-America and the Caribbean is directly related to agricultural products. The region faces a food crisis which has reduced large population groups’ access to food. This work contributes to the study of obtaining precooked composite flour made from biofortified crops using protein, vitamin A and/or minerals. This study evaluated the effect of precooked flour’s composition and precooking on its solubility in water, water absorption capacity, consistency and viscosity; such flour was obtained by extrusion and drying on rollers. The composite flours were obtained from cassava roots, sweet potato tubers, corn, rice and bean grains and cassava leaves. Four composite flours were formulated taking four- to six-year-old children’s daily nutrient requirements (protein, iron, zinc and beta-carotenes as a basis. The extruder was operated at 90ºC, 300 rpm screw rotation speed, 17.64 g/min feed flow, with 30% moisture mixture. The dryer rollers were operated at 4 rpm roller rotation speed, 90ºC surface temperature and 1 mm separation between rollers. It was determined that flour dried on rollers led to more complete cooking and modified starch granule structure than precooking by extrusion, thereby producing flour having greater solubility in water, less water absorption, higher consistency and smaller viscosity, comparable to that of pattern flour.

78 FR 58996 - Tapered Roller Bearings from the People's Republic of China: Notice of Court Decision Not in...

Science.gov (United States)

2013-09-25

... Sawblades Mfrs. Coalition v. United States, 626 F.3d 1374 (Fed. Cir. 2010) (``Diamond Sawblades''), the... a complaint with the CIT to challenge various aspects of the Final Results. \\2\\ Tapered Roller...

78 FR 45912 - Tapered Roller Bearings and Parts Thereof, Finished and Unfinished, From the People's Republic of...

Science.gov (United States)

2013-07-30

... DEPARTMENT OF COMMERCE International Trade Administration [A-570-601] Tapered Roller Bearings and..., International Trade Administration, U.S. Department of Commerce, 14th Street and Constitution Avenue NW... Duty New Shipper Review AGENCY: Import Administration, International Trade Administration, Department...

The positioning of federate sports in Portugal: handball, basketball, roller hockey and volleyball

OpenAIRE

Gonçalves, Celina; Correia, Abel

2005-01-01

Sport is constituted by a multiplicity of activities with different purposes, concepts and cultural representations. Before the increase of supply, Sports Federations need to understand the practitioners in relation to the several possibilities of practice and to position their sports according to their competitors. In this context, the purpose of this study is the positioning of team federate sports (handball, basketball, roller hockey and volleyball). According to Lindon et al.,...

78 FR 40692 - Tapered Roller Bearings and Parts Thereof, Finished and Unfinished, From the People's Republic of...

Science.gov (United States)

2013-07-08

... DEPARTMENT OF COMMERCE International Trade Administration [A-570-601] Tapered Roller Bearings and..., International Trade Administration, Department of Commerce. SUMMARY: The Department of Commerce (Department) is... Department selected one mandatory respondent for individual examination (i.e., Changshan Peer Bearing Co. Ltd...

The Selection of Materials for Roller Chains From The Perspective Of Manufacturing Process

Directory of Open Access Journals (Sweden)

Rahmat Saptono

2010-10-01

Full Text Available The selection of materials for an engineering component is not only requested by its design function and shape, but also the sequence through which it is manufactured. The manufacturing operation of roller chains involves drawing and trimming processes aimed at producing semi-finished chain drives component with a well-standardized dimension. In addition to final combination of properties required by design constraints, the ability of materials to be formed into a desired shape and geometry without failure is also critical. The objective of materials selection should therefore involve additional attributes that are not typically  accommodated by the standard procedure of materials selection. The present paper deals with the selection of materials for roller chains from the perspective of manufacturing process. Ears and un-uniform wall thickness have been identified as a key problem in the mass production of component. Provided all process parameters were established, the  anisotropy factor of materials is critical. Simulative test can be reasonably used to obtain material performance indices that can be added up to the standard procedure of material selection. Of three commercially available steel grades evaluated with regard to the criteria defined, one grade is more suitable for the present objective.

Contact toxicity of insecticides for attract-and-kill applications against adult Plodia interpunctella (Hübner) (Lepidoptera: Pyralidae).

Science.gov (United States)

Campos, Manuel; Phillips, Thomas W

2010-07-01

The Indian meal moth (IMM), Plodia interpunctella (Hübner), is an important pest of stored food products. Contact toxicities of 13 insecticides applied to different surfaces were evaluated at registered label and a higher dose for killing adult males. The ultimate objective was to develop attract-and-kill technologies for P. interpunctella. Two-day-old adult males were exposed to treated surfaces for 2.0 s and then paired with virgin females for mating and oviposition over a 24 h period. Permethrins and pyrethrins (organic pyrethrin and pyrethrin plus a synergist) caused over 70% mortality to males. Oviposition was impacted by these insecticides, while egg hatch was not. A second experiment tested the 8 week residual toxicity of cyfluthrin, permethrin and pyrethrin at label and at a higher dose of 20 g AI L(-1) on five surfaces: plastic-coated paper, metal, painted plastic, unpainted plastic and wood. Permethrin at 20 g AI L(-1) suppressed males at over 80% for up to 8 weeks and retained activity on surfaces made with plastic-coated paper, metal or plastic. Oviposition was variable among treatments. Egg hatch was generally unaffected by treatment. Effective attract-and-kill surfaces can be developed for killing IMM males and thereby potentially lead to reduced reproduction and, ultimately, population suppression. Copyright (c) 2010 Society of Chemical Industry.

Compressive Sensing of Roller Bearing Faults via Harmonic Detection from Under-Sampled Vibration Signals.

Science.gov (United States)

Tang, Gang; Hou, Wei; Wang, Huaqing; Luo, Ganggang; Ma, Jianwei

2015-10-09

The Shannon sampling principle requires substantial amounts of data to ensure the accuracy of on-line monitoring of roller bearing fault signals. Challenges are often encountered as a result of the cumbersome data monitoring, thus a novel method focused on compressed vibration signals for detecting roller bearing faults is developed in this study. Considering that harmonics often represent the fault characteristic frequencies in vibration signals, a compressive sensing frame of characteristic harmonics is proposed to detect bearing faults. A compressed vibration signal is first acquired from a sensing matrix with information preserved through a well-designed sampling strategy. A reconstruction process of the under-sampled vibration signal is then pursued as attempts are conducted to detect the characteristic harmonics from sparse measurements through a compressive matching pursuit strategy. In the proposed method bearing fault features depend on the existence of characteristic harmonics, as typically detected directly from compressed data far before reconstruction completion. The process of sampling and detection may then be performed simultaneously without complete recovery of the under-sampled signals. The effectiveness of the proposed method is validated by simulations and experiments.

Lab-scale roller table mill for investigating the grinding behaviour of coal

Energy Technology Data Exchange (ETDEWEB)

Werner, V.; Zelkowski, J.; Schoenert, K. [Inst. for Energy Process Engineering and Fuel Technology and Inst. of Mineral Processing, Univ. Clausthal, Clausthal-Zellerfeld (Germany)

1999-11-01

The test mill is equipped with one roller. The material bed can be discharged completely after overroling. Grinding force, torque and gap width are measured. Cycle tests with three coals have been performed for simulating a closed circuit process. The grinding behaviour is characterized by the following relations: compaction of the particle bed and specific power draft vs. specific grinding force, production of fine material (dust), circuit factor, specific surface of the dust and specific work-input of the grinding circuit vs. specific power draft. (orig.)

Marine aggregates and transparent exopolymeric particles (TEPs) as substrates for the stramenopilan fungi, the thraustochytrids: Roller table experimental approach.

Digital Repository Service at National Institute of Oceanography (India)

Damare, V.S.; Raghukumar, S.

In order to understand the kind of organic substrates utilized by thraustochytrids in the coastal water column, their growth in the presence of Transparent Exopolymeric Substances (TEPS) and aggregates generated in roller table experiments...

77 FR 2031 - Tapered Roller Bearings and Parts Thereof, Finished and Unfinished From the People's Republic of...

Science.gov (United States)

2012-01-13

... Parts Thereof, Finished and Unfinished From the People's Republic of China: Extension of the Time Limit..., International Trade Administration, U.S. Department of Commerce, 14th Street and Constitution Avenue NW..., finished and unfinished from the People's Republic of China. See Tapered Roller Bearings and Parts Thereof...

76 FR 76143 - Tapered Roller Bearings and Parts Thereof, Finished and Unfinished, From the People's Republic of...

Science.gov (United States)

2011-12-06

..., the United Steel, Paper and Forestry, Rubber, Manufacturing, Energy, Allied Industrial and Service... manufacturing of tapered roller bearings and parts thereof in the United States, also notified the Department... manufacturing the domestic like product, and therefore, is an interested party pursuant to section 771(9)(D) of...

Post-cracking tensile behaviour of steel-fibre-reinforced roller-compacted-concrete for FE modelling and design purposes

International Nuclear Information System (INIS)

Jafarifar, N.; Pilakoutas, K.; Angelakopoulos, H.; Bennett, T.

2017-01-01

Fracture of steel-fibre-reinforced-concrete occurs mostly in the form of a smeared crack band undergoing progressive microcracking. For FE modelling and design purposes, this crack band could be characterised by a stress-strain (σ-ε) relationship. For industrially-produced steel fibres, existing methodologies such as RILEM TC 162-TDF (2003) propose empirical equations to predict a trilinear σ-ε relationship directly from bending test results. This paper evaluates the accuracy of these methodologies and their applicability for roller-compacted-concrete and concrete incorporating steel fibres recycled from post-consumer tyres. It is shown that the energy absorption capacity is generally overestimated by these methodologies, sometimes up to 60%, for both conventional and roller-compacted concrete. Tensile behaviour of fibre-reinforced-concrete is estimated in this paper by inverse analysis of bending test results, examining a variety of concrete mixes and steel fibres. A multilinear relationship is proposed which largely eliminates the overestimation problem and can lead to safer designs. [es

Automatic Identification of Subtechniques in Skating-Style Roller Skiing Using Inertial Sensors

Science.gov (United States)

Sakurai, Yoshihisa; Fujita, Zenya; Ishige, Yusuke

2016-01-01

This study aims to develop and validate an automated system for identifying skating-style cross-country subtechniques using inertial sensors. In the first experiment, the performance of a male cross-country skier was used to develop an automated identification system. In the second, eight male and seven female college cross-country skiers participated to validate the developed identification system. Each subject wore inertial sensors on both wrists and both roller skis, and a small video camera on a backpack. All subjects skied through a 3450 m roller ski course using a skating style at their maximum speed. The adopted subtechniques were identified by the automated method based on the data obtained from the sensors, as well as by visual observations from a video recording of the same ski run. The system correctly identified 6418 subtechniques from a total of 6768 cycles, which indicates an accuracy of 94.8%. The precisions of the automatic system for identifying the V1R, V1L, V2R, V2L, V2AR, and V2AL subtechniques were 87.6%, 87.0%, 97.5%, 97.8%, 92.1%, and 92.0%, respectively. Most incorrect identification cases occurred during a subtechnique identification that included a transition and turn event. Identification accuracy can be improved by separately identifying transition and turn events. This system could be used to evaluate each skier’s subtechniques in course conditions. PMID:27049388

Automatic Identification of Subtechniques in Skating-Style Roller Skiing Using Inertial Sensors

Directory of Open Access Journals (Sweden)

Yoshihisa Sakurai

2016-04-01

Full Text Available This study aims to develop and validate an automated system for identifying skating-style cross-country subtechniques using inertial sensors. In the first experiment, the performance of a male cross-country skier was used to develop an automated identification system. In the second, eight male and seven female college cross-country skiers participated to validate the developed identification system. Each subject wore inertial sensors on both wrists and both roller skis, and a small video camera on a backpack. All subjects skied through a 3450 m roller ski course using a skating style at their maximum speed. The adopted subtechniques were identified by the automated method based on the data obtained from the sensors, as well as by visual observations from a video recording of the same ski run. The system correctly identified 6418 subtechniques from a total of 6768 cycles, which indicates an accuracy of 94.8%. The precisions of the automatic system for identifying the V1R, V1L, V2R, V2L, V2AR, and V2AL subtechniques were 87.6%, 87.0%, 97.5%, 97.8%, 92.1%, and 92.0%, respectively. Most incorrect identification cases occurred during a subtechnique identification that included a transition and turn event. Identification accuracy can be improved by separately identifying transition and turn events. This system could be used to evaluate each skier’s subtechniques in course conditions.

MacDonald Dam reconstruction : using roller-compacted concrete

Energy Technology Data Exchange (ETDEWEB)

O' Neil, E. [AMEC Earth and Environmental Ltd., Sydney, NS (Canada)

2007-04-01

Located in Nova Scotia, the MacDonald Dam was commissioned in 1928. The dam consists of a 122 metre-long, 16 metre-high concrete structure comprised of an intake structure, stoplog openings, and a 34 metre-long free-overflow spillway. A 488 metre-long power canal was added as an upgrade in the 1950s. This paper provided details of the roller-compact concrete (RCC) used in the dam's recent rehabilitation following a dam failure analysis in 2003 by Nova Scotia Power Inc. RCC was chosen to help keep the dam's construction project on schedule. The layout and cross-section of the spillway was selected with consideration given to the RCC placing operation. A lift thickness of 0.20 m was selected. A formed ogee crest consisting of conventional reinforced concrete was constructed on top of the RCC. The downstream steps of the spillway were also covered with cast-in-place concrete. A low level sluice was designed to resist the weight of the wet RCC. The design compressive strength of the RCC was 20 MPa. The forms used to support the cast-in-place facing concrete on the upstream face of the dam were constructed full height and were braced back to the downstream face of the existing concrete structure prior to the start of RCC placement. Formwork inserts were placed in the facing concrete as construction progressed. Crack inducers were pre-placed on the forms. Aggregates from a local source were transported to a pug mill as the RCC construction progressed. The RCC was spread into 0.20 m lifts using a small bull-dozer, and the facing concrete was vibrated into the lift below. RCC lifts were compacted using a 9 tonne vibratory drum roller. The RCC placing operation was completed over a period of 10 days. Following the completion of the RCC portion of the dam, the remainder of the cast-in-place concrete was completed. It was concluded that the RCC provided a durable, low-maintenance structure that was completed at a lower price and in a shorter time-frame than

Investigating contact toxicity of Geranium and Artemisia essential oils on Bemisia tabaci Gen.

Directory of Open Access Journals (Sweden)

Fatemeh Yarahmadi

2013-04-01

Full Text Available Objective: Sweet potato whitefly, Bemisia tabaci Gen. (B. tabaci, is one of the most important pests of various greenhouse crops in Iran. Nowadays, chemical insecticides are broadly used for control of the pests that causes risk to consumer's health. For the first time, contact toxicity of Pelargonium roseum Andrews and Artemisia sieberi Besser essential oils on B. tabaci and its possible application against the whitefly was evaluated in 2012. Materials and Methods: Essential oil with concentrations of 2500, 1250, 125, and 12 ppm were used. Infested leaves of greenhouse cucumber were treated by mentioned concentrations. After 24 hours, mortality of B. tabaci was recorded and compared after correcting by Abbot's formula. Results: Results showed that all concentrations of the essential oil could significantly reduce population of B. tabaci compared with the control treatment. Phytotoxicity of the treated leaves were recorded after 24, 48, and 72 hours and compared with the control. Concentrations of 2500, 1250, and 125 ppm caused severe phytotoxicity on greenhouse cucumber leaves and therefore are not suitable for greenhouse application. Phytotoxicity of 12 ppm was relatively low. Conclusions: This data implicated suitable protective effects of the essential oils to the pest infestation. Therefore, essential oils distillated from Geranium and Artemisia could be applied to control B. tabaci in greenhouse cucumber at V/V 12 ppm.

Microstructure and soft magnetic properties of Finemet-type ribbons obtained by twin-roller melt-spinning

International Nuclear Information System (INIS)

Pozo Lopez, G.; Fabietti, L.M.; Condo, A.M.; Urreta, S.E.

2010-01-01

Soft magnetic ribbons of Finemet-type (Fe 73.5 Cu 1 Nb 3 Si 13.5 B 9 ) alloys are synthesized by the twin-roller melt-spinning technique directly from the melt, at tangential wheel speeds of 15, 18, 19 and 20 m/s. The microstructure and the magnetic properties are characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), differential thermal analysis (DTA), thermo-gravimetric analysis (TGA) and hysteresis loops measurements. Samples cooled at 20 m/s are amorphous, while those quenched at lower wheel speeds are partially crystalline. All samples studied present saturation magnetization values (150-160 A m 2 /kg) higher than the commercial Finemet alloys (∼135 A m 2 /kg), obtained by controlled crystallization of amorphous single-roller melt-spun alloys. Optimal soft magnetic properties - σ S =(154±8) A m 2 /kg and H C =(6.9±0.9) A/m - are found in samples quenched at 19 m/s, consisting of size-distributed bcc Fe-Si nanograins (∼18 nm in average) embedded in an amorphous residual matrix. A minority nanocrystalline magnetic phase (≤10 nm) is also detected.

Performance of integrated systems of automated roller shade systems and daylight responsive dimming systems

Energy Technology Data Exchange (ETDEWEB)

Park, Byoung-Chul; Choi, An-Seop; Jeong, Jae-Weon [Department of Architectural Engineering, Sejong University, Kunja-Dong, Kwangjin-Gu, Seoul (Korea, Republic of); Lee, Eleanor S. [Building Technologies Department, Lawrence Berkeley National Laboratory, Berkeley, CA (United States)

2011-03-15

Daylight responsive dimming systems have been used in few buildings to date because they require improvements to improve reliability. The key underlying factor contributing to poor performance is the variability of the ratio of the photosensor signal to daylight workplane illuminance in accordance with sun position, sky condition, and fenestration condition. Therefore, this paper describes the integrated systems between automated roller shade systems and daylight responsive dimming systems with an improved closed-loop proportional control algorithm, and the relative performance of the integrated systems and single systems. The concept of the improved closed-loop proportional control algorithm for the integrated systems is to predict the varying correlation of photosensor signal to daylight workplane illuminance according to roller shade height and sky conditions for improvement of the system accuracy. In this study, the performance of the integrated systems with two improved closed-loop proportional control algorithms was compared with that of the current (modified) closed-loop proportional control algorithm. In the results, the average maintenance percentage and the average discrepancies of the target illuminance, as well as the average time under 90% of target illuminance for the integrated systems significantly improved in comparison with the current closed-loop proportional control algorithm for daylight responsive dimming systems as a single system. (author)

Comparative toxicity of ten organic chemicals to four earthworm species

Energy Technology Data Exchange (ETDEWEB)

Neuhauser, E.F.; Durkin, P.R.; Malecki, M.R.; Anatra, M.

1986-01-01

Ten organic chemicals were tested for toxicity to four earthworm species: Allolobophora tuberculata, Eisenia fetida, Eudrilus eugeniae and Perionyx excavatus, using the European Economic Community's (EEC) earthworm artificial soil and contact testing procedure. The phenols were the most toxic chemicals tested, followed by the amine, substituted benzenes, halogenated aliphatic hydrocarbon, polycyclic aromatic hydrocarbon and phthalate as the least toxic chemical tested. Correlations among species within each type of test for a given chemical were extremely high, suggesting that the selection of earthworm test species does not markedly affect the assessment of a chemical's toxicity. The correlation between the two tests was low for all test species. The contact test LC50 for a given chemical cannot be directly correlated to an artificial soil test LC50 for the same earthworm species.

Assessing the toxicity of sediments using the medaka embryo-larval assay and 2 other bioassays.

Science.gov (United States)

Barhoumi, Badreddine; Clérandeau, Christelle; Landi, Laure; Pichon, Anaïk; Le Bihanic, Florane; Poirier, Dominique; Anschutz, Pierre; Budzinski, Hélène; Driss, Mohamed Ridha; Cachot, Jérôme

2016-09-01

Sediments are sinks for aquatic pollutants, and analyzing toxicity in such complex matrices is still challenging. To evaluate the toxicity of bioavailable pollutants accumulated in sediments from the Bizerte lagoon (Tunisia), a novel assay, the medaka embryo-larval assay by sediment contact, was applied. Japanese medaka (Oryzias latipes) embryos were incubated in direct contact with sediment samples up to hatching. Lethal and sublethal adverse effects were recorded in embryos and larvae up to 20 d postfertilization. Results from medaka embryo-larval assay were compared with cytotoxicity (Microtox®), genotoxicity (SOS chromotest), and pollutant content of sediments. The results highlight differences in the contamination profile and toxicity pattern between the different studied sediments. A significant correlation was shown between medaka embryo-larval assay by sediment contact and SOS chromotest responses and concentrations of most organic pollutants studied. No correlation was shown between pollutant levels and Microtox. According to the number of sediment samples detected as toxic, medaka embryo-larval assay by sediment contact was more sensitive than Microtox, which in turn was more sensitive than the SOS chromotest; and medaka embryo-larval assay by sediment contact allowed sediment toxicity assessment of moderately polluted sediments without pollutant extraction and using an ecologically realistic exposure scenario. Although medaka embryo-larval assay by sediment contact should be tested on a larger sample set, the results show that it is sensitive and convenient enough to monitor the toxicity of natural sediments. Environ Toxicol Chem 2016;35:2270-2280. © 2016 SETAC. © 2016 SETAC.

Fatigue damage of steel components

DEFF Research Database (Denmark)

Fæster, Søren; Zhang, Xiaodan; Huang, Xiaoxu

2014-01-01

Railway rails and the inner ring in roller bearings in wind turbines are both experiencing steel-to-steel contact in small areas with huge loads resulting in extremely high stresses in the base materials......Railway rails and the inner ring in roller bearings in wind turbines are both experiencing steel-to-steel contact in small areas with huge loads resulting in extremely high stresses in the base materials...

Alred Roller – An Innovator and a Traditionalist

Directory of Open Access Journals (Sweden)

Zavarský Ján

2017-12-01

Full Text Available This study focuses on the scenographer Alfred Roller (1864–1935 and his productions of Wagner’s musical dramas, with emphasis on Tristan and Isolde and Parsifal. It places Roller’s aesthetics in a historical, aesthetic, and artistic context, points to his inspiration by the Swiss scenography reformer Adolphe Appia, and cooperation with the music composer and conductor Gustav Mahler in the Vienna Court Opera. The text analyses the specifics of Roller’s scenography, which diverged from illusive stage and used light work as an important production principle. It concludes with a summary of the effect of Roller’s aesthetics on Ľudovít Hradský, the first leader of the production team at the Slovak National Theatre (1923–1928. The visual aspects of the Slovak National Theatre’s productions in that period were strongly inspired by expressionism and Art Nouveau, which were typical of German theatre at that time.

Abrasion Resistance and Mechanical Properties of Waste-Glass-Fiber-Reinforced Roller-compacted Concrete

Science.gov (United States)

Yildizel, S. A.; Timur, O.; Ozturk, A. U.

2018-05-01

The potential use of waste glass fibers in roller-compacted concrete (RCC) was investigated with the aim to improve its performance and reduce environmental effects. The research was focused on the abrasion resistance and compressive and flexural strengths of the reinforced concrete relative to those of reference mixes without fibers. The freeze-thaw resistance of RCC mixes was also examined. It was found that the use of waste glass fibers at a rate of 2 % increased the abrasion resistance of the RCC mixes considerably.

Occupational irritant contact folliculitis associated with triphenyl tin fluoride (TPTF) exposure

DEFF Research Database (Denmark)

Andersen, Klaus Ejner; Petri, M

1982-01-01

Triphenyl tin fluoride (TPTF) is a bioactive organo-tin compound used in concentrations 2-12% as anti-foulants in boat paints. The chemical is moderately toxic to the skin. An occupational irritant contact folliculitis from TPTF in a marine paint plant worker is described. Contact allergy...

Toxicity of selected organic chemicals to the earthworm Eisenia fetida

Energy Technology Data Exchange (ETDEWEB)

Neuhauser, E.F.; Loehr, R.C.; Malecki, M.R.; Milligan, D.L.; Durkin, P.R.

A number of methods recently have been developed to biologically evaluate the impact of man's activities on soil ecosystems. Two test methods, the 2-d contact test and the 14-d artificial soil test, were used to evaluate the impact of six major classes of organic chemicals on the earthworm Eisenia fetida (Savigny). Of the organic chemicals tested, phenols and amines were the most toxic to the worms, followed in descending order of toxicity by the substituted aromatics, halogenated aliphatics, polycyclic aromatic hydrocarbons, and phthalates. No relationship was found between earthworm toxicity as determined by the contact test and rat, Rattus norvegicus Berkenhout and mouse, Mus musculus L. LD/sub 50/ values. The physicochemical parameters of water solubility, vapor pressure, and octanol/water partition coefficient for the chemicals tested in the contact test did not show a significant relationship to the E. fetida LC/sub 50/ values. These studies indicate that: (i) earthworms can be a suitable biomonitoring tool to assist in measuring the impact of organic chemicals in wastes added to soils and (ii) contact and artificial soil tests can be useful in measuring biological impacts.

High-throughput creation of micropatterned PDMS surfaces using microscale dual roller casting

International Nuclear Information System (INIS)

DiBartolomeo, Franklin J; Ge, Ning; Trinkle, Christine A

2012-01-01

This work introduces microscale dual roller casting (MDRC), a novel high-throughput fabrication method for creating continuous micropatterned surfaces using thermosetting polymers. MDRC utilizes a pair of rotating, heated cylindrical molds with microscale surface patterns to cure a continuous microstructured film. Using unmodified polydimethylsiloxane as the thermosetting polymer, we were able to create optically transparent, biocompatible surfaces with submicron patterning fidelity. Compared to other roll-to-roll fabrication processes, this method offers increased flexibility in the types of materials and topography that can be generated, including dual-sided patterning, embedded materials and tunable film thickness. (paper)

Influence of ambient moisture on the compaction behavior of microcrystalline cellulose powder undergoing uni-axial compression and roller-compaction: a comparative study using near-infrared spectroscopy.

Science.gov (United States)

Gupta, Abhay; Peck, Garnet E; Miller, Ronald W; Morris, Kenneth R

2005-10-01

This study evaluates the effect of variation in the ambient moisture on the compaction behavior of microcrystalline cellulose (MCC) powder. The study was conducted by comparing the physico-mechanical properties of, and the near infrared (NIR) spectra collected on, compacts prepared by roller compaction with those collected on simulated ribbons, that is, compacts prepared under uni-axial compression. Relative density, moisture content, tensile strength (TS), and Young modulus were used as key sample attributes for comparison. Samples prepared at constant roller compactor settings and feed mass showed constant density and a decrease in TS with increasing moisture content. Compacts prepared under uni-axial compression at constant pressure and compact mass showed the opposite effect, that is, density increased while TS remained almost constant with increasing moisture content. This suggests difference in the influence of moisture on the material under roller compaction, in which the roll gap (i.e., thickness and therefore density) remains almost constant, vs. under uni-axial compression, in which the thickness is free to change in response to the applied pressure. Key sample attributes were also related to the NIR spectra using multivariate data analysis by the partial least squares projection to latent structures (PLS). Good agreement was observed between the measured and the NIR-PLS predicted values for all key attributes for both, the roller compacted samples as well as the simulated ribbons. Copyright (c) 2005 Wiley-Liss, Inc. and the American Pharmacists Association

Load beam unit replaceable inserts for dry coal extrusion pumps

Science.gov (United States)

Saunders, Timothy; Brady, John D.

2012-11-13

A track assembly for a particulate material extrusion pump according to an exemplary aspect of the present disclosure includes a link assembly with a roller bearing. An insert mounted to a load beam located such that the roller bearing contacts the insert.

Occupational irritant contact dermatitis due to petroleum naphtha

OpenAIRE

Aslı Aytekin; Arzu Karataş Toğral

2014-01-01

Irritant contact dermatitis (ICD) is responsible for the vast majority of occupational contact dermatitis and usually seen in professional groups working with wet hand. However, today, with the increasing business lines, employees are exposed to a variety of irritants. Occupational exposure to many chemicals and toxic irritants affect not only the skin, but also the other systems. Therefore, this situation resulting with loss of work and changes in business may become a public health problem....

Justification of the Shape of a Non-Circular Cross-Section for Drilling With a Roller Cutter

Science.gov (United States)

Buyalich, Gennady; Husnutdinov, Mikhail

2017-11-01

The parameters of the shape of non-circular cross-section affect not only the process of blasting, but also the design of the tool and the process of drilling as well. In the conditions of open-pit mining, it is reasonable to use a roller cutter to produce a non-circular cross-section of blasting holes. With regard to the roller cutter, the impact of the cross-section shape on the oscillations of the axial force arising upon its rotation is determined. It is determined that a polygonal shape with rounded comers of the borehole walls connections and their convex shape, which ensures a smaller range of the total axial force and the torque deflecting the bit from the axis of its rotation is the rational form of the non-circular cross-section of the borehole in terms of bit design. It has been shown that the ratio of the number of cutters to the number of borehole corners must be taken into account when justifying the shape of the cross-section, both from the point of view of the effectiveness of the explosion action and from the point of view of the rational design of the bit.

Microneedle physical contact as a therapeutic for abnormal scars

OpenAIRE

Yeo, David C.; Balmayor, Elizabeth R.; Schantz, Jan-Thorsten; Xu, Chenjie

2017-01-01

Background Abnormal (keloid and hypertrophic) scars are a significant affliction with no satisfactory single modality therapy to-date. Available options are often ineffective, painful, potentially hazardous, and require healthcare personnel involvement. Herein a self-administered microneedle device based on drug-free physical contact for inhibiting abnormal scars is reported. Its therapeutic activity through microneedle contact eliminates hazards associated with toxic anti-scarring drugs whil...

VIRTUAL MODEL OF A ROLLER CONVEYOR INTEGRATED INTO A LOGISTIC FLOW

Directory of Open Access Journals (Sweden)

POPESCU Adrian

2015-11-01

Full Text Available In this article is presented, with the help of graphics, a logistic flow for palletizing and wrapping operations. The loaded pallets are transported by means of a roller conveyor. Creating the virtual model for the conveyer allows us to emphasize the compatibility elements between on the one hand the mechanical assemblies of the flow components and on the other hand the subassemblies of the conveyer structure. The paper has focused on the presentation of the conveyor specific assembly and how are placed the sensors on the mechanical structure of the conveyor. Finally, the main working phases are graphically presented within the flow, highlighting the loaded pallet positions in the flow.

Use of flyash in roller compacted concrete for Ghatghar pumped storage scheme in Maharashtra

Energy Technology Data Exchange (ETDEWEB)

Damani, R.L.; Kshirsagar, S.L.; Narkhede, C.L. [MERI, Nashik (India)

2003-07-01

The paper described the use of 'Roller Compacted Concrete' (RCE) in which about 60% of the cement will be replaced by fly ash for construction of two storage dams - Upper dam and Lower dam in the Thane district of India. These are part of the Ghatghar Pumped Storage Scheme to generate hydropower. Fly ash from Eklahare and Dahav thermal power plant and processed fly ash, Pozzocrete 63 and 83b grade, all proved suitable for the RCC mix. 1 tab.

System and method for conveying an assembly

KAUST Repository

Eitelhuber, Georg

2015-01-01

angles. A carriage assembly can include a drive wheel and at least two roller sets. The drive wheel can be configured to contact the first planar side and is configured to translate the carriage assembly along the rail. The at least two roller sets can

Cheap non-toxic non-corrosive method of glass cleaning evaluated by contact angle, AFM, and SEM-EDX measurements.

Science.gov (United States)

Dey, Tania; Naughton, Daragh

2017-05-01

Glass surface cleaning is the very first step in advanced coating deposition and it also finds use in conserving museum objects. However, most of the wet chemical methods of glass cleaning use toxic and corrosive chemicals like concentrated sulfuric acid (H 2 SO 4 ), piranha (a mixture of concentrated sulfuric acid and 30% hydrogen peroxide), and hydrogen fluoride (HF). On the other hand, most of the dry cleaning techniques like UV-ozone, plasma, and laser treatment require costly instruments. In this report, five eco-friendly wet chemical methods of glass cleaning were evaluated in terms of contact angle (measured by optical tensiometer), nano-scale surface roughness (measured by atomic force microscopy or AFM), and elemental composition (measured by energy dispersive x-ray spectroscopy or SEM-EDX). These glass cleaning methods are devoid of harsh chemicals and costly equipment, hence can be applied in situ in close proximity with plantation such as greenhouse or upon subtle objects such as museum artifacts. Out of these five methods, three methods are based on the chemical principle of chelation. It was found that the citric acid cleaning method gave the greatest change in contact angle within the hydrophilic regime (14.25° for new glass) indicating effective cleansing and the least surface roughness (0.178 nm for new glass) indicating no corrosive effect. One of the glass sample showed unique features which were traced backed to the history of the glass usage.

76 FR 7841 - Agency Information Collection Activities; Proposed Collections; Toxic Chemical Release Reporting...

Science.gov (United States)

2011-02-11

... agencies, and others to promote reductions in toxic chemical releases. Industrial facilities use the TRI... Activities; Proposed Collections; Toxic Chemical Release Reporting; Request for Comments on Proposed Renewal... the individual listed in the preceding FOR FURTHER INFORMATION CONTACT section. Title: Toxic Chemical...

Process for the irradiation of a film-like material

International Nuclear Information System (INIS)

Takimoto, Kazuo; Inoue, Takashi.

1969-01-01

Herein provided is a process for curing a polymerizable coating applied to a strip-like material by irradiating the film with high energy radiation. A plurality of rollers are arranged on both sides of the radiation path in a rectangular configuration such that only the underside of the film contacts the rollers as it is unwound in spiral fashion from a feed bobbin and rewound by a take-up bobbin located within the rectangle. The rollers are further positioned to feed the film in a direction perpendicular to the radiation beam path and to assure that successive levels of the strip superimposed while being inwardly wound are mutually parallel, uniformly spaced and adjusted to precisely intercept the radiation beam. Such an arrangement prevents a polymerizable liquid coating applied to the surface of the strip from contacting the rollers and allows effective repetitive irradiation of the strip as it passes through successive levels of the spiral before being rewound. (Owens, K. J.)

Effects of Cardinal Direction on Distribution and Populational Dynamism of Oak Leaf Roller (Tortrix viridana L. on Quercus infectoria Oliv. and Q. libani Lindl.

Directory of Open Access Journals (Sweden)

mohammadreza zargaran

2018-01-01

Full Text Available Introduction Various pests attack oak trees and in most cases heavily damage them. The European oak leaf roller is one of the important oak pests in some provinces of the Zagros, and it is an important pest of oak forests in some European and North African countries, as well as in Iraq and other regions of Iran. In Iran, it is scattered in the Zagros oak forests, especially in Kohkiluyeh and Boyer Ahmad, Lorestan, Chahar Mahal and Bakhtiari, Fars, and West Azarbaijan Provinces. Repeated removal of oak leaves, particularly by herbivores such as T. viridana in spring, reduces stored photosynthates in trees leading to their decreased diametrical growth. Materials and Methods The Ghabre-Hossein region (Piranshahr was selected as the field operations region because it is one of the most important infestation centers of the European oak leaf roller in the oak forests of West-Azerbaijan. The research was carried out in two consecutive years. Samples of larval instars were taken in early May. Since the sample plot in sampling methods can be points or lines (transects, the four cardinal directions were selected in this study and transects at 100 m intervals were located in each direction.To reduce sampling error, Aleppo (Quercus infectoria and Lebanon (Q. libani oak trees were selected for measurements that were similar in appearance and almost uniform with crowns or trunks aligned along the transects. In each studied tree, four suitable branches were selected (one in each cardinal direction, and the number of larvae from the tip of each branch to a length of 50 cm inwards was counted and recorded in forms prepared beforehand. Considering studies that were carried out regarding the biology of the pest, the larvae were counted in mid-May when all larvae were in their last (fifth instar. In all, 30 Aleppo and 30 Lebanon oak trees were selected in each cardinal direction, and four branches in each direction of these trees were measured. The survey method

Assessment of Real-Time Compaction Quality Test Indexes for Rockfill Material Based on Roller Vibratory Acceleration Analysis

Directory of Open Access Journals (Sweden)

Tianbo Hua

2018-01-01

Full Text Available Compaction quality is directly related to the structure and seepage stability of a rockfill dam. To timely and accurately test the compaction quality of the rockfill material, four real-time test indexes were chosen to characterize the soil compaction degree based on the analysis of roller vibratory acceleration, including acceleration peak value (ap, acceleration root mean square value (arms, crest factor value (CF, and compaction meter value (CMV. To determine which of these indexes is the most appropriate, a two-part field compaction experiment was conducted using a vibratory roller in different filling zones of the dam body. Data on rolling parameters, real-time test indexes, and compaction quality indexes were collected to perform statistical regression analyses. Combined with the spectrum analysis of the acceleration signal, it was found that the CF index best characterizes the compaction degree of the rockfill material among the four indexes. Furthermore, the quantitative relations between the real-time index and compaction quality index were established to determine the control criterion of CF, which can instruct the site work of compaction quality control in the rockfill rolling process.

Adaptive Technology Application for Vibration-Based Diagnostics of Roller Bearings on Industrial Plants

Directory of Open Access Journals (Sweden)

Mironov Aleksey

2014-09-01

Full Text Available Roller bearings are widely used in equipment of different applications; therefore, the issues related to the assessment of bearing technical state and localization of bearing faults are quite important and relevant. The reason is that technical state of a bearing is a critical component, which determines efficiency of a mechanism or equipment. For bearings inspection and diagnostics, various methods of vibration-based diagnostics are used. The adaptive technology for vibration-based diagnostics developed in „D un D centrs” is an effective tool for evaluation of technical state of bearings in operation compared to the existing SKF method.

Decreasing inventory of a cement factory roller mill parts using reliability centered maintenance method

Science.gov (United States)

Witantyo; Rindiyah, Anita

2018-03-01

According to data from maintenance planning and control, it was obtained that highest inventory value is non-routine components. Maintenance components are components which procured based on maintenance activities. The problem happens because there is no synchronization between maintenance activities and the components required. Reliability Centered Maintenance method is used to overcome the problem by reevaluating maintenance activities required components. The case chosen is roller mill system because it has the highest unscheduled downtime record. Components required for each maintenance activities will be determined by its failure distribution, so the number of components needed could be predicted. Moreover, those components will be reclassified from routine component to be non-routine component, so the procurement could be carried out regularly. Based on the conducted analysis, failure happens in almost every maintenance task are classified to become scheduled on condition task, scheduled discard task, schedule restoration task and no schedule maintenance. From 87 used components for maintenance activities are evaluated and there 19 components that experience reclassification from non-routine components to routine components. Then the reliability and need of those components were calculated for one-year operation period. Based on this invention, it is suggested to change all of the components in overhaul activity to increase the reliability of roller mill system. Besides, the inventory system should follow maintenance schedule and the number of required components in maintenance activity so the value of procurement will be decreased and the reliability system will increase.

Failure of the chassis of roller skates for agonistic figure skating

Directory of Open Access Journals (Sweden)

Giorgio Olmi

2015-04-01

Full Text Available The subject of this work was to investigate the early failure, which occurred in the chassis of a roller skate for figure skating. The paper deals with the preliminary analysis of the crack and with the integrated approach, which had to be followed to overcome the problem. Literature in the fields of physiology and biomechanics was studied to correctly simulate the load distribution on the chassis. Finite element simulation, experimental stress analysis and analytical modeling of impact phenomena had to be combined together to estimate the entity of dynamic loads and the corresponding state of stress. The analysis led to the determination of the primary cause of failure, bending fatigue, and to the suggestion of a simple solution to improve and optimize the project.

Field Assessment and Specification Review for Roller-Integrated Compaction Monitoring Technologies

Directory of Open Access Journals (Sweden)

David J. White

2011-01-01

Full Text Available Roller-integrated compaction monitoring (RICM technologies provide virtually 100-percent coverage of compacted areas with real-time display of the compaction measurement values. Although a few countries have developed quality control (QC and quality assurance (QA specifications, broader implementation of these technologies into earthwork construction operations still requires a thorough understanding of relationships between RICM values and traditional in situ point test measurements. The purpose of this paper is to provide: (a an overview of two technologies, namely, compaction meter value (CMV and machine drive power (MDP; (b a comprehensive review of field assessment studies, (c an overview of factors influencing statistical correlations, (d modeling for visualization and characterization of spatial nonuniformity; and (e a brief review of the current specifications.

Contact Lenses for Color Blindness.

Science.gov (United States)

Badawy, Abdel-Rahman; Hassan, Muhammad Umair; Elsherif, Mohamed; Ahmed, Zubair; Yetisen, Ali K; Butt, Haider

2018-06-01

Color vision deficiency (color blindness) is an inherited genetic ocular disorder. While no cure for this disorder currently exists, several methods can be used to increase the color perception of those affected. One such method is the use of color filtering glasses which are based on Bragg filters. While these glasses are effective, they are high cost, bulky, and incompatible with other vision correction eyeglasses. In this work, a rhodamine derivative is incorporated in commercial contact lenses to filter out the specific wavelength bands (≈545-575 nm) to correct color vision blindness. The biocompatibility assessment of the dyed contact lenses in human corneal fibroblasts and human corneal epithelial cells shows no toxicity and cell viability remains at 99% after 72 h. This study demonstrates the potential of the dyed contact lenses in wavelength filtering and color vision deficiency management. © 2018 The Authors. Published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Hydrodynamic sliding bearings vs. roller bearings. Segmented sliding bearings for higher rotational speed; Hydrodynamische Gleitlager versus Waelzlager. Segmentgleitlager fuer hoehere Drehzahlen

Energy Technology Data Exchange (ETDEWEB)

Hagenhoff, M.; Sauer, M. [Main-Metall-Giesserei Fritz Schorr GmbH und Co. KG, Altenglan (Germany)

2004-10-01

Hydrodynamic sliding bearings are considered only in cases when roller bearings reach their speed limits and there is no other solution. However, this view neglects the fact that there are modern, optimised sliding bearings which have more advantages over roller bearings than should be expected. Many producers of sliding bearings also have computer programs enabling them to offer customised solutions, i.e. optimal adaptation of the bearings to their specific operating conditions. (orig.) [German] Hydrodynamische Gleitlager werden oft erst dann in Betracht gezogen, wenn man an die Drehzahlgrenzen von Waelzlagern stoesst und keine andere sinnvolle Alternative mehr in Frage kommt. Dabei uebersieht man leicht, dass es moderne, optimierte Gleitlagerkonstruktionen gibt, die weitaus haeufiger ihre Staerken im Vergleich zu Waelzlagern ausspielen koennen als zunaechst vermutet. Viele Gleitlagerhersteller haben zudem heute Berechnungsprogramme zur Verfuegung, die eine optimale Anpassung der Lager an die speziellen Betriebsbedingungen erlauben. (orig.)

Evaluation of Contact Toxicity and Repellency of the Essential Oil of Pogostemon cablin Leaves and Its Constituents Against Blattella germanica (Blattodae: Blattelidae).

Science.gov (United States)

Liu, Xin Chao; Liu, Qiyong; Chen, Han; Liu, Qi Zhi; Jiang, Shi Yao; Liu, Zhi Long

2015-01-01

The aim of this research was to evaluate contact toxicity and repellency of the essential oil of Pogostemon cablin (Blanco) Bentham leaves against German cockroaches (Blattella germanica) (L.) and to isolate any active constituents. Essential oil of P. cablin leaves was obtained by hydrodistillation and analyzed by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). Twenty-three components were identified in the essential oil, and the main constituents were patchoulol (41.31%), pogostone (18.06%), α-bulnesene (6.56%), caryophyllene (5.96%), and seychellene (4.32%). Bioactivity-directed chromatographic separation of the essential oil led to the isolation of pogostone, patchoulol, and caryophyllene as active compounds. The essential oil of P. cablin leaves exhibited acute toxicity against male B. germanica adults with an LC50 value of 23.45 μg per adult. The constituent compound, pogostone (LC50 = 8.51 μg per adult) showed stronger acute toxicity than patchoulol (LC50 = 207.62 μg per adult) and caryophyllene (LC50 = 339.90 μg per adult) against the male German cockroaches. The essential oil of P. cablin leaves and the three isolated constituents exhibited strong repellent activity against German cockroaches at a concentration of 5 ppm. The results indicated that the essential oil of P. cablin leaves and its major constituents have good potential as a source for natural insecticides and repellents. © The Author 2015. Published by Oxford University Press on behalf of the Entomological Society of America. For Permissions, please e-mail: journals.permissions@oup.com.

System and method for conveying an assembly

KAUST Repository

Eitelhuber, Georg

2015-01-15

An apparatus, system, and method for conveying an assembly along a track. A rail can include a first planar side, a second planar side, and a third planar side. The first, second, and third planar sides can be arranged to form at least two acute angles. A carriage assembly can include a drive wheel and at least two roller sets. The drive wheel can be configured to contact the first planar side and is configured to translate the carriage assembly along the rail. The at least two roller sets can be configured to contact the two other sides to maintain the carriage in contact with the rail.

Multivariable H force/level control of the twin-roller strip caster

International Nuclear Information System (INIS)

Cavazos, A.; Edwards, J.B.

2005-01-01

Twin-roller steel strip casters may offer some advantages with respect to classical continuous casting hot rolling processes. Some works have reported control aspects of this process and although the process has been found to be highly interactive and non-linear, little or no attention has been given to its multivariable characteristics. The purpose of this work is to design a multivariable control capable of decoupling the system. This paper presents some important aspects of the strip caster modeling and reports the simulation results of the application of the multivariable H-optimal control for nominal performance to force/level control. Various controllers have been designed for different pool level heights and it is shown that they can decouple the system, allowing the application of PI decentralized controllers to considerably improve performance. (author)

Nano-enhanced food contact materials and the in vitro toxicity to human intestinal cells of nano-ZnO at low dose

International Nuclear Information System (INIS)

Claonadh, Niall O; Casey, Alan; Mukherjee, Sanchali Gupta; Chambers, Gordon; Lyons, Sean; Higginbotham, Clement

2011-01-01

Nano Zinc Oxide (nZnO) has been shown to display antimicrobial effects which have lead to its application in a number of areas such as antimicrobial surface coatings, anti bacterial wound dressings and more recently in polymer composite systems for use in food contact materials. Concerns have been raised due to the incorporation of nanoparticles in food packaging stemming from the possibility of repeated low dose direct exposure, through ingestion, primarily due to degradation and nanoparticle leaching from the polymer composite. To address these concerns, composites consisting of nZnO and polyethylene were formed using twin screw extrusion to mimic commercial methods of food contact material production. A leaching study was performed using Atomic Absorption Spectroscopy in order to determine the concentration of nZnO leached from the composite. Composite stability studies were performed and a leached nZnO concentration was evaluated. This concentration range was then utilised in a series of tests aimed at determining the toxicity response associated with nZnO when exposed to an intestinal model. In this study two human colorectal carcinoma cell lines, HT29 (ATCC No: HTB-38) and SW480 (ATTC No: CCL-228), were employed as a model to represent areas exposed by ingestion. These lines were exposed to a concentration range of nZnO which incorporated the concentration leached from the composites. The cytotoxic effects of nZnO were evaluated using four cytotoxic endpoints namely the Neutral Red, Alamar Blue, Coomassie Blue and MTT assays. The results of these studies are presented and their implications for the use on nano ZnO in direct food contact surfaces will be discussed.

Nano-enhanced food contact materials and the in vitro toxicity to human intestinal cells of nano-ZnO at low dose

Energy Technology Data Exchange (ETDEWEB)

Claonadh, Niall O; Casey, Alan; Mukherjee, Sanchali Gupta; Chambers, Gordon [Nanolab Research Centre, Focas Institute, Dublin Institute of Technology, Dublin (Ireland); Lyons, Sean; Higginbotham, Clement, E-mail: Niall.OClaonadh@DIT.ie, E-mail: Alan.Casey@DIT.ie [Materials Research Institute, Athlone Institute of Technology, Westmeath (Ireland)

2011-07-06

Nano Zinc Oxide (nZnO) has been shown to display antimicrobial effects which have lead to its application in a number of areas such as antimicrobial surface coatings, anti bacterial wound dressings and more recently in polymer composite systems for use in food contact materials. Concerns have been raised due to the incorporation of nanoparticles in food packaging stemming from the possibility of repeated low dose direct exposure, through ingestion, primarily due to degradation and nanoparticle leaching from the polymer composite. To address these concerns, composites consisting of nZnO and polyethylene were formed using twin screw extrusion to mimic commercial methods of food contact material production. A leaching study was performed using Atomic Absorption Spectroscopy in order to determine the concentration of nZnO leached from the composite. Composite stability studies were performed and a leached nZnO concentration was evaluated. This concentration range was then utilised in a series of tests aimed at determining the toxicity response associated with nZnO when exposed to an intestinal model. In this study two human colorectal carcinoma cell lines, HT29 (ATCC No: HTB-38) and SW480 (ATTC No: CCL-228), were employed as a model to represent areas exposed by ingestion. These lines were exposed to a concentration range of nZnO which incorporated the concentration leached from the composites. The cytotoxic effects of nZnO were evaluated using four cytotoxic endpoints namely the Neutral Red, Alamar Blue, Coomassie Blue and MTT assays. The results of these studies are presented and their implications for the use on nano ZnO in direct food contact surfaces will be discussed.

Effect of the variation in the ambient moisture on the compaction behavior of powder undergoing roller-compaction and on the characteristics of tablets produced from the post-milled granules.

Science.gov (United States)

Gupta, Abhay; Peck, Garnet E; Miller, Ronald W; Morris, Kenneth R

2005-10-01

Effect of variation in the ambient moisture levels on the compaction behavior of a 10% acetaminophen (APAP) powder blend in microcrystalline cellulose (MCC) powder was studied by comparing the physical and mechanical properties of ribbons prepared by roller compaction with those of simulated ribbons, i.e., tablets prepared under uni-axial compression. Relative density, moisture content, tensile strength, and Young's modulus were used as key compact properties for comparison. Moisture was found to facilitate the particle rearrangement of both, the APAP and the MCC particles, as well as the deformation of the MCC particles. The tensile strength of the simulated ribbons also showed an increase with increasing moisture content. An interesting observation was that the tensile strength of the roller compacted samples first increased and then decreased with increasing moisture content. Variation in the ambient moisture during roller compaction was also found to influence the characteristics of tablets produced from the granules obtained post-milling the ribbons. A method to study this influence is also reported. Copyright (c) 2005 Wiley-Liss, Inc. and the American Pharmacists Association

Macular hemorrhage after roller coaster riding in a single-eyed patient with congenital glaucoma

Directory of Open Access Journals (Sweden)

Dilek Guven

Full Text Available ABSTRACT A 21-year-old female presented with a 4-day history of decreased vision in her only functional eye (right eye, OD. She had a history of multiple ocular surgeries in both eyes because of congenital glaucoma and had lost light perception in her left eye several years prior. Ophthalmological examination revealed 0.15 Snellen visual acuity, and fundoscopy revealed nearly total cupping and pallor of the optic disc and multiple retinal hemorrhagic foci in the macula in OD. Lesions spontaneously resolved over a few months. Gravitational forces during a roller coaster ride may have caused this macular hemorrhage.

Sandvik's HM 150 roller in action on the world's largest conveyor bridge in the Lusatia region; Sandvik HM 150 auf der weltgroessten Foerderbruecke in der Lausitz im Einsatz

Energy Technology Data Exchange (ETDEWEB)

Waliczek, Sven; Raddatz, Ulrich [Sandvik Mining and Construction Central Europe GmbH, Essen (Germany)

2010-09-15

Prince Herrmann Ludwig Heinrich von Pueckler-Muskau, a landscape gardening genius, built the Muskau Park in the Lusatia region in 1817 - it is part of a UNESCO world heritage site today. In the same era, 1850, the first lignite was mined in the region and still today, Vattenfall, the Swedish company, extracts lignite without subsidies - in Jaenschwalde among other places, one out of the five opencast mines currently in operation. As one of the largest employers and apprenticing companies in East Germany, Vattenfall currently employs almost 8000 employees and about 800 apprentices. Sandvik Mining and Construction also plays a leading role - in the literal sense. At the Jaenschwalde location there are 320 sets of 5-roller garlands of HM150 formed rollers in action on the overburden conveyor bridge AFB 60m (Figure 1) - on belt five, the main belt conveyor (belt type 3000 ST3000-18:8, idler spacing approx. 800 mm) and on belt eight, the stockpile belt conveyor (belt type 2750 ST2500-18:8, idler spacing approx. 800 mm). It all began in the spring of 2004. Bernhard Hofmayer, Production Manager at Sandvik, introduced the HM150 formed roller to Vattenfall. The engineers were impressed by the completely new design and the innovative assembly technique. The discussion about the advantages and disadvantages of the component optimised formed roller were ready to begin. (orig.)

Kinematic and dynamic modeling and approximate analysis of a roller chain drive

DEFF Research Database (Denmark)

Fuglede, Niels; Thomsen, Jon Juel

2016-01-01

for analytical studies of the coupled motion of the chain spans and driven sprocket. Parametric excitation of the spans come from sprocket angular displacements, and the driven sprocket acts as a boundary which can be compliant in the axial direction. External transverse excitation of the spans comes from...... polygonal action, and is treated through kinematic forcing at the moving string boundaries. Perturbation analysis of the model is carried out using the method of multiple scales. Results show a multitude of internal and external resonance conditions, and some examples are presented of both decoupled...... and coupled motion. Together, the kinematic and dynamic model are aimed toward providing a framework for conducting and understanding both numerical, and experimental investigations of roller chain drive dynamics....

Long-Life, Lightweight, Multi-Roller Traction Drives for Planetary Vehicle Surface Exploration

Science.gov (United States)

Klein, Richard C.; Fusaro, Robert L.; Dimofte, Florin

2012-01-01

NASA s initiative for Lunar and Martian exploration will require long lived, robust drive systems for manned vehicles that must operate in hostile environments. The operation of these mechanical drives will pose a problem because of the existing extreme operating conditions. Some of these extreme conditions include operating at a very high or very cold temperature, operating over a wide range of temperatures, operating in very dusty environments, operating in a very high radiation environment, and operating in possibly corrosive environments. Current drive systems use gears with various configurations of teeth. These gears must be lubricated with oil (or grease) and must have some sort of a lubricant resupply system. For drive systems, oil poses problems such as evaporation, becoming too viscous and eventually freezing at cold temperatures, being too thin to lubricate at high temperatures, being degraded by the radiation environment, being contaminated by the regolith (soil), and if vaporized (and not sealed), it will contaminate the regolith. Thus, it may not be advisable or even possible to use oil because of these limitations. An oil-less, compact traction vehicle drive is a drive designed for use in hostile environments like those that will be encountered on planetary surfaces. Initially, traction roller tests in vacuum were conducted to obtain traction and endurance data needed for designing the drives. From that data, a traction drive was designed that would fit into a prototype lunar rover vehicle, and this design data was used to construct several traction drives. These drives were then tested in air to determine their performance characteristics, and if any final corrections to the designs were necessary. A limitation with current speed reducer systems such as planetary gears and harmonic drives is the high-contact stresses that occur at tooth engagement and in the harmonic drive wave generator interface. These high stresses induce high wear of solid

Dropout Reasons in Iranian Youth Roller Skaters

Directory of Open Access Journals (Sweden)

Hosein H E Y D A R I

2014-12-01

Full Text Available The main drop - out reasons from the sport of roller skating amongst Iranian youth skaters has been examined. A questionnaire with 53 items (adopted from Enoksen, 2011 representing seven subscales namel y: training factors and facilities, executive factors and team, education and work obligations, motivational aspects, social - cultural environment, choice of other sport activities and interests and economic factors was especially developed for this researc h. Responses were measured on a Likert scale ranging from “strongly disagree” to “strongly agree” in relation to each statement. In all 11 2 skaters predominantly male (mean age 17.1, SD = 1.63 with a mean = 5.43 years of experience (SD = 2.92 that had di scontinued in the past two years completed the questionnaire. Results of one sample t - tests showed that all factors expect “social - cultural environment” are significant indicators for drop out from skating with “economical factors” scoring the highest rank ing. Correlational analysis showed that younger participants agree more strongly th at “executive factors and team” and “education and work obligations” were the best predictors of drop out. Those with fewer years of experience considered “training factors and facilities”, “motivational aspects and social and cultural environment” as more likely reasons for quitting. Implications of the findings are discussed.

Quantitative evaluation of hand cranking a roller pump in a crisis management drill.

Science.gov (United States)

Tomizawa, Yasuko; Tokumine, Asako; Ninomiya, Shinji; Momose, Naoki; Matayoshi, Toru

2008-01-01

The heart-lung machines for open-heart surgery have improved over the past 50 years; they rarely break down and are almost always equipped with backup batteries. The hand-cranking procedure only becomes necessary when a pump breaks down during perfusion or after the batteries have run out. In this study, the performance of hand cranking a roller pump was quantitatively assessed by an objective method using the ECCSIM-Lite educational simulator system. A roller pump connected to an extracorporeal circuit with an oxygenator and with gravity venous drainage was used. A flow sensor unit consisting of electromagnetic sensors was used to measure arterial and venous flow rates, and a built-in pressure sensor was used to measure the water level in the reservoir. A preliminary study of continuous cranking by a team of six people was conducted as a surprise drill. This system was then used at a perfusion seminar. At the seminar, 1-min hand-cranking drills were conducted by volunteers according to a prepared scenario. The data were calculated on site and trend graphs of individual performances were given to the participants as a handout. Preliminary studies showed that each person's performance was different. Results from 1-min drills showed that good performance was not related to the number of clinical cases experienced, years of practice, or experience in hand cranking. Hand cranking to maintain the target flow rate could be achieved without practice; however, manipulating the venous return clamp requires practice. While the necessity of performing hand cranking during perfusion due to pump failure is rare, we believe that it is beneficial for perfusionists and patients to include hand-cranking practice in periodic extracorporeal circulation crisis management drills because a drill allows perfusionists to mentally rehearse the procedures should such a crisis occur.

Acute Lameness in a Roller Pigeon ( Columba livia ) with Multicentric Lymphosarcoma.

Science.gov (United States)

Williams, Susan M; Williams, Robert J; Gogal, Robert M

2017-06-01

A 3-yr-old adult female roller pigeon ( Columba livia ) used as part of a breeding pair for an ongoing research study presented with acute left limb lameness. Palpation of the left leg and region revealed a large lump near the coxofemoral joint. The bird was able to ambulate in the cage, but would not brood her hatchling. The bird was humanely euthanized and necropsy was performed. Grossly, multiple large white to pale tan nodules were noted in the pancreas, lung, rib cage, intestines, and unilaterally in the left kidney. Microscopic examination of the various organs revealed neoplastic proliferation of round cells consistent with lymphoblasts. Immunohistochemistry was performed with the use of antibodies to CD3, CD79a, CD20, and CD21 to phenotype the cells. The results indicated that the neoplastic infiltrating cells were predominantly of T-cell origin.

The physiological and biomechanical contributions of poling to roller ski skating.

Science.gov (United States)

Sandbakk, Øyvind; Ettema, Gertjan; Holmberg, Hans-Christer

2013-08-01

Poling is considered to make a significant contribution to cross-country skiing with the skating technique. To better understand this contribution, the current investigation compared roller ski skating on a treadmill with the so-called G3 skating technique with (G3-P) and without poling (G3-NP). Seven male elite skiers performed 5-min submaximal tests at 8, 12, and 15 km h(-1), as well as an incremental test to exhaustion with both techniques on a 5 % incline. Ventilatory variables were assessed by open-circuit indirect calorimetry and three-dimensional kinematics analyzed using the Qualisys Pro Reflex system. G3-P was associated with approximately 15 % higher peak velocity and 10 % higher peak oxygen uptake than G3-NP in the incremental test (both P skating, specifically by enhancing peak oxygen uptake, skiing efficiency and associated biomechanical variables.

Vibration analysis of paper machine's asymmetric tube roll supported by spherical roller bearings

Science.gov (United States)

Heikkinen, Janne E.; Ghalamchi, Behnam; Viitala, Raine; Sopanen, Jussi; Juhanko, Jari; Mikkola, Aki; Kuosmanen, Petri

2018-05-01

This paper presents a simulation method that is used to study subcritical vibrations of a tube roll in a paper machine. This study employs asymmetric 3D beam elements based on the Timoshenko beam theory. An asymmetric beam model accounts for varying stiffness and mass distributions. Additionally, a detailed rolling element bearing model defines the excitations arising from the set of spherical roller bearings at both ends of the rotor. The results obtained from the simulation model are compared against the results from the measurements. The results indicate that the waviness of the bearing rolling surfaces contributes significantly to the subcritical vibrations while the asymmetric properties of the tube roll have only a fractional effect on the studied vibrations.

Roller compaction: Effect of morphology and amorphous content of lactose powder on product quality.

Science.gov (United States)

Omar, Chalak S; Dhenge, Ranjit M; Osborne, James D; Althaus, Tim O; Palzer, Stefan; Hounslow, Michael J; Salman, Agba D

2015-12-30

The effect of morphology and amorphous content, of three types of lactose, on the properties of ribbon produced using roller compaction was investigated. The three types of lactose powders were; anhydrous SuperTab21AN, α-lactose monohydrate 200 M, and spray dried lactose SuperTab11SD. The morphology of the primary particles was identified using scanning electron microscopy (SEM) and the powder amorphous content was quantified using NIR technique. SEM images showed that 21AN and SD are agglomerated type of lactose whereas the 200 M is a non-agglomerated type. During ribbon production, an online thermal imaging technique was used to monitor the surface temperature of the ribbon. It was found that the morphology and the amorphous content of lactose powders have significant effects on the roller compaction behaviour and on ribbon properties. The agglomerated types of lactose produced ribbon with higher surface temperature and tensile strength, larger fragment size, lower porosity and lesser fines percentages than the non-agglomerated type of lactose. The lactose powder with the highest amorphous content showed to result in a better binding ability between the primary particles. This type of lactose produced ribbons with the highest temperature and tensile strength, and the lowest porosity and amount of fines in the product. It also produced ribbon with more smooth surfaces in comparison to the other two types of lactose. It was noticed that there is a relationship between the surface temperature of the ribbon during production and the tensile strength of the ribbon; the higher the temperature of the ribbon during production the higher the tensile strength of the ribbon. Copyright © 2015 Elsevier B.V. All rights reserved.

Lead Toxicity: A Probable Cause of Abdominal Pain in Drug Abusers

Directory of Open Access Journals (Sweden)

Hossein Froutan

2011-05-01

Full Text Available Background: Lead toxicity is caused by ingestion, inhalation, or contact with particles or vapors containing lead. It can present with nonspecific signs and symptoms such as abdominal pain, constipation, irritability, difficulty concentrating, and anemia. In this study, we have tried to find a relationship between lead poisoning and drug abuse.Methods: In a cross sectional study, drug addicts presenting with abdominal pain referring to GI center ofImam Khomeini hospital in 2008 were observed. Patients having occupational contact with lead were excluded from the study. Required data included age, sex, clinical findings, Para clinic results and blood lead level. Results were analyzed through SPSS-15 software.Results: 42 patients (all male with average age of 46.9 ± 10.1 years were included in the study. Averageblood lead level was 51.17±27.96µg/dl. 22 patients (52.6% had lead toxicity. A significant relation was found between lead toxicity and mode of opium drug use; however relation between lead toxicity and duration of addiction was not significant. Similarly, a meaningful relation was found between lead toxicity and abnormal liver function test, urine tests, ECG, presence of basophilic stippling and hyperuricemia.Conclusion: There seems to be a significant relation between opium drug abuse and lead toxicity. Further studies with more cases and ethnicities are needed.

Cylinder deactivation for valve trains with roller finger follower; Zylinderabschaltung fuer Ventiltriebe mit Rollenschlepphebeln

Energy Technology Data Exchange (ETDEWEB)

Hoffmann, Hermann; Loch, Adam; Widmann, Richard [Mahle International GmbH, Stuttgart (Germany). Zentrale Voraussentwicklung; Kreussen, Gerhard; Rebbert, Martin [FEV Motorentechnik GmbH, Aachen (Germany). Abt. Dynamik; Meehsen, Daniel [FEV Motorentechnik GmbH, Aachen (Germany). Abt. Mechanik Versuch

2009-04-15

Cylinder deactivation increases efficiency of gasoline engines without negative effects in terms of exhaust gas emissions or driving dynamics. In particular, the advantageous cost/benefit ratio and great affinity to technologies currently used in gasoline engines support cylinder deactivation as the right path in meeting future market demands. The design and function of cylinder deactivation for valve trains with roller finger follower will be explained and examined with regard to functional aspects, such as stiffness, mass, and kinematic behavior. Based on initial results, design and production characteristics of this new technology are evaluated and technical control interactions in engine applications are presented by Mahle. (orig.)

Abrasion Resistance of Nano Silica Modified Roller Compacted Rubbercrete: Cantabro Loss Method and Response Surface Methodology Approach

Science.gov (United States)

Adamu, Musa; Mohammed, Bashar S.; Shafiq, Nasir

2018-04-01

Roller compacted concrete (RCC) when used for pavement is subjected to skidding/rubbing by wheels of moving vehicles, this causes pavement surface to wear out and abrade. Therefore, abrasion resistance is one of the most important properties of concern for RCC pavement. In this study, response surface methodology was used to design, evaluate and analyze the effect of partial replacement of fine aggregate with crumb rubber, and addition of nano silica on the abrasion resistance of roller compacted rubbercrete (RCR). RCR is the terminology used for RCC pavement where crumb rubber was used as partial replacement to fine aggregate. The Box-Behnken design method was used to develop the mixtures combinations using 10%, 20%, and 30% crumb rubber with 0%, 1%, and 2% nano silica. The Cantabro loss method was used to measure the abrasion resistance. The results showed that the abrasion resistance of RCR decreases with increase in crumb rubber content, and increases with increase in addition of nano silica. The analysis of variance shows that the model developed using response surface methodology (RSM) has a very good degree of correlation, and can be used to predict the abrasion resistance of RCR with a percentage error of 5.44%. The combination of 10.76% crumb rubber and 1.59% nano silica yielded the best combinations of RCR in terms of abrasion resistance of RCR.

Hot roller embossing system equipped with a temperature margin-based controller

Energy Technology Data Exchange (ETDEWEB)

Kim, Seyoung, E-mail: seyoungkim@kimm.re.kr; Son, Youngsu; Lee, Sunghee; Ham, Sangyong; Kim, Byungin [Department of Robotics and Mechatronics, Korea Institute of Machinery and Materials (KIMM), Daejeon (Korea, Republic of)

2014-08-15

A temperature control system was proposed for hot roller embossing. The roll surface was heated using induction coils and cooled with a circulating chilled water system. The temperature of the roll surface was precisely controlled by a temperature margin-based control algorithm that we developed. Implementation of the control system reduced deviations in the roll surface temperature to less than ±2 °C. The tight temperature control and the ability to rapidly increase and decrease the roll temperature will allow optimum operating parameters to be developed quickly. The temperature margin-based controller could also be used to optimize the time course of electrical power and shorten the cooling time by choosing an appropriate temperature margin, possibly for limited power consumption. The chiller-equipped heating roll with the proposed control algorithm is expected to decrease the time needed to determine the optimal embossing process.

New roller cone bits with unique nozzle designs reduce drilling costs

International Nuclear Information System (INIS)

Moffitt, S.R.; Pearce, D.E.; Ivie, C.R.

1992-01-01

This paper reports that selection of the optimum rock bit design to achieve the lowest drilling cost in a given application is often difficult due to a large number of rock bit performance considerations. However, in a majority of applications increased penetration rate is the key consideration in reducing drilling costs. Discovery of a new bit design concept has led to the development of roller cone bits that achieve significant penetration rate increases using superior hydraulic nozzle designs. Prototype designs have achieved 20 to 40% increases in penetration rate with comparable footage drilled when tested in 6 1/2, 8 1/2, 8-3/4, 9-7/8 and 12 1/4 IADC 437, 517 and 537 type bits in the U.S., North Sea, Italy, and Oman. Second-generation designs tested in a full-scale drilling laboratory have delivered 70% increases in penetration rates

Hot roller embossing system equipped with a temperature margin-based controller

International Nuclear Information System (INIS)

Kim, Seyoung; Son, Youngsu; Lee, Sunghee; Ham, Sangyong; Kim, Byungin

2014-01-01

A temperature control system was proposed for hot roller embossing. The roll surface was heated using induction coils and cooled with a circulating chilled water system. The temperature of the roll surface was precisely controlled by a temperature margin-based control algorithm that we developed. Implementation of the control system reduced deviations in the roll surface temperature to less than ±2 °C. The tight temperature control and the ability to rapidly increase and decrease the roll temperature will allow optimum operating parameters to be developed quickly. The temperature margin-based controller could also be used to optimize the time course of electrical power and shorten the cooling time by choosing an appropriate temperature margin, possibly for limited power consumption. The chiller-equipped heating roll with the proposed control algorithm is expected to decrease the time needed to determine the optimal embossing process

Research on the Influence of Weighing Accuracy Caused by the Position of Tension Wheel on the Electronic Belt-Conveyor Scale

Science.gov (United States)

Zhang, Kun; Zhang, Hu; Song, Qiuzhi

2018-01-01

In this paper, a Single- Idler electronic belt-conveyor scale is the Object of study. The contact force between the belt and the supporting roller is calculated by the finite element analysis software ABAQUS. The relationship between the tension distance of the tension wheel and the contact force between the belt and the weighing roller is obtained. The best stretching distance is found through analysis. And the conclusion which is the weighing error is different at the same stretching distance but the different weight of material is obtained. A compensation mechanism is proposed to improve the weighing accuracy.

In vitro toxicity assessment of extracts derived from sol-gel coatings on polycarbonate intended to be used in food contact applications.

Science.gov (United States)

Séverin, Isabelle; Lionti, Krystelle; Dahbi, Laurence; Loriot, Catherine; Toury, Bérangère; Chagnon, Marie-Christine

2016-07-01

Polycarbonate is a widely used polymer in food contact applications all around the world. However, due to the potential release of Bisphenol A (BPA) during repeated washing cycles, its use becomes compromised as BPA is known for being an endocrine disruptor for rodents. In order to tackle this issue, sol-gel coatings based on organoalkoxysiloxane were developed on PC, to act as a physical barrier. To this end, two sol-gel systems based on tetraethylorthosilicate (TEOS), methyltriethoxysilane (MTES) and 3-glycidyloxypropyltriethoxysilane (GPTES), three common sol-gel precursors, were prepared. The coatings derived from the latter two systems were then studied with regards to their potential toxicity in vitro. Migration tests were performed in food simulants, and the maximal migration was obtained in ethanol 10% (v/v) for one system and in isooctane for the other one. In vitro genotoxicity was assessed with the Ames test (OECD 471) and the micronucleus assay (OECD 487), and no genotoxic effect was observed. Moreover, the estrogenic activity of the extracts was studied with a transcriptional activation assay using transient transfection in human cells; none of the extracts was found estrogenic. These negative in vitro results are highly promising for the future use of these new barrier coating formulations onto food contact materials. Copyright © 2016 Elsevier Ltd. All rights reserved.

Soft contact lenses: Basic characteristics, advantages and complications associated with their use

Directory of Open Access Journals (Sweden)

Milosavljević Miloš

2016-01-01

Full Text Available Soft contact lenses have an important place in ophthalmology, both for the correction of refractive anomalies and tor the treatment of some eye diseases. From the moment when adequately biocompatible materials were found, for a very sensitive environment such as the human eye, from early 60s of the 20th century, starts irrepressible expansion of soft contact lenses. The reason for this expansion of soft contact lenses lies in advantages they undoubtedly have in comparison to glasses, but also in comparison to hard and semi-hard contact lenses. Unfortunately, in parallel with the increasing number of users of this type of optical aids, increases the incidence of complications that can arise. Complications can be very diverse in nature and severity, and they can be classified into three major groups: symptoms of eye dryness, infections and allergic-toxic complications. Symptoms of dry eye are very common for users of contact lenses, and their occurrence is especially provoked by certain factors, such as cigarette smoke or prolonged watching the computer screen or TV. These complications are usually not so dangerous and can easily be solved by applying artificial tears. Infections are not so common and occur as a result of inadequate maintenance of contact lenses. If the symptoms are recognized early, infections are mostly stopped at the level of conjunctivitis and are treated fairly quickly and easily. Otherwise, the infection can progress to ulcerative keratitis, the most severe complication of inadequate application of soft contact lenses, and in some cases it can even lead to blindness. Allergic-toxic complications generally occur in susceptible persons and their occurrence in most cases means contraindication for further wearing of soft contact lenses. This case report underlines possible role of rheumatoid factor in estimation of the patient's response to administered therapy.

Disentangling migratory routes and wintering grounds of Iberian near-threatened European Rollers Coracias garrulus.

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Juan Rodríguez-Ruiz

Full Text Available Long-distance migrants are suffering drastic declines in the last decades. Causes beneath this problem are complex due to the wide spatial and temporal scale involved. We aim to reveal migratory routes, stopover areas, wintering grounds, and migratory strategies for the most southwestern populations of the near-threatened European Roller Coracias garrulus in order to identify conservation key areas for the non-breeding stage of this species. To this end, we used tracking data from seven satellite transmitters fitted to birds breeding in different populations throughout the Iberian Peninsula and four geolocators fitted to individuals in a southeastern Iberian population. Precise satellite data were used to describe daily activity patterns and speed in relation to the main regions crossed during the migration. Individuals from the most southwestern Iberian populations made a detour towards the Atlantic African coast whereas those from northeastern populations followed a straight north-to-south route. We identified important stopover areas in the Sahel belt, mainly in the surroundings of the Lake Chad, and wintering grounds on southwestern Africa farther west than previously reported for the species. Concerning the migratory strategy, satellite data revealed: 1 a mainly nocturnal flying activity, 2 that migration speed depended on the type of crossed habitat, with higher average speed while crossing the desert; and 3 that the migration was slower and lasted longer in autumn than in spring. The studied populations showed weak migratory connectivity, suggesting the confluence of birds from a wide range of breeding grounds in a restricted wintering area. Therefore, we suggest to target on defining precisely key areas for this species and identifying specific threats in them in order to develop an appropriate global conservation programme for the European Roller.

Toxicity of essential oil compounds against Exorista sorbillans ...

African Journals Online (AJOL)

Essential oils of Ageratum conyzoides and Ocimum species are potential candidates for management of Exorista sorbillans (Wiedemann) (Diptera: Culicidae), a serious pest of silkworm. Considering that the pure compounds in essential oil may exhibit efficacy against the parasitoid, contact and topical toxicity of 22 essential ...

Application of Toxic Chinese Medicine in Chinese Pharmacopoeia

Science.gov (United States)

Zhao, Hui; Feng, Yu; Mao, Mingsan

2018-01-01

Objective: Explore the application characteristics of proprietary Chinese medicine prescriptions containing toxic herbs in pharmacopoeia. Methods: In this paper, according to the clinical application of pharmacopoeia proprietary Chinese medicine is divided into table agent, Qushu agent, diarrhea agent, heat agent, Wen Li agent, cough and asthma agents, resuscitation agent, Gutian agent, Fuzheng agent, Anshen agent, hemostatic agent, The traditional Chinese medicine prescription and the clinical application of the Chinese herbal medicine containing the toxic Chinese medicine were analyzed and sorted out., Summed up the compatibility of toxic herbs and application characteristics. Results: Toxic Chinese herbal medicine in the cure of traditional Chinese medicine to play a long-standing role, through the overall thinking, dialectical thinking, and thinking of toxic Chinese medicine in the analysis of Chinese medicine that [2], toxic Chinese medicine in the application of proprietary Chinese medicine can not lack. Conclusion: Pharmacopoeia included proprietary Chinese medicine not only in the clinical treatment of good, but also the application of its toxic traditional Chinese medicine and its understanding of the enrichment of the toxic characteristics of traditional Chinese medicine and treatment-related disease pathology between the points of contact for patients with clinical applications Based on and theoretical guidance of Chinese medicine [3].

The influence of API concentration on the roller compaction process: modeling and prediction of the post compacted ribbon, granule and tablet properties using multivariate data analysis.

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Boersen, Nathan; Carvajal, M Teresa; Morris, Kenneth R; Peck, Garnet E; Pinal, Rodolfo

2015-01-01

While previous research has demonstrated roller compaction operating parameters strongly influence the properties of the final product, a greater emphasis might be placed on the raw material attributes of the formulation. There were two main objectives to this study. First, to assess the effects of different process variables on the properties of the obtained ribbons and downstream granules produced from the rolled compacted ribbons. Second, was to establish if models obtained with formulations of one active pharmaceutical ingredient (API) could predict the properties of similar formulations in terms of the excipients used, but with a different API. Tolmetin and acetaminophen, chosen for their different compaction properties, were roller compacted on Fitzpatrick roller compactor using the same formulation. Models created using tolmetin and tested using acetaminophen. The physical properties of the blends, ribbon, granule and tablet were characterized. Multivariate analysis using partial least squares was used to analyze all data. Multivariate models showed that the operating parameters and raw material attributes were essential in the prediction of ribbon porosity and post-milled particle size. The post compacted ribbon and granule attributes also significantly contributed to the prediction of the tablet tensile strength. Models derived using tolmetin could reasonably predict the ribbon porosity of a second API. After further processing, the post-milled ribbon and granules properties, rather than the physical attributes of the formulation were needed to predict downstream tablet properties. An understanding of the percolation threshold of the formulation significantly improved the predictive ability of the models.

Acute, fatal Sarcocystis calchasi-associated hepatitis in Roller pigeons (Columba livia f. dom.) at Philadelphia Zoo.

Science.gov (United States)

Trupkiewicz, J G; Calero-Bernal, R; Verma, S K; Mowery, J; Davison, S; Habecker, P; Georoff, T A; Ialeggio, D M; Dubey, J P

2016-01-30

Four Roller pigeons (Columba livia f. dom.) at the Philadelphia Zoo died suddenly. Necropsy examination revealed macroscopic hepatitis. Microscopically, the predominant lesions were in liver, characterized with necrosis and mixed cell inflammatory response. Sarcocystis calchasi-like schizonts and free merozoites were identified in liver. Transmission electron microscopy confirmed that schizonts were in hepatocytes. A few schizonts were in spleen. PCR using S. calchasi-specific primers confirmed the diagnosis. Neither lesions nor protozoa were found in brain and muscles. This is the first report of acute visceral S. calchasi-associated sarcocystosis in naturally infected avian hosts. Published by Elsevier B.V.

Contact mechanics: contact area and interfacial separation from small contact to full contact

International Nuclear Information System (INIS)

Yang, C; Persson, B N J

2008-01-01

We present a molecular dynamics study of the contact between a rigid solid with a randomly rough surface and an elastic block with a flat surface. The numerical calculations mainly focus on the contact area and the interfacial separation from small contact (low load) to full contact (high load). For a small load the contact area varies linearly with the load and the interfacial separation depends logarithmically on the load. For a high load the contact area approaches the nominal contact area (i.e. complete contact), and the interfacial separation approaches zero. The numerical results have been compared with analytical theory and experimental results. They are in good agreement with each other. The present findings may be very important for soft solids, e.g. rubber, or for very smooth surfaces, where complete contact can be reached at moderately high loads without plastic deformation of the solids

Toxicity of several contact insecticides to Tribolium castaneum (Herbst populations after selection with pirimiphos-methyl and deltamethrin

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Goran Andrić

2015-12-01

Full Text Available Laboratory bioassays were conducted to detect possible alteration in susceptibility of two field Tribolium castaneum (Herbst populations (sampled in a warehouse in Nikinci and a silo in Jakovo to dichlorvos, malathion, chlorpyrifos-methyl, pirimiphos-methyl, deltamethrin and bifenthrin after previous selection with the LD80 of pirimiphos-methyl and deltamethrin. Data from the topical application bioassays show that chlorpyrifos-methyl was the most toxic insecticide to T. castaneum adults of the Nikinci population selected with pirimiphosmethyl and deltamethrin, while malathion was the weakest, and both selection procedures changed/reduced significantly only the toxicity of deltamethrin and bifenthrin, increasing their resistance ratios (RR at the LD50 from 1.1 to 1.8 (bifenthrin and from 0.9 to 2.2 (deltamethrin. Deltamethrin was the most toxic insecticide for Jakovo adults selected with the LD80 of pirimiphosmethyl, while malathion was again the least toxic. Selection of that population had no effect on insecticide toxicity, except of malathion, which had a rise in RR at the LD50 from 26.0 to 29.8.

A comparative study of physical and chemical properties of different pozzolanic materials used for roller compacted concrete RCC dams

OpenAIRE

Husein Malkawi Abdallah I.; Shatnawi Ehab; Husein Malkawi Dima A.

2017-01-01

This paper addresses the feasibility and the efficiency of using Natural Pozzolan and/or Rock flour in Roller Compacted Concrete (RCC) gravity dams. For this purpose, five identical mortar trial mixes were prepared using five different supplementary materials, i.e., fly ash produced in South Africa (proven to be effective in RCC construction), fly ash produced in Turkey, Jordanian natural pozzolan, Saudi natural pozzolan, and rock flour from Mujib Dam basalt quarry. The physical and chemical ...

Heavy Load Rollers in Logistic Systems

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B. Künne

2003-01-01

Full Text Available Wheels with polyurethane bandages are in common use in logistic systems with friction gear actuation. Many research projects have studied the mechanical construction of these heavy load wheels. The studies have been theoretical as well as experimental. Research interests at the department of machine elements include the wear in the presence of intermediate material on the contact area between the bandage surface and the contact surface on which the wheel rolls off. This problem, which is observed when examining this tribochemical system, has not been studied before. Within this project both one-phase intermediate materials such as sand, water, cutting-cooling-emulsion, metal splinters and two-phase intermediate materials such as sand/water and combinations of the latter were taken into consideration. In addition, the exposure of the bandage hardness, the cross linking agent of the polyurethane, the mechanical stress, and the slip are observed. The analysis of the experimental results indicates that friction gear actuators can be constructed abrasion-optimised, taking into account special interfering effects in the form of intermediate materials in the contact area.

The formation mechanism for printed silver-contacts for silicon solar cells.

Science.gov (United States)

Fields, Jeremy D; Ahmad, Md Imteyaz; Pool, Vanessa L; Yu, Jiafan; Van Campen, Douglas G; Parilla, Philip A; Toney, Michael F; van Hest, Maikel F A M

2016-04-01

Screen-printing provides an economically attractive means for making Ag electrical contacts to Si solar cells, but the use of Ag substantiates a significant manufacturing cost, and the glass frit used in the paste to enable contact formation contains Pb. To achieve optimal electrical performance and to develop pastes with alternative, abundant and non-toxic materials, a better understanding the contact formation process during firing is required. Here, we use in situ X-ray diffraction during firing to reveal the reaction sequence. The findings suggest that between 500 and 650 °C PbO in the frit etches the SiNx antireflective-coating on the solar cell, exposing the Si surface. Then, above 650 °C, Ag(+) dissolves into the molten glass frit - key for enabling deposition of metallic Ag on the emitter surface and precipitation of Ag nanocrystals within the glass. Ultimately, this work clarifies contact formation mechanisms and suggests approaches for development of inexpensive, nontoxic solar cell contacting pastes.

Occupational irritant contact dermatitis due to petroleum naphtha

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Aslı Aytekin

2014-12-01

Full Text Available Irritant contact dermatitis (ICD is responsible for the vast majority of occupational contact dermatitis and usually seen in professional groups working with wet hand. However, today, with the increasing business lines, employees are exposed to a variety of irritants. Occupational exposure to many chemicals and toxic irritants affect not only the skin, but also the other systems. Therefore, this situation resulting with loss of work and changes in business may become a public health problem. The diagnosis of occupational contact dermatitis should not be limited only with tests for allergens, detailed history of exposure to workplace substances and careful examination of product safety forms are necessary. In addition, by establishing close relationship between occupational physicians and employers, preventive measures should be taken before similar diseases occur in other workers in the same work place. In order to highlight this issue, a 32-year-old male patient working in an invitation card fabric is presented in this case report. Irritant contact dermatitis secondary to “petroleum naphta” was present in the patient’s arms. Another important feature of this case, as far as we know, this is the first case of irritant contact dermatitis due to naphtha in the literature.

Lactobacilli require physical contact to reduce staphylococcal TSST-1 secretion and vaginal epithelial inflammatory response.

Science.gov (United States)

Younes, Jessica A; Reid, Gregor; van der Mei, Henny C; Busscher, Henk J

2016-06-01

ITALIC! Staphylococcus aureusbiofilms can be found on vaginal epithelia, secreting toxins and causing inflammation. The co-vaginal species ITALIC! Lactobacilluscan alter staphylococcal-induced epithelial secretion of inflammatory cytokines and quench staphylococcal toxic shock syndrome toxin-1 secretion. It is hypothesized that these effects of lactobacilli require direct physical contact between lactobacilli, staphylococci and the epithelium. Indeed, lactobacilli only reduced ITALIC! S. aureus-induced inflammatory cytokine expression when allowed physical contact with vaginal epithelial cells. Furthermore, a reduction in toxic shock syndrome toxin-1 secretion only occurred when a probiotic ITALIC! Lactobacillusstrain was allowed contact, but not when being physically separated from ITALIC! S. aureus Bacterial-probe atomic force microscopy demonstrated that lactobacilli and staphylococci strongly adhere to epithelial cells, while lactobacilli adhere stronger to staphylococci than staphylococci to each other, giving lactobacilli opportunity to penetrate and reside in staphylococcal biofilms, as visualized using confocal laser scanning microscopy with fluorescence ITALIC! in situhybridization probes. These results identify that physical contact and biochemical signaling by lactobacilli are intrinsically linked mechanisms that reduce virulence of ITALIC! S. aureusbiofilm. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Evaluation of the combination of radio frequency, infrared energy and mechanical rollers with suction to improve skin surface irregularities (cellulite) in a limited treatment area.

Science.gov (United States)

Kulick, Michael

2006-12-01

This IRB-approved (Institutional Review Board) study evaluated the efficacy of a device that combines radio frequency, infrared energy and mechanical rollers/suction (ELOS technology) to reduce skin surface irregularities in a limited treatment zone. Sixteen patients were enrolled and received two treatments per week for 4 consecutive weeks. Treatments were limited to a 20.53 cm x 33.02 cm area of the posterior or lateral thigh and lasted for 15 minutes. Maximum machine settings were used for all but one individual at every treatment. Evaluations consisted of a patient questionnaire and photographic assessment of skin contour by three physicians at 3 and 6 months after the last session who were blind to the treatment each patient received. Physician evaluators determined that all patients were improved at both post-treatment periods. The average improvement at 3 and 6 months was 62% and 50%, respectively. All patients felt they were improved. One patient described the treatment as painful and required reduced treatment parameters after the initial treatment. Bruising within the treatment area was observed in five patients following the initial sessions but this did not alter the treatment protocol and did not occur in subsequent treatments. One patient had a superficial skin burn due to poor electrode contact that did not require corrective treatment.

The influence of incline and speed on work rate, gross efficiency and kinematics of roller ski skating.

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Sandbakk, Øyvind; Ettema, Gertjan; Holmberg, Hans-Christer

2012-08-01

During competitions, elite cross-country skiers produce higher external work rates on uphill than on flat terrain. However, it is not presently known whether this reflects solely higher energy expenditure. Furthermore, the kinematic factors associated with these higher rates of uphill work have not yet been examined. Therefore, in the present investigation the work rate and associated kinematic parameters at similar metabolic rates during roller ski skating on flat and uphill terrains have been compared. Seven elite male skiers performed six 5-min sub-maximal exercise bouts at the same low, moderate and high metabolic rates on 2 and 8% inclines, while roller skiing on a treadmill employing the G3 skating technique. The work rate was calculated as work against gravity and friction, whereas the energetic equivalent of VO(2) was taken as the metabolic rate. Gross efficiency was defined as work rate divided by metabolic rate. Kinematic parameters were analyzed in three dimensions. At the same metabolic rate, the work rate, cycle rate, work per cycle and relative duration of propulsive phases during a cycle of movement were all higher on the 8% than on the 2% incline at all speeds (all P < 0.05). At similar work rates, gross efficiency was greater on the 8% incline (P < 0.05). In conclusion, these elite skiers consistently demonstrated higher work rates on the 8% incline. To achieve the higher work rates on the steeper incline, these elite skiers employed higher cycle rates and performed more work per cycle, in association with a longer relative propulsive phase.

A contact mechanics model for ankle implants with inclusion of surface roughness effects

International Nuclear Information System (INIS)

Hodaei, M; Farhang, K; Maani, N

2014-01-01

Total ankle replacement is recognized as one of the best procedures to treat painful arthritic ankles. Even though this method can relieve patients from pain and reproduce the physiological functions of the ankle, an improper design can cause an excessive amount of metal debris due to wear, causing toxicity in implant recipient. This paper develops a contact model to treat the interaction of tibia and talus implants in an ankle joint. The contact model describes the interaction of implant rough surfaces including both elastic and plastic deformations. In the model, the tibia and the talus surfaces are viewed as macroscopically conforming cylinders or conforming multi-cylinders containing micrometre-scale roughness. The derived equations relate contact force on the implant and the minimum mean surface separation of the rough surfaces. The force is expressed as a statistical integral function of asperity heights over the possible region of interaction of the roughness of the tibia and the talus implant surfaces. A closed-form approximate equation relating contact force and minimum separation is used to obtain energy loss per cycle in a load–unload sequence applied to the implant. In this way implant surface statistics are related to energy loss in the implant that is responsible for internal void formation and subsequent wear and its harmful toxicity to the implant recipient. (paper)

A contact mechanics model for ankle implants with inclusion of surface roughness effects

Science.gov (United States)

Hodaei, M.; Farhang, K.; Maani, N.

2014-02-01

Total ankle replacement is recognized as one of the best procedures to treat painful arthritic ankles. Even though this method can relieve patients from pain and reproduce the physiological functions of the ankle, an improper design can cause an excessive amount of metal debris due to wear, causing toxicity in implant recipient. This paper develops a contact model to treat the interaction of tibia and talus implants in an ankle joint. The contact model describes the interaction of implant rough surfaces including both elastic and plastic deformations. In the model, the tibia and the talus surfaces are viewed as macroscopically conforming cylinders or conforming multi-cylinders containing micrometre-scale roughness. The derived equations relate contact force on the implant and the minimum mean surface separation of the rough surfaces. The force is expressed as a statistical integral function of asperity heights over the possible region of interaction of the roughness of the tibia and the talus implant surfaces. A closed-form approximate equation relating contact force and minimum separation is used to obtain energy loss per cycle in a load-unload sequence applied to the implant. In this way implant surface statistics are related to energy loss in the implant that is responsible for internal void formation and subsequent wear and its harmful toxicity to the implant recipient.

Experimental Research on the Impact of Thin-Wall Ratio and the Fillet Radius of Forming Roller on the Limiting Spinning Ratio of AMS 5504 Sheets

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Kut S.

2017-12-01

Full Text Available Results of experimental investigations of metal spinning process of AMS 5504 sheets. cylindrical drawpieces with use of discs-shaped sheet with various diameter and thickness were shown in this work. Tests were performed on two roller metal spinning machine of a vertical axis Leifeld SFC 800 V500.

A G-function-based reliability-based design methodology applied to a cam roller system

International Nuclear Information System (INIS)

Wang, W.; Sui, P.; Wu, Y.T.

1996-01-01

Conventional reliability-based design optimization methods treats the reliability function as an ordinary function and applies existing mathematical programming techniques to solve the design problem. As a result, the conventional approach requires nested loops with respect to g-function, and is very time consuming. A new reliability-based design method is proposed in this paper that deals with the g-function directly instead of the reliability function. This approach has the potential of significantly reducing the number of calls for g-function calculations since it requires only one full reliability analysis in a design iteration. A cam roller system in a typical high pressure fuel injection diesel engine is designed using both the proposed and the conventional approach. The proposed method is much more efficient for this application

Instrumented roll technology for the design space development of roller compaction process.

Science.gov (United States)

Nesarikar, Vishwas V; Vatsaraj, Nipa; Patel, Chandrakant; Early, William; Pandey, Preetanshu; Sprockel, Omar; Gao, Zhihui; Jerzewski, Robert; Miller, Ronald; Levin, Michael

2012-04-15

Instrumented roll technology on Alexanderwerk WP120 roller compactor was developed and utilized successfully for the measurement of normal stress on ribbon during the process. The effects of process parameters such as roll speed (4-12 rpm), feed screw speed (19-53 rpm), and hydraulic roll pressure (40-70 bar) on normal stress and ribbon density were studied using placebo and active pre-blends. The placebo blend consisted of 1:1 ratio of microcrystalline cellulose PH102 and anhydrous lactose with sodium croscarmellose, colloidal silicon dioxide, and magnesium stearate. The active pre-blends were prepared using various combinations of one active ingredient (3-17%, w/w) and lubricant (0.1-0.9%, w/w) levels with remaining excipients same as placebo. Three force transducers (load cells) were installed linearly along the width of the roll, equidistant from each other with one transducer located in the center. Normal stress values recorded by side sensors and were lower than normal stress values recorded by middle sensor and showed greater variability than middle sensor. Normal stress was found to be directly proportional to hydraulic pressure and inversely to screw to roll speed ratio. For active pre-blends, normal stress was also a function of compressibility. For placebo pre-blends, ribbon density increased as normal stress increased. For active pre-blends, in addition to normal stress, ribbon density was also a function of gap. Models developed using placebo were found to predict ribbon densities of active blends with good accuracy and the prediction error decreased as the drug concentration of active blend decreased. Effective angle of internal friction and compressibility properties of active pre blend may be used as key indicators for predicting ribbon densities of active blend using placebo ribbon density model. Feasibility of on-line prediction of ribbon density during roller compaction was demonstrated using porosity-pressure data of pre-blend and normal stress

Analysis of laboratory compaction methods of roller compacted concrete

Science.gov (United States)

Trtík, Tomáš; Chylík, Roman; Bílý, Petr; Fládr, Josef

2017-09-01

Roller-Compacted Concrete (RCC) is an ordinary concrete poured and compacted with machines typically used for laying of asphalt road layers. One of the problems connected with this technology is preparation of representative samples in the laboratory. The aim of this work was to analyse two methods of preparation of RCC laboratory samples with bulk density as the comparative parameter. The first method used dynamic compaction by pneumatic hammer. The second method of compaction had a static character. The specimens were loaded by precisely defined force in laboratory loading machine to create the same conditions as during static rolling (in the Czech Republic, only static rolling is commonly used). Bulk densities obtained by the two compaction methods were compared with core drills extracted from real RCC structure. The results have shown that the samples produced by pneumatic hammer tend to overestimate the bulk density of the material. For both compaction methods, immediate bearing index test was performed to verify the quality of compaction. A fundamental difference between static and dynamic compaction was identified. In static compaction, initial resistance to penetration of the mandrel was higher, after exceeding certain limit the resistance was constant. This means that the samples were well compacted just on the surface. Specimens made by pneumatic hammer actively resisted throughout the test, the whole volume was uniformly compacted.

Documentation of roller-bearing effect on butterfly inspired grooves

Science.gov (United States)

Gautam, Sashank; Lang, Amy

2017-11-01

Butterfly wings are covered with scales in a roof shingle pattern which align together to form grooves. The increase or decrease of laminar friction drag depends on the flow orientation to the scales. Flow in the longitudinal direction to the grooves encounters increased surface area which increases the friction drag. However, in the transverse direction, for low Re laminar flow, a single vortex is formed inside each groove and is predicted to remain stable due to the very low Re of the flow in each cavity. These embedded vortices act as roller bearings to the flow above, such that the fluid from the outer boundary layer does not mix with fluid inside the cavities. This leads to a reduction of skin friction drag when compared to a smooth surface. When the cavity flow Re is increased beyond a critical point, the vortex becomes unstable and the low-momentum fluid in the grooves mixes with the outer boundary layer flow, increasing the drag. The objective of this experiment is to determine the critical Re where the embedded vortex transitions from a stable to an unstable state using DPIV. Subsequently, for steady vortex conditions, a comparison of skin friction drag between the grooved and flat plate can show that the butterfly scaled surface can result in sub-laminar friction drag. The National Science Foundation (Grant No. 1335848).

Toxicity of petroleum hydrocarbon distillates to soil organisms.

Science.gov (United States)

Cermak, Janet H; Stephenson, Gladys L; Birkholz, Detlef; Wang, Zhendi; Dixon, D George

2010-12-01

Canadian standards for petroleum hydrocarbons in soil are based on four distillate ranges (F1, C6-C10; F2, >C10-C16; F3, >C16-C34; and F4, >C34). Concerns have arisen that the ecological soil contact standards for F3 may be overly conservative. Oil distillates were prepared and characterized, and the toxicity of F3 and two subfractions, F3a (>C16-C23) and F3b (>C23-C34), to earthworms (Eisenia andrei), springtails (Orthonychiurus folsomi), and northern wheatgrass (Elymus lanceolatus), as well as the toxicity of F2 to earthworms, was determined. Clean soil was spiked with individual distillates and measured concentrations were determined for select tests. Results agree with previous studies with these distillates. Reported toxicities of crude and petroleum products to invertebrates were generally comparable to that of F3 and F3a. The decreasing order of toxicity was F3a > F3 > F3b with invertebrates, and F3a > F3b > F3 with plants. The toxicities of F3a and F3b were not sufficiently different to recommend regulating hydrocarbons based on these distillate ranges. The results also suggest that test durations may be insufficient for determining toxicity of higher distillate ranges, and that the selection of species and endpoints may significantly affect interpretation of toxicity test results. Copyright © 2010 SETAC.

Ouabain modulates cell contacts as well as functions that depend on cell adhesion.

Science.gov (United States)

Larre, Isabel; Contreras, Ruben G; Cereijido, Marcelino

2011-01-01

Ouabain, a toxic of vegetal origin used for centuries to treat heart failure, has recently been demonstrated to have an endogenous counterpart, most probably ouabain itself, which behaves as a hormone. Therefore, the challenge now is to discover the physiological role of hormone ouabain. We have recently shown that it modulates cell contacts such as gap junctions, which communicate neighboring cells, as well as tight junctions (TJs), which are one of the two differentiated features of epithelial cells, the other being apical/basolateral polarity. The importance of cell contacts can be hardly overestimated, since the most complex object in the universe, the brain, assembles itself depending on what cells contacts what other(s) how, when, and how is the molecular composition and special arrangement of the contacts involved. In the present chapter, we detail the protocols used to demonstrate the effect of ouabain on the molecular structure and functional properties of one of those cell-cell contacts: the TJ.

The effects of the arm swing on biomechanical and physiological aspects of roller ski skating.

Science.gov (United States)

Hegge, Ann Magdalen; Ettema, Gertjan; de Koning, Jos J; Rognstad, Asgeir Bakken; Hoset, Martin; Sandbakk, Øyvind

2014-08-01

This study analyzed the biomechanical and physiological effects of the arm swing in roller ski skating, and compared leg-skating (i.e. ski skating without poles) using a pronounced arm swing (SWING) with leg-skating using locked arms (LOCKED). Sixteen elite male cross-country skiers performed submaximal stages at 10, 15 and 20kmh(-1) on a 2% inclined treadmill in the two techniques. SWING demonstrated higher peak push-off forces and a higher force impulse at all speeds, but a longer cycle length only at the highest speed (all Pskating increases the ski forces and aerobic energy cost at low and moderate speeds, whereas the greater forces at high speed lead to a longer cycle length and smaller anaerobic contribution. Copyright © 2014 Elsevier B.V. All rights reserved.

Toxicity of carbon nanotubes to the activated sludge process

International Nuclear Information System (INIS)

Luongo, Lauren A.; Zhang Xiaoqi

2010-01-01

The discharge of carbon nanotubes (CNTs) from industrial waste or disposal of such materials from commercial and/or domestic use will inevitably occur with increasing production and enter into wastewater treatment facilities with unknown consequences. Therefore, a better knowledge of the toxicity of CNTs to biological processes in wastewater treatment will be critical. This study examined the toxicity of multi-walled carbon nanotubes (MWCNTs) on the microbial communities in activated sludge. A comparative study using the activated sludge respiration inhibition test was performed on both unsheared mixed liquor and sheared mixed liquor to demonstrate the potential toxicity posed by MWCNTs and to illustrate the extent of extracellular polymeric substances (EPS) in protecting the microorganisms from the toxicity of CNTs. Respiration inhibition was observed for both unsheared and sheared mixed liquor when MWCNTs were present, however, greater respiration inhibition was observed for the sheared mixed liquor. The toxicity observed by the respiration inhibition test was determined to be dose-dependent; the highest concentration of MWCNTs exhibited the highest respiration inhibition. Scanning Electron Microscopy (SEM) images demonstrated direct physical contact between MWCNTs and activated sludge flocs.

Closure Report for Corrective Action Unit 404: Roller Coaster Sewage Lagoons and North Disposal Trench, Tonopah Test Range, Nevada with ROTC 1, Revision 0

Energy Technology Data Exchange (ETDEWEB)

Lynn Kidman

1998-09-01

This Closure Report provides the documentation for closure of the Roller Coaster Sewage Lagoons and North Disposal Trench Comective Action Unit (CAU) 404. CAU 404 consists of the Roller Coaster Sewage Lagoons (Corrective Action Site [CAS] TA-03-O01-TA-RC) and the North Disposal Trench (CAS TA-21-001-TA-RC). The site is located on the Tonopah Test Range, approximately 225 kilometers (km) (140 miles [mi]) northwest ofLas Vegas, Nevada. . The sewage lagoons received ~quid sanitary waste horn the Operation Roller Coaster Man Camp in 1963 and debris from subsequent range and construction cleanup activities. The debris and ordnance was subsequently removed and properly dispos~, however, pesticides were detected in soil samples born the bottom of the lagoons above the U,S. Environmental Protection Agency Region IX Prelimimuy Remediation Goals (EPA 1996). . The North Disposal Trench was excavated in 1963. Debris from the man camp and subsequent range and construction cleanup activities was placed in the trench. Investigation results indicated that no constituents of concern were detected in soil samples collected from the trench. Remedial alternative proposed in the Comctive Action Decision Document (CADD) fm the site was “Covering” (DOE, 1997a). The Nevada Division of”Enviromnental Protection (NDEP)-approved Correction Action Plan (CAP) proposed the “Covering” niethodology (1997b). The closure activities were completed in accorhce with the approwil CAP and consisted of baclctllling the sewage lagoons and disposal trench, constructing/planting an engineered/vegetative cover in the area of the sewage lagoons and dikposal trencQ installing a perimeter fence and signs, implementing restrictions on fi~e use, and preparing a Post-Closure Monitoring Plan. “ Since closure activities. for CAU 404 have been completed in accordance with the Nevada Division of Environmental Protection-approved CAP (DOE, 1997b) as documented in this Closure Report, the U.S. Department of

The effects of poling on physiological, kinematic and kinetic responses in roller ski skating.

Science.gov (United States)

Grasaas, Erik; Hegge, Ann Magdalen; Ettema, Gertjan; Sandbakk, Øyvind

2014-09-01

We investigated the effects of poling on physiological, kinematic and kinetic responses in the G4 skating technique where the poling movement is synchronized with the leg push-off on one side (strong side) followed by a forward arm swing during the leg push-off on the other side (weak side). G4 skating with (G4-P) and without (G4-NP) poling was compared in 17 elite male cross-country skiers during 4-min submaximal tests on a 2% inclined roller ski treadmill at 10, 15 and 20 km h(-1). G4-P demonstrated less ventilatory stress and higher gross efficiency compared to G4-NP at all velocities, and the blood lactate concentration was lower at the high velocity (all P skating technique. Thus, poling provides possibilities to increase total propulsion, to reduce ski forces and to enhance skiing efficiency.

Study on the effect of Shahin-Dezh green Tuff on the mechanical characteristics of roller compact concrete

Directory of Open Access Journals (Sweden)

Sadegh Dardaei

2016-12-01

Full Text Available Due to the growing popularity of concrete structure and increasing use of them, especially Roller compacted concrete, applying Pozzolan and replacing cement with Pozzolan is very important. Nowadays, the use of the additive for cement replacement is common in RCC mix design due to its technical advantages and economic benefits as there is large quantity of Pozzolan mineral resources in Iran. In this paper the impact of produced concrete has been fully considered as well as the effect of this Pozzolan on the compressive strength, tensile strength and permeability by using green Tuff obtained from available Pozzolan in western Azarbaijan. The due results prove that Shahin-Dezh green Tuff improves concretes quality.

The impact of the provisions of the suspensions on the track of conveyor with suspended belt and distributed drive at jamming rollers

OpenAIRE

Tolkachev E.N.

2018-01-01

The article is devoted to the topical issue, which is related to simulation of the failures of drives suspensions of the conveyor with suspended belt and distributed drive. Using the developed mathematical model of the failures drives suspensions due to jamming rollers to the reference design of conveyor with suspended belt and distributed drive is performed modelling of dynamic characteristics. Investigation of the influence of the location of the failed drives suspensions on the track on th...

Toxicity screening of soils from different mine areas—A contribution to track the sensitivity and variability of Arthrobacter globiformis assay

Energy Technology Data Exchange (ETDEWEB)

Marques, Catarina R., E-mail: crmarques@ua.pt [Departamento de Biologia and CESAM (Centro de Estudos do Ambiente e do Mar), Universidade de Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro (Portugal); Caetano, Ana L. [Departamento de Biologia and CESAM (Centro de Estudos do Ambiente e do Mar), Universidade de Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro (Portugal); Haller, Andreas [ECT Oekotoxikologie GmbH, Böttgerstraße 2–14, D-65439 Flörsheim a. M. (Germany); Gonçalves, Fernando [Departamento de Biologia and CESAM (Centro de Estudos do Ambiente e do Mar), Universidade de Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro (Portugal); Pereira, Ruth [Faculdade de Ciências da Universidade do Porto, Rua do Campo Alegre, s/n, 4169-007 Porto (Portugal); Interdisciplinary Centre of Marine and Environmental Research (CIIMAR/CIMAR), Universidade do Porto, Rua dos Bragas 289, P 4050-123 Porto (Portugal); Römbke, Jörg [ECT Oekotoxikologie GmbH, Böttgerstraße 2–14, D-65439 Flörsheim a. M. (Germany)

2014-06-01

Highlights: • The assay gave rapid and feasible discrimination of toxic soils to A. globiformis. • Sensitive and low variability response to soils from different regions. • Soil properties may interfere with metal toxicity and fluorescence measurements. • Proposal of a toxicity threshold for the contact assay regarding soils. • A. globiformis assay should be included in the Tier I of risk assessment frameworks. - Abstract: This study used the Arthrobacter globiformis solid-contact test for assessing the quality of soils collected in areas subjected to past and present mine activities in Europe (uranium mine, Portugal) and North Africa (phosphogypsum pile, Tunisia; iron mine, Morocco). As to discriminate the influence of soils natural variability from the effect of contaminants, toxicity thresholds were derived for this test, based on the dataset of each study area. Furthermore, the test sensitivity and variability was also evaluated. As a result, soils that inhibited A. globiformis dehydrogenase activity above 45% or 50% relatively to the control, were considered to be toxic. Despite the soil metal content determined, the properties of soils seemed to influence dehydrogenase activity. Overall, the contact test provided a coherent outcome comparing to other more time-consuming and effort-demanding ecotoxicological assays. Our results strengthened the feasibility and ecological relevance of this assay, which variability was quite reduced hence suggesting its potential integration within the test battery of tier 1 of soil risk assessment schemes.

Toxicity screening of soils from different mine areas—A contribution to track the sensitivity and variability of Arthrobacter globiformis assay

International Nuclear Information System (INIS)

Marques, Catarina R.; Caetano, Ana L.; Haller, Andreas; Gonçalves, Fernando; Pereira, Ruth; Römbke, Jörg

2014-01-01

Highlights: • The assay gave rapid and feasible discrimination of toxic soils to A. globiformis. • Sensitive and low variability response to soils from different regions. • Soil properties may interfere with metal toxicity and fluorescence measurements. • Proposal of a toxicity threshold for the contact assay regarding soils. • A. globiformis assay should be included in the Tier I of risk assessment frameworks. - Abstract: This study used the Arthrobacter globiformis solid-contact test for assessing the quality of soils collected in areas subjected to past and present mine activities in Europe (uranium mine, Portugal) and North Africa (phosphogypsum pile, Tunisia; iron mine, Morocco). As to discriminate the influence of soils natural variability from the effect of contaminants, toxicity thresholds were derived for this test, based on the dataset of each study area. Furthermore, the test sensitivity and variability was also evaluated. As a result, soils that inhibited A. globiformis dehydrogenase activity above 45% or 50% relatively to the control, were considered to be toxic. Despite the soil metal content determined, the properties of soils seemed to influence dehydrogenase activity. Overall, the contact test provided a coherent outcome comparing to other more time-consuming and effort-demanding ecotoxicological assays. Our results strengthened the feasibility and ecological relevance of this assay, which variability was quite reduced hence suggesting its potential integration within the test battery of tier 1 of soil risk assessment schemes

Occupational contact urticaria and protein contact dermatitis.

Science.gov (United States)

Doutre, Marie-Sylvie

2005-01-01

Irritant dermatitis and eczema are the most prevalent occupational skin diseases. Less common are immediate contact reactions such as contact urticaria and protein contact dermatitis. Occupational contact urticaria can be subdivided into two categories, immunological and non immunological. However, some agents can induce these two types of reactions. Contact urticaria to natural rubber latex is particularly frequent among health care personnel, but contact urticaria to a wide variety of other substances occurs in many other occupations. Among those at risk are cooks, bakers, butchers, restaurant personnel, veterinarians, hairdressers, florists, gardeners, and forestry workers. Protein contact dermatitis in some of these occupations is caused principally by proteins of animal or plant origin, especially among individuals with a history of atopic dermatitis. Diagnosis requires careful interrogation, clinical examination and skin tests (open tests and prick tests with immediate lecture) to identify a particular contact allergen.

THE DETERMINATION AND APPRECIATION OF OCCUPATIONAL TOXICITY AT WORK

Directory of Open Access Journals (Sweden)

Oana CHIVU

2017-05-01

Full Text Available The occupational toxins are those chemicals that workers come into contact with during the exercise of the profession and which under certain conditions have harmful effects on the body. The paper aims to address the determination and assessment of occupational toxicities in a workplace with the aim of ensuring an adequate working enviro nment as well as preventing occupational diseases, accidents and chronic fatigue.

THE DETERMINATION AND APPRECIATION OF OCCUPATIONAL TOXICITY AT WORK

OpenAIRE

Oana CHIVU; Claudiu BABIS; Andrei DIMITRESCU

2017-01-01

The occupational toxins are those chemicals that workers come into contact with during the exercise of the profession and which under certain conditions have harmful effects on the body. The paper aims to address the determination and assessment of occupational toxicities in a workplace with the aim of ensuring an adequate working enviro nment as well as preventing occupational diseases, accidents and chronic fatigue.

Degradation Assessment and Fault Diagnosis for Roller Bearing Based on AR Model and Fuzzy Cluster Analysis

Directory of Open Access Journals (Sweden)

Lingli Jiang

2011-01-01

Full Text Available This paper proposes a new approach combining autoregressive (AR model and fuzzy cluster analysis for bearing fault diagnosis and degradation assessment. AR model is an effective approach to extract the fault feature, and is generally applied to stationary signals. However, the fault vibration signals of a roller bearing are non-stationary and non-Gaussian. Aiming at this problem, the set of parameters of the AR model is estimated based on higher-order cumulants. Consequently, the AR parameters are taken as the feature vectors, and fuzzy cluster analysis is applied to perform classification and pattern recognition. Experiments analysis results show that the proposed method can be used to identify various types and severities of fault bearings. This study is significant for non-stationary and non-Gaussian signal analysis, fault diagnosis and degradation assessment.

Toxicity evaluation of 2-hydroxybiphenyl and other compounds involved in studies of fossil fuels biodesulphurisation.

Science.gov (United States)

Alves, L; Paixão, S M

2011-10-01

The acute toxicity of some compounds used in fossil fuels biodesulphurisation studies, on the respiration activity, was evaluated by Gordonia alkanivorans and Rhodococcus erythropolis. Moreover, the effect of 2-hydroxybiphenyl on cell growth of both strains was also determined, using batch (chronic bioassays) and continuous cultures. The IC₅₀ values obtained showed the toxicity of all the compounds tested to both strains, specially the high toxicity of 2-HBP. These results were confirmed by the chronic toxicity data. The toxicity data sets highlight for a higher sensitivity to the toxicant by the strain presenting a lower growth rate, due to a lower cells number in contact with the toxicant. Thus, microorganisms exhibiting faster generation times could be more resistant to 2-HBP accumulation during a BDS process. The physiological response of both strains to 2-HBP pulse in a steady-state continuous culture shows their potential to be used in a future fossil fuel BDS process. Copyright © 2011 Elsevier Ltd. All rights reserved.

The effects of adding waste plastic fibers on some properties of roller compacted concrete

Directory of Open Access Journals (Sweden)

Abed Adil

2018-01-01

Full Text Available An attempt to produce of roller compacted concrete (RCC improved by adding waste plastic fibers (WPFs resulting from cutting the PET beverage bottles was recorded in this study. The method which is used for production of RCC is an approved design method for ACI committee (5R-207,1980[1]. WPF was added by volumetric percentages ranging between (0.5 to 2 % and reference concrete mix was produced for comparison reason. Many tests were conducted on the models produced by rolling compacted concrete like compressive strength, flexural strength, modulus of elasticity, dry density, water absorption and ultrasonic pulse velocity. The analysis of the results showed that the use of plastic waste fibers (1% had led to improvement in the properties of each of the compressive strength and flexural strength compared with reference concrete. Results also showed that the addition of these, fibers increase water absorption and reduce the speed of Ultrasonic pulse velocity.

Comparative toxicity of chemicals to earthworms

Energy Technology Data Exchange (ETDEWEB)

Callahan, C.A.; Shirazi, M.A. (Environmental Protection Agency, Corvallis, OR (United States)); Neuhauser, E.F. (Niagara Mohawk Power Corp., Syracuse, NY (United States))

1994-02-01

The concentration-response (mortality) relationships of four species of earthworms, Eisenia fetida (Savigny), Allolobophora tuberculata (Eisen), Eudrilus eugeniae (Kinberg), and Perionyx excavatus (Perrier) are summarized for 62 chemicals and two test protocols. A Weibull function is used to summarize these data for each chemical in terms of sensitivity and toxicity, in addition to the LC50. The estimation of the Weibull parameters a and k summarize the entire concentration-response relationship. This technique should be applicable to a variety of testing protocols with different species whenever the goal is summarizing the shape of the concentration-response curves to fully evaluate chemical impact on organisms. In some cases for these data four orders of magnitude separate LC50s of the soil test and the contact test for the same chemical and species. All four species appear to be similar in range of toxicity and tolerance to these chemicals, suggesting that Eisenia fetida and may be representative of these four species and these chemicals.

Distribution of potentially toxic elements in urban soils of Bratislava; Distribucia potencialne toxickych prvkov v urbannych podach Bratislavy

Energy Technology Data Exchange (ETDEWEB)

Lahka, L.; Tatarkova, V.; Toth, R. [Univerzita Komenskeho, Prirodovedecka fakulta, Katedra geochemie, 84215 Bratislava (Slovakia)

2013-04-16

Potentially toxic elements naturally occur in soils, but their contents are increased in urban environment due to anthropogenic activities. The main sources of urban soil contamination with potentially toxic elements are chemical, energetic, building and blowing industry, engineering, traffic and municipal waste incineration plants. Contaminated urban soils can pose significant risks to human health trough dust inhalation, soil ingestion, and dermal contact. The primary objectives of the present study were: to assess concentrations of potentially toxic elements in soils of nursery schools, to investigate relationships between potentially toxic elements and physicochemical properties of soils, to identify the main possible sources. (authors)

Rolling induced size effects in elastic–viscoplastic sheet metals

DEFF Research Database (Denmark)

Nielsen, Kim Lau

2015-01-01

sheet rolling, where a non-homogeneous material deformation takes place between the rollers. Large strain gradients develop where the rollers first come in contact with the sheet, and a higher order plasticity model is employed to illustrate their influence at small scales. The study reveals...... presented revolves around the rolling induced effect of visco-plasticity (ranging hot and cold rolling) in combination with strain gradient hardening – including both dissipative and energetic contributions. To bring out first order effects on rolling at small scale, the modeling efforts are limited to flat...

One Health and Toxic Cyanobacteria | Science Inventory | US ...

Science.gov (United States)

One Health and toxic cyanobacteria Blooms of toxic freshwater blue-green algae or cyanobacteria (HABs) have been in the news after HABs associated with human and animal health problems have been reported in Florida, California and Utah during 2016. HABs occur in warm, slow moving or stagnant surface waters that are enriched with nutrients such as nitrogen and phosphorous. People are exposed to potentially toxic HABs during recreation in contaminated water, after exposure to contaminated drinking water or to blue-green algae supplements. Animals may be exposed to toxic HABs after drinking contaminated surface waters or coming into contact with HABs then ingesting cyanobacteria from their bodies during self-grooming activities. As HABs are being reported more frequently in the US, it is important for veterinarians to secure good exposure histories and to recognize the potential signs and health consequences of HAB exposures. We will review the current knowledge about human and animal health effects associated with freshwater HABs and scenarios that pose the highest risks for illnesses and deaths. This abstract does not necessarily reflect EPA policy. This is a summary of One Health and Cyanobacteria for public health and public practice veterinarians at the American Veterinary Medical Association annual convention. This product is associated with SSWR 4.01B

Contact and Repellant Activities of Zerumbone and Its Analogues from the Essential Oil of Zingiber zerumbet (L.) Smith against Lasioderma serricorne.

Science.gov (United States)

Wu, Yan; Guo, Shan-Shan; Huang, Dong-Ye; Wang, Cheng-Fang; Wei, Jian-Yu; Li, Zhi-Hua; Sun, Jian-Sheng; Bai, Jia-Feng; Tian, Zhao-Fu; Wang, Ping-Juan; Du, Shu-Shan

2017-04-03

The contact toxicity and repellent activities of the essential oil extracted from the rhizomes of Zingiber zerumbet (L.) Smith (Zingiberaceae) was evaluated against cigarette beetles (Lasioderma serricorne). The essential oil obtained by hydrodistillation was investigated by GC-FID and GC-MS. The main constituents of the essential oil were zerumbone (40.2%), α-caryophyllene (8.6%), humulene epoxide II (7.3%), camphene (5.9%) and fenchene (4.7%). Zerumbone and its analogues totally are accounting for 60.3% of the essential oil. It was found that the essential oil possessed contact toxicity against L. serricorne adults with a LD 50 value of 48.3 µg/adult. α-Caryophyllene (LD 50 = 13.1 µg/adult) exhibited stronger contact toxicity against L. serricorne than humulene oxide (LD 50 = 31.2 µg/adult), β-caryophyllene (LD 50 = 35.5 µg/adult) and zerumbone (LD 50 = 42.4 µg/adult). Moreover, α-caryophyllene possessed strong repellent activity (Class IV and V, respectively) against the beetles at 78.63 nL/cm 2 , after 2 and 4 h treatment. The results indicate that zerumbone and its analogues might be developed into natural insecticides or repellents for control of cigarette beetles, but their bioactivities are affected by their structures.

Injectible candidate sealants for fetal membrane repair: Bonding and toxicity in vitro

Science.gov (United States)

Bilic, Grozdana; Brubaker, Carrie; Messersmith, Phillip B.; Mallik, Ajit S.; Quinn, Thomas M.; Haller, Claudia; Done, Elisa; Gucciardo, Leonardo; Zeisberger, Steffen M.; Zimmermann, Roland; Deprest, Jan; Zisch, Andreas H.

2010-01-01

Objective This study was undertaken to test injectible surgical sealants that are biocompatible with fetal membranes, eventually for closure of iatrogenic membrane defects. Study Design Dermabond, Histoacryl, Tissucol fibrin glue, and three types of in situ forming poly(ethylene glycol)-based polymer hydrogels were tested for acute toxicity upon direct contact with fetal membranes for 24h. For determination of elution toxicity, extracts of sealants were incubated on amnion cell cultures for 72h. Bonding and toxicity was assessed through morphological and/or biochemical analysis. Results Extracts of all adhesives were non-toxic for cultured cells. However, only Tissucol and one type of poly(ethylene glycol)-based hydrogel, mussel-mimetic tissue adhesive, showed efficient, non-disruptive, non-toxic bonding to fetal membranes. Mussel-mimetic tissue adhesive applied over membrane defects created with a 3.5 mm trocar accomplished leak-proof closure that withstood membrane stretch in an in vitro model. Conclusion A synthetic hydrogel-type tissue adhesive emerged as potential sealing modality for iatrogenic membrane defects that merits further evaluation in vivo. PMID:20096254

Tunable functionality and toxicity studies of titanium dioxide nanotube layers

International Nuclear Information System (INIS)

Feschet-Chassot, E.; Raspal, V.; Sibaud, Y.; Awitor, O.K.; Bonnemoy, F.; Bonnet, J.L.; Bohatier, J.

2011-01-01

In this study, we have developed a simple process to fabricate scalable titanium dioxide nanotube layers which show a tunable functionality. The titanium dioxide nanotube layers were prepared by electrochemical anodization of Ti foil in 0.4 wt.% hydrofluoric acid solution. The nanotube layers structure and morphology were characterized using X-ray diffraction and scanning electron microscopy. The surface topography and wettability were studied according to the anodization time. The sample synthesized displayed a higher contact angle while the current density reached a local minimum. Beyond this point, the contact angles decreased with anodization time. Photo-degradation of acid orange 7 in aqueous solution was used as a probe to assess the photocatalytic activity of titanium dioxide nanotube layers under UV irradiation. We obtained better photocatalytic activity for the sample fabricated at higher current density. Finally we used the Ciliated Protozoan T. pyriformis, an alternative cell model used for in vitro toxicity studies, to predict the toxicity of titanium dioxide nanotube layers in a biological system. We did not observe any characteristic effect in the presence of the titanium dioxide nanotube layers on two physiological parameters related to this organism, non-specific esterases activity and population growth rate.

Evaluation of the toxic properties of naturally weathered Exxon Valdez crude oil to surrogate wildlife species

International Nuclear Information System (INIS)

Stubblefield, W.A.; Hancock, G.A.; Ford, W.H.; Prince, H.H.; Ringer, R.K.

1995-01-01

The toxic properties of naturally weathered Exxon Valdez crude oil (WEVC) to avian and mammalian wildlife species were evaluated using the surrogate species, mallard duck, Anas platyrhynchos, and European ferret, Mustela putorius. This study was conducted to evaluate the potential for toxic (rather than physical) injury to wildlife species that may have been exposed to WEVC, either through external contact or through dietary uptake. Previous studies have assessed the toxicity of unweathered crude oils, including Alaska North Slope Crude, but little information exists regarding the toxicity of a naturally weathered crude oil, typical of that encountered following a spill. A battery of laboratory toxicity tests was conducted, in compliance with standard and published test procedures, to evaluate acute and subchronic toxicity of WEVC. These included tests of food avoidance, reproductive effects, and direct eggshell application toxicity. Naturally weathered EVC, recovered postspill from Prince William Sound, was used as the test material. 36 refs., 7 figs., 4 tabs

Toxicity and motor changes in Africanized honey bees (Apis mellifera L.) exposed to fipronil and imidacloprid.

Science.gov (United States)

Bovi, Thaís S; Zaluski, Rodrigo; Orsi, Ricardo O

2018-01-01

This study evaluated the in vitro toxicity and motor activity changes in African-derived adult honey bees (Apis mellifera L.) exposed to lethal or sublethal doses of the insecticides fipronil and imidacloprid. Mortality of bees was assessed to determine the ingestion and contact lethal dose for 24 h using probit analysis. Motor activities in bees exposed to lethal (LD50) and sublethal doses (1/500th of the lethal dose) of both insecticides were evaluated in a behavioral observation box at 1 and 4 h. Ingestion and contact lethal doses of fipronil were 0.2316 ? 0.0626 and 0.0080 ? 0.0021 μg/bee, respectively. Ingestion and contact lethal doses of imidacloprid were 0.1079 ? 0.0375 and 0.0308 ? 0.0218 μg/bee, respectively. Motor function of bees exposed to lethal doses of fipronil and imidacloprid was impaired; exposure to sublethal doses of fipronil but not imidacloprid impaired motor function. The insecticides evaluated in this study were highly toxic to African-derived A. mellifera and caused impaired motor function in these pollinators.

Toxic potential of palytoxin.

Science.gov (United States)

Patocka, Jiří; Gupta, Ramesh C; Wu, Qing-hua; Kuca, Kamil

2015-10-01

This review briefly describes the origin, chemistry, molecular mechanism of action, pharmacology, toxicology, and ecotoxicology of palytoxin and its analogues. Palytoxin and its analogues are produced by marine dinoflagellates. Palytoxin is also produced by Zoanthids (i.e. Palythoa), and Cyanobacteria (Trichodesmium). Palytoxin is a very large, non-proteinaceous molecule with a complex chemical structure having both lipophilic and hydrophilic moieties. Palytoxin is one of the most potent marine toxins with an LD50 of 150 ng/kg body weight in mice exposed intravenously. Pharmacological and electrophysiological studies have demonstrated that palytoxin acts as a hemolysin and alters the function of excitable cells through multiple mechanisms of action. Palytoxin selectively binds to Na(+)/K(+)-ATPase with a Kd of 20 pM and transforms the pump into a channel permeable to monovalent cations with a single-channel conductance of 10 pS. This mechanism of action could have multiple effects on cells. Evaluation of palytoxin toxicity using various animal models revealed that palytoxin is an extremely potent neurotoxin following an intravenous, intraperitoneal, intramuscular, subcutaneous or intratracheal route of exposure. Palytoxin also causes non-lethal, yet serious toxic effects following dermal or ocular exposure. Most incidents of palytoxin poisoning have manifested after oral intake of contaminated seafood. Poisonings in humans have also been noted after inhalation, cutaneous/systemic exposures with direct contact of aerosolized seawater during Ostreopsis blooms and/or through maintaining aquaria containing Cnidarian zoanthids. Palytoxin has a strong potential for toxicity in humans and animals, and currently this toxin is of great concern worldwide.

Molecular dynamics study of contact mechanics: contact area and interfacial separation from small to full contact

OpenAIRE

Yang, C.; Persson, B. N. J.

2007-01-01

We report a molecular dynamics study of the contact between a rigid solid with a randomly rough surface and an elastic block with a flat surface. We study the contact area and the interfacial separation from small contact (low load) to full contact (high load). For small load the contact area varies linearly with the load and the interfacial separation depends logarithmically on the load. For high load the contact area approaches to the nominal contact area (i.e., complete contact), and the i...

The impact of the provisions of the suspensions on the track of conveyor with suspended belt and distributed drive at jamming rollers

Directory of Open Access Journals (Sweden)

Tolkachev E.N.

2018-03-01

Full Text Available The article is devoted to the topical issue, which is related to simulation of the failures of drives suspensions of the conveyor with suspended belt and distributed drive. Using the developed mathematical model of the failures drives suspensions due to jamming rollers to the reference design of conveyor with suspended belt and distributed drive is performed modelling of dynamic characteristics. Investigation of the influence of the location of the failed drives suspensions on the track on the main technical characteristics of the conveyor belt with suspended belt was carried out.

Optimal contact definition for reconstruction of Contact Maps

Directory of Open Access Journals (Sweden)

Stehr Henning

2010-05-01

Full Text Available Abstract Background Contact maps have been extensively used as a simplified representation of protein structures. They capture most important features of a protein's fold, being preferred by a number of researchers for the description and study of protein structures. Inspired by the model's simplicity many groups have dedicated a considerable amount of effort towards contact prediction as a proxy for protein structure prediction. However a contact map's biological interest is subject to the availability of reliable methods for the 3-dimensional reconstruction of the structure. Results We use an implementation of the well-known distance geometry protocol to build realistic protein 3-dimensional models from contact maps, performing an extensive exploration of many of the parameters involved in the reconstruction process. We try to address the questions: a to what accuracy does a contact map represent its corresponding 3D structure, b what is the best contact map representation with regard to reconstructability and c what is the effect of partial or inaccurate contact information on the 3D structure recovery. Our results suggest that contact maps derived from the application of a distance cutoff of 9 to 11Å around the Cβ atoms constitute the most accurate representation of the 3D structure. The reconstruction process does not provide a single solution to the problem but rather an ensemble of conformations that are within 2Å RMSD of the crystal structure and with lower values for the pairwise average ensemble RMSD. Interestingly it is still possible to recover a structure with partial contact information, although wrong contacts can lead to dramatic loss in reconstruction fidelity. Conclusions Thus contact maps represent a valid approximation to the structures with an accuracy comparable to that of experimental methods. The optimal contact definitions constitute key guidelines for methods based on contact maps such as structure prediction through

転がり -滑り接触下におけるＷＣサーメット溶射皮膜の耐久性に関する研究

OpenAIRE

DEWAN, MUHAMMAD, NURUZZAMAN; デワン, ムハマド, ヌルザマン; DEWAN, MUHAMMAD, NURUZZAMAN

2005-01-01

Surface durability of thermally sprayed WC-Cr-Ni cermet coating in lubricated rolling with sliding contact conditions was examined using a two-roller testing machine. The coating was formed onto the axially ground, blasted and circumferentially ground ro

Contact angle and local wetting at contact line.

Science.gov (United States)

Li, Ri; Shan, Yanguang

2012-11-06

This theoretical study was motivated by recent experiments and theoretical work that had suggested the dependence of the static contact angle on the local wetting at the triple-phase contact line. We revisit this topic because the static contact angle as a local wetting parameter is still not widely understood and clearly known. To further clarify the relationship of the static contact angle with wetting, two approaches are applied to derive a general equation for the static contact angle of a droplet on a composite surface composed of heterogeneous components. A global approach based on the free surface energy of a thermodynamic system containing the droplet and solid surface shows the static contact angle as a function of local surface chemistry and local wetting state at the contact line. A local approach, in which only local forces acting on the contact line are considered, results in the same equation. The fact that the local approach agrees with the global approach further demonstrates the static contact angle as a local wetting parameter. Additionally, the study also suggests that the wetting described by the Wenzel and Cassie equations is also the local wetting of the contact line rather than the global wetting of the droplet.

[Sport injuries in full contact and semi-contact karate].

Science.gov (United States)

Greier, K; Riechelmann, H; Ziemska, J

2014-03-01

Karate enjoys great popularity both in professional and recreational sports and can be classified into full, half and low contact styles. The aim of this study was the analysis of sports injuries in Kyokushinkai (full contact) and traditional Karate (semi-contact). In a retrospective study design, 215 active amateur karateka (114 full contact, 101 semi-contact) were interviewed by means of a standardised questionnaire regarding typical sport injuries during the last 36 months. Injuries were categorised into severity grade I (not requiring medical treatment), grade II (single medical treatment), grade III (several outpatient medical treatments) and grade IV (requiring hospitalisation). In total, 217 injuries were reported in detail. 125 injuries (58%) occurred in full contact and 92 (42%) in semi-contact karate. The time related injury rate of full contact karateka was 1.9/1000 h compared to 1.3/1000 h of semi-contact karateka (p injuries were musculoskeletal contusions (33% full contact, 20% semi-contact), followed by articular sprains with 19% and 16%. The lower extremity was affected twice as often in full contact (40%) as in semi-contact (20%) karate. Training injuries were reported by 80% of the full contact and 77% of the semi-contact karateka. Most injuries, both in training and competition, occurred in kumite. 75% of the reported injuries of full contact and 70% of semi-contact karateka were classified as low grade (I or II). The high rate of injuries during training and kumite (sparring) points to specific prevention goals. The emphasis should be put on proprioceptive training and consistent warm-up. In the actual competition the referees play a vital role regarding prevention. © Georg Thieme Verlag KG Stuttgart · New York.

FDA toxicity databases and real-time data entry

International Nuclear Information System (INIS)

Arvidson, Kirk B.

2008-01-01

Structure-searchable electronic databases are valuable new tools that are assisting the FDA in its mission to promptly and efficiently review incoming submissions for regulatory approval of new food additives and food contact substances. The Center for Food Safety and Applied Nutrition's Office of Food Additive Safety (CFSAN/OFAS), in collaboration with Leadscope, Inc., is consolidating genetic toxicity data submitted in food additive petitions from the 1960s to the present day. The Center for Drug Evaluation and Research, Office of Pharmaceutical Science's Informatics and Computational Safety Analysis Staff (CDER/OPS/ICSAS) is separately gathering similar information from their submissions. Presently, these data are distributed in various locations such as paper files, microfiche, and non-standardized toxicology memoranda. The organization of the data into a consistent, searchable format will reduce paperwork, expedite the toxicology review process, and provide valuable information to industry that is currently available only to the FDA. Furthermore, by combining chemical structures with genetic toxicity information, biologically active moieties can be identified and used to develop quantitative structure-activity relationship (QSAR) modeling and testing guidelines. Additionally, chemicals devoid of toxicity data can be compared to known structures, allowing for improved safety review through the identification and analysis of structural analogs. Four database frameworks have been created: bacterial mutagenesis, in vitro chromosome aberration, in vitro mammalian mutagenesis, and in vivo micronucleus. Controlled vocabularies for these databases have been established. The four separate genetic toxicity databases are compiled into a single, structurally-searchable database for easy accessibility of the toxicity information. Beyond the genetic toxicity databases described here, additional databases for subchronic, chronic, and teratogenicity studies have been prepared

Contact and Non-contact Measurements of Grinding Pins

Directory of Open Access Journals (Sweden)

Magdziak Marek

2015-01-01

Full Text Available The paper presents the results of contact and non-contact measurements of external profiles of selected grinding pins. The measurements were conducted in order to choose the appropriate measuring technique in the case of the considered measurement task. In the case of contact measurements the coordinate measuring machine ACCURA II was applied. The used coordinate measuring machine was equipped with the contact scanning probe VAST XT and the Calypso inspection software. Contact coordinate measurements were performed by using of different measurement strategies. The applied strategies included different scanning velocities and distances between measured points. Non-contact measurements were conducted by means of the tool presetter produced by the Mahr company. On the basis of gained results the guidelines concerning measurements of grinding pins were formulated. The measurements of analyzed grinding pins performed by means of the non-contact measuring system are characterized by higher reproducibility than the contact measurements. The low reproducibility of contact measurements may be connected with the inaccuracy of the selected coordinate measuring machine and the measuring probe, the measurement parameters and environmental conditions in the laboratory where the coordinate measuring machine is located. Moreover, the paper presents the possible application of results of conducted investigations. The results of non-contact measurements can be used in the simulation studies of grinding processes. The simulations may reduce the costs of machining processes.

Toxicity of uranium and lead on osteoblastic bone cells

International Nuclear Information System (INIS)

Milgram, S.; Thiebault, C.; Carriere, M.; Gouget, B.; Malaval, L.

2007-01-01

Bone is one of the main retention organs affected by uranium (U) and lead (Pb). Intoxications have been documented to inhibit bone formation and impair bone modeling and remodeling. However, only few studies dealt with cellular and molecular mechanisms of their toxicity. The purpose of this study was to investigate the acute cytotoxicity of U and Pb and their phenotypic effects on ROS17/2.8 osteoblastic cells. The most likely forms of the toxics in contact with cells after blood contamination were selected for cell exposure. Results show that whatever their speciation, bone cells are always more sensitive to Pb than to U. Moreover, Pb is toxic when it is left free in the exposure medium or when it is complexed with bicarbonate, cysteine or citrate, but not with albumin or phosphate. U is more cytotoxic when it is complexed with transferrin than with bicarbonate. A direct correlation between toxicity and cellular accumulation could be observed. Beside, exposure of U or Pb to bone cells induces a speciation-dependant variation of RNA expression of two markers of bone formation and mineralization: osteocalcin (OCN) and bone sialoprotein (BSP). OCN and BSP-expression could be activated in sub-toxic condition, respectively, by Pb-albumin (1.6-fold) and U-bicarbonate (2.3-fold). In the meantime, U-transferrin and Pb-citrate lead to an inhibition of the two markers. This study shows a complex mechanism of toxicity of two heavy metals with a significant phenotypic impact on osteoblastic cells highly dependant on metal speciation which controls cell accumulation. (authors)

Direct soil contact values for ecological receptors exposed to weathered petroleum hydrocarbon (PHC) fraction 2.

Science.gov (United States)

Angell, Robin A; Kullman, Steve; Shrive, Emma; Stephenson, Gladys L; Tindal, Miles

2012-11-01

Ecological tier 1 Canada-wide standards (CWS) for petroleum hydrocarbon (PHC) fraction 2 (F2; >nC10-C16) in soil were derived using ecotoxicological assessment endpoints (effective concentrations [ECs]/lethal concentrations [LCs]/inhibitory concentrations, 25% [IC25s]) with freshly spiked (fresh) fine- and coarse-grained soils. These soil standards might be needlessly conservative when applied to field samples with weathered hydrocarbons. The purpose of the present study was to assess the degradation and toxicity of weathered PHC F2 in a fine-grained soil and to derive direct soil contact values for ecological receptors. Fine-grained reference soils were spiked with distilled F2 and weathered for 183 d. Toxicity tests using plants and invertebrates were conducted with the weathered F2-spiked soils. Endpoint EC/IC25s were calculated and used to derive soil standards for weathered F2 in fine-grained soil protective of ecological receptors exposed via direct soil contact. The values derived for weathered F2 were less restrictive than current ecological tier 1 CWS for F2 in soil. Copyright © 2012 SETAC.

Haloacetonitriles: metabolism and toxicity.

Science.gov (United States)

Lipscomb, John C; El-Demerdash, Ebtehal; Ahmed, Ahmed E

2009-01-01

The haloacetonitriles (HANs) exist in drinking water exclusively as byproducts of disinfection. HANs are found in drinking water more often, and in higher concentrations, when surface water is treated by chloramination. Human exposure occurs through consumption of finished drinking water; oral and dermal contact also occurs, and results from showering, swimming and other activities. HANs are reactive and are toxic to gastrointestinal tissues following oral administration. Such toxicity is characterized by GSH depletion, increased lipid peroxidation, and covalent binding of HAN-associated radioactivity to gut tissues. The presence of GSH in cells is an important protective mechanism against HAN toxicity; depletion of cellular GSH results in increased toxicity. Some studies have demonstrated an apparently synergistic effect between ROS and HAN administration, that may help explain effects observed in GI tissues. ROS are produced in gut tissues, and in vitro evidence indicates that ROS may contribute to the degradation and formation of reactive intermediates from HANs. The rationale for ROS involvement may involve HAN-induced depletion of GSH and the role of GSH in scavenging ROS. In addition to effects on GI tissues, studies show that HAN-derived radiolabel is found covalently bound to proteins and DNA in several organs and tissues. The addition of antioxidants to biologic systems protects against HAN-induced DNA damage. The protection offered by antioxidants supports the role of oxidative stress and the potential for a threshold in han-induced toxicity. However, additional data are needed to substantiate evidence for such a threshold. HANs are readily absorbed from the GI tract and are extensively metabolized. Elimination occurs primarily in urine, as unconjugated one-carbon metabolites. Evidence supports the involvement of mixed function oxidases, the cytochrome P450 enzyme family and GST, in HAN metabolism. Metabolism represents either a detoxification or

Quantitative surface topography assessment of directly compressed and roller compacted tablet cores using photometric stereo image analysis

DEFF Research Database (Denmark)

Allesø, Morten; Carstensen, Jens Michael; Holm, Per

2016-01-01

Surface topography, in the context of surface smoothness/roughness, was investigated by the use of an image analysis technique, MultiRay™, related to photometric stereo, on different tablet batches manufactured either by direct compression or roller compaction. In the present study, oblique...... illumination of the tablet (darkfield) was considered and the area of cracks and pores in the surface was used as a measure of tablet surface topography; the higher a value, the rougher the surface. The investigations demonstrated a high precision of the proposed technique, which was able to rapidly (within...... milliseconds) and quantitatively measure the obtained surface topography of the produced tablets. Compaction history, in the form of applied roll force and tablet punch pressure, was also reflected in the measured smoothness of the tablet surfaces. Generally it was found that a higher degree of plastic...

An elastic-plastic contact model for line contact structures

Science.gov (United States)

Zhu, Haibin; Zhao, Yingtao; He, Zhifeng; Zhang, Ruinan; Ma, Shaopeng

2018-06-01

Although numerical simulation tools are now very powerful, the development of analytical models is very important for the prediction of the mechanical behaviour of line contact structures for deeply understanding contact problems and engineering applications. For the line contact structures widely used in the engineering field, few analytical models are available for predicting the mechanical behaviour when the structures deform plastically, as the classic Hertz's theory would be invalid. Thus, the present study proposed an elastic-plastic model for line contact structures based on the understanding of the yield mechanism. A mathematical expression describing the global relationship between load history and contact width evolution of line contact structures was obtained. The proposed model was verified through an actual line contact test and a corresponding numerical simulation. The results confirmed that this model can be used to accurately predict the elastic-plastic mechanical behaviour of a line contact structure.

THE METHODS OF CALCULATIONS OF THE TEMPERATURE BREAKDOWN FIELD IN THE LINE OF THE MODEM HIGH-SPEED WIRE MILL

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S. M. Zhuchkov

2007-01-01

Full Text Available The calculation methods of the temperature field of the breakdown, being rolled in lines of the modern high-speed wire mill, is developed on the basis of solving of problem of the contact exchange of hot metal with cold rollers.

Equilibrium contact angle or the most-stable contact angle?

Science.gov (United States)

Montes Ruiz-Cabello, F J; Rodríguez-Valverde, M A; Cabrerizo-Vílchez, M A

2014-04-01

It is well-established that the equilibrium contact angle in a thermodynamic framework is an "unattainable" contact angle. Instead, the most-stable contact angle obtained from mechanical stimuli of the system is indeed experimentally accessible. Monitoring the susceptibility of a sessile drop to a mechanical stimulus enables to identify the most stable drop configuration within the practical range of contact angle hysteresis. Two different stimuli may be used with sessile drops: mechanical vibration and tilting. The most stable drop against vibration should reveal the changeless contact angle but against the gravity force, it should reveal the highest resistance to slide down. After the corresponding mechanical stimulus, once the excited drop configuration is examined, the focus will be on the contact angle of the initial drop configuration. This methodology needs to map significantly the static drop configurations with different stable contact angles. The most-stable contact angle, together with the advancing and receding contact angles, completes the description of physically realizable configurations of a solid-liquid system. Since the most-stable contact angle is energetically significant, it may be used in the Wenzel, Cassie or Cassie-Baxter equations accordingly or for the surface energy evaluation. © 2013 Elsevier B.V. All rights reserved.

Effect of internal woven roller shade and glazing on the energy and daylighting performances of an office building in the cold climate of Shillong

International Nuclear Information System (INIS)

Singh, Ramkishore; Lazarus, I.J.; Kishore, V.V.N.

2015-01-01

Highlights: • We simulated a number of glazing and interior roller shade alternatives. • Office room has been simulated for three window-to-wall ratios in a cold climate. • Daylighting and energy performances have been assessed for each alternative. • Maximum energy savings have been estimated in the office with a 30% glazed area. • Energy saving decreases for larger glazed area and fabric transmittance. - Abstract: The energy and visual performances of the façades are defined by many parameters including façade size, properties of glazings and shadings, and their arrangements as well as control strategies. In this study, a number of combinations of internal woven roller shades and four double glazings have been proposed and assessed in integrated manner in order to improve the energy efficiency and visual comfort in new or existing office buildings. Office rooms facing south, east, north and west have been simulated for cold climate, by varying glazed areas and proposed glazing and shading alternatives. Results have been calculated, compared and analyzed in terms of the energy consumptions, energy saving potentials, daylight autonomy, useful daylight illuminance and discomfort glare free time, for each of the combinations. Simulation results show that the choice of glazing and shading alternatives can have substantial impact on energy and visual performances of the office space. Regardless of façade orientation, the maximum energy saving is achieved for a window-to-wall ratio (WWR) of 30%. Saving potential decreases significantly for larger glazed area and for each façade orientation. For all façade orientations and glazed areas (except for 30% WWR in the north wall), a bare low-e coated double glazing (U = 1.616 W/m"2 K, SHGC = 0.209, τ_v = 0.301) is found to be the most energy efficient choice. For 30% north glazing, the energy efficiency can be maximized with a different bare low-e coated double glazing (U = 1.628 W/m"2 K, SHGC = 0.370, τ_v = 0

Fractionation of extracts from paper and board food contact materials forin vitroscreening of toxicity

DEFF Research Database (Denmark)

Bengtström, Linda; Trier, Xenia; Granby, Kit

2014-01-01

materials, information on the exposure as well as on the toxicity of substances in the packaging must be obtained. This study describes a comprehensive method for the extraction and fractionation of substances present in paper and board FCMs for further investigation by in vitro testing and chemical...... assay. Both raw extracts and two of the fractions of the raw extracts gave a positive response in the AhR assay. The strategy of extraction followed by fractionation offers a powerful tool in order to make the workflow for screening FCMs for potentially adverse effects more efficient....

Toxicity of Prudhoe Bay crude oil to mallard duck (Anas Platyrhynchos) embryos

International Nuclear Information System (INIS)

Lusimbo, W.S.

1999-01-01

This thesis examined the rates and timing of mortality and hatchability of mallard duck embryos that have been exposed to Prudhoe Bay crude oil (PBCO). The objective was to identify any pathological abnormalities that may suggest that the chorioallantoic membrane (CAM) is a target organ of toxicity. The study involved the external application of PBCO to the eggshell to mimic the natural route of exposure. Embryo mortality was then determined at different days of incubation and the most sensitive age of incubation to oil was established. On the basis of initial results, the following 3 hypothesis were formulated: (1) the CAM is a target organ of oil toxicity, (2) injury to the CAM compromises its physiological role of calcium mobilization from the eggshell, and (3) oil exposure causes anemia and damage to red blood cells of mallard embryos. Data was compared with data reported in chicken embryos exposed to the same type of petroleum oil. It was shown that the toxic effects of PBCO to mallard duck embryos were similar to those found in chicken embryos. Oil-exposed embryos exhibited high mortality and reduced growth. Pathological changes in liver, kidneys and bursa of Fabricius, in oil-exposed mallard embryos were also similar to those of exposed chicken embryos. It was noted that this is the first study to recognize and describe pathological changes in the chorioallantoic membrane (CAM) of avian embryos exposed to petroleum oil. Lesions in the CAM were found in areas right beneath the oil on the egg shell and in areas distant from any such direct contact, suggesting that direct contact with the oil was not the main cause of injury to the CAM. The occurrence of lesions in CAM were highest immediately following exposure to PBCO. The lesions observed suggest two different kids of toxic effects, lethal injury to cells in various tissues, and alteration in the timing of organ development. The author notes that more remains to be learned regarding the toxic effects of

Bearing life in contaminated oil and oil passing into bearing for tapered roller bearing; Ensui koro jikuuke ni okeru ibutsu yuchu deno jumyo to kantsu yuryo

Energy Technology Data Exchange (ETDEWEB)

Asai, Y; Oshima, H; Sakamoto, K [Koyo Seiko Co. Ltd., Osaka (Japan)

1997-10-01

In this paper a relationship between depth of dents, area of dents gathered and bearing life has been investigated for tapered roller bearings used in differential gear case. It is effective for the longer bearing life to reduce hard particles of Fe especially among several contaminations existing in the gear case. It is also effective to make oil level lower in the case from the view point for reduction of number of dents. 8 refs., 8 figs., 4 tabs.

Toxic effect evaluation of the lead acetate and chromium chloride on anaerobic bacterial metabolism

International Nuclear Information System (INIS)

Wills, Beatriz; Naranjo, Fernando

2004-01-01

The toxicity of trivalent chromium and lead to anaerobic sludge system was studied. Performed assay was tested in 60 mL serum vials, the toxicity test to succeed in two steps, first with formic acid and then whey powder as a substrate. Anaerobic toxicity assays were performed taking into account, methane gas production and oxidation-reduction potential (ORP) rate, these tests were considered a useful indicator for monitoring a anaerobic sludge suffering from toxicants, over 72 hours with metals dosage against the control. First of all, exploratory assays in order to know different chromium and lead concentrations were carried out. The assays degradation activity reduced methane by 50% that came into contact with 3.322 mg Cr 3 +/L and 1.415 mg Pb/L and 2.291 mg Cr 3 +/Land 1.982 mg Pb/L with formic acid and whey powder as a substrate respectively. Heavy metal concentrations that caused 50% inhibition of methanogenesis during whey and formic acid methanation indicated that toxicity decreased in order Pb>>Cr

Privacy Impact Assessment for the Confidential Business Information Records Access System for the Toxic Control Substances Act

Science.gov (United States)

This system collects submission data from the Toxic Substances Control Act (TSCA) and contact information for EPA contractors and employees who are CBI cleared. Learn how this data is collected, how it will be used, and the purpose of data collection.

Long-term (30 days toxicity of NiO nanoparticles for adult zebrafish Danio rerio

Directory of Open Access Journals (Sweden)

Kovrižnych Jevgenij A.

2014-03-01

Full Text Available Nickel oxide in the form of nanoparticles (NiO NPs is extensively used in different industrial branches. In a test on adult zebrafish, the acute toxicity of NiO NPs was shown to be low, however longlasting contact with this compound can lead to its accumulation in the tissues and to increased toxicity. In this work we determined the 30-day toxicity of NiO NPs using a static test for zebrafish Danio rerio. We found the 30-day LC50 value to be 45.0 mg/L, LC100 (minimum concentration causing 100% mortality was 100.0 mg/L, and LC0 (maximum concentration causing no mortality was 6.25 mg/L for adult individuals of zebrafish. Considering a broad use of Ni in the industry, NiO NPs chronic toxicity may have a negative impact on the population of aquatic organisms and on food web dynamics in aquatic systems.

Speciation in Metal Toxicity and Metal-Based Therapeutics

Directory of Open Access Journals (Sweden)

Douglas M. Templeton

2015-04-01

Full Text Available Metallic elements, ions and compounds produce varying degrees of toxicity in organisms with which they come into contact. Metal speciation is critical to understanding these adverse effects; the adjectives “heavy” and “toxic” are not helpful in describing the biological properties of individual elements, but detailed chemical structures are. As a broad generalization, the metallic form of an element is inert, and the ionic salts are the species that show more significant bioavailability. Yet the salts and other chelates of a metal ion can give rise to quite different toxicities, as exemplified by a range of carcinogenic potential for various nickel species. Another important distinction comes when a metallic element is organified, increasing its lipophilicity and hence its ability to penetrate the blood brain barrier, as is seen, for example, with organic mercury and tin species. Some metallic elements, such as gold and platinum, are themselves useful therapeutic agents in some forms, while other species of the same element can be toxic, thus focusing attention on species interconversions in evaluating metal-based drugs. The therapeutic use of metal-chelating agents introduces new species of the target metal in vivo, and this can affect not only its desired detoxification, but also introduce a potential for further mechanisms of toxicity. Examples of therapeutic iron chelator species are discussed in this context, as well as the more recent aspects of development of chelation therapy for uranium exposure.

Reducing contact resistance in graphene devices through contact area patterning.

Science.gov (United States)

Smith, Joshua T; Franklin, Aaron D; Farmer, Damon B; Dimitrakopoulos, Christos D

2013-04-23

Performance of graphene electronics is limited by contact resistance associated with the metal-graphene (M-G) interface, where unique transport challenges arise as carriers are injected from a 3D metal into a 2D-graphene sheet. In this work, enhanced carrier injection is experimentally achieved in graphene devices by forming cuts in the graphene within the contact regions. These cuts are oriented normal to the channel and facilitate bonding between the contact metal and carbon atoms at the graphene cut edges, reproducibly maximizing "edge-contacted" injection. Despite the reduction in M-G contact area caused by these cuts, we find that a 32% reduction in contact resistance results in Cu-contacted, two-terminal devices, while a 22% reduction is achieved for top-gated graphene transistors with Pd contacts as compared to conventionally fabricated devices. The crucial role of contact annealing to facilitate this improvement is also elucidated. This simple approach provides a reliable and reproducible means of lowering contact resistance in graphene devices to bolster performance. Importantly, this enhancement requires no additional processing steps.

Ability of Cu2+-montmorillonite to accept an toxic pollutants

International Nuclear Information System (INIS)

Janikova, V.; Jona, E.; Janik, R.; Pavlik, V.

2015-01-01

It is global problem that toxic pollutants are in the permanent contact to people through soil and water. Nowadays, it is important to eliminate these pollutants for future generations and to keep environment in the health condition. In relation to this article, aromatic organic compounds like benzene, phenol and aniline were chosen. These are used in various branches of industry, mainly in rubber industry or for production of dyes and in addition, phenol is commonly used in cosmetics or in food industry. Montmorillonite is clay mineral consisting of 2:1 sheets (tetrahedral:octahedral) and interlayer space where exchangeable cations and water molecules are present. Due to its structure, montmorillonite is able to accept some compounds or pollutants. This is the reason why it is mainly used as the covering material of radioactive waste in order to remove toxic pollutants. For investigation of toxic pollutants removing, XRD powder diffraction, infrared spectroscopy and thermal analysis were used. Our results show that Cu 2+ -montmorillonite is able to accept toxic benzene ring-based pollutants into interlayer. This mentioned ability can be proven on the basis of the investigation results relating to difference of interlayer distance, typical frequencies of -OH group or -NH 2 group, while these results were supplemented by thermal properties. (authors)

Biomechanical characteristics and speed adaptation during kick double poling on roller skis in elite cross-country skiers.

Science.gov (United States)

Göpfert, Caroline; Holmberg, Hans-Christer; Stöggl, Thomas; Müller, Erich; Lindinger, Stefan Josef

2013-06-01

Recent developments in cross-country ski racing should promote the use of kick double poling. This technique, however, has not been the focus in athletes' training and has barely been investigated. The aims of the present study were to develop a function-based phase definition and to analyse speed adaptation mechanisms for kick double poling in elite cross-country skiers. Joint kinematics and pole/plantar forces were recorded in 10 athletes while performing kick double poling at three submaximal roller skiing speeds. A speed increase was associated with increases in cycle length and rate, while absolute poling and leg push-off durations shortened. Despite maintained impulses of force, the peak and average pole/leg forces increased. During double poling and leg push-off, ranges of motion of elbow flexion and extension increased (p push-off showed high variability among elite skiers, thus illustrating important aspects for technique training.

Prioritized Contact Transport Stream

Science.gov (United States)

Hunt, Walter Lee, Jr. (Inventor)

2015-01-01

A detection process, contact recognition process, classification process, and identification process are applied to raw sensor data to produce an identified contact record set containing one or more identified contact records. A prioritization process is applied to the identified contact record set to assign a contact priority to each contact record in the identified contact record set. Data are removed from the contact records in the identified contact record set based on the contact priorities assigned to those contact records. A first contact stream is produced from the resulting contact records. The first contact stream is streamed in a contact transport stream. The contact transport stream may include and stream additional contact streams. The contact transport stream may be varied dynamically over time based on parameters such as available bandwidth, contact priority, presence/absence of contacts, system state, and configuration parameters.

American Contact Dermatitis Society Contact Allergy Management Program: An Epidemiologic Tool to Determine Relative Prevalence of Contact Allergens.

Science.gov (United States)

Scheman, Andrew; Severson, David

2016-01-01

Data on the prevalence of contact allergy in North America are currently reported by groups of academic contact allergy specialists at select academic centers. Sampling of data from numerous centers across North America, including practices performing more limited patch testing, would provide a broader perspective of contact allergen prevalence in North America. The American Contact Dermatitis Society Contact Allergy Management Program is an ideal tool for collection of epidemiologic data regarding contact allergy prevalence in North America. The aim of the study was to identify the relative prevalence of contact allergy to common contact allergens in North America. Mapping of Contact Allergy Management Program (CAMP) data was performed to allow analysis of how frequently searches were performed for various contact allergens. The number of searches performed for specific allergens provides a measure of the relative prevalence of contact allergy to these allergens. The top 35 allergens for the period from November 18, 2012 to November 18, 2013 are reported. Although these data are useful, specific recommendations for minor alterations to CAMP are discussed, which will allow future CAMP data to be stratified and more powerful. With minor modifications, CAMP can provide a quantum leap in the reporting of contact allergy epidemiologic data in North America.

Structural Design and Economic Evaluation of Roller Compacted Concrete Pavement with Recycled Aggregates

Science.gov (United States)

Abut, Yavuz; Taner Yildirim, Salih

2017-10-01

Using recycled aggregates in the concrete offers advantages in many areas such as waste management, energy save and natural resources, conservation of ecological balance, low CO2 emissions, and users are encouraged in this regard to use these materials. In this study, the profit / loss account arising in the structural design phase was investigated when Reclaimed Asphalt Pavement (RAP), which is limited to use in Roller Compacted Concrete (RCC) pavements, was used as coarse aggregate. RAP materials were used as coarse aggregates by the levels of 0%, 15% and 20% and mechanical properties such as compressive strength, flexural strength, splitting tensile strength and modulus of elasticity were investigated. In the last stage, the mechanical properties obtained from these experimental studies were entered into KENSLABS software as input, and the slab layer thicknesses were determined according to three different subgrade conditions and a certain fatigue criterion. According to the results, it has been determined that the use of RAP at a level of 20% is a serious reducing effect on mechanical properties and and the use of RAP at a level of 15% does not bring a great economic benefit but it is reasonable to use it as coarse aggregate in RCC mixes in consideration of environmental effects.

Toxicity of azodrin on the morphology and acetylcholinesterase activity of the earthworm Eisenia foetida

International Nuclear Information System (INIS)

Rao, J.V.; Kavitha, P.

2004-01-01

The acute toxicity of azodrin (monocrotophos, an organophosphorus insecticide) was determined on a soil organism, Eisenia foetida. The median lethal concentrations (LC 50 ) were derived from a 48-h paper contact test and from artificial soil tests. The LC 50 of azodrin in the paper contact test was 0.46±0.1 μg cm -2 (23±6 mg L -1 ) and those in the 7- and 14-day artificial soil tests were 171±21 and 132±20 mg kg -1 , respectively. The neurotoxic potentiality of azodrin was assessed by using a marker enzyme, acetylcholinesterase (AChE; EC 3.1.1.7) in both in vitro and in vivo experiments. The progressive signs of morphological destruction are correlated with percentage inhibition of AChE in the in vivo experiments. The kinetics of AChE activity in the presence and absence of azodrin indicated that the toxicant is competitive in nature. This study demonstrated that azodrin causes concentration-dependent changes in the morphology and AChE activity of the earthworm E. foetida

Toxic and hormetic-like effects of three components of citrus essential oils on adult Mediterranean fruit flies (Ceratitis capitata.

Directory of Open Access Journals (Sweden)

Stella A Papanastasiou

Full Text Available Plant essential oils (EOs and a wide range of their individual components are involved in a variety of biological interactions with insect pests including stimulatory, deterrent, toxic and even hormetic effects. Both the beneficial and toxic properties of citrus EOs on the Mediterranean fruit fly (medfly have been experimentally evidenced over the last years. However, no information is available regarding the toxic or beneficial effects of the major components of citrus EOs via contact with the adults of the Mediterranean fruit fly. In the present study, we explored the toxicity of limonene, linalool and α-pinene (3 of the main compounds of citrus EOs against adult medflies and identified the effects of sub-lethal doses of limonene on fitness traits in a relaxed [full diet (yeast and sugar] and in a stressful (sugar only feeding environment. Our results demonstrate that all three compounds inferred high toxicity to adult medflies regardless of the diet, with males being more sensitive than females. Sub-lethal doses of limonene (LD20 enhanced the lifespan of adult medflies when they were deprived of protein. Fecundity was positively affected when females were exposed to limonene sub-lethal doses. Therefore, limonene, a major constituent of citrus EOs, induces high mortality at increased doses and positive effects on life history traits of medfly adults through contact at low sub-lethal doses. A hormetic-like effect of limonene to adult medflies and its possible underlying mechanisms are discussed.

Language Contact.

Science.gov (United States)

Nelde, Peter Hans

1995-01-01

Examines the phenomenon of language contact and recent trends in linguistic contact research, which focuses on language use, language users, and language spheres. Also discusses the role of linguistic and cultural conflicts in language contact situations. (13 references) (MDM)

Evaluation of anti-tuberculosis antibodies in healthy contact and non-contacts persons

International Nuclear Information System (INIS)

Aziz, N; Bukhari, M.H; Muneer, M; Tayyab, M; Chaudhry, N.A.

2006-01-01

This study was conducted to see the presence of the antimycobacterial antibodies in healthy household contacts of tuberculosis patients and healthy normal subjects who have never been in contact with tuberculosis patients. A total of 200 subjects, 120 with history of household contact and 80 without such history were included in the study. Routine Haematological investigations were performed and all the sera of 200 subjects were tested who 19M, 19G and IgA anti tuberculosis antibodies using ELISA technique. There was no difference in the average age of the household contacts and non-contacts. The complaints of pyrexia, night sweats and loss of weight was more in house hold contacts as compared to non-contacts. The awareness about BCG vaccination was equal among the household contacts and non-contacts. The combined serological positivity of the household contacts was 65.8% and the combined serological positivity for non-contacts was 34.1%. There was no statistically significant difference in the presence of 19M among household contacts as compared to non-contacts. However both IgG and 19A were present in significantly higher number of household contacts as compared to non contacts. This study concludes that the persons living in the house with a patient suffering from active pulmonary tuberculosis (household contact) have more chances of being infected with Mycobacterium tuberculosis as compared to the healthy non-contacts. (author)

Contact Lens Care

Science.gov (United States)

... Consumers Consumer Information by Audience For Women Contact Lens Care Share Tweet Linkedin Pin it More sharing ... www.fda.gov/medwatch Learn More about Contact Lens Care Other Tips on Contact Lenses Decorative Contact ...

Thyroid cancer in toxic and non-toxic multinodular goiter

Directory of Open Access Journals (Sweden)

Cerci C

2007-01-01

Full Text Available Background : Many authors have claimed that hyperthyroidism protects against thyroid cancer and believed that the incidence of malignancy is lower in patients with toxic multinodular goiter (TMG than in those with non-toxic multinodular goiter. But in recent studies, it was reported that the incidence of malignancy with TMG is not as low as previously thought. Aim : To compare the thyroid cancer incidence in patients with toxic and non-toxic multinodular goiter. Settings and Design : Histology reports of patients treated surgically with a preoperative diagnosis of toxic and non-toxic multinodular goiter were reviewed to identify the thyroid cancer incidence. Patients having a history of neck irradiation or radioactive iodine therapy were excluded from the study. Materials and Methods : We reviewed 294 patients operated between 2001-2005 from toxic and non-toxic multinodular goiter. One hundred and twenty-four of them were toxic and 170 were non-toxic. Hyperthyroidism was diagnosed by elevated tri-iodothyroinine / thyroxine ratios and low thyroid-stimulating hormone with clinical signs and symptoms. All patients were evaluated with ultrasonography and scintigraphy and fine needle aspiration biopsy. Statistical Analysis Used : Significance of the various parameters was calculated by using ANOVA test. Results : The incidence of malignancy was 9% in the toxic and 10.58% in the non-toxic multinodular goiter group. Any significant difference in the incidence of cancer and tumor size between the two groups could not be detected. Conclusions : The incidence of malignancy in toxic multinodular goiter is not very low as thought earlier and is nearly the same in non-toxic multinodular goiter.

Preclinical evaluations of norcantharidin-loaded intravenous lipid microspheres with low toxicity.

Science.gov (United States)

Lin, Xia; Zhang, Bo; Zhang, Keru; Zhang, Yu; Wang, Juan; Qi, Na; Yang, Shenshen; He, Haibing; Tang, Xing

2012-12-01

The aim of this study was to perform a systematic preclinical evaluation of norcantharidin (NCTD)-loaded intravenous lipid microspheres (NLM). Pharmacokinetics, biodistribution, antitumor efficacy and drug safety assessment (including acute toxicity, subchronic toxicity, hemolysis testing, intravenous stimulation and injection anaphylaxis) of NLM were carried out in comparison with the commercial product disodium norcantharidate injection (NI). The pharmacokinetics of NLM in rats was similar to that of NI, and a non-linear correlation was observed between AUC and dose. A comparable antitumor efficacy of NLM and NI was observed in mice inoculated with A549, BEL7402 and BCAP-37 cell lines. It was worth noting that the NLM produced a lower drug concentration in heart compared with NI, and significantly reduced the cardiac and renal toxicity. The LD(50) of NLM was twice higher than that of NI. In NLM, over 80% of NCTD was loaded in the lipid phase or bound with phospholipids. Thus, NCTD was sequestered by direct contacting with body fluids and largely avoided distribution into tissues, consequently leading to significantly reduced cardiac and renal toxicity. These preclinical results suggested that NLM could be a useful potential carrier for parenteral administration of NCTD, while providing a superior safety profile.

Apparent contact angle and contact angle hysteresis on liquid infused surfaces.

Science.gov (United States)

Semprebon, Ciro; McHale, Glen; Kusumaatmaja, Halim

2016-12-21

We theoretically investigate the apparent contact angle and contact angle hysteresis of a droplet placed on a liquid infused surface. We show that the apparent contact angle is not uniquely defined by material parameters, but also has a dependence on the relative size between the droplet and its surrounding wetting ridge formed by the infusing liquid. We derive a closed form expression for the contact angle in the limit of vanishing wetting ridge, and compute the correction for small but finite ridge, which corresponds to an effective line tension term. We also predict contact angle hysteresis on liquid infused surfaces generated by the pinning of the contact lines by the surface corrugations. Our analytical expressions for both the apparent contact angle and contact angle hysteresis can be interpreted as 'weighted sums' between the contact angles of the infusing liquid relative to the droplet and surrounding gas phases, where the weighting coefficients are given by ratios of the fluid surface tensions.

A remote engineering solution for automating a roller hearth kiln

Directory of Open Access Journals (Sweden)

João Bosco da Mota Alves

2008-07-01

Full Text Available Remote engineering (also known as online engineering may be defined as a combination of control engineering and telematics. In this area, specific activities require computacional skills in order to develop projects where electrical devives are monitored and / or controlled, in an intercative way, through a distributed network (e.g. Intranet or Internet. In our specific case, we will be dealing with an industrial plant. Within the last few years, there has been an increase in the number of activities related to remote engineering, which may be connected to the phenomenon of the large extension experienced by the Internet (e.g. bandwith, number of users, development tools, etc.. This increase opens new and future possibilities to the implementation of advance teleworking (or e-working positions. In this paper we present the architecture for a remote application, accessible through the Internet, able to monitor and control a roller hearth kiln, used in a ceramics industry for firing materials. The proposed architecture is based on a micro web server, whose main function is to monitor and control the firing process, by reading the data from a series of temperature sensors and by controlling a series of electronic valves and servo motors. This solution is also intended to be a low-cost alternative to other potential solutions. The temperature readings are obtained through K-type thermopairs and the gas flow is controlled through electrovalves. As the firing process should not be stopped before its complete end, the system is equipped with a safety device for that specific purpose. For better understanding the system to be automated and its operation we decided to develop a scale model (100:1 and experiment on it the devised solution, based on a Micro Web Server.

Evaluation of metal–nanowire electrical contacts by measuring contact end resistance

International Nuclear Information System (INIS)

Park, Hongsik; Beresford, Roderic; Xu, Jimmy; Ha, Ryong; Choi, Heon-Jin; Shin, Hyunjung

2012-01-01

It is known, but often unappreciated, that the performance of nanowire (NW)-based electrical devices can be significantly affected by electrical contacts between electrodes and NWs, sometimes to the extent that it is really the contacts that determine the performance. To correctly understand and design NW device operation, it is thus important to carefully measure the contact resistance and evaluate the contact parameters, specific contact resistance and transfer length. A four-terminal pattern or a transmission line model (TLM) pattern has been widely used to measure contact resistance of NW devices and the TLM has been typically used to extract contact parameters of NW devices. However, the conventional method assumes that the electrical properties of semiconducting NW regions covered by a metal are not changed after electrode formation. In this study, we report that the conventional methods for contact evaluation can give rise to considerable errors because of an altered property of the NW under the electrodes. We demonstrate that more correct contact resistance can be measured from the TLM pattern rather than the four-terminal pattern and correct contact parameters including the effects of changed NW properties under electrodes can be evaluated by using the contact end resistance measurement method. (paper)

Development of a control model for a four wheel mecanum vehicle

CSIR Research Space (South Africa)

De Villiers, M

2012-01-01

Full Text Available in this paper accounts for the fact that the contact point in fact changes position down the axle of the wheel as the angle roller moves on the ground. The developed control model is verified with experimental results. Using the refined model, control of Mecanum...

Sadhana | Indian Academy of Sciences

Indian Academy of Sciences (India)

This paper presents the possibility of restoration of worn contact surfaces of rollers for continuous casting of steel. Permanent effort of steel producers to extend the lifespan of these components requires the implementation of new filler materials or modifying technological renovation processes to reduce the economic costs.

Extracorporeal tubing in the roller pump raceway: physical changes and particulate generation.

Science.gov (United States)

Spiwak, Allison J Bednarski; Horbal, Alexander; Leatherbury, Robert; Hansford, Derek J

2008-09-01

Plasticized polyvinyl chloride tubing is used as the blood conduit in the heart lung bypass circuit. The section in the roller pump undergoes rigorous compression. Fatigue leads to material changes in weight and length of the bulk material. Particles are released during normal pump operation. This study evaluates the time course of particle loss. Three segments of 1/2" ID tubing run in the raceway for 30-minute, 1-hour, or 2-hour. The fluid path of each segment includes an oxygenator; a castor oil blend was used for the prime. The 5 mL sample was acquired at 10 minute intervals. Raceway tubing segments were measured for a change in weight and length. The same procedure repeated with 1/4" ID and 3/8" ID tubing. All tubing increased at least 5 mm by the 2-hour trial. There were no remarkable changes in weight. Particles were measured for size and percent volume. Tubing with 1/2" ID performed most consistently for particle release during all trials. Particles were observed as small as 1 nm. Particles as large as 3 micron could be confirmed. For all tubing there was particle release by 30 minutes. Perfusionists must consider tubing inner diameter and wall thickness in choosing the pPVC for the raceway in order to minimize particulate emboli. This research suggests that 3/8" ID tubing produces spalls inconsistently compared to 2" ID tubing. Thinner wall thickness tubing also has the potential to limit spall formation.

Contextualizing Intergroup Contact: Do Political Party Cues Enhance Contact Effects?

DEFF Research Database (Denmark)

Sønderskov, Kim Mannemar; Thomsen, Jens Peter Frølund

2015-01-01

This article examines intergroup contact effects in different political contexts. We expand on previous efforts of social psychologists by incorporating the messages of political parties as a contextual trigger of group membership awareness in contact situations. We argue that the focus among...... political parties on us-them categorizations heightens the awareness of group memberships. This focus in turn enhances the positive intergroup contact effect by stimulating majority members to perceive contacted persons as prototypical outgroup members. A multilevel analysis of 22 countries and almost 37......,000 individuals confirms that the ability of intergroup contact to reduce antiforeigner sentiment increases when political parties focus intensively on immigration issues and cultural differences. Specifically, both workplace contact and interethnic friendship become more effective in reducing antiforeigner...

Toxicity of middle distillates from dermal exposure.

Science.gov (United States)

Koschier, F J

1999-02-01

This report focuses on recent studies that investigated the effects of kerosine dermal exposure on neurotoxicity and reproductive/developmental toxicity. Background toxicity information will also be reviewed for kerosine range mid distillates. The kerosine range mid distillates have a carbon range of C9-C16 and have a boiling range of 302-554 degrees F (150-290 degrees C). This category includes kerosine, aviation fuels (e.g., Jet A, JP-5 and JP-8), no. 1 fuel oil and diesel fuel oil. In general, the kerosine range mid distillates demonstrate relatively low acute toxicity by any route of exposure. High inhalation exposures can induce central nervous system depression characterized by ataxia, hypoactivity and prostration. Kerosines are known to cause skin irritation and inflammation under conditions of acute and repeated exposure in animals and humans, but are only slightly irritating to the eye and are not skin sensitizers. In addition, the absorption of kerosine range mid distillates through the skin has been demonstrated to be fairly rapid, but limited to approximately 10-15% of the applied dose after 24 hours. The kerosine range mid distillates are generally inactive in genetic toxicity tests although positive studies have been reported. Positive results, while at times equivocal, have been reported for straight run kerosine and jet fuel A in the mouse lymphoma assay with metabolic activation, and hydrodesulfurized kerosine (mouse) and jet fuel A (rat) in the bone marrow cytogenetic assay. Effects on the nervous and reproductive systems have been reported in humans and experimental animals under conditions where inhalation and dermal exposure to specific kerosine type fuels are sometimes difficult to separate. Recent laboratory studies have addressed this point and examined the effects of dermal exposure. In these studies, rats were exposed to hydrodesulfurized kerosine by skin application to determine the potential of dermal contact to cause reproductive

Analysis and development of the method for calculating calibration of the working plank in the cold tube roller rolling mills

Directory of Open Access Journals (Sweden)

S. V. Pilipenko

2017-05-01

Full Text Available Analysis and development of the existing method of calculation of the calibrated profile of the working strips mills CTRR roller cold rolling pipe to ensure the required distribution of energy-power parameters along the cone. In presented paper, which has for aim the development of existing method for calculating the profile of calibrated working plank in the cold tube roller rolling mills, the analysis had been made and it was proposed to use Besier-lines while building the the profile of the plank working surface. It was established that the use of Besier spline-curve for calculating the calibration of supporting planks creates the possibility to calculate the parameters proceeding from reduction over the external diameter. The proposed method for calculating deformation parameters in CTRR mills is the result of development of existing method and as such shows the scientific novelty. Comparison of the plots for distribution of the force parameters of the CTRR process along the cone of deformation presents as evidence the advantage of the method to be proposed. The decrease of reduction value at the end of deformation zone favors the manufacture of tubes with lesser wall thickness deviation (especially longitudinal one, caused with waviness induced by the cold pilgering process. Joined the further development of the method of calculating the deformation parameters CTRR. It is proposed for the calculation of the calibration work surface support bracket mills CTRR to use a spline Bezier. The practical significance of the proposed method consists in the fact that calculation of all zones of the plank by means of one dependence allows simplifying the process of manufacturing the latter in machines with programmed numerical control. In this case the change of reduction parameters over the thickness of the wall will not exert the considerable influence on the character of the force parameters (the character and not the value distribution along the

Measuring contact area in a sliding human finger-pad contact.

Science.gov (United States)

Liu, X; Carré, M J; Zhang, Q; Lu, Z; Matcher, S J; Lewis, R

2018-02-01

The work outlined in this paper was aimed at achieving further understanding of skin frictional behaviour by investigating the contact area between human finger-pads and flat surfaces. Both the static and the dynamic contact areas (in macro- and micro-scales) were measured using various techniques, including ink printing, optical coherence tomography (OCT) and Digital Image Correlation (DIC). In the studies of the static measurements using ink printing, the experimental results showed that the apparent and the real contact area increased with load following a piecewise linear correlation function for a finger-pad in contact with paper sheets. Comparisons indicated that the OCT method is a reliable and effective method to investigate the real contact area of a finger-pad and allow micro-scale analysis. The apparent contact area (from the DIC measurements) was found to reduce with time in the transition from the static phase to the dynamic phase while the real area of contact (from OCT) increased. The results from this study enable the interaction between finger-pads and contact object surface to be better analysed, and hence improve the understanding of skin friction. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Sequential Fuzzy Diagnosis Method for Motor Roller Bearing in Variable Operating Conditions Based on Vibration Analysis

Directory of Open Access Journals (Sweden)

Yi Cao

2013-06-01

Full Text Available A novel intelligent fault diagnosis method for motor roller bearings which operate under unsteady rotating speed and load is proposed in this paper. The pseudo Wigner-Ville distribution (PWVD and the relative crossing information (RCI methods are used for extracting the feature spectra from the non-stationary vibration signal measured for condition diagnosis. The RCI is used to automatically extract the feature spectrum from the time-frequency distribution of the vibration signal. The extracted feature spectrum is instantaneous, and not correlated with the rotation speed and load. By using the ant colony optimization (ACO clustering algorithm, the synthesizing symptom parameters (SSP for condition diagnosis are obtained. The experimental results shows that the diagnostic sensitivity of the SSP is higher than original symptom parameter (SP, and the SSP can sensitively reflect the characteristics of the feature spectrum for precise condition diagnosis. Finally, a fuzzy diagnosis method based on sequential inference and possibility theory is also proposed, by which the conditions of the machine can be identified sequentially as well.

Electric contact arcing

International Nuclear Information System (INIS)

Cuthrell, R.E.

1976-01-01

Electrical contacts must function properly in many types of components used in nuclear weapon systems. Design, application, and testing of these components require detailed knowledge of chemical and physical phenomena associated with stockpile storage, stockpile testing, and operation. In the past, investigation of these phenomena has led to significant discoveries on the effects of surface contaminants, friction and wear, and the mechanics of closure on contact performance. A recent investigation of contact arcing phenomena which revealed that, preceding contact closure, arcs may occur at voltages lower than had been previously known is described. This discovery is important, since arcing may damage contacts, and repetitive testing of contacts performed as part of a quality assurance program might produce cumulative damage that would yield misleading life-test data and could prevent proper operation of the contacts at some time in the future. This damage can be avoided by determining the conditions under which arcing occurs, and ensuring that these conditions are avoided in contact testing

Acute and chronic systemic chromium toxicity.

Science.gov (United States)

Gad, S C

1989-10-01

Although chromium and compounds containing it have been recognized as having potential severe adverse effects on health for more than 160 years, understanding of the systemic toxicology and true hazard of these compounds is still not complete. A review of the current state of knowledge is attempted in this paper, with appropriate attention given to the complications of multiple valence states and solubility. Selected chromium compounds, particularly hexavalent ones, are carcinogens, corrosives, delayed contact sensitizers, and have the kidney as their primary target organ. But chromium is also an essential element for humans. The body clearly possesses some effective detoxification mechanisms for some degree of exposure to hexavalent chrome compounds. The significant features of acute and chronic chromium toxicity are presented in view of these considerations.

EAF Slag Aggregate in Roller-Compacted Concrete Pavement: Effects of Delay in Compaction

Directory of Open Access Journals (Sweden)

My Ngoc-Tra Lam

2018-04-01

Full Text Available This study investigates the effect of delay in compaction on the optimum moisture content and the mechanical propertie s (i.e., compressive strength, ultrasonic pulse velocity, splitting tensile strength, and modulus of elasticity of roller-compacted concrete pavement (RCCP made of electric arc furnace (EAF slag aggregate. EAF slag with size in the range of 4.75–19 mm was used to replace natural coarse aggregate in RCCP mixtures. A new mixing method was proposed for RCCP using EAF slag aggregate. The optimum moisture content of RCCP mixtures in this study was determined by a soil compaction method. The Proctor test assessed the optimum moisture content of mixtures at various time after mixing completion (i.e., 0, 15, 30, 60, and 90 min. Then, the effect of delay in compaction on the mechanical properties of RCCP mixtures at 28 days of age containing EAF slag aggregate was studied. The results presented that the negative effect on water content in the mixture caused by the higher water absorption characteristic of EAF slag was mitigated by the new mixing method. The optimum water content and maximum dry density of RCCP experience almost no effect from the delay in compaction. The compressive strength and splitting tensile strength of RCCP using EAF slag aggregate fulfilled the strength requirements for pavement with 90 min of delay in compaction.

Aqueous media treatment and decontamination of hazardous chemical and biological substances by contact plasma

International Nuclear Information System (INIS)

Pivovarov, A.; Kravchenko, A.; Kublanovsky, V.

2009-01-01

Usage of non-equilibrium contact plasma for processes of decontamination and neutralization in conditions of manifestation of chemical, biological and radiation terrorism takes on special significance due to portability of equipment and its mobility in places where toxic liquid media hazardous for people's health are located. Processes of decontamination of aqueous media, seminated with pathogenic microorganisms and viruses, treatment of water containing toxic heavy metals, cyanides, surface-active substances, and heavy radioactive elements, are investigated. Examples of activation processes in infected water and toxic aqueous solutions present convincing evidence of the way, how new quality technological approach for achievement of high enough degree of the said media treatment is used in each specific case. Among new properties of water activated as a result of action of non-equilibrium contact plasma, it is necessary to mention presence of cluster structure, confirmed by well-known spectral and physical-chemical methods, presence of peroxide compounds, active particles and radicals. Anti-microbial activity which is displayed under action of plasma in aqueous media (chemically pure water, drinking water, aqueous solutions of sodium chloride, potassium iodide, as well as other inorganic compounds) towards wide range of pathogenic and conventionally pathogenic microorganisms allows use them as reliable, accessible and low-cost preparations for increasing the degree of safety of food products. Combination of such processes with known methods of filtration and ultra-filtration gives an efficient and available complex capable of withstanding any threats, which may arise for population and living organisms. Present-day level of machine-building, electrical engineering, and electronics allows predict creation of industrial plasma installations, adapted to conditions of various terrorist threats, with minimized power consumption and optimized technological parameters

Aqueous media treatment and decontamination of hazardous chemical and biological substances by contact plasma

Energy Technology Data Exchange (ETDEWEB)

Pivovarov, A; Kravchenko, A [Ukrainian State University of Chemical Engineering, Dnepropetrovsk (Ukraine); Kublanovsky, V [V. I. Vernadsky Institute of General and Inorganic Chemistry of National Academy of Science, Kiev (Ukraine)

2009-07-01

Usage of non-equilibrium contact plasma for processes of decontamination and neutralization in conditions of manifestation of chemical, biological and radiation terrorism takes on special significance due to portability of equipment and its mobility in places where toxic liquid media hazardous for people's health are located. Processes of decontamination of aqueous media, seminated with pathogenic microorganisms and viruses, treatment of water containing toxic heavy metals, cyanides, surface-active substances, and heavy radioactive elements, are investigated. Examples of activation processes in infected water and toxic aqueous solutions present convincing evidence of the way, how new quality technological approach for achievement of high enough degree of the said media treatment is used in each specific case. Among new properties of water activated as a result of action of non-equilibrium contact plasma, it is necessary to mention presence of cluster structure, confirmed by well-known spectral and physical-chemical methods, presence of peroxide compounds, active particles and radicals. Anti-microbial activity which is displayed under action of plasma in aqueous media (chemically pure water, drinking water, aqueous solutions of sodium chloride, potassium iodide, as well as other inorganic compounds) towards wide range of pathogenic and conventionally pathogenic microorganisms allows use them as reliable, accessible and low-cost preparations for increasing the degree of safety of food products. Combination of such processes with known methods of filtration and ultra-filtration gives an efficient and available complex capable of withstanding any threats, which may arise for population and living organisms. Present-day level of machine-building, electrical engineering, and electronics allows predict creation of industrial plasma installations, adapted to conditions of various terrorist threats, with minimized power consumption and optimized technological parameters

Toxicity of fluorescent tracers and their degradation byproducts

Directory of Open Access Journals (Sweden)

Philippe Gombert

2017-01-01

Full Text Available Tracer tests are frequently used to delineate catchment area of water supply springs in karstic zones. In the karstic chalk of Normandy, the main tracers used are fluorescent: uranine, sulforhodamine B, naphtionate, and Tinopal®. In this area, a statistical analysis shows that less than half of the injected tracers joins the monitored restitution points and enters the drinking water system where they undergo chlorination. Most of the injected tracers is absorbed in the rock matrix or is thrown out of the aquifer via karstic springs: then it can join superficial waters where it is degraded due to the sun and air action. The paper presents firstly the laboratory degradation of a first batch of fluorescent tracers in contact with chlorine, in order to simulate their passage through a water treatment system for human consumption. A second batch of the same tracers is subjected to agents of natural degradation: ultraviolet illumination, sunlight and air sparging. Most tracers is degraded, and toxicity and ecotoxicity tests (on rats, daphniae and algae are performed on degradation byproducts. These tests do not show any acute toxicity but a low to moderate ecotoxicity. In conclusion, the most used fluorescent tracers of the Normandy karstic chalk and their artificial and natural degradation byproducts do not exhibit significant toxicity to humans and the aquatic environment, at the concentrations generally noted at the restitution points.

Integrating the fish embryo toxicity test as triad element for sediment toxicity assessment based on the water framework directive approach

Energy Technology Data Exchange (ETDEWEB)

Bartzke, Mariana [Dept. Aquatic Ecotoxicology, Goethe Univ. Frankfurt am Main (Germany); Gobio GmbH, Aarbergen/Kettenbach (Germany); Dept. Bioanalytical Ecotoxicology, Helmholtz Centre for Environmental Research, UFZ, Leipzig (Germany); Delov, Vera [Dept. Aquatic Ecotoxicology, Goethe Univ. Frankfurt am Main (Germany); Gobio GmbH, Aarbergen/Kettenbach (Germany); Ecotoxicology, Fraunhofer Inst. for Molecular Biology and Applied Ecology IME, Aachen (Germany); Stahlschmidt-Allner, Petra; Allner, Bernhard [Gobio GmbH, Aarbergen/Kettenbach (Germany); Oehlmann, Joerg [Dept. Aquatic Ecotoxicology, Goethe Univ. Frankfurt am Main (Germany)

2010-04-15

Purpose: The objective of this study was to complement analyses according to the European Union Water Framework Directive (WFD) with a sediment toxicity analysis as part of an integrated river assessment. To this end, Hessian water courses were analyzed using the sediment quality triad concept according to Chapman with chemical analyses, in situ effect evaluations, and ecotoxicological assessments. For the ecotoxicological assessment (fish embryo toxicity test with Danio rerio), a new evaluation scheme was developed, the fish teratogenicity index (FTI), that allows for a classification of sediments into ecological quality classes compliant to the WFD. Materials and methods sediment and macrozoobenthos samples were taken from tributaries of the rivers Fulda and Lahn. Sediments were characterized regarding particle size, carbon, heavy metals, and polyaromatic hydrocarbon content. Macroinvertebrate samples were taken via multi-habitat sampling. The fish embryo toxicity test with D. rerio was conducted as a contact assay on the basis of DIN 38415-6. Results and discussion The integrated assessment indicated a significant influence of heavy metals and carbon content on macroinvertebrate communities. The bioaccessibility of sediment pollutants were clearly demonstrated by the FTI, which showed a wide range of adverse effects. A significant linear relationship between metals and the FTI was detected. However, there was no statistically significant evidence that macroinvertebrate communities were affected by the hydromorphological quality clements at the sampling sites. Conclusions The new scheme for the assessment of fish embryo toxicity test was successfully applied. The results suggest that sediment compounds impact macroinvertebrate communities and early development of fish. It demonstrates that the quality of sediments should be evaluated on a routine basis as part of an integrated river assessment. (orig.)

RELATIONSHIP BETWEEN ROLLING AND SLIP RESISTANCE IN ROLLING BEARINGS

Directory of Open Access Journals (Sweden)

L. M. Bondarenko

2016-06-01

Full Text Available Purpose. About one of the causes of slip rolling is known from the second half of the 19th century, it was believed that the slip resistance appears at the place of contact due to different speeds on the arc of contact. Only in the mid-20th century it was proved that this resistance is negligible in rolling resistance. However (for some unknown reason it is ignored the fact that in practice in rolling bearings may rotate both the inner ring with a stationary outer one, and vice versa almost in equal relations. It is not taken into account the fact that the ball or roller in the rolling bearings runs the different distance along the roller path of the outer and inner bearing cages in one revolution. This fact is not taken into account in determining the calculated values for the friction coefficient of a rolling bearing reduced to the shaft. Therefore, the aim of this work is to determine the influence of path length on the track riding the outer and inner race of the bearing on the determination of the calculated value of the coefficient of friction of rolling bearings is given to the shaft. Methodology. The solution technique is based on the theory of plane motion of a rigid body, the theory of Hertzian contact deformation and the analytical dependencies for determination of coefficient of rolling friction. Findings. The obtained dependences on determination of rolling resistance of the balls or rollers along the bearing tracks of inner and outer bearing cages as well as path difference metering of the rolling on them allows to analytically obtain the rolling resistance and slipping for any size of bearings and different devices of bearing units. It is also possible at the design stage of rolling nodes to handle not only the design but also the content of the node. Originality. Using the analytical dependences for determination of the rolling resistance of bodies at point and line contacts, and also account for the difference in the path of the

Allergic Contact Dermatitis

Directory of Open Access Journals (Sweden)

Meltem Önder

2009-03-01

Full Text Available Allergic contact dermatitis is the delayed type hypersensitivity reaction to exogenous agents. Allergic contact dermatitis may clinically present acutely after allergen exposure and initial sensitization in a previously sensitized individual. Acute phase is characterized by erythematous, scaly plaques. In severe cases vesiculation and bullae in exposed areas are very characteristic. Repeated or continuous exposure of sensitized individual with allergen result in chronic dermatitis. Lichenification, erythematous plaques, hyperkeratosis and fissuring may develop in chronic patients. Allergic contact dermatitis is very common dermatologic problem in dermatology daily practice. A diagnosis of contact dermatitis requires the careful consideration of patient history, physical examination and patch testing. The knowledge of the clinical features of the skin reactions to various contactans is important to make a correct diagnosis of contact dermatitis. It can be seen in every age, in children textile product, accessories and touch products are common allergens, while in adults allergic contact dermatitis may be related with topical medicaments. The contact pattern of contact dermatitis depends on fashion and local traditions as well. The localization of allergic reaction should be evaluated and patients’ occupation and hobbies should be asked. The purpose of this review is to introduce to our collaques up dated allergic contact dermatitis literatures both in Turkey and in the World.

Use of the thin layer activation technique to measure on-line aeronautical components wear

International Nuclear Information System (INIS)

Chevalier, A.; Dubois, G.; Escuriol, M.; Monnot, R.; Pommier, S.; Fehsenfeld, P.; Kleinrahm, A.; Delvigne, T.; Le Menestrel, M.

1992-01-01

The superficial activation technique was applied in order to study the phenomena odscaling at the level of a reactor bearing. The exterior path of the bearing roller was activated on its whole contact surface and to a depth of 80 μm, according to the reaction 56 Fe(p, n) 56 Co. In spite of a very low rate of activation of 0.5 MBq, the first signs of scaling were detected 30 min before a notable rise in the vibratory level could be recorded. Then, the amount of scaled matter escaping from the outer ring of the roller could be followed continuously, with a precision of 0.2 mg. 5 refs., 7 figs

Post-Closure Inspection Report for Corrective Action Unit 404: Roller Coaster Sewage Lagoons and North Disposal Trench Tonopah Test Range, Nevada, Calendar Year 2000

Energy Technology Data Exchange (ETDEWEB)

K. B. Campbell

2001-06-01

Post-closure monitoring requirements for the Roller Coaster Sewage Lagoons and North Disposal Trench (Corrective Action Unit [CAW 404]) (Figure 1) are described in Closure Report for Corrective Action Unit 404, Roller Coaster Sewage Lagoons and North Disposal Trench, Tonopah Test Range, Nevada, report number DOE/NV--187. The Closure Report (CR) was submitted to the Nevada Division of Environmental Protection (NDEP) on September 11, 1998. Permeability results of soils adjacent to the engineered cover and a request for closure of CAU 404 were transmitted to the NDEP on April 29, 1999. The CR (containing the Post-Closure Monitoring Plan) was approved by the NDEP on May 18, 1999. Post-closure monitoring at CAU 404 consists of the following: (1) Site inspections done twice a year to evaluate the condition of the unit; (2) Verification that the site is secure; (3) Notice of any subsidence or deficiencies that may compromise the integrity of the unit; (4) Remedy of any deficiencies within 90 days of discovery; and (5) Preparation and submittal of an annual report. Site inspections were conducted on June 19, 2000, and November 21, 2000. The site inspections were conducted after completion of the revegetation activities (October 30, 1997) and NDEP approval of the CR (May 18, 1999). All site inspections were conducted in accordance with the Post-Closure Monitoring Plan in the NDEP-approved CR. This report includes copies of inspection checklists, photographs, recommendations, and conclusions. The Post-Closure Inspection Checklists are found in Attachment A, a copy of the field notes is found in Attachment B, and copies of the inspection photographs are found in Attachment C.

Toxicity of seven foliar insecticides to four insect parasitoids attacking citrus and cotton pests.

Science.gov (United States)

Prabhaker, Nilima; Morse, J G; Castle, S J; Naranjo, S E; Henneberry, T J; Toscano, N C

2007-08-01

Laboratory studies were carried out to compare the toxicity of seven foliar insecticides to four species of adult beneficial insects representing two families of Hymenoptera: Aphelinidae (Aphytis melinus Debach, Eretmocerus eremicus Rose & Zolnerowich, and Encarsiaformosa Gahan) and Mymaridae (Gonatocerus ashmeadi Girault) that attack California red scale, Aonidiella aurantii (Maskell); sweetpotato whitefly, Bemisia tabaci (Gennadius) (both E. eremicus and E. formosa); and glassy-winged sharpshooter, Homalodisca vitripennis (Germar), respectively. Insecticides from four pesticide classes were evaluated using a petri dish bioassay technique across a range of concentrations to develop dosage-mortality regressions. Insecticides tested included acetamiprid (neonicotinoid); chlorpyrifos (organophosphate); bifenthrin, cyfluthrin, and fenpropathrin (pyrethroids); and buprofezin and pyriproxyfen (insect growth regulators [IGRs]). Chlorpyrifos was consistently the most toxic pesticide to all four species of beneficial insects tested based on LC50 values recorded 24 h posttreatment compared with 48-h LC50 values with the neonicotinoid and pyrethroids or 96 h with the IGRs. Among the three pyrethroids, fenpropathrin was usually less toxic (except similar toxicity to A. melinus) than was cyfluthrin, and it was normally less toxic (except similar toxicity with E. formosa) than was bifenthrin. Acetamiprid was generally less toxic than bifenthrin (except similar toxicity with G. ashmeadi). The IGRs buprofezin and pyriproxyfen were usually less toxic than the contact pesticides, but we did not test for possible impacts on female fecundity. For all seven pesticides tested, A. melinus was the most susceptible parasitoid of the four test species. The data presented here will provide pest managers with specific information on the compatibility of select insecticides with natural enemies attacking citrus and cotton, Gossypium hirsutum L., pests.

Perception of noxious compounds by contact chemoreceptors of the blowfly, Phormia regina: putative role of an odorant-bindingpProtein.

Science.gov (United States)

Ozaki, Mamiko; Takahara, Teruhiko; Kawahara, Yasuhiro; Wada-Katsumata, Ayako; Seno, Keiji; Amakawa, Taisaku; Yamaoka, Ryohei; Nakamura, Tadashi

2003-05-01

The blowfly, Phormia regina, has sensilla with four contact-chemoreceptor cells and one mechanoreceptor cell on its labellum. Three of the four chemoreceptor cells are called the sugar, the salt and the water receptor cells, respectively. However, the specificity of the remaining chemoreceptor cell, traditionally called the "fifth cell", has not yet been clarified. Referring to behavioral evaluation of the oral toxicity of monoterpenes, we measured the electrophysiological response of the "fifth cell" to these compounds. Of all the monoterpenes examined, D-limonene exhibited the strongest oral toxicity and induced the severest aversive behavior with vomiting and/or excretion in the fly. D-Limonene, when dispersed in an aqueous stimulus solution including dimethyl sulfoxide or an odorant-binding protein (OBP) found in the contact-chemoreceptor sensillum, the chemical sense-related lipophilic ligand-binding protein (CRLBP), evoked impulses from the "fifth cell". Considering the relationship between the aversive effects of monoterpenes and the response of the "fifth cell" to these effects, we propose that the "fifth cell" is a warning cell that has been differentiated as a taste system for detecting and avoiding dangerous foods. Here we suggest that in the insect contact-chemoreceptor sensillum, CRLBP carries lipophilic members of the noxious taste substances to the "fifth cell" through the aqueous sensillum lymph. This insect OBP may functionally be analogous to the von Ebner's grand protein in taste organs of mammals.

Experimental investigation on the electrical contact behavior of rolling contact connector

Energy Technology Data Exchange (ETDEWEB)

Chen, Junxing; Yang, Fei, E-mail: yfei2007@mail.xjtu.edu.cn; Luo, Kaiyu; Zhu, Mingliang; Wu, Yi; Rong, Mingzhe [State Key Laboratory of Electrical Insulation and Power Equipment, Xi’an Jiaotong University, Xi’an 710049 (China)

2015-12-15

Rolling contact connector (RCC) is a new technology utilized in high performance electric power transfer systems with one or more rotating interfaces, such as radars, satellites, wind generators, and medical computed tomography machines. Rolling contact components are used in the RCC instead of traditional sliding contacts to transfer electrical power and/or signal. Since the requirement of the power transmission is increasing in these years, the rolling electrical contact characteristics become more and more important for the long-life design of RCC. In this paper, a typical form of RCC is presented. A series of experimental work are carried out to investigate the rolling electrical contact characteristics during its lifetime. The influence of a variety of factors on the electrical contact degradation behavior of RCC is analyzed under both vacuum and air environment. Based on the surface morphology and elemental composition changes in the contact zone, which are assessed by field emission scanning electron microscope and confocal laser scanning microscope, the mechanism of rolling electrical contact degradation is discussed.

Improvement of Energy Efficiency and Environmental Safety of Thermal Energy Through the Implementation of Contact Energy Exchange Processes

Science.gov (United States)

Varlamov, Gennadii Borysovich; Romanova, Kateryna Alexandrovna; Nazarova, Iryna; Daschenko, Olga; Kapustiansky, Andry

2017-12-01

Energy efficiency improvement and ecological safety of heat power plants are urgent problems, which require scientifically grounded approaches and solutions. These problems can be solved partly within the presented heat-and-power cycles by including contact energy exchange equipment in the circuits of existing installations. A significant positive effect is obtained in the contact energy exchange installations, such as gas-steam installation `Aquarius' and the contact hydrogen heat generator that also can use hydrogen as a fuel. In these plants, the efficiency increases approximately by 10-12% in comparison with traditional installations, and the concentration of toxic substances, such as nitrogen oxides and carbon monoxide in flue gas can be reduced to 30 mg/m3 and to 5 mg/m3, respectively. Moreover, the plants additionally `generate' the clean water, which can be used for technical purposes.

CONTACT RESISTANCE MODELING

Directory of Open Access Journals (Sweden)

S. V. LOSKUTOV

2018-05-01

Full Text Available Purpose. To determine the contribution of the real contact spots distribution in the total conductivity of the conductors contact. Methodology. The electrical contact resistance research was carried out on models. The experimental part of this work was done on paper with a graphite layer with membranes (the first type and conductive liquids with discrete partitions (the second type. Findings. It is shown that the contact electrical resistance is mainly determined by the real area of metal contact. The experimental dependence of the electrical resistance of the second type model on the distance between the electrodes and the potential distribution along the sample surface for the first type model were obtained. The theoretical model based on the principle of electric field superposition was considered. The dependences obtained experimentally and calculated by using the theoretical model are in good agreement. Originality. The regularity of the electrical contact resistance formation on a large number of membranes was researched for the first time. A new model of discrete electrical contact based on the liquid as the conducting environment with nuclear membrane partitions was developed. The conclusions of the additivity of contact and bulk electrical resistance were done. Practical value. Based on these researches, a new experimental method of kinetic macroidentation that as a parameter of the metal surface layer deformation uses the real contact area was developed. This method allows to determine the value of average contact stresses, yield point, change of the stress on the depth of deformation depending on the surface treatment.

Friction and universal contact area law for randomly rough viscoelastic contacts.

Science.gov (United States)

Scaraggi, M; Persson, B N J

2015-03-18

We present accurate numerical results for the friction force and the contact area for a viscoelastic solid (rubber) in sliding contact with hard, randomly rough substrates. The rough surfaces are self-affine fractal with roughness over several decades in length scales. We calculate the contribution to the friction from the pulsating deformations induced by the substrate asperities. We also calculate how the area of real contact, A(v, p), depends on the sliding speed v and on the nominal contact pressure p, and we show how the contact area for any sliding speed can be obtained from a universal master curve A(p). The numerical results are found to be in good agreement with the predictions of an analytical contact mechanics theory.

Current knowledge on biomarkers for contact sensitization and allergic contact dermatitis

DEFF Research Database (Denmark)

Koppes, Sjors A.; Engebretsen, Kristiane A.; Agner, Tove

2017-01-01

Contact sensitization is common and affects up to 20% of the general population. The clinical manifestation of contact sensitization is allergic contact dermatitis. This is a clinical expression that is sometimes difficult to distinguish from other types of dermatitis, for example irritant...... and atopic dermatitis. Several studies have examined the pathogenesis and severity of allergic contact dermatitis by measuring the absence or presence of various biomarkers. In this review, we provide a non-systematic overview of biomarkers that have been studied in allergic contact dermatitis. These include...... genetic variations and mutations, inflammatory mediators, alarmins, proteases, immunoproteomics, lipids, natural moisturizing factors, tight junctions, and antimicrobial peptides. We conclude that, despite the enormous amount of data, convincing specific biomarkers for allergic contact dermatitis are yet...

Coordinate transformation in the model of long Josephson contacts: geometrically equivalent contacts

International Nuclear Information System (INIS)

Semerdzhieva, E.G.; Boyadzhiev, T.L.; ); Shukrinov, Yu.M.; Physical Technical Institute Dushanbe, 734063

2005-01-01

The transition from model of long Josephson variable-width contact to the contact model with coordinate-dependent Josephson current amplitude is realized by transforming the coordinates. This sets up a correspondence between Josephson contacts of variable width and quasi-one-dimensional contacts of variable thickness barrier layer. It is shown, that for contacts of exponentially varying width the barrier layer of the corresponding quasi-one-dimensional contact contains the distributed resistive inhomogeneity which is an attractor to magnetic flux vortices. With numerical experiments, a 'critical current-magnetic field' dependence for a resistive microinhomogeneity Josephson contact was plotted, and its comparison with the critical curve for a contact of exponentially varying width was made. Thus, this demonstrates that the distributed inhomogeneity may be replaced by a local one at the JC end what technologically, may offer definite advantages

Simulation Results: Optimization of Contact Ratio for Interdigitated Back-Contact Solar Cells

Directory of Open Access Journals (Sweden)

Vinay Budhraja

2017-01-01

Full Text Available In the fabrication of interdigitated back contact (IBC solar cells, it is very important to choose the right size of contact to achieve the maximum efficiency. Line contacts and point contacts are the two possibilities, which are being chosen for IBC structure. It is expected that the point contacts would give better results because of the reduced recombination rate. In this work, we are simulating the effect of contact size on the performance of IBC solar cells. Simulations were done in three dimension using Quokka, which numerically solves the charge carrier transport. Our simulation results show that around 10% of contact ratio is able to achieve optimum cell efficiency.

The Power and Joy of Derby: Women’s Participation, Empowerment, and Transformation in a Flat-Track Roller Derby Team

Directory of Open Access Journals (Sweden)

John Paul

2015-11-01

Full Text Available In what ways do sports make a difference in the lives of the people who play them? In this paper, we employ a sporting feminist perspective to answer this question and detail how women benefit from the sport of roller derby. Our analyses are structured around the themes of the body (exploring examples of bodily empowerment and reconceptualization; the team (highlighting feminist themes of loyalty and team as family; and the crowd (identifying the ways in which derby is “sold” to the crowd, as well as the ways in which athletes use derby to challenge conceptions of beauty, desirability, and femininity. In the end, this work comments on the multiple examples of feminist expression and positive sporting participation found in derby, including the use of sport to reject notions of weakness and fragility, and a greater willingness to critically assess gender inequities beyond the world of sport.

Toxicity identification evaluation methods for identification of toxicants in refinery effluents

International Nuclear Information System (INIS)

Barten, K.A.; Mount, D.R.; Hackett, J.R.

1993-01-01

During the last five years, the authors have used Toxicity Identification Evaluation (TIE) methods to characterize and identify the source(s) of toxicity in effluents from dozens of municipal and industrial facilities. In most cases, specific chemicals responsible for toxicity have been identified. Although generally successful, the initial experience was that for several refinery effluents, they were able only to qualitatively characterize the presence of organic toxicants; standard toxicant identification procedures were not able to isolate specific organic chemicals. They believe that organic toxicity in these refinery effluents is caused by multiple organic compounds rather than by just a few; evidence for this includes an inability to isolate toxicity in a small number of fractions using liquid chromatography and the presence of very large numbers of compounds in isolated fractions. There is also evidence that the toxicant(s) may be ionic, in that the toxicity of whole effluent and isolated fractions often show increasing toxicity with decreasing pH. Finally, positive-pressure filtration has also reduced toxicity in some samples. In this presentation the authors summarize their experiences with refinery effluents, focusing on typical patterns they have observed and alternative procedures they have used to better understand the nature of these toxicants

In vitro toxicity analysis of nanoscale aluminum: Particle size and shape effects

Science.gov (United States)

Palazuelos Jorganes, Maria

2007-12-01

Nanostructured materials promise to revolutionize many key areas of science and technology. As our ability to manipulate matter at the nanoscale increases, there is a need to assess the effects of these materials on human health and the environment. Materials at the nanoscale are interesting and useful because they possess properties that are different from the equivalent bulk or molecular scale. These same properties can make toxicological profiles very different from those of the same materials on a different scale. There is a rising consensus that toxicity analysis of nanomaterials should start from a thorough physicochemical characterization of the materials under investigation in order to be able to establish a proper correlation between the nanoparticles characteristics and their effects and behavior in physiological environments. This research is a clear example of the necessity of comprehensive studies when investigating the toxicity of nanomaterials. Aluminum nanoparticles are being extensively used for their very unique energetic properties. These materials offer a very promising market that is fostering many startup companies which are expected to consolidate on strong technological positions. Aluminum is generally recognized as a non-toxic material to humans and it is widely used for applications which imply direct human contact. The effect of aluminum nanoparticles in human health is still an unknown. My research consisted of an in vitro toxicity screening of aluminum materials from nano to micron size, including spherical irregularly shaped particles. Several issues relating to size, shape, detection and characterization of nanoparticles in the different environments relevant to in vitro toxicity analysis were addressed and suitable protocols were developed. Lung human epithelial cells were exposed to different concentrations of these materials and the effects were analyzed by means of various toxicity tests. Some of the materials investigated caused

First contact diagnosis and management of contact lens-related complications.

Science.gov (United States)

Fagan, Xavier J; Jhanji, Vishal; Constantinou, Marios; Amirul Islam, F M; Taylor, Hugh R; Vajpayee, Rasik B

2012-08-01

To describe the spectrum of contact lens-related problems in cases presenting to a tertiary referral eye hospital. A retrospective case record analysis of 111 eyes of 97 consecutive patients was undertaken over a period of five months at the Royal Victorian Eye and Ear Hospital, Melbourne, Australia. Contact lens-related complications (CLRC) were classified into microbial keratitis, sterile corneal infiltrates, corneal epitheliopathy and contact lens-related red eye (CLARE). Main parameters examined were nature of the first contact, clinical diagnosis, and management pattern. Forty-two percent of the initial presentations were to health care practitioners (HCPs) other than ophthalmologists. Mean duration from the onset of symptoms to presentation was 6.3 ± 10.9 days. Forty-nine percent (n = 54) of patients had an associated risk factor, most commonly overnight use of contact lenses (n = 14, 13 %). Most common diagnosis at presentation was corneal epitheliopathy (68 %) followed by sterile infiltrates (10 %), CLARE (8 %) and microbial keratitis (6 %). No significant differences were found in the pattern of treatment modalities administered by ophthalmologists and other HCPs. HCPs other than ophthalmologists are the first contact for contact lens-related problems in a significant proportion of patients. These HCPs manage the majority of CLRC by direct treatment or immediate referral.

Characteristics of suspended solids affect bifenthrin toxicity to the calanoid copepods Eurytemora affinis and Pseudodiaptomus forbesi.

Science.gov (United States)

Parry, Emily; Lesmeister, Sarah; Teh, Swee; Young, Thomas M

2015-10-01

Bifenthrin is a pyrethroid pesticide that is highly toxic to aquatic invertebrates. The dissolved concentration is generally thought to be the best predictor of acute toxicity. However, for the filter-feeding calanoid copepods Eurytemora affinis and Pseudodiaptomus forbesi, ingestion of pesticide-bound particles could prove to be another route of exposure. The present study investigated bifenthrin toxicity to E. affinis and P. forbesi in the presence of suspended solids from municipal wastewater effluent and surface water of the San Francisco (CA, USA) Estuary. Suspended solids mitigated the toxicity of total bifenthrin to E. affinis and P. forbesi, but mortality was higher than what would be predicted from dissolved concentrations alone. The results indicate that the toxicity and bioavailability of particle-associated bifenthrin was significantly correlated with counts of 0.5-µm to 2-µm particle sizes. Potential explanations could include direct ingestion of bifenthrin-bound particles, changes in food consumption and feeding behavior, and physical contact with small particles. The complex interactions between pesticides and particles of different types and sizes demonstrate a need for future ecotoxicological studies to investigate the role of particle sizes on aquatic organisms. © 2015 SETAC.

The role of incline, performance level and gender on the gross mechanical efficiency of roller ski skating

Directory of Open Access Journals (Sweden)

Øyvind eSandbakk

2013-10-01

Full Text Available The ability to efficiently utilize metabolic energy to produce work is a key factor for endurance performance. The present study investigated the effects of incline, performance level and gender on the gross mechanical efficiency during roller ski skating. Thirty-one male and nineteen female elite cross-country skiers performed a 5-min submaximal session at approximately 75% of VO2peak on a 5% inclined treadmill using the G3 skating technique. Thereafter, a 5-min session on a 12% incline using the G2 skating technique was performed at a similar work rate. Gross efficiency was calculated as the external work rate against rolling friction and gravity divided by the metabolic rate using gas exchange. Performance level was determined by the amount of skating FIS points (the Federation of International Skiing approved scoring system for ski racing where fewer points indicate a higher performance level. Strong significant correlations between work rate and metabolic rate within both inclines and gender were revealed (r=-0.89-0.98 and P

Introducing Toxics

OpenAIRE

David C. Bellinger

2013-01-01

With this inaugural issue, Toxics begins its life as a peer-reviewed, open access journal focusing on all aspects of toxic chemicals. We are interested in publishing papers that present a wide range of perspectives on toxicants and naturally occurring toxins, including exposure, biomarkers, kinetics, biological effects, fate and transport, treatment, and remediation. Toxics differs from many other journals in the absence of a page or word limit on contributions, permitting authors to present ...

Toxic shock syndrome

Science.gov (United States)

Staphylococcal toxic shock syndrome; Toxic shock-like syndrome; TSLS ... Toxic shock syndrome is caused by a toxin produced by some types of staphylococcus bacteria. A similar problem, called toxic shock- ...

An Exploratory Analysis of Stream Teratogenicity and Human Health Using Zebrafish Whole-Sediment Toxicity Test

Directory of Open Access Journals (Sweden)

Matthew Dellinger

2014-02-01

Full Text Available This study demonstrates a novel application of effect-based toxicity testing for streams that may provide indications of co-perturbation to ecological and human health. For this study, a sediment contact assay using zebrafish (Danio rerio embryos was adapted to serve as an indicator of teratogenic stress within river sediments. Sediment samples were collected from Lake Michigan tributary watersheds. Sediment contact assay responses were then compared to prevalence of congenital heart disease (CHD and vital statistic birth indicators aggregated from civil divisions associated with the watersheds. Significant risk relationships were detected between variation in early life-stage (ELS endpoints of zebrafish embryos 72 h post-fertilization and the birth prevalence of human congenital heart disease, low birthweight and infant mortality. Examination of principal components of ELS endpoints suggests that variance related to embryo heart and circulatory malformations is most closely associated with human CHD prevalence. Though toxicity assays are sometimes used prospectively, this form of investigation can only be conducted retrospectively. These results support the hypothesis that bioassays normally used for ecological screening can be useful as indicators of environmental stress to humans and expand our understanding of environmental–human health linkages.

Skin lesions simulating blue toe syndrome caused by prolonged contact with a millipede

Directory of Open Access Journals (Sweden)

Augusto Scardazan Heeren Neto

2014-04-01

Full Text Available Venomous animals are those that, by means of a hunting and defense mechanism, are able to inject their prey with a toxic substance produced in their bodies, directly from specialized glands (e.g., tooth, sting, spur through which the poison passes. Millipedes are poisonous animals; they can be harmful to humans, and their effects usually manifest as erythematous, purpuric, and cyanotic lesions; local pain; and paresthesia. Here, we report a case of skin contact with a millipede for 6h resulting in skin lesions similar to blue toe syndrome.

Contact isotopic- and contact ion-exchange between two adsorbents

International Nuclear Information System (INIS)

Bunzl, K.; Mohan, R.; Haimerl, M.

1975-01-01

The kinetics of contact ion exchange processes between an ion exchange membrane and resin ion exchange beads, stirred in pure water, was investigated. A general criterion was derived, which indicates whether diffusion of the ions between the intermingling electric double layers or the collision frequency between the two adsorbents is the rate dermining step. Since the latter process proved to be rate controlling under our experimental conditions, the corresponding rate equations were derived under various initial and boundary conditions. Experimentally, the kinetics of contact isotopic exchange of Cs + - and Na + -ions as well as of the reverse contact ion exchange process of Cs + -versus Na + -ions were investigated by using Na 22 and Cs 137 radioisotopes. The experiments reveal in quantitative accord with the theory that the rate of collision controlled contact ion exchange processes depends mainly on the 'exchange coefficient', the separation factor and the collision frequency. While the latter two quantities were determined independently by separate experiments, the 'exchange coefficient' was evaluated from a contact isotopic exchange experiment. (orig.) [de

ComplexContact: a web server for inter-protein contact prediction using deep learning

KAUST Repository

Zeng, Hong; Wang, Sheng; Zhou, Tianming; Zhao, Feifeng; Li, Xiufeng; Wu, Qing; Xu, Jinbo

2018-01-01

ComplexContact (http://raptorx2.uchicago.edu/ComplexContact/) is a web server for sequence-based interfacial residue-residue contact prediction of a putative protein complex. Interfacial residue-residue contacts are critical for understanding how proteins form complex and interact at residue level. When receiving a pair of protein sequences, ComplexContact first searches for their sequence homologs and builds two paired multiple sequence alignments (MSA), then it applies co-evolution analysis and a CASP-winning deep learning (DL) method to predict interfacial contacts from paired MSAs and visualizes the prediction as an image. The DL method was originally developed for intra-protein contact prediction and performed the best in CASP12. Our large-scale experimental test further shows that ComplexContact greatly outperforms pure co-evolution methods for inter-protein contact prediction, regardless of the species.

ComplexContact: a web server for inter-protein contact prediction using deep learning

KAUST Repository

Zeng, Hong

2018-05-20

ComplexContact (http://raptorx2.uchicago.edu/ComplexContact/) is a web server for sequence-based interfacial residue-residue contact prediction of a putative protein complex. Interfacial residue-residue contacts are critical for understanding how proteins form complex and interact at residue level. When receiving a pair of protein sequences, ComplexContact first searches for their sequence homologs and builds two paired multiple sequence alignments (MSA), then it applies co-evolution analysis and a CASP-winning deep learning (DL) method to predict interfacial contacts from paired MSAs and visualizes the prediction as an image. The DL method was originally developed for intra-protein contact prediction and performed the best in CASP12. Our large-scale experimental test further shows that ComplexContact greatly outperforms pure co-evolution methods for inter-protein contact prediction, regardless of the species.

ComplexContact: a web server for inter-protein contact prediction using deep learning.

Science.gov (United States)

Zeng, Hong; Wang, Sheng; Zhou, Tianming; Zhao, Feifeng; Li, Xiufeng; Wu, Qing; Xu, Jinbo

2018-05-22

ComplexContact (http://raptorx2.uchicago.edu/ComplexContact/) is a web server for sequence-based interfacial residue-residue contact prediction of a putative protein complex. Interfacial residue-residue contacts are critical for understanding how proteins form complex and interact at residue level. When receiving a pair of protein sequences, ComplexContact first searches for their sequence homologs and builds two paired multiple sequence alignments (MSA), then it applies co-evolution analysis and a CASP-winning deep learning (DL) method to predict interfacial contacts from paired MSAs and visualizes the prediction as an image. The DL method was originally developed for intra-protein contact prediction and performed the best in CASP12. Our large-scale experimental test further shows that ComplexContact greatly outperforms pure co-evolution methods for inter-protein contact prediction, regardless of the species.

Metabolic responses of Eisenia fetida after sub-lethal exposure to organic contaminants with different toxic modes of action

Energy Technology Data Exchange (ETDEWEB)

McKelvie, Jennifer R.; Wolfe, David M.; Celejewski, Magda A. [Department of Physical and Environmental Sciences, University of Toronto, 1265 Military Trail Toronto, ON M1C 1A4 (Canada); Alaee, Mehran [Environment Canada, 867 Lakeshore Rd., P.O. Box 5050, Burlington, ON L7R 4A6 (Canada); Simpson, Andre J. [Department of Physical and Environmental Sciences, University of Toronto, 1265 Military Trail Toronto, ON M1C 1A4 (Canada); Simpson, Myrna J., E-mail: myrna.simpson@utoronto.ca [Department of Physical and Environmental Sciences, University of Toronto, 1265 Military Trail Toronto, ON M1C 1A4 (Canada)

2011-12-15

Nuclear magnetic resonance (NMR) - based metabolomics has the potential to identify toxic responses of contaminants within a mixture in contaminated soil. This study evaluated the metabolic response of Eisenia fetida after exposure to an array of organic compounds to determine whether contaminant-specific responses could be identified. The compounds investigated in contact tests included: two pesticides (carbaryl and chlorpyrifos), three pharmaceuticals (carbamazephine, estrone and caffeine), two persistent organohalogens (Aroclor 1254 and PBDE 209) and two industrial compounds (nonylphenol and dimethyl phthalate). Control and contaminant-exposed metabolic profiles were distinguished using principal component analysis and potential contaminant-specific biomarkers of exposure were found for several contaminants. These results suggest that NMR-based metabolomics offers considerable promise for differentiating between the different toxic modes of action (MOA) associated with sub-lethal toxicity to earthworms. - Highlights: > NMR-based earthworm metabolomic analysis of the toxic mode of action of various environmental contaminants. > Organic chemicals with different toxic modes of action resulted in varied metabolomic responses for E. fetida. > NMR-based metabolomics differentiates between the different modes of action associated with sub-lethal toxicity. - {sup 1}H NMR metabolomics was used to identify potential biomarkers of organic contaminant exposure in Eisenia fetida earthworms.

Current knowledge on biomarkers for contact sensitization and allergic contact dermatitis.

Science.gov (United States)

Koppes, Sjors A; Engebretsen, Kristiane A; Agner, Tove; Angelova-Fischer, Irena; Berents, Teresa; Brandner, Johanna; Brans, Richard; Clausen, Maja-Lisa; Hummler, Edith; Jakasa, Ivone; Jurakić-Tončic, Ružica; John, Swen M; Khnykin, Denis; Molin, Sonja; Holm, Jan O; Suomela, Sari; Thierse, Hermann-Josef; Kezic, Sanja; Martin, Stefan F; Thyssen, Jacob P

2017-07-01

Contact sensitization is common and affects up to 20% of the general population. The clinical manifestation of contact sensitization is allergic contact dermatitis. This is a clinical expression that is sometimes difficult to distinguish from other types of dermatitis, for example irritant and atopic dermatitis. Several studies have examined the pathogenesis and severity of allergic contact dermatitis by measuring the absence or presence of various biomarkers. In this review, we provide a non-systematic overview of biomarkers that have been studied in allergic contact dermatitis. These include genetic variations and mutations, inflammatory mediators, alarmins, proteases, immunoproteomics, lipids, natural moisturizing factors, tight junctions, and antimicrobial peptides. We conclude that, despite the enormous amount of data, convincing specific biomarkers for allergic contact dermatitis are yet to be described. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Toxicity detection of sodium nitrite, borax and aluminum potassium sulfate using electrochemical method.

Science.gov (United States)

Yu, Dengbin; Yong, Daming; Dong, Shaojun

2013-04-01

Based on the inhibition effect on the respiratory chain activity of microorganisms by toxicants, an electrochemical method has been developed to measure the current variation of a mediator in the presence of microorganisms contacted with a toxicant. Microelectrode arrays were adopted in this study, which can accelerate the mass transfer rate of an analyte to the electrode and also increase the total current signal, resulting in an improvement in detection sensitivity. We selected Escherichia coli as the testee and the standard glucose-glutamic acid as an exogenous material. Under oxygen restriction, the experiments in the presence of toxicant were performed at optimum conditions (solution pH 7.0, 37 degrees C and reaction for 3 hr). The resulting solution was then separated from the suspended microorganisms and was measured by an electrochemical method, using ferricyanide as a mediator. The current signal obtained represents the reoxidation of ferrocyanide, which was transformed to inhibiting efficiency, IC50, as a quantitative measure of toxicity. The IC50 values measured were 410, 570 and 830 mg/L for sodium nitrite, borax and aluminum potassium sulfate, respectively. The results show that the toxicity sequence for these three food additives is consistent with the value reported by other methods. Furthermore, the order of damage degree to the microorganism was also observed to be: sodium nitrite > borax > aluminum potassium sulfate > blank, according to the atomic force microscopy images of E. coli after being incubated for 3 hr with the toxic compound in buffer solutions. The electrochemical method is expected to be a sensitive and simple alternative to toxicity screening for chemical food additives.

Quaternionic contact Einstein structures and the quaternionic contact Yamabe problem

CERN Document Server

Ivanov, Stefan; Vassilev, Dimiter

2014-01-01

A partial solution of the quaternionic contact Yamabe problem on the quaternionic sphere is given. It is shown that the torsion of the Biquard connection vanishes exactly when the trace-free part of the horizontal Ricci tensor of the Biquard connection is zero and this occurs precisely on 3-Sasakian manifolds. All conformal transformations sending the standard flat torsion-free quaternionic contact structure on the quaternionic Heisenberg group to a quaternionic contact structure with vanishing torsion of the Biquard connection are explicitly described. A "3-Hamiltonian form" of infinitesimal conformal automorphisms of quaternionic contact structures is presented.

Post-Closure Inspection Report for Corrective Action Unit 404: Roller Coaster Sewage Lagoons and North Disposal Trench Tonopah Test Range, Nevada, Calendar Year 2000; TOPICAL

International Nuclear Information System (INIS)

K. B. Campbell

2001-01-01

Post-closure monitoring requirements for the Roller Coaster Sewage Lagoons and North Disposal Trench (Corrective Action Unit[CAW 404]) (Figure 1) are described in Closure Report for Corrective Action Unit 404, Roller Coaster Sewage Lagoons and North Disposal Trench, Tonopah Test Range, Nevada, report number DOE/NV-187. The Closure Report (CR) was submitted to the Nevada Division of Environmental Protection (NDEP) on September 11, 1998. Permeability results of soils adjacent to the engineered cover and a request for closure of CAU 404 were transmitted to the NDEP on April 29, 1999. The CR (containing the Post-Closure Monitoring Plan) was approved by the NDEP on May 18, 1999. Post-closure monitoring at CAU 404 consists of the following: (1) Site inspections done twice a year to evaluate the condition of the unit; (2) Verification that the site is secure; (3) Notice of any subsidence or deficiencies that may compromise the integrity of the unit; (4) Remedy of any deficiencies within 90 days of discovery; and (5) Preparation and submittal of an annual report. Site inspections were conducted on June 19, 2000, and November 21, 2000. The site inspections were conducted after completion of the revegetation activities (October 30, 1997) and NDEP approval of the CR (May 18, 1999). All site inspections were conducted in accordance with the Post-Closure Monitoring Plan in the NDEP-approved CR. This report includes copies of inspection checklists, photographs, recommendations, and conclusions. The Post-Closure Inspection Checklists are found in Attachment A, a copy of the field notes is found in Attachment B, and copies of the inspection photographs are found in Attachment C

Susceptibility of the eggs of the field slug Deroceras reticulatum to contact with pesticides and substances of biological origin on artificial soil

NARCIS (Netherlands)

Iglesias, J.; Castillejo, J.; Ester, A.; Castro, R.; Lombardia, M.J.

2002-01-01

The toxicity of 14 substances, including a number of pesticides, to the eggs of the pest slug Deroceras reticulatum was determined in laboratory experiments. Eggs were kept in contact with a precisely defined artificial soil to which a range of concentrations of the test substances had been applied.

A hybrid approach to fault diagnosis of roller bearings under variable speed conditions

Science.gov (United States)

Wang, Yanxue; Yang, Lin; Xiang, Jiawei; Yang, Jianwei; He, Shuilong

2017-12-01

Rolling element bearings are one of the main elements in rotating machines, whose failure may lead to a fatal breakdown and significant economic losses. Conventional vibration-based diagnostic methods are based on the stationary assumption, thus they are not applicable to the diagnosis of bearings working under varying speeds. This constraint limits the bearing diagnosis to the industrial application significantly. A hybrid approach to fault diagnosis of roller bearings under variable speed conditions is proposed in this work, based on computed order tracking (COT) and variational mode decomposition (VMD)-based time frequency representation (VTFR). COT is utilized to resample the non-stationary vibration signal in the angular domain, while VMD is used to decompose the resampled signal into a number of band-limited intrinsic mode functions (BLIMFs). A VTFR is then constructed based on the estimated instantaneous frequency and instantaneous amplitude of each BLIMF. Moreover, the Gini index and time-frequency kurtosis are both proposed to quantitatively measure the sparsity and concentration measurement of time-frequency representation, respectively. The effectiveness of the VTFR for extracting nonlinear components has been verified by a bat signal. Results of this numerical simulation also show the sparsity and concentration of the VTFR are better than those of short-time Fourier transform, continuous wavelet transform, Hilbert-Huang transform and Wigner-Ville distribution techniques. Several experimental results have further demonstrated that the proposed method can well detect bearing faults under variable speed conditions.

Contact Dermatitis in Pediatrics.

Science.gov (United States)

Pelletier, Janice L; Perez, Caroline; Jacob, Sharon E

2016-08-01

Contact dermatitis is an umbrella term that describes the skin's reaction to contacted noxious or allergenic substances. The two main categories of contact dermatitis are irritant type and allergic type. This review discusses the signs, symptoms, causes, and complications of contact dermatitis. It addresses the testing, treatment, and prevention of contact dermatitis. Proper management of contact dermatitis includes avoidance measures for susceptible children. Implementation of a nickel directive (regulating the use of nickel in jewelry and other products that come into contact with the skin) could further reduce exposure to the most common allergens in the pediatric population. [Pediatr Ann. 2016;45(8):e287-e292.]. Copyright 2016, SLACK Incorporated.

Anaerobic biodegradability and toxicity of complex or toxicant wastewater

International Nuclear Information System (INIS)

Wills Betancur, B.A.

1995-01-01

As a first approximation to wastewater classification in susceptibility terms to treatment by anaerobic biological system, anaerobic biodegradability trials are accomplished to leached of sanitary landfill, to wastewater of coffee grain wet treatment plant and to wastewater of fumaric acid recuperation plant. In the last Plant, anaerobic toxicity trials and lethal toxicity on the Daphnia pulex micro-crustacean are made too. Anaerobic biological trials are made continuing the Wageningen University (Holland) Methodology (1.987). Lethal toxicity biological trials are made following the Standard Methods for the Examination of Water and Wastewater(18th edition, 1992). In development of this investigation project is found that fumaric acid recuperation plant leached it has a low anaerobic biodegradability, a high anaerobic toxicity and a high lethal toxicity over Daphnia pulex, for such reasons this leached is cataloged as complex and toxic wastewater. The other hand, wastewater of coffee grain wet treatment plant and wastewater of sanitary landfill they are both highly biodegradability and not-toxic, for such reasons these wastewaters are cataloged as susceptible to treatment by anaerobic biological system

Evaluation of silica nanoparticle toxicity after topical exposure for 90 days

Directory of Open Access Journals (Sweden)

Ryu HJ

2014-12-01

Full Text Available Hwa Jung Ryu,1,* Nak-won Seong,2,* Byoung Joon So,1 Heung-sik Seo,2 Jun-ho Kim,2 Jeong-Sup Hong,2 Myeong-kyu Park,2 Min-Seok Kim,2 Yu-Ri Kim,3 Kyu-Bong Cho,4 Mu yeb Seo,2 Meyoung-Kon Kim,3 Eun Ho Maeng,2 Sang Wook Son1 1Department of Dermatology, Korea University College of Medicine, Seoul, South Korea; 2Korea Testing and Research Institute, Gyunggi-Do, South Korea; 3Department of Biochemistry and Molecular Biology, Korea University College of Medicine, Seoul, South Korea; 4Department of Clinical Laboratory Science, Shinheung College, Uijeongbu, South Korea *These authors contributed equally to this work Abstract: Silica is a very common material that can be found in both crystalline and amorphous forms. Well-known toxicities of the lung can occur after exposure to the crystalline form of silica. However, the toxicities of the amorphous form of silica have not been thoroughly studied. The majority of in vivo studies of amorphous silica nanoparticles (NPs were performed using an inhalation exposure method. Since silica NPs can be commonly administered through the skin, a study of dermal silica toxicity was necessary to determine any harmful effects from dermal exposures. The present study focused on the results of systemic toxicity after applying 20 nm colloidal silica NPs on rat skin for 90 days, in accordance with the Organization for Economic Cooperation and Development test guideline 411 with a good laboratory practice system. Unlike the inhalation route or gastrointestinal route, the contact of silica NPs through skin did not result in any toxicity or any change in internal organs up to a dose of 2,000 mg/kg in rats. Keywords: silica nanoparticles, toxicity, dermal route

Projecting social contact matrices in 152 countries using contact surveys and demographic data.

Directory of Open Access Journals (Sweden)

Kiesha Prem

2017-09-01

Full Text Available Heterogeneities in contact networks have a major effect in determining whether a pathogen can become epidemic or persist at endemic levels. Epidemic models that determine which interventions can successfully prevent an outbreak need to account for social structure and mixing patterns. Contact patterns vary across age and locations (e.g. home, work, and school, and including them as predictors in transmission dynamic models of pathogens that spread socially will improve the models' realism. Data from population-based contact diaries in eight European countries from the POLYMOD study were projected to 144 other countries using a Bayesian hierarchical model that estimated the proclivity of age-and-location-specific contact patterns for the countries, using Markov chain Monte Carlo simulation. Household level data from the Demographic and Health Surveys for nine lower-income countries and socio-demographic factors from several on-line databases for 152 countries were used to quantify similarity of countries to estimate contact patterns in the home, work, school and other locations for countries for which no contact data are available, accounting for demographic structure, household structure where known, and a variety of metrics including workforce participation and school enrolment. Contacts are highly assortative with age across all countries considered, but pronounced regional differences in the age-specific contacts at home were noticeable, with more inter-generational contacts in Asian countries than in other settings. Moreover, there were variations in contact patterns by location, with work-place contacts being least assortative. These variations led to differences in the effect of social distancing measures in an age structured epidemic model. Contacts have an important role in transmission dynamic models that use contact rates to characterize the spread of contact-transmissible diseases. This study provides estimates of mixing patterns for

Projecting social contact matrices in 152 countries using contact surveys and demographic data.

Science.gov (United States)

Prem, Kiesha; Cook, Alex R; Jit, Mark

2017-09-01

Heterogeneities in contact networks have a major effect in determining whether a pathogen can become epidemic or persist at endemic levels. Epidemic models that determine which interventions can successfully prevent an outbreak need to account for social structure and mixing patterns. Contact patterns vary across age and locations (e.g. home, work, and school), and including them as predictors in transmission dynamic models of pathogens that spread socially will improve the models' realism. Data from population-based contact diaries in eight European countries from the POLYMOD study were projected to 144 other countries using a Bayesian hierarchical model that estimated the proclivity of age-and-location-specific contact patterns for the countries, using Markov chain Monte Carlo simulation. Household level data from the Demographic and Health Surveys for nine lower-income countries and socio-demographic factors from several on-line databases for 152 countries were used to quantify similarity of countries to estimate contact patterns in the home, work, school and other locations for countries for which no contact data are available, accounting for demographic structure, household structure where known, and a variety of metrics including workforce participation and school enrolment. Contacts are highly assortative with age across all countries considered, but pronounced regional differences in the age-specific contacts at home were noticeable, with more inter-generational contacts in Asian countries than in other settings. Moreover, there were variations in contact patterns by location, with work-place contacts being least assortative. These variations led to differences in the effect of social distancing measures in an age structured epidemic model. Contacts have an important role in transmission dynamic models that use contact rates to characterize the spread of contact-transmissible diseases. This study provides estimates of mixing patterns for societies for which

Contact allergy and allergic contact dermatitis in adolescents: prevalence measures and associations

DEFF Research Database (Denmark)

Mørtz, Charlotte G; Lauritsen, Jens Martin; Bindslev-Jensen, Carsten

2002-01-01

The aims of this cross-sectional study were to establish the prevalence measures of contact allergy and allergic contact dermatitis in 8th grade schoolchildren (aged 12-16 years) in Odense, Denmark, and to examine the associations with atopic dermatitis, inhalant allergy and hand eczema. Contact...... allergy to a standard series allergen was found in 15.2% of schoolchildren. The point prevalence of allergic contact dermatitis was 0.7% and the lifetime prevalence 7.2%, predominantly in girls. The most common contact allergens were nickel (8.6%) and fragrance mix (1.8%). Nickel allergy was clinically...... relevant in 69% and fragrance allergy in 29% of cases. A significant association was found between contact allergy and hand eczema while no association was found between contact allergy and atopic dermatitis or inhalant allergy. In the future this cohort of schoolchildren will be followed with regard...

Current knowledge on biomarkers for contact sensitization and allergic contact dermatitis

NARCIS (Netherlands)

Koppes, Sjors A.; Engebretsen, Kristiane A.; Agner, Tove; Angelova-Fischer, Irena; Berents, Teresa; Brandner, Johanna; Brans, Richard; Clausen, Maja-Lisa; Hummler, Edith; Jakasa, Ivone; Jurakić-Tončic, Ružica; John, Swen M.; Khnykin, Denis; Molin, Sonja; Holm, Jan O.; Suomela, Sari; Thierse, Hermann-Josef; Kezic, Sanja; Martin, Stefan F.; Thyssen, Jacob P.

2017-01-01

Contact sensitization is common and affects up to 20% of the general population. The clinical manifestation of contact sensitization is allergic contact dermatitis. This is a clinical expression that is sometimes difficult to distinguish from other types of dermatitis, for example irritant and

Toxic effects of two essential oils and their constituents on the mealworm beetle, Tenebrio molitor.

Science.gov (United States)

Martínez, L C; Plata-Rueda, A; Colares, H C; Campos, J M; Dos Santos, M H; Fernandes, F L; Serrão, J E; Zanuncio, J C

2017-12-14

The study identified insecticidal effects from the cinnamon and clove essential oils in Tenebrio molitor L. (Coleoptera: Tenebrionidae). The lethal concentrations (LC50 and LC90), lethal time, and repellent effect on larvae, pupae, and adults of T. molitor after exposure to six concentrations of each essential oil and toxic compounds were evaluated. The chemical composition of the cinnamon oil was also determined and primary compounds were eugenol (10.19%), trans-3-caren-2-ol (9.92%), benzyl benzoate (9.68%), caryophyllene (9.05%), eugenyl acetate (7.47%), α-phellandrene (7.18%), and α-pinene (6.92%). In clove essential oil, the primary compounds were eugenol (26.64%), caryophyllene (23.73%), caryophyllene oxide (17.74%), 2-propenoic acid (11.84%), α-humulene (10.48%), γ-cadinene (4.85%), and humulene oxide (4.69%). Cinnamon and clove essential oils were toxic to T. molitor. In toxic chemical compounds, eugenol have stronger contact toxicity in larvae, pupae, and adult than caryophyllene oxide, followed by α-pinene, α-phellandrene, and α-humulene. In general, the two essential oils were toxic and repellent to adult T. molitor. Cinnamon and clove essential oils and their compounds caused higher mortality and repellency on T. molitor and, therefore, have the potential for integrated management programs of this insect.

Relationship between the real contact area and contact force in pre-sliding regime

International Nuclear Information System (INIS)

Song Baojiang; Yan Shaoze

2017-01-01

The pre-sliding regime is typically neglected in the dynamic modelling of mechanical systems. However, the change in contact state caused by static friction may decrease positional accuracy and control precision. To investigate the relationship between contact status and contact force in pre-sliding friction, an optical experimental method is presented in this paper. With this method, the real contact state at the interface of a transparent material can be observed based on the total reflection principle of light by using an image processing technique. A novel setup, which includes a pair of rectangular trapezoidal blocks, is proposed to solve the challenging issue of accurately applying different tangential and normal forces to the contact interface. The improved Otsu’s method is used for measurement. Through an experimental study performed on polymethyl methacrylate (PMMA), the quantity of contact asperities is proven to be the dominant factor that affects the real contact area. The relationship between the real contact area and the contact force in the pre-sliding regime is studied, and the distribution of static friction at the contact interface is qualitatively discussed. New phenomena in which the real contact area expands along with increasing static friction are identified. The aforementioned relationship is approximately linear at the contact interface under a constant normal pressure, and the distribution of friction stress decreases from the leading edge to the trailing edge. (paper)

Contact Lens Risks

Science.gov (United States)

... There is a risk of eye infection from bacteria in swimming pool water, hot tubs, lakes and the ocean Replace your contact lens storage case every 3 months or as directed by your eye care professional. Other Risks of Contact Lenses Other risks of contact lenses include pink eye ( ...

Noneczematous Contact Dermatitis

Science.gov (United States)

Foti, Caterina; Vestita, Michelangelo; Angelini, Gianni

2013-01-01

Irritant or allergic contact dermatitis usually presents as an eczematous process, clinically characterized by erythematoedematovesicous lesions with intense itching in the acute phase. Such manifestations become erythematous-scaly as the condition progresses to the subacute phase and papular-hyperkeratotic in the chronic phase. Not infrequently, however, contact dermatitis presents with noneczematous features. The reasons underlying this clinical polymorphism lie in the different noxae and contact modalities, as well as in the individual susceptibility and the various targeted cutaneous structures. The most represented forms of non-eczematous contact dermatitis include the erythema multiforme-like, the purpuric, the lichenoid, and the pigmented kinds. These clinical entities must obviously be discerned from the corresponding “pure” dermatitis, which are not associated with contact with exogenous agents. PMID:24109520

Evaluation Standard for Safety Coefficient of Roller Compacted Concrete Dam Based on Finite Element Method

Directory of Open Access Journals (Sweden)

Bo Li

2014-01-01

Full Text Available The lack of evaluation standard for safety coefficient based on finite element method (FEM limits the wide application of FEM in roller compacted concrete dam (RCCD. In this paper, the strength reserve factor (SRF method is adopted to simulate gradual failure and possible unstable modes of RCCD system. The entropy theory and catastrophe theory are used to obtain the ultimate bearing resistance and failure criterion of the RCCD. The most dangerous sliding plane for RCCD failure is found using the Latin hypercube sampling (LHS and auxiliary analysis of partial least squares regression (PLSR. Finally a method for determining the evaluation standard of RCCD safety coefficient based on FEM is put forward using least squares support vector machines (LSSVM and particle swarm optimization (PSO. The proposed method is applied to safety coefficient analysis of the Longtan RCCD in China. The calculation shows that RCCD failure is closely related to RCCD interface strength, and the Longtan RCCD is safe in the design condition. Considering RCCD failure characteristic and combining the advantages of several excellent algorithms, the proposed method determines the evaluation standard for safety coefficient of RCCD based on FEM for the first time and can be popularized to any RCCD.

Toxicity of Rhododendron anthopogonoides Essential Oil and Its Constituent Compounds towards Sitophilus zeamais

Directory of Open Access Journals (Sweden)

Qi Zhi Liu

2011-08-01

Full Text Available The screening of several Chinese medicinal plants for insecticidal principles showed that essential oil of Rhododendron anthopogonoides flowering aerial parts possessed significant toxicity against maize weevils, Sitophilus zeamais. A total of 37 components were identified in the essential oil and the main constituents of the essential oil were 4-phenyl-2-butanone (27.22%, nerolidol (8.08%, 1,4-cineole (7.85%, caryophyllene (7.63% and γ-elemene (6.10%, followed by α-farnesene (4.40% and spathulenol (4.19%. Repeated bioactivity-directed chromatographic separation on silica gel columns led us to isolate three compounds, namely 4-phenyl-2-butanone, 1,4-cineole, and nerolidol. 4-Phenyl-2-butanone shows pronounced contact toxicity against S. zeamais (LD50 = 6.98 mg/adult and was more toxic than either 1,4-cineole or nerolidol (LD50 = 50.86 mg/adult and 29.30 mg/adult, respectively against the maize weevils, while the crude essential oil had a LD50 value of 11.67 mg/adult. 4-Phenyl-2-butanone and 1,4-cineole also possessed strong fumigant toxicity against the adults of S. zeamais (LC50 = 3.80 mg/L and 21.43 mg/L while the crude essential oil had a LC50 value of 9.66 mg/L.

Apparent Contact Angle and Contact Angle Hysteresis on Liquid Infused Surfaces

OpenAIRE

Semprebon, Ciro; McHale, Glen; Kusumaatmaja, Halim

2016-01-01

We theoretically investigate the apparent contact angle and contact angle hysteresis of a droplet placed on a liquid infused surface. We show that the apparent contact angle is not uniquely defined by material parameters, but also has a strong dependence on the relative size between the droplet and its surrounding wetting ridge formed by the infusing liquid. We derive a closed form expression for the contact angle in the limit of vanishing wetting ridge, and compute the correction for small b...

A comparative study of physical and chemical properties of different pozzolanic materials used for roller compacted concrete RCC dams

Directory of Open Access Journals (Sweden)

Husein Malkawi Abdallah I.

2017-01-01

Full Text Available This paper addresses the feasibility and the efficiency of using Natural Pozzolan and/or Rock flour in Roller Compacted Concrete (RCC gravity dams. For this purpose, five identical mortar trial mixes were prepared using five different supplementary materials, i.e., fly ash produced in South Africa (proven to be effective in RCC construction, fly ash produced in Turkey, Jordanian natural pozzolan, Saudi natural pozzolan, and rock flour from Mujib Dam basalt quarry. The physical and chemical properties of these pozzolanic materials were determined. The effectiveness of each one of these mineral admixtures used as a cement replacement material in controlling alkali silica reaction are studied and analyzed. Correlations were made between the mechanical properties for the five proposed mixes and a control mix using the Jordanian Portland Cement. The results demonstrate that the performance of Natural Pozzolana and/or rock flour as compared with that of fly ash and other pozzolanic material is very satisfactory and can be effectively used in RCC construction.

Toxicidade por fumigação, contato e ingestão de óleos essenciais para Sitophilus zeamais Motschulsky, 1885 (Coleoptera: Curculionidae Toxicity by fumigation, contact and ingestion of essential oils in Sitophilus zeamais Motschulsky, 1885 (Coleoptera: Curculionidae

Directory of Open Access Journals (Sweden)

Rodrigo Leandro Braga de Castro Coitinho

2011-02-01

Full Text Available A espécie Sitophilus zeamais é uma das principais pragas do milho armazenado no Brasil. O controle é feito, comumente, utilizando-se medidas de higienização e limpeza, bem como inseticidas sintéticos fumigantes e protetores. A busca por produtos menos tóxicos, biodegradáveis e seguros do ponto de vista ecológico, é muito bem aceita pela sociedade. Assim, os objetivos do presente trabalho foram testar a toxicidade de contato e ingestão e fumigante de óleos essenciais e do composto orgânico natural eugenol para adultos de S. zeamais. Os valores de CL50 dos óleos essenciais provenientes de folhas de Piper hispidinervum, Eugenia uniflora, Cinnamomum zeylanicum, P. marginatum, Schinus terebinthifolius, Melaleuca leucadendron, dos frutos verdes de S terebinthifolius e do composto eugenol, nos testes de contato e ingestão, foram estimados em 1,0; 11,6; 14,2; 21,1; 57,7; 75,8; 98,8 e 14,8 µL/40 g de milho, respectivamente. As razões de toxicidade (RT variaram entre 1,3 e 98,8. Na fumigação em adultos, as concentrações letais dos óleos variaram de 0,53 a 94,7 µL/L de ar, obedecendo à seguinte ordem decrescente de toxicidade: P. hispidinervum > P. aduncum > S. terebinthifolius > frutos verdes de S. terebinthifolius > P. marginatum > eugenol e as RT variaram entre 2,0 a 178,7.The Sitophilus zeamais species is a major pest of stored maize in Brazil. The control is made, usually, using measures of hygiene and cleanliness, synthetic insecticides and fumigant protectors. The search for less toxic products, biodegradable and safe from an ecological point of view is very well accepted by society. the objective of this study was to test the toxicity by contact and ingestion and fumigant of essential oils and eugenol natural organic compound for adults of S. zeamais. The values of LC50 in oil from leaves of Piper hispidinervum, Eugenia uniflora, Cinnamomum zeylanicum, P. marginatum, Schinus terebinthifolius, Melaleuca leucadendron, green

Analysis of toxic and heavy metals in cataract extraction from human eyes

International Nuclear Information System (INIS)

Tanvir, R.; Qureshi, S.A.; Ahmed, R.

1999-01-01

Surma and many other substances are frequently used for the treatment of eyes and for cosmetic purposes, which may contain large quantities of toxic and heavy metals particularly lead. Toxic metals may also enter into the body through different food chain system and also due to heavy traffic and contaminated dusts in the air of the overcrowded cities. Eyes being exposed part of human body has maximum chances to get in contact with polluted atmosphere. This study has been undertaken to find the role of toxic elements in the formation of cataract in eyes. Samples of eye lenses were collected and carefully digested in 3 ml of conc. HClO/sub 4/ and 1 ml of conc. HNO/sub 3/. Then analysis of Zn, Cd, Pb, Cu, was carried out in 0.02 m HClO/sub 4/ using differential pulse anodic stripping voltametry. Levels of Zn, Cd, Pb and Cu in eye lenses are from 324 - 5746 mug/g, 3 - 240 mug/g, 3 - 240 mug/g, 25 - 120 mug /g and 23 - 485 mug/g, respectively. Chemical composition of ocular fluid indicates that Pb, Cd, Cu, Zn are not present in it normally. In addition to other factors , role of heavy and toxic metals in the formation of cataract cannot be overlooked. Therefore, use of surma and other cosmetics should be discouraged. (author)

Sampling the stratum corneum for toxic chemicals.

Science.gov (United States)

Coman, Garrett; Blickenstaff, Nicholas R; Blattner, Collin M; Andersen, Rosa; Maibach, Howard I

2014-01-01

Dermal exposure is an important pathway in environmental health. Exposure comes from contaminated water, soil, treated surfaces, textiles, aerosolized chemicals, and agricultural products. It can occur in homes, schools, play areas, and work settings in the form of industrial sources, consumer products, or hazardous wastes. Dermal exposure is most likely to occur through contact with liquids, water, soil, sediment, and contaminated surfaces. The ability to detect and measure exposure to toxic materials on the skin is an important environmental health issue. The stratum corneum is the skin's first and principal barrier layer of protection from the outside world. It has a complex structure that can effectively protect against a wide variety of physical, chemical, and biological contaminants. However, there are a variety of chemical agents that can damage the stratum corneum and the underlying epidermis, dermis and subcutis, and/or enter systemic circulation through the skin. There are numerous ways of sampling the stratum corneum for these toxic materials like abrasion techniques, biopsy, suction blistering, imaging, washing, wipe sampling, tape stripping, and spot testing. Selecting a method likely depends on the particular needs of the situation. Hence, there is a need to review practical considerations for their use in sampling the stratum corneum for toxins.

Bioluminescent Vibrio fischeri assays in the assessment of seasonal and spatial patterns in toxicity of contaminated river sediments

Directory of Open Access Journals (Sweden)

Sergio Jarque

2016-11-01

Full Text Available Several bacteria-based assays, notably Vibrio fischeri luminescence assays, are often used as environmental monitoring tool for toxicity in sediments that may serve as both sinks and secondary source of contamination in aquatic ecosystems. In this study, we used 30-s kinetic bioassays based on V. fischeri to evaluate the toxicity associated to sediments from five localities with different contamination inputs (Morava River and its tributary Drevnice River in the south-eastern part of the Czech Republic. Toxicity assessed as half maximal inhibitory concentration (IC50 over the course of a year-long sampling was compared in bottom sediments and freshly trapped particulate material. Standard approach based on testing of aqueous elutriates was compared with toxicity of whole sediments (contact suspension toxicity. Bottom sediments showed lower toxicity compared to freshly trapped suspended materials in all cases. On the other hand, standardized elutriates induced generally weaker effects than suspended sediments likely due to losses during the extraction process. Toxicity generally increased during winter reaching maximum peaks in early spring months in all five sites. Total organic carbon (TOC was found to be highly correlated with toxic effects. Toxicity from sites with direct industrial and agricultural water inputs also correlated with concentrations of metals, polycyclic aromatic hydrocarbons (PAHs and polychlorinated biphenyls (PCBs. Single time point sampling followed by the extraction and testing of elutriates, do not truly reflect the spatial and temporal variability in natural sediments and may lead to underestimation of ecotoxic risks.

Introducing Toxics

Directory of Open Access Journals (Sweden)

David C. Bellinger

2013-04-01

Full Text Available With this inaugural issue, Toxics begins its life as a peer-reviewed, open access journal focusing on all aspects of toxic chemicals. We are interested in publishing papers that present a wide range of perspectives on toxicants and naturally occurring toxins, including exposure, biomarkers, kinetics, biological effects, fate and transport, treatment, and remediation. Toxics differs from many other journals in the absence of a page or word limit on contributions, permitting authors to present their work in as much detail as they wish. Toxics will publish original research papers, conventional reviews, meta-analyses, short communications, theoretical papers, case reports, commentaries and policy perspectives, and book reviews (Book reviews will be solicited and should not be submitted without invitation. Toxins and toxicants concern individuals from a wide range of disciplines, and Toxics is interested in receiving papers that represent the full range of approaches applied to their study, including in vitro studies, studies that use experimental animal or non-animal models, studies of humans or other biological populations, and mathematical modeling. We are excited to get underway and look forward to working with authors in the scientific and medical communities and providing them with a novel venue for sharing their work. [...

Contact with turf algae alters the coral microbiome: contact versus systemic impacts

Science.gov (United States)

Pratte, Zoe A.; Longo, Guilherme O.; Burns, Andrew S.; Hay, Mark E.; Stewart, Frank J.

2018-03-01

Coral reefs are degrading to algae-dominated reefs worldwide, with alterations of coral microbiomes commonly co-occurring with reef demise. The severe thermal anomaly during the 2016 El Niño event in the South Pacific killed many corals and stressed others. We examined the microbiome of turf algae and of the coral Porites sp. in contact with turf during this thermal event to investigate algal turf effects on the coral microbiome during a period of environmental stress. The microbial composition of turf did not differ between coral-contacted and non-contacted turfs. However, microbiomes of corals in direct contact with turf were similar to those of the turf microbiome, but differed significantly from coral portions 5 cm from the point of turf/coral contact and from portions of the coral that looked most healthy, regardless of location. Although the majority of significant differences occurred in coral samples at the point of contact, a small subset of microbial taxa was enriched in coral tissues taken 5 cm from turf contact compared to all other sample types, including samples from areas of the coral that appeared most healthy. These results suggest that the coral microbiome is susceptible to colonization by microbes from turf, but not vice versa. Results also suggest that algal contact elicits a subtle shift in the coral microbiome just beyond the contact site. The combination of turf microbiome stability and coral microbiome vulnerability at areas of contact may contribute to the continued decline in coral cover and increase in algal cover associated with coral-algae phase shifts.

Patients with multiple contact allergies

DEFF Research Database (Denmark)

Carlsen, Berit Christina; Andersen, Klaus Ejner; Menné, Torkil

2008-01-01

Patients with multiple contact allergies, also referred to as polysensitized, are more frequent than predicted from prevalence of single sensitivities. The understanding of why some people develop multiple contact allergies, and characterization of patients with multiple contact allergies...... of developing multiple contact allergies. Evidence of allergen clusters among polysensitized individuals is also reviewed. The literature supports the idea that patients with multiple contact allergies constitute a special entity within the field of contact allergy. There is no generally accepted definition...... of patients with multiple contact allergies. We suggest that contact allergy to 3 or more allergens are defined as multiple contact allergies....

Low temperature deposition of bifacial CIGS solar cells on Al-doped Zinc Oxide back contacts

Energy Technology Data Exchange (ETDEWEB)

Cavallari, Nicholas, E-mail: nicholas.cavallari@imem.cnr.it [IMEM-CNR, Parco Area delle Scienze 37/a, 43124 Parma (Italy); Department of Mathematical, Physical and Computer Sciences, University of Parma, Parco Area delle Scienze 7/a, 43124 Parma (Italy); Pattini, Francesco; Rampino, Stefano; Annoni, Filippo [IMEM-CNR, Parco Area delle Scienze 37/a, 43124 Parma (Italy); Barozzi, Mario [FBK—CMM—Micro Nano Facility, Via Sommarive 18, 38123 Trento (Italy); Bronzoni, Matteo; Gilioli, Edmondo; Gombia, Enos [IMEM-CNR, Parco Area delle Scienze 37/a, 43124 Parma (Italy); Maragliano, Carlo [Solar Bankers LLC, Phoenix, AZ (United States); Mazzer, Massimo [IMEM-CNR, Parco Area delle Scienze 37/a, 43124 Parma (Italy); Pepponi, Giancarlo [FBK—CMM—Micro Nano Facility, Via Sommarive 18, 38123 Trento (Italy); Spaggiari, Giulia; Fornari, Roberto [IMEM-CNR, Parco Area delle Scienze 37/a, 43124 Parma (Italy); Department of Mathematical, Physical and Computer Sciences, University of Parma, Parco Area delle Scienze 7/a, 43124 Parma (Italy)

2017-08-01

Highlights: • AZO and CIGS were deposited by Low-Temperature Pulsed Electron Deposition (LT-PED). • CIGS/AZO contacts with ohmic behavior and resistance of 1.07 Ω cm{sup 2} were fabricated. • LT-PED deposition of AZO and CIGS prevents formation of Ga{sub 2}O{sub 3} interlayer. • CIGS-based bifacial solar cells with AZO back contact were realized. • Front PV efficiency of 9.3% and equivalent bifacial efficiency of 11.6% were achieved. - Abstract: We report on the fabrication and characterization of Cu(In,Ga)Se{sub 2} (CIGS)-based thin film bifacial solar cells using Al-doped ZnO (AZO) as cost-effective and non-toxic transparent back contact. We show that, by depositing both CIGS and AZO by Low Temperature Pulsed Electron Deposition at a maximum temperature of 250 °C, a good ohmic contact is formed between the two layers and good quality solar cells can be fabricated as a result. Photovoltaic efficiencies as high as 9.3% (front illumination), 5.1% (backside illumination) and 11.6% (bifacial illumination) have been obtained so far. These values are remarkably higher than those previously reported in the literature. We demonstrate that this improvement is ascribed to the low-temperature deposition process that avoids the formation of Ga{sub 2}O{sub 3} at the CIGS/AZO interface and favours the formation of a low-resistivity contact in agreement with device simulations.

The reproductive and developmental toxicity of High Flash Aromatic Naphtha.

Science.gov (United States)

McKee, R H; Wong, Z A; Schmitt, S; Beatty, P; Swanson, M; Schreiner, C A; Schardein, J L

1990-01-01

Catalytic reforming is a refining process that converts naphthenes to aromatics by dehydrogenation to make higher octane gasoline blending components. A portion of this wide boiling range hydrocarbon stream can be separated by distillation and used for other purposes. One such application is a mixture of predominantly 9-carbon aromatic molecules (C9 aromatics, primarily isomers of ethyltoluene and trimethylbenzene), which is removed and used as a solvent--High Flash Aromatic Naphtha. A program was initiated to assess the toxicological properties of High Flash Aromatic Naphtha since there may be human exposure through inhalation or external body contact. The current study was conducted to assess the potential for developmental toxicity in the mouse and for reproductive toxicity in the rat. In the developmental toxicity study in CD-1 mice, exposure of dams by inhalation to near lethal levels (1500 ppm) resulted in fetal mortality, reduced weight, delayed ossification, and an increased incidence of cleft palate. At 500 ppm, a level at which maternal weight gain was slightly reduced, fetal weight gain was also reduced, but there was no other evidence of developmental effects. The lowest exposure level (100 ppm) did not cause any maternal or developmental toxicity. There was no consistent evidence of reproductive toxicity in rats, even at exposure levels which resulted in significantly reduced parental weight gain. In addition, when parental exposure was stopped on GD (gestation day) 20, birth weights as well as postnatal survival were generally similar to control values, even in the 1500 ppm exposure group. Postnatal weight gain was also similar to controls early in weaning, but, if maternal exposure was reinitiated, weight gain was reduced in the high exposure group. However, when exposure was continued until delivery, pups in the high exposure group exhibited reduced litter size, birth weight and poor survival. Thus it was likely that the reduction in fetal weight

Discovering less toxic ionic liquids by using the Microtox® toxicity test.

Science.gov (United States)

Hernández-Fernández, F J; Bayo, J; Pérez de los Ríos, A; Vicente, M A; Bernal, F J; Quesada-Medina, J

2015-06-01

New Microtox® toxicity data of 16 ionic liquids of different cationic and anionic composition were determined. The ionic liquids 1-butyl-1-methylpyrrolidinium trifluoromethanesulfonate, [BMPyr(+)][TFO(-)], 1-butyl-1-methylpyrrolidinium chloride, [BMPyr(+)][Cl(-)], hydroxypropylmethylimidazolium fluoroacetate, [HOPMIM(+)][FCH2COO(-)], and hydroxypropylmethylimidazolium glycolate [HOPMIM(+)][glycolate(-)] were found to be less toxic than conventional organic solvent such as chloroform or toluene, accoding the Microtox® toxicity assays. The toxicity of pyrrolidinium cation was lower than the imidazolium and pyridinium ones. It was found that the inclusion of an hydroxyl group in the alkyl chain length of the cation also reduce the toxicity of the ionic liquid. To sum up, the Microtox® toxicity assays can be used as screening tool to easily determined the toxicity of a wide range of ionic liquids and the toxicity data obtained could allow the obtention of structure-toxicity relationships to design less toxic ionic liquids. Copyright © 2015 Elsevier Inc. All rights reserved.

Experimental and numerical investigation of contact-area-limited doping for top-contact pentacene thin-film transistors with Schottky contact.

Science.gov (United States)

Noda, Kei; Wada, Yasuo; Toyabe, Toru

2015-10-28

Effects of contact-area-limited doping for pentacene thin-film transistors with a bottom-gate, top-contact configuration were investigated. The increase in the drain current and the effective field-effect mobility was achieved by preparing hole-doped layers underneath the gold contact electrodes by coevaporation of pentacene and 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4TCNQ), confirmed by using a thin-film organic transistor advanced simulator (TOTAS) incorporating Schottky contact with a thermionic field emission (TFE) model. Although the simulated electrical characteristics fit the experimental results well only in the linear regime of the transistor operation, the barrier height for hole injection and the gate-voltage-dependent hole mobility in the pentacene transistors were evaluated with the aid of the device simulation. This experimental data analysis with the simulation indicates that the highly-doped semiconducting layers prepared in the contact regions can enhance the charge carrier injection into the active semiconductor layer and concurrent trap filling in the transistor channel, caused by the mitigation of a Schottky energy barrier. This study suggests that both the contact-area-limited doping and the device simulation dealing with Schottky contact are indispensable in designing and developing high-performance organic thin-film transistors.

Role of Firing Temperature, Sheet Resistance, and Contact Area in Contact Formation on Screen-Printed Metal Contact of Silicon Solar Cell

Science.gov (United States)

Ahmad, Samir Mahmmod; Leong, Cheow Siu; Sopian, K.; Zaidi, Saleem H.

2018-03-01

Formation of an Ohmic contact requires a suitable firing temperature, appropriate doping profile, and contact dimensions within resolution limits of the screen-printing process. In this study, the role of the peak firing temperature in standard rapid thermal annealing (RTA) six-zone conveyor belt furnace (CBF) and two inexpensive alternate RTA systems [a custom-designed, three-zone, 5″-diameter quartz tube furnace (QTF) and a tabletop, 3″-diameter rapid thermal processing (RTP)] has been investigated. In addition, the role of sheet resistance and contact area in achieving low-resistance ohmic contacts has been examined. Electrical measurements of ohmic contacts between silver paste/ n +-emitter layer with varying sheet resistances and aluminum paste/ p-doped wafer were carried out in transmission line method configuration. Experimental measurements of the contact resistivity ( ρ c) exhibited the lowest values for CBF at 0.14 mΩ cm2 for Ag and 100 mΩ cm2 for Al at a peak firing temperature of 870°C. For the QTF configuration, lowest measured contact resistivities were 3.1 mΩ cm2 for Ag and 74.1 mΩ cm2 for Al at a peak firing temperature of 925°C. Finally, for the RTP configuration, lowest measured contact resistivities were 1.2 mΩ cm2 for Ag and 68.5 mΩ cm2 for Al at a peak firing temperature of 780°C. The measured contact resistivity exhibits strong linear dependence on sheet resistance. The contact resistivity for Ag decreases with contact area, while for Al the opposite behavior is observed.

An approximate JKR solution for a general contact, including rough contacts

Science.gov (United States)

Ciavarella, M.

2018-05-01

In the present note, we suggest a simple closed form approximate solution to the adhesive contact problem under the so-called JKR regime. The derivation is based on generalizing the original JKR energetic derivation assuming calculation of the strain energy in adhesiveless contact, and unloading at constant contact area. The underlying assumption is that the contact area distributions are the same as under adhesiveless conditions (for an appropriately increased normal load), so that in general the stress intensity factors will not be exactly equal at all contact edges. The solution is simply that the indentation is δ =δ1 -√{ 2 wA‧ /P″ } where w is surface energy, δ1 is the adhesiveless indentation, A‧ is the first derivative of contact area and P‧‧ the second derivative of the load with respect to δ1. The solution only requires macroscopic quantities, and not very elaborate local distributions, and is exact in many configurations like axisymmetric contacts, but also sinusoidal waves contact and correctly predicts some features of an ideal asperity model used as a test case and not as a real description of a rough contact problem. The solution permits therefore an estimate of the full solution for elastic rough solids with Gaussian multiple scales of roughness, which so far was lacking, using known adhesiveless simple results. The result turns out to depend only on rms amplitude and slopes of the surface, and as in the fractal limit, slopes would grow without limit, tends to the adhesiveless result - although in this limit the JKR model is inappropriate. The solution would also go to adhesiveless result for large rms amplitude of roughness hrms, irrespective of the small scale details, and in agreement with common sense, well known experiments and previous models by the author.

HTSC-Josephson step contacts

International Nuclear Information System (INIS)

Herrmann, K.

1994-03-01

In this work the properties of josephson step contacts are investigated. After a short introduction into Josephson step contacts the structure, properties and the Josphson contacts of YBa 2 Cu 3 O 7-x high-T c superconductors is presented. The fabrication of HTSC step contacts and the microstructure is discussed. The electric properties of these contacts are measured together with the Josephson emission and the magnetic field dependence. The temperature dependence of the stationary transport properties is given. (WL)

Ocular surface displacement with and without contact lenses during non-contact tonometry.

Science.gov (United States)

Rimayanti, Ulfah; Kiuchi, Yoshiaki; Uemura, Shohei; Takenaka, Joji; Mochizuki, Hideki; Kaneko, Makoto

2014-01-01

To evaluate the displacement of the central ocular surface during non-contact tonometry with and without soft contact lenses and determine the factors associated with the displacement of the central ocular surface and intraocular pressure (IOP) reading changes caused by wearing soft contact lenses (CLs). One eye each in 21 subjects was studied. The cornea was photographed using a high-speed camera at 5,000 frames/sec during non-contact tonometry without contact lenses (NCL), with -5.0 diopters (D), -0.5 D and +5.0 D CL. The displacement of the ocular surface and the factors affecting displacement at the IOP reading and maximum displacement time were investigated. The IOP readings while wearing +5 D CL were significantly higher than those obtained while wearing -5 D CL. The ocular surface displacement between +5 D CL and other groups were significantly different. A significant positive correlation was found between the ocular surface displacement of subjects at the IOP reading time and the IOP obtained with the non-contact tonometer. A significant negative correlation was found between the ocular surface curvature and the IOP obtained using the non-contact tonometer. The radius of curvature of the ocular surface affected the displacement during the IOP reading and maximum displacement time. Our results indicate that soft contact lens use changes the ocular surface behavior and IOP readings during non-contact tonometry. The radius of curvature of the eye affects the ocular surface displacement and IOP readings in this situation.

Improved protein structure reconstruction using secondary structures, contacts at higher distance thresholds, and non-contacts.

Science.gov (United States)

Adhikari, Badri; Cheng, Jianlin

2017-08-29

Residue-residue contacts are key features for accurate de novo protein structure prediction. For the optimal utilization of these predicted contacts in folding proteins accurately, it is important to study the challenges of reconstructing protein structures using true contacts. Because contact-guided protein modeling approach is valuable for predicting the folds of proteins that do not have structural templates, it is necessary for reconstruction studies to focus on hard-to-predict protein structures. Using a data set consisting of 496 structural domains released in recent CASP experiments and a dataset of 150 representative protein structures, in this work, we discuss three techniques to improve the reconstruction accuracy using true contacts - adding secondary structures, increasing contact distance thresholds, and adding non-contacts. We find that reconstruction using secondary structures and contacts can deliver accuracy higher than using full contact maps. Similarly, we demonstrate that non-contacts can improve reconstruction accuracy not only when the used non-contacts are true but also when they are predicted. On the dataset consisting of 150 proteins, we find that by simply using low ranked predicted contacts as non-contacts and adding them as additional restraints, can increase the reconstruction accuracy by 5% when the reconstructed models are evaluated using TM-score. Our findings suggest that secondary structures are invaluable companions of contacts for accurate reconstruction. Confirming some earlier findings, we also find that larger distance thresholds are useful for folding many protein structures which cannot be folded using the standard definition of contacts. Our findings also suggest that for more accurate reconstruction using predicted contacts it is useful to predict contacts at higher distance thresholds (beyond 8 Å) and predict non-contacts.

Toxicity of fluoride to aquatic species and evaluation of toxicity modifying factors.

Science.gov (United States)

Pearcy, Krysta; Elphick, James; Burnett-Seidel, Charlene

2015-07-01

The present study was performed to investigate the toxicity of fluoride to a variety of freshwater aquatic organisms and to establish whether water quality variables contribute substantively to modifying its toxicity. Water hardness, chloride, and alkalinity were tested as possible toxicity modifying factors for fluoride using acute toxicity tests with Hyalella azteca and Oncorhynchus mykiss. Chloride appeared to be the major toxicity modifying factor for fluoride in these acute toxicity tests. The chronic toxicity of fluoride was evaluated with a variety of species, including 3 fish (Pimephales promelas, O. mykiss, and Salvelinus namaycush), 3 invertebrates (Ceriodaphnia dubia, H. azteca, and Chironomus dilutus), 1 plant (Lemna minor), and 1 alga (Pseudokirchneriella subcapitata). Hyalella azteca was the most sensitive species overall, and O. mykiss was the most sensitive species of fish. The role of chloride as a toxicity modifying factor was inconsistent between species in the chronic toxicity tests. © 2015 SETAC.

Metabolic responses of Eisenia fetida after sub-lethal exposure to organic contaminants with different toxic modes of action

International Nuclear Information System (INIS)

McKelvie, Jennifer R.; Wolfe, David M.; Celejewski, Magda A.; Alaee, Mehran; Simpson, Andre J.; Simpson, Myrna J.

2011-01-01

Nuclear magnetic resonance (NMR) - based metabolomics has the potential to identify toxic responses of contaminants within a mixture in contaminated soil. This study evaluated the metabolic response of Eisenia fetida after exposure to an array of organic compounds to determine whether contaminant-specific responses could be identified. The compounds investigated in contact tests included: two pesticides (carbaryl and chlorpyrifos), three pharmaceuticals (carbamazephine, estrone and caffeine), two persistent organohalogens (Aroclor 1254 and PBDE 209) and two industrial compounds (nonylphenol and dimethyl phthalate). Control and contaminant-exposed metabolic profiles were distinguished using principal component analysis and potential contaminant-specific biomarkers of exposure were found for several contaminants. These results suggest that NMR-based metabolomics offers considerable promise for differentiating between the different toxic modes of action (MOA) associated with sub-lethal toxicity to earthworms. - Highlights: → NMR-based earthworm metabolomic analysis of the toxic mode of action of various environmental contaminants. → Organic chemicals with different toxic modes of action resulted in varied metabolomic responses for E. fetida. → NMR-based metabolomics differentiates between the different modes of action associated with sub-lethal toxicity. - 1 H NMR metabolomics was used to identify potential biomarkers of organic contaminant exposure in Eisenia fetida earthworms.

Microbial contamination and chemical toxicity of the Rio Grande

Directory of Open Access Journals (Sweden)

Valles Adrian

2004-04-01

Full Text Available Abstract Background The Rio Grande River is the natural boundary between U.S. and Mexico from El Paso, TX to Brownsville, TX. and is one of the major water resources of the area. Agriculture, farming, maquiladora industry, domestic activities, as well as differences in disposal regulations and enforcement increase the contamination potential of water supplies along the border region. Therefore, continuous and accurate assessment of the quality of water supplies is of paramount importance. The objectives of this study were to monitor water quality of the Rio Grande and to determine if any correlations exist between fecal coliforms, E. coli, chemical toxicity as determined by Botsford's assay, H. pylori presence, and environmental parameters. Seven sites along a 112-Km segment of the Rio Grande from Sunland Park, NM to Fort Hancock, TX were sampled on a monthly basis between January 2000 and December 2002. Results The results showed great variability in the number of fecal coliforms, and E. coli on a month-to-month basis. Fecal coliforms ranged between 0–106 CFU/100 ml while E. coli ranged between 6 to > 2419 MPN. H. pylori showed positive detection for all the sites at different times. Toxicity ranged between 0 to 94% of inhibition capacity (IC. Since values above 50% are considered to be toxic, most of the sites displayed significant chemical toxicity at different times of the year. No significant correlations were observed between microbial indicators and chemical toxicity. Conclusion The results of the present study indicate that the 112-Km segment of the Rio Grande river from Sunland Park, NM to Fort Hancock, TX exceeds the standards for contact recreation water on a continuous basis. In addition, the presence of chemical toxicity in most sites along the 112-Km segment indicates that water quality is an area of concern for the bi-national region. The presence of H. pylori adds to the potential health hazards of the Rio Grande. Since no

Effect of implanted doses of N+-ions on the contact resistance of copper contacts

International Nuclear Information System (INIS)

Dubravec, B.; Kovac, P.; Lipka, F.; Padysak, M.

1997-01-01

The paper deals with the effect of implanted doses of N + ions on the contact resistance. Dependencies of the contact resistance versus contact force R c =f(F c ) and microhardness of implanted surfaces were measured for three implanted profiles. The influence of the aggressive environs on the contact resistance of implanted contact is given too

Electrical contacts principles and applications

CERN Document Server

Slade, Paul G

2013-01-01

Covering the theory, application, and testing of contact materials, Electrical Contacts: Principles and Applications, Second Edition introduces a thorough discussion on making electric contact and contact interface conduction; presents a general outline of, and measurement techniques for, important corrosion mechanisms; considers the results of contact wear when plug-in connections are made and broken; investigates the effect of thin noble metal plating on electronic connections; and relates crucial considerations for making high- and low-power contact joints. It examines contact use in switch

Ocular surface displacement with and without contact lenses during non-contact tonometry.

Directory of Open Access Journals (Sweden)

Ulfah Rimayanti

Full Text Available PURPOSE: To evaluate the displacement of the central ocular surface during non-contact tonometry with and without soft contact lenses and determine the factors associated with the displacement of the central ocular surface and intraocular pressure (IOP reading changes caused by wearing soft contact lenses (CLs. METHODS: One eye each in 21 subjects was studied. The cornea was photographed using a high-speed camera at 5,000 frames/sec during non-contact tonometry without contact lenses (NCL, with -5.0 diopters (D, -0.5 D and +5.0 D CL. The displacement of the ocular surface and the factors affecting displacement at the IOP reading and maximum displacement time were investigated. RESULTS: The IOP readings while wearing +5 D CL were significantly higher than those obtained while wearing -5 D CL. The ocular surface displacement between +5 D CL and other groups were significantly different. A significant positive correlation was found between the ocular surface displacement of subjects at the IOP reading time and the IOP obtained with the non-contact tonometer. A significant negative correlation was found between the ocular surface curvature and the IOP obtained using the non-contact tonometer. The radius of curvature of the ocular surface affected the displacement during the IOP reading and maximum displacement time. CONCLUSIONS: Our results indicate that soft contact lens use changes the ocular surface behavior and IOP readings during non-contact tonometry. The radius of curvature of the eye affects the ocular surface displacement and IOP readings in this situation.

Lifetime limitations of ohmic, contacting RF MEMS switches with Au, Pt and Ir contact materials due to accumulation of ‘friction polymer’ on the contacts

International Nuclear Information System (INIS)

Czaplewski, David A; Nordquist, Christopher D; Dyck, Christopher W; Patrizi, Gary A; Kraus, Garth M; Cowan, William D

2012-01-01

We present lifetime limitations and failure analysis of many packaged RF MEMS ohmic contacting switches with Au–Au, Au–Ir, and Au–Pt contact materials operating with 100 µN of contact force per contact in hermetically sealed glass wall packages. All metals were tested using the same switch design in a controlled environment to provide a comparison between the performance of the different materials and their corresponding failure mechanisms. The switch lifetimes of the different contact materials varied from several hundred cycles to 200 million cycles with different mechanisms causing failures for different contact materials. Switches with Au–Au contacts failed due to adhesion when thoroughly cleaned while switches with dissimilar metal contacts (Au–Ir and Au–Pt) operated without adhesion failures but failed due to carbon accumulation on the contacts even in a clean, packaged environment as a result of the catalytic behavior of the contact materials. Switch lifetimes correlated inversely with catalytic behavior of the contact metals. The data suggests the path to increase switch lifetime is to use favorable catalytic materials as contacts, design switches with higher contact forces to break through any residual contamination, and use cleaner, probably smaller, packages. (paper)

Quantitative surface topography assessment of directly compressed and roller compacted tablet cores using photometric stereo image analysis.

Science.gov (United States)

Allesø, Morten; Holm, Per; Carstensen, Jens Michael; Holm, René

2016-05-25

Surface topography, in the context of surface smoothness/roughness, was investigated by the use of an image analysis technique, MultiRay™, related to photometric stereo, on different tablet batches manufactured either by direct compression or roller compaction. In the present study, oblique illumination of the tablet (darkfield) was considered and the area of cracks and pores in the surface was used as a measure of tablet surface topography; the higher a value, the rougher the surface. The investigations demonstrated a high precision of the proposed technique, which was able to rapidly (within milliseconds) and quantitatively measure the obtained surface topography of the produced tablets. Compaction history, in the form of applied roll force and tablet punch pressure, was also reflected in the measured smoothness of the tablet surfaces. Generally it was found that a higher degree of plastic deformation of the microcrystalline cellulose resulted in a smoother tablet surface. This altogether demonstrated that the technique provides the pharmaceutical developer with a reliable, quantitative response parameter for visual appearance of solid dosage forms, which may be used for process and ultimately product optimization. Copyright © 2015 Elsevier B.V. All rights reserved.

Long-term thermal two- and three-dimensional analysis of roller compacted concrete dams supported by monitoring verification

Energy Technology Data Exchange (ETDEWEB)

Kuzmanovic, V.; Savic, L. [Belgrade Univ. (Serbia). Faculty of Civil Engineering; Stefanakos, J. [National Technical Univ. of Athens (Greece). Dept. of Water Resources and Environmental Engineering

2010-04-15

This study investigated the long-term thermal-field evolution of roller compacted concrete (RCC) dams. Thermal computational analyses of the dams are needed as a result of the layer-based construction technologies used to build the dams. Two-dimensional (2-D) and 3-D unsteady phased models of the RCC dams were used to determine the time evolution of thermal field in a dam based on the Platanovryssi dam in Greece. The finite element method (FEM) was used to account for the dam geometry, different types of concrete used; actual initial and boundary conditions; the thermal and mechanical properties of the dam as a function of aging and temperature; and the RCC construction technology. The influence of all the parameters on the thermal behaviour of the RCC gravity dam was analyzed. Results of the study showed that the 2-D model accurately described the RCC dam thermal field. The thermal behaviour of the dam was influenced primarily by the thermal properties of the mixture and the boundary conditions. Variations of layer thickness did not significantly influence the temperature field. 18 refs., 3 tabs., 10 figs.

Negative intergroup contact is more influential, but positive intergroup contact is more common: Assessing contact prominence and contact prevalence in five Central European countries

Czech Academy of Sciences Publication Activity Database

Graf, Sylvie; Paolini, S.; Rubin, M.

2014-01-01

Roč. 44, č. 96 (2014), 536–547 ISSN 0046-2772 R&D Projects: GA ČR GA13-25656S Institutional support: RVO:68081740 Keywords : intergroup contact * negative contact * outgroup attitudes Subject RIV: AN - Psychology Impact factor: 1.712, year: 2014

Ergonomic factors related to drop-off detection with the long cane: effects of cane tips and techniques.

Science.gov (United States)

Kim, Dae Shik; Emerson, Robert S Wall; Curtis, Amy B

2010-06-01

This study examined the effect of cane tips and cane techniques on drop-off detection with the long cane. Blind pedestrians depend on a long cane to detect drop-offs. Missing a drop-off may result in falls or collision with moving vehicles in the street. Although cane tips appear to affect a cane user's ability to detect drop-offs, few experimental studies have examined such effect. A repeated-measures design with block randomization was used for the study. Participants were 17 adults who were legally blind and had no other disabilities. Participants attempted to detect the drop-offs of varied depths using different cane tips and cane techniques. Drop-off detection rates were similar between the marshmallow tip (77.0%) and the marshmallow roller tip (79.4%) when both tips were used with the constant contact technique, p = .294. However, participants detected drop-offs at a significantly higher percentage when they used the constant contact technique with the marshmallow roller tip (79.4%) than when they used the two-point touch technique with the marshmallow tip (63.2%), p marshmallow roller tip (perceived as a less advantageous tip) was more effective than the two-point touch technique used with a marshmallow tip (perceived as a more advantageous tip) in detecting drop-offs. The findings of the study may help cane users and orientation and mobility specialists select appropriate cane techniques and cane tips in accordance with the cane user's characteristics and the nature of the travel environment.

Contact Angle Goniometer

Data.gov (United States)

Federal Laboratory Consortium — Description:The FTA32 goniometer provides video-based contact angle and surface tension measurement. Contact angles are measured by fitting a mathematical expression...

The steady-state tangential contact problem for a falling drop type of contact area on corrugated rail by simplified theory of rolling contact

Science.gov (United States)

Piotrowski, Jerzy

1991-10-01

Investigation of contact mechanical nonlinearities of a mathematical model of corrugation revealed that the typical shape of contact patch resembles a falling drop of water. A contact patch of that shape was approximated with a figure composed of two parts of ellipses with different eccentricities. The contact pressure distribution was assumed as a smoothing ensemble of two paraboloidal distributions. The description of a general case of double half elliptical contact area was given but a special case of double half elliptical contact is more interesting as it possesses some Hertzian properties. It was shown how three geometrical parameters of double half elliptical contact can be chosen when actual, non-Hertzian contact is known. A linear theory was written which indicates that the lateral vibrations of the rail may be excited only due to shape variation on corrugation even if any other cause for these vibrations does not exist. For nonlinear theory a computer program, based on FASTSIM algorithm by Kalker, was written. The aim is to calculate the creep forces and frictional power density distribution over the contact area. Also, a graphic program visualizing the solution was written. Numerical results are not provided; unattended and unsolved problems relevant for this type of contact are listed.

78 FR 14549 - National Contact Center; Information Collection; National Contact Center Customer Evaluation Survey

Science.gov (United States)

2013-03-06

...] National Contact Center; Information Collection; National Contact Center Customer Evaluation Survey AGENCY... National Contact Center customer evaluation surveys. In this request, the previously approved surveys have... several months. These temporary surveys will allow the National Contact Center to compare its customer...

Toxicity alarm: Case history

International Nuclear Information System (INIS)

Hogan, D.; Retallack, J.

1993-01-01

In late fall 1991, the Novacor petrochemical plant near Joffre, Alberta experienced a toxicity alarm, the first since its startup 14 years ago. Fish exposed to a normal toxicity test were stressed within 2 h and showed 100% mortality after 24 h. A history of the events leading up to, during, and after the toxicity alarm is presented. The major effluent sources were three cooling water systems. Although these sources are well characterized, the event causes were not immediately clear. Initial toxic screening indicated that one was very toxic, another moderately toxic, and the third not toxic at all. All three systems utilized the same chemical treatment program to avoid fouling: stabilized phosphates with minor variants. The most toxic of the cooling systems operated at 10-12 cycles, had three chemicals for biocide control, and had three makeup streams. Toxic and nontoxic system characteristics were compared. An in-depth modified toxicity identification and evaluation program was then performed to identify and evaluate the cause of the toxicity alarm for future prevention. The most probable causes of toxicity were identified by elimination. The combination of high numbers of cycles, hydrocarbons in the makeup water, and bromine added as an antifoulant resulted in formation of aromatic bromamines which are capable of causing the toxic condition experienced. 2 tabs

INSECTICIDAL TOXICITY OF 1,8-CINEOLE, CAMPHOR AND EUGENOL ON TRIBOLIUM CASTANEUM (HERBST

Directory of Open Access Journals (Sweden)

Anita Liška

2011-06-01

Full Text Available Contact and fumigant activity of 1,8-cineole, camphor and eugenol compounds were tested In laboratory conditions on adult, larvae and pupae of the red flour beetle Tribolium castaneum (Herbst, as well as their effect on progeny emergence. Positive results were obtained with contact application for all three tested compounds and on all three stages of development of T. castaneum, with the highest activity of 1,8-cineole, followed by eugenol and camphor. Ingeneral, fumigant activity of all three compounds was lower in comparison to contact application, with the best activity of 1,8-cineole, followed by camphor and eugenol on all three developmental stages of T. castaneum. However, lower activity was recorded for fumigation of the space 50% filled with wheat grain for all three tested compounds on all three stages, with the best activity of 1,8-cineole, followed by camphor and eugenol, whereas eugenol showed no toxicity to the adult stage. The activity of 1,8-cineole and eugenol in the space 50% filled with wheat grain decreased by 3.5 and 32 times, respectively, whereas the activity of camphor had no significant difference on the larvae. Toxicity of the tested compounds on pupae T. castaneum was either lethal or directly affected to metamorphosis pupae. There were significant differences observed in the efficacy of the tested compounds on the gender of the pupae, with the most markedly differences for 1,8-cineole, followed by camphor and the minimal for eugenol. Males were more sensitive to the applied compounds, whereas females had more deformed units, especially in the fumigation treatment with camphor. The most tolerant stage on the contact and fumigant application of all compounds was the pupae stage. Eugenol and 1,8-cineole had influence on the reduction of T. castaneum progeny emergence, whereas camphor had no such effect. Due to a high potential of 1,8-cineole for the control of the red flour beetle Tribolium castaneum (Herbst (at all

A contact angle hysteresis model based on the fractal structure of contact line.

Science.gov (United States)

Wu, Shuai; Ma, Ming

2017-11-01

Contact angle is one of the most popular concept used in fields such as wetting, transport and microfludics. In practice, different contact angles such as equilibrium, receding and advancing contact angles are observed due to hysteresis. The connection among these contact angles is important in revealing the chemical and physical properties of surfaces related to wetting. Inspired by the fractal structure of contact line, we propose a single parameter model depicting the connection of the three angles. This parameter is decided by the fractal structure of the contact line. The results of this model agree with experimental observations. In certain cases, it can be reduced to other existing models. It also provides a new point of view in understanding the physical nature of the contact angle hysteresis. Interestingly, some counter-intuitive phenomena, such as the binary receding angles, are indicated in this model, which are waited to be validated by experiments. Copyright © 2017 Elsevier Inc. All rights reserved.

Mechanical Contact Experiments and Simulations

DEFF Research Database (Denmark)

Nielsen, Chris Valentin; Martins, P; Zhang, W.

2011-01-01

Mechanical contact is studied under dynamic development by means of a combined numerical and experimental investigation. The experiments are designed to allow dynamical development of non-planar contact areas with significant expansion in all three directions as the load is increased. Different....... The overall investigation serves for testing and validating the numerical implementation of the mechanical contact, which is one of the main contributions to a system intended for 3D simulation of resistance welding. Correct modelling of contact between parts to be welded, as well as contact with electrodes......, is crucial for satisfactory modelling of the resistance welding process. The resistance heating at the contact interfaces depends on both contact area and pressure, and as the contact areas develop dynamically, the presented tests are relevant for assessing the validity and accuracy of the mechanical contact...

Antimony Toxicity

Directory of Open Access Journals (Sweden)

Shyam Sundar

2010-12-01

Full Text Available Antimony toxicity occurs either due to occupational exposure or during therapy. Occupational exposure may cause respiratory irritation, pneumoconiosis, antimony spots on the skin and gastrointestinal symptoms. In addition antimony trioxide is possibly carcinogenic to humans. Improvements in working conditions have remarkably decreased the incidence of antimony toxicity in the workplace. As a therapeutic, antimony has been mostly used for the treatment of leishmaniasis and schistosomiasis. The major toxic side-effects of antimonials as a result of therapy are cardiotoxicity (~9% of patients and pancreatitis, which is seen commonly in HIV and visceral leishmaniasis co-infections. Quality control of each batch of drugs produced and regular monitoring for toxicity is required when antimonials are used therapeutically.

Use of the aquatic plant Elodea canadensis to assess toxicity and genotoxicity of Yenisei River sediments.

Science.gov (United States)

Zotina, Tatiana A; Trofimova, Elena A; Medvedeva, Marina Yu; Dementyev, Dmitry V; Bolsunovsky, Alexander Ya

2015-10-01

The toxicity, cytotoxicity, and genotoxicity of bulk sediments from the Yenisei River (Siberia, Russia) were estimated in laboratory bioassays based on several endpoints in the aquatic plant Elodea canadensis. The bottom sediment samples were collected in the Yenisei River upstream and downstream of the sources of chemical and radioactive contamination. The testing revealed different sensitivities of Elodea endpoints to the quality of the bottom sediment: weight of shoots Elodea) was the highest in sediments with chemical pollution, whereas the highest inhibition of toxicity endpoints (shoot and root length) occurred in sediments with the highest level of radioactive pollution. The extreme response of Elodea endpoints to the quality of certain sediment samples may be regarded as related to the possible presence of unknown toxicants. The results show that E. canadensis can be used as an indicator species in laboratory contact testing of bottom sediment. The responses of shoot and root length growth endpoints of Elodea can be recommended as basic sensitivity indicators of bottom sediment toxicity. Analysis of cells carrying abnormal chromosomes in the apical root meristem of Elodea can be performed optionally in the same test to assess the genotoxicity of sediments. © 2015 SETAC.

Colored Contact Lens Dangers

Medline Plus

Full Text Available ... One Use Facts About Colored Contacts and Halloween Safety Colored Contact Lens Facts Over-the-Counter Costume ... Costume Contact Lenses Can Ruin Vision Eye Makeup Safety In fact, it is illegal to sell colored ...

Differential toxicity and influence of salinity on acute toxicity of ...

African Journals Online (AJOL)

Differential toxicity and influence of salinity on acute toxicity of copper sulphate and lead nitrate against Oreochromis niloticus. KA Bawa-Allah, F Osuala, J Effiong. Abstract. This study investigated the salinity-tolerance of Oreochromis niloticus and the influence of salinity changes on the acute toxicities of copper sulphate ...

Estimating the Contact Endurance of the AISI 321 Stainless Steel Under Contact Gigacycle Fatigue Tests

Science.gov (United States)

Savrai, R. A.; Makarov, A. V.; Osintseva, A. L.; Malygina, I. Yu.

2018-02-01

Mechanical testing of the AISI 321 corrosion resistant austenitic steel for contact gigacycle fatigue has been conducted with the application of a new method of contact fatigue testing with ultrasonic frequency of loading according to a pulsing impact "plane-to-plane" contact scheme. It has been found that the contact endurance (the ability to resist the fatigue spalling) of the AISI 321 steel under contact gigacycle fatigue loading is determined by its plasticity margin and the possibility of additional hardening under contact loading. It is demonstrated that the appearance of localized deep and long areas of spalling on a material surface can serve as a qualitative characteristic for the loss of the fatigue strength of the AISI 321 steel under impact contact fatigue loading. The value of surface microhardness measured within contact spots and the maximum depth of contact damages in the peripheral zone of contact spots can serve as quantitative criteria for that purpose.

Colored Contact Lens Dangers

Medline Plus

Full Text Available ... One Use Facts About Colored Contacts and Halloween Safety Colored Contact Lens Facts Over-the-Counter Costume ... use of colored contact lenses , from the U.S. Food and Drug Administration (FDA). Are the colored lenses ...

Toxicity levels to humans during acute exposure to hydrogen fluoride - An update

International Nuclear Information System (INIS)

Halton, D.M.

1995-09-01

In March 1993, the Atomic Energy Control Board (AECB) commissioned and update of a 1984 review on the acute toxicity of hydrogen fluoride (HF). The study places particular emphasis on the effects of inhalation of gaseous HF and is divided into two main parts: a literature review and a lethal concentration (LC) estimation. The literature review summarizes data under four categories: animal studies, controlled human studies, community exposure, and industrial exposure. Data in these areas were critically reviewed for their relevance to lethal concentrations at LC LO , LC 10 and LC 50 levels that were derived in the 1984 report. In the last ten years, only one relevant animal study has been published. No new controlled human studies were found but a community exposure incident was reported. There were three new industrial/accidental exposures reported since 1984. Evaluation of new data does not change the lethal concentration estimates made in the 1984 report, but does indicate the absence of appropriate models to estimate the lethality of irritant and corrosive gases. In the last 10 years, much literature on the evaluation of major hazards has been published and suggests that such assessments are of growing political, economic and social importance. Numerous articles have been published on the acute toxicity of HF from skin contact and chronic toxicity from repeated airborne exposure. These publications offer important insights into the nature of HF toxicity. Several avenues of investigative research are suggested. (author). 55 refs., 4 tabs

Toxic Effects of Bisphenol A, Propyl Paraben, and Triclosan on Caenorhabditis elegans

Directory of Open Access Journals (Sweden)

María Cecilia García-Espiñeira

2018-04-01

Full Text Available Bisphenol A (BPA is a ubiquitous plasticizer which is absorbed by ingestion and dermal contact; propyl paraben (PPB inhibits the microbiome and extends the shelf life of many personal care products, whereas triclosan (TCS is commonly found in antiseptics, disinfectants, or additives. In this work, Caenorhabditis elegans was used as a biological model to assess the toxic effects of BPA, PPB, and TCS. The wild type strain, Bristol N2, was used in bioassays with the endpoints of lethality, growth, and reproduction; green fluorescent protein (GFP transgenic strains with the hsp-3, hsp-4, hsp-16.2, hsp-70, sod-1, sod-4, cyp-35A4, cyp-29A2, and skn-1 genes were evaluated for their mRNA expression through fluorescence measurement; and quick Oil Red O (q ORO was utilized to stain lipid deposits. Lethality was concentration-dependent, while TCS and PPB showed more toxicity than BPA. BPA augmented worm length, while PPB reduced it. All toxicants moderately increased the width and the width–length ratio. BPA and PPB promoted reproduction, in contrast to TCS, which diminished it. All toxicants affected the mRNA expression of genes related to cellular stress, control of reactive oxygen species, and nuclear receptor activation. Lipid accumulation occurred in exposed worms. In conclusion, BPA, PPB, and TCS alter the physiology of growth, lipid accumulation, and reproduction in C. elegans, most likely through oxidative stress mechanisms.

Toxicity levels to humans during acute exposure to hydrogen fluoride - An update

Energy Technology Data Exchange (ETDEWEB)

Halton, D M

1995-09-01

In March 1993, the Atomic Energy Control Board (AECB) commissioned and update of a 1984 review on the acute toxicity of hydrogen fluoride (HF). The study places particular emphasis on the effects of inhalation of gaseous HF and is divided into two main parts: a literature review and a lethal concentration (LC) estimation. The literature review summarizes data under four categories: animal studies, controlled human studies, community exposure, and industrial exposure. Data in these areas were critically reviewed for their relevance to lethal concentrations at LC{sub LO}, LC{sub 10} and LC{sub 50} levels that were derived in the 1984 report. In the last ten years, only one relevant animal study has been published. No new controlled human studies were found but a community exposure incident was reported. There were three new industrial/accidental exposures reported since 1984. Evaluation of new data does not change the lethal concentration estimates made in the 1984 report, but does indicate the absence of appropriate models to estimate the lethality of irritant and corrosive gases. In the last 10 years, much literature on the evaluation of major hazards has been published and suggests that such assessments are of growing political, economic and social importance. Numerous articles have been published on the acute toxicity of HF from skin contact and chronic toxicity from repeated airborne exposure. These publications offer important insights into the nature of HF toxicity. Several avenues of investigative research are suggested. (author). 55 refs., 4 tabs.

Structural, Functional, and Metabolic Brain Markers Differentiate Collision versus Contact and Non-Contact Athletes.

Science.gov (United States)

Churchill, Nathan W; Hutchison, Michael G; Di Battista, Alex P; Graham, Simon J; Schweizer, Tom A

2017-01-01

There is growing concern about how participation in contact sports affects the brain. Retrospective evidence suggests that contact sports are associated with long-term negative health outcomes. However, much of the research to date has focused on former athletes with significant health problems. Less is known about the health of current athletes in contact and collision sports who have not reported significant medical issues. In this cross-sectional study, advanced magnetic resonance imaging (MRI) was used to evaluate multiple aspects of brain physiology in three groups of athletes participating in non-contact sports ( N  = 20), contact sports ( N  = 22), and collision sports ( N  = 23). Diffusion tensor imaging was used to assess white matter microstructure based on measures of fractional anisotropy (FA) and mean diffusivity (MD); resting-state functional MRI was used to evaluate global functional connectivity; single-voxel spectroscopy was used to compare ratios of neural metabolites, including N -acetyl aspartate (NAA), creatine (Cr), choline, and myo-inositol. Multivariate analysis revealed structural, functional, and metabolic measures that reliably differentiated between sport groups. The collision group had significantly elevated FA and reduced MD in white matter, compared to both contact and non-contact groups. In contrast, the collision group showed significant reductions in functional connectivity and the NAA/Cr metabolite ratio, relative to only the non-contact group, while the contact group overlapped with both non-contact and collision groups. For brain regions associated with contact sport participation, athletes with a history of concussion also showed greater alterations in FA and functional connectivity, indicating a potential cumulative effect of both contact exposure and concussion history on brain physiology. These findings indicate persistent differences in brain physiology for athletes participating in contact and collision sports

Classification of baseline toxicants for QSAR predictions to replace fish acute toxicity studies.

Science.gov (United States)

Nendza, Monika; Müller, Martin; Wenzel, Andrea

2017-03-22

Fish acute toxicity studies are required for environmental hazard and risk assessment of chemicals by national and international legislations such as REACH, the regulations of plant protection products and biocidal products, or the GHS (globally harmonised system) for classification and labelling of chemicals. Alternative methods like QSARs (quantitative structure-activity relationships) can replace many ecotoxicity tests. However, complete substitution of in vivo animal tests by in silico methods may not be realistic. For the so-called baseline toxicants, it is possible to predict the fish acute toxicity with sufficient accuracy from log K ow and, hence, valid QSARs can replace in vivo testing. In contrast, excess toxicants and chemicals not reliably classified as baseline toxicants require further in silico, in vitro or in vivo assessments. Thus, the critical task is to discriminate between baseline and excess toxicants. For fish acute toxicity, we derived a scheme based on structural alerts and physicochemical property thresholds to classify chemicals as either baseline toxicants (=predictable by QSARs) or as potential excess toxicants (=not predictable by baseline QSARs). The step-wise approach identifies baseline toxicants (true negatives) in a precautionary way to avoid false negative predictions. Therefore, a certain fraction of false positives can be tolerated, i.e. baseline toxicants without specific effects that may be tested instead of predicted. Application of the classification scheme to a new heterogeneous dataset for diverse fish species results in 40% baseline toxicants, 24% excess toxicants and 36% compounds not classified. Thus, we can conclude that replacing about half of the fish acute toxicity tests by QSAR predictions is realistic to be achieved in the short-term. The long-term goals are classification criteria also for further groups of toxicants and to replace as many in vivo fish acute toxicity tests as possible with valid QSAR

Evaluation of contact sensitivity to topical drugs in patients with contact dermatitis

Directory of Open Access Journals (Sweden)

Bilge Bülbül Şen

2013-03-01

Full Text Available Background and Design: Topical drugs are an important group of contact allergens. The present study aimed to evaluate contact sensitivity to topical drugs in patients with contact dermatitis. Materials and Methods: Between 2003 and 2008, 129 patients were followed up at the Department of Dermatology at Ankara University School of Medicine with clinically suspected contact sensitivity to topical drugs. In this study, the patch test reactions to the European Standard Battery and topical drugs used by the patients and medicament patch test results were evaluated. Results: Positive patch test reaction to one or more allergens was found in 80 (62.0% of 129 patients included in the study. Sixty-one of the 80 patients (61/129, 47.3% had positive patch test reaction to medicaments. Medicament sensitivity was detected in 37.9% (49/129 of subjects. Nitrofurazone was found to be the most common allergen (18.6%. Discussion: The present study showed that topical drugs are a frequent cause of allergic contact dermatitis. Therefore, the probability of contact sensitivity to topical drugs should also be considered in patients with the clinical diagnosis of allergic contact dermatitis and, suspected cases should be evaluated further with patch testing in order to find the responsible allergens.

Dermatitis, contact (image)

Science.gov (United States)

This picture shows a skin inflammation (dermatitis) caused by contact with a material that causes an allergic reaction in this person. Contact dermatitis is a relatively common condition, and can be caused ...

[News on occupational contact dermatitis].

Science.gov (United States)

Crépy, Marie-Noëlle; Bensefa-Colas, Lynda

2014-03-01

Contact dermatitis--irritant contact dermatitis, allergic contact dermatitis and protein contact dermatitis--are the most common occupational skin diseases, most often localized to the hands. Contact urticaria is rarer The main occupational irritants are wet work, detergents and disinfectants, cutting oils, and solvents. The main occupational allergens are rubber additives, metals (chromium, nickel, cobalt), plastics (epoxy resins, acrylic), biocides and plants. Diagnosis is based on clinical examination, medical history and allergy testing. For a number of irritating or sensitizing agents, irritant or allergic dermatitis can be notified as occupational diseases. The two main prevention measures are reducing skin contact with irritants and complete avoidance of skin contact with offending allergens.

Lettuce contact allergy.

Science.gov (United States)

Paulsen, Evy; Andersen, Klaus E

2016-02-01

Lettuce (Lactuca sativa L.) and its varieties are important vegetable crops worldwide. They are also well-known, rarely reported, causes of contact allergy. As lettuce allergens and extracts are not commercially available, the allergy may be underdiagnosed. The aims of this article are to present new data on lettuce contact allergy and review the literature. Lettuce is weakly allergenic, and occupational cases are mainly reported. Using aimed patch testing in Compositae-allergic patients, two recent Danish studies showed prevalence rates of positive lettuce reactions of 11% and 22%. The majority of cases are non-occupational, and may partly be caused by cross-reactivity. The sesquiterpene lactone mix seems to be a poor screening agent for lettuce contact allergy, as the prevalence of positive reactions is significantly higher in non-occupationally sensitized patients. Because of the easy degradability of lettuce allergens, it is recommended to patch test with freshly cut lettuce stem and supplement this with Compositae mix. As contact urticaria and protein contact dermatitis may present as dermatitis, it is important to perform prick-to-prick tests, and possibly scratch patch tests as well. Any person who is occupationally exposed to lettuce for longer periods, especially atopics, amateur gardeners, and persons keeping lettuce-eating pets, is potentially at risk of developing lettuce contact allergy. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Mixed Lubricated Line Contacts

NARCIS (Netherlands)

Faraon, I.C.

2005-01-01

The present work deals with friction in mixed lubricated line contacts. Components in systems are becoming smaller and due to, for instance power transmitted, partial contact may occur. In industrial applications, friction between the moving contacting surfaces cannot be avoided, therefore it is

New Cosmetic Contact Allergens

Directory of Open Access Journals (Sweden)

An Goossens

2015-02-01

Full Text Available Allergic and photo-allergic contact dermatitis, and immunologic contact urticaria are potential immune-mediated adverse effects from cosmetics. Fragrance components and preservatives are certainly the most frequently observed allergens; however, all ingredients must be considered when investigating for contact allergy.

Contact and symplectic topology

CERN Document Server

Colin, Vincent; Stipsicz, András

2014-01-01

Symplectic and contact geometry naturally emerged from the mathematical description of classical physics. The discovery of new rigidity phenomena and properties satisfied by these geometric structures launched a new research field worldwide. The intense activity of many European research groups in this field is reflected by the ESF Research Networking Programme "Contact And Symplectic Topology" (CAST). The lectures of the Summer School in Nantes (June 2011) and of the CAST Summer School in Budapest (July 2012) provide a nice panorama of many aspects of the present status of contact and symplectic topology. The notes of the minicourses offer a gentle introduction to topics which have developed in an amazing speed in the recent past. These topics include 3-dimensional and higher dimensional contact topology, Fukaya categories, asymptotically holomorphic methods in contact topology, bordered Floer homology, embedded contact homology, and flexibility results for Stein manifolds.

Follicular contact dermatitis revisited: A review emphasizing neomycin-associated follicular contact dermatitis

Science.gov (United States)

Cohen, Philip R

2014-01-01

Follicular contact dermatitis clinically presents as individual papules that include a central hair follicle. Pathologic features involve the follicle and the surrounding dermis: spongiosis and vesicle formation of the follicular epithelium associated with perifollicular and perivascular lymphocytic inflammation. Using the PubMed database, an extensive literature search was performed on follicular contact dermatitis and neomycin. Relevant papers were reviewed and the clinical and pathologic features, the associated chemicals (including a more detailed description of neomycin), the hypothesized pathogenesis, and the management of follicular contact dermatitis were described. Several agents-either as allergens or irritants-have been reported to elicit follicular contact dermatitis. Several hypotheses have been suggested for the selective involvement of the follicles in follicular contact dermatitis: patient allergenicity, characteristics of the agent, vehicle containing the agent, application of the agent, and external factors. The differential diagnosis of follicular contact dermatitis includes not only recurrent infundibulofolliculitis, but also drug eruption, mite infestation, viral infection, and dermatoses that affect hair follicles. The primary therapeutic intervention for follicular contact dermatitis is withdrawal of the causative agent; treatment with a topical corticosteroid preparation may also promote resolution of the dermatitis. In conclusion, follicular contact dermatitis may be secondary to allergens or irritants; topical antibiotics, including neomycin, may cause this condition. Several factors may account for the selective involvement of the hair follicle in this condition. Treatment of the dermatitis requires withdrawal of the associated topical agent; in addition, topical corticosteroids may be helpful to promote resolution of lesions. PMID:25516854

Reducing the toxicity of refinery effluent using seed extract and micro porous carbon from seed husks of moringa oleifera

International Nuclear Information System (INIS)

Gbem, T. T.; Balogun, J. K.; Lawal, F. A.

1998-01-01

Contamination of the environment with industrial chemicals and/or effluent has become a major problem. In this study, the toxicity of an NNPC refinery effluent was tested by exposing a commonly occurring invertebrate, Chironomus sp. (early larva stage) using the 96-h static bioassay to establish the LC 5 0 value. Seed extract from a widely distributed tropical plant, moringa oleifera was used to treat the effluent employing a modified laboratory jar test procedure. Hardness and alkalinity were reduced to between 19 and 30% with reduction found to be dose-dependent. Adsorption isotherms were established and were found to approximate the Langmuir type. Char from M. oleifera seed husks was also used to test the sorption of toxicants. A single toxicant from the effluent phenol, was used for sorption studies using pseudo-equilibrium batch contact experiments. Sorption was found to obey a Freundlich type adsorption isotherm (of the form q = KC), Retesting the toxicity of the effluent by re-introducing a different set of the test organism after treatment yielded no significant mortality. Moringa oleifera seed extract, char and possibly activated carbon from seed husks hold a promise to further reduction of the toxicity of refinery effluent

Contact materials for nanoelectronics

KAUST Repository

Alshareef, Husam N.

2011-02-01

In this article, we review current research activities in contact material development for electronic and nanoelectronic devices. A fundamental issue in contact materials research is to understand and control interfacial reactions and phenomena that modify the expected device performance. These reactions have become more challenging and more difficult to control as new materials have been introduced and as device sizes have entered the deep nanoscale. To provide an overview of this field of inquiry, this issue of MRS Bulletin includes articles on gate and contact materials for Si-based devices, junction contact materials for Si-based devices, and contact materials for alternate channel substrates (Ge and III-V), nanodevices. © 2011 Materials Research Society.

Contact Lens-Related Eye Infections

Science.gov (United States)

... Español Eye Health / Eye Health A-Z Contact Lens-Related Eye Infections Sections Contact Lens-Related Eye ... Six Steps to Avoid Contact Lens Infections Contact Lens-Related Eye Infections Leer en Español: Infecciones relacionadas ...

Estimating children's exposure to toxic elements in contaminated toys and children's jewelry via saliva mobilization.

Science.gov (United States)

Guney, Mert; Nguyen, Alain; Zagury, Gerald J

2014-09-19

Children's potential for exposure to potentially toxic elements in contaminated jewelry and toys via mouth contact has not yet been fully evaluated. Various toys and jewelry (metallic toys and jewelry [MJ], plastic toys, toys with paint or coating, and brittle/pliable toys; n = 32) were tested using the saliva extraction (mouthing) compartment of the DIN and RIVM bioaccessibility protocols to assess As, Ba, Cd, Cr, Cu, Mn, Ni, Pb, Sb, and Se mobilization via saliva. Total concentrations of As, Cd, Cu, Ni, Pb, and Sb were found elevated in analyzed samples. Four metals were mobilized to saliva from 16 MJ in significant quantities (>1 μg for highly toxic Cd and Pb, >10 μg for Cu and Ni). Bioaccessible concentrations and hazard index values for Cd exceeded limit values, for young children between 6 mo- and 3 yr-old and according to both protocols. Total and bioaccessible metal concentrations were different and not always correlated, encouraging the use of bioaccessibility for more accurate hazard assessments. Bioaccessibility increased with increasing extraction time. Overall, the risk from exposure to toxic elements via mouthing was high only for Cd and for MJ. Further research on children's exposure to toxic elements following ingestion of toy or jewelry material is recommended.

Biosorption study of radiotoxic nuclide and toxic heavy metals using green adsorbent

International Nuclear Information System (INIS)

Bagla, Hemlata K.

2014-01-01

Our research scientifically illuminates the pioneering and successful application of the ancient Indian epitome of energy, Dry Cow Dung Powder, DCP, a combo humiresin, in its naive 'as it is form' for the bioremediation of toxic pollutants. The potential of DCP to sequester toxic heavy metal ions such as Cr(III), Cr(VI). Cd(II), Hg(II) and radionuclide 90 Sr(II) has been successfully demonstrated, employing tracer technique. The Batch equilibration method and all the important parameters such as pH, dose of sorbent, metal ion concentration, contact time, agitation speed, temperature and interference of different salts have been studied and optimized. The study on thermodynamic, kinetic and isotherm modeling of biosorption indicates that it is feasible, eco-friendly and efficient process to employ DCP for the removal of metal ions from aqueous medium. Spectroscopic analysis by FTIR and EDAX effectively explain the mechanism involved in the biosorption by DCP. The adsorption capacity and the pseudo-second order rate constant were also obtained by regression analysis. Thus DCP proves to be Eco-friendly resin for the removal of these toxic pollutants such as Cr(III), Cr(VI), Cd(II), Hg(II) and 90 Sr(II) from aqueous medium. (author)

Are diverse societies less cohesive? Testing contact and mediated contact theories.

Science.gov (United States)

McKenna, Sarah; Lee, Eunro; Klik, Kathleen A; Markus, Andrew; Hewstone, Miles; Reynolds, Katherine J

2018-01-01

Previous research has demonstrated that there is a negative relationship between ethnic diversity in a local community and social cohesion. Often the way social cohesion is assessed, though, varies across studies and only some aspects of the construct are included (e.g., trust). The current research explores the relationship between diversity and social cohesion across a number of indicators of social cohesion including neighbourhood social capital, safety, belonging, generalized trust, and volunteering. Furthermore, social psychological theories concerning the role of positive contact and its impact on feelings of threat are investigated. Using a sample of 1070 third generation 'majority' Australians and structural equation modelling (SEM), findings suggest ethnic diversity is related to positive intergroup contact, and that contact showed beneficial impacts for some indicators of social cohesion both directly and indirectly through reducing perceived threat. When interethnic contact and perceived threat are included in the model there is no direct negative effect between diversity and social cohesion. The theoretical implications of these findings are outlined including the importance of facilitating opportunities for positive contact in diverse communities.

Correlation between atopic manifestation and lung toxicity following chest irradiation for breast cancer

International Nuclear Information System (INIS)

Hirota, Saeko; Shimizu, Tadafumi; Kubota, Satoshi

2007-01-01

The purpose of this study was to identify the impact of atopic manifestations on the occurrence of the lung toxicity following chest irradiation for breast cancer. Collection of 1,173 patients who had undergone radiotherapy on their 1,177 chest walls or postsurgical mammary glands at 9 institutions including ours. They received treatment consecutively from December 1980 through October 2005, with which we formed the basis of this analysis. Patients with any of the following medical history were defined as having atopic manifestations (n=111): asthma, allergic rhinitis, atopic dermatitis, contact dermatitis, and allergy to food or drug. Of them, patients who were observed for at least 6 months or who suffered from lung toxicity at any time, were classified as Group A (n=85). On the other hand, patients in our institute who were observed for at least 6 months or who suffered from lung toxicity at any time regardless of atopic manifestations, were classified as Group B (n=113), and patients without any atopic manifestation were classified as Group C (n=92). Grade 3 or higher lung toxicity in National Cancer Institute, Common Toxicity Criteria for Adverse Events (NCI-CTCAE) (v 3.0), occurred in 8.2%, id est (i.e.) 7 cases, of Group A, 2.7% of Group B, and 1.1% of Group C (p=0.0293 Group C against Group A). Three cases were classified as classical pneumonitis, and the other 4 sporadic pneumonitis such as Cryptogenic Organizing Pneumonia and Chronic Eosinophilic Pneumonia. Both of the histologically proven COP and CEP patients showed atopic manifestations in our institute. The detail clinical features are described in the main text. Having atopic manifestations suggests that there may be risk of lung toxicity following chest irradiation for breast cancer. (author)

Focusing on Contact Lens Safety

Science.gov (United States)

... their practices. Decorative contacts (also called “costume,” colored,” “fashion,” or “plano” contacts). The FDA has often warned ... Lenses Decorative Contact Lenses Hydrogen Peroxide Solution Related Consumer Updates 'Colored' and Decorative Contact Lenses: A Prescription ...

Development of an aerostatic bearing system for roll-to-roll printed electronics

Science.gov (United States)

Chen, Shasha; Chen, Weihai; Liu, Jingmeng; Chen, Wenjie; Jin, Yan

2018-06-01

Roll-to-roll printed electronics is proved to be an effective way to fabricate electrical devices on various substrates. High precision overlay alignment plays a key role to create multi-layer electrical devices. Multiple rollers are adopted to support and transport the substrate web. In order to eliminate the negative effect of the machining error and assembling error of the roller, a whole roll-to-roll system including two aerostatic bearing devices with arrayed restrictors is proposed in this paper. Different to the conventional roller, the aerostatic bearing device can create a layer of air film between the web and the device to realize non-contact support and transport. Based on simplified Navier–Stokes equations, the theoretical model of the air film is established. Moreover, the pressure distribution of the whole flow field and single restrictor in different positions are modeled by conducting numerical simulation with computational fluid dynamics (CFD) software FLUENT. The load capacity curves and stiffness curves are generated to provide guidance for optimizing the structure of the device. A prototype of the aerostatic bearing system is set up and the experiment tests are carried out. For the proposed aerostatic bearing roller with a diameter of 100 mm and length of 200 mm, the experimental results show the aerostatic bearing method can achieve the position accuracy in a range of 1 μm in the vertical direction of the web, which is much better than that using existing methods.

Contact-impact algorithms on parallel computers

International Nuclear Information System (INIS)

Zhong Zhihua; Nilsson, Larsgunnar

1994-01-01

Contact-impact algorithms on parallel computers are discussed within the context of explicit finite element analysis. The algorithms concerned include a contact searching algorithm and an algorithm for contact force calculations. The contact searching algorithm is based on the territory concept of the general HITA algorithm. However, no distinction is made between different contact bodies, or between different contact surfaces. All contact segments from contact boundaries are taken as a single set. Hierarchy territories and contact territories are expanded. A three-dimensional bucket sort algorithm is used to sort contact nodes. The defence node algorithm is used in the calculation of contact forces. Both the contact searching algorithm and the defence node algorithm are implemented on the connection machine CM-200. The performance of the algorithms is examined under different circumstances, and numerical results are presented. ((orig.))

Direct measurement of graphene contact resistivity to pre-deposited metal in buried contact test structure

KAUST Repository

Qaisi, Ramy M.; Smith, Casey; Ghoneim, Mohamed T.; Yu, Qingkai; Hussain, Muhammad Mustafa

2013-01-01

We demonstrate a buried contact based novel test structure for direct contact resistivity measurement of graphene-metal interfaces. We also observe excellent contact resistivity 1 μO-cm2 without any additional surface modification suggesting that the intrinsic Au-graphene contact is sufficient for achieving devices with low contact resistance. The chemical mechanical polishing less test structure and data described herein highlights an ideal methodology for systematic screening and engineering of graphene-metal contact resistivity to enable low power high speed carbon electronics. © 2013 IEEE.