bluuebunny/crossref_metadata_2025_split huggingface dataset:
Development of an Energy Saving Hydraulic Stepper Drive
Authors: Gradl Christoph , Kovacic Ivo , Scheidl Rudolf 
Published: October 2014

Stepper drives can realize quite precise, incremental motions without position sensors. Sensorless hydraulic motion control is strongly demanded by industry and, therefore, is an established idea in hydraulics for a while. Some concepts have been proposed in the past and a few of them have also been realized and applied in specific cases. But it is expected that digital hydraulics — due to its intrinsic discrete nature — can create new, more advantageous hydraulic versions of stepper drives.
In this paper, a new stepper drive is presented and investigated. It creates the steps by fixed fluid quanta generated by a so called digital flow unit. That unit is realized by a hydraulic cylinder-piston unit which displaces a defined fluid quantum by each limited forward stroke of that piston. The unit is controlled by a fast switching valve which connects the piston areas alternately with the pressure-, tank- and output-line. The return motion is generated by a return spring. Energy saving is accomplished by storing the supply pressure surplus intermediately in the kinetic energy of the piston and converting that energy to displace part of the quantum to the consumer line without hydraulic energy from the supply line. Different detail concepts of this stepper drive are theoretically assessed.
The transient behavior, the performance characteristics and the energy efficiency of a preferred concept are investigated by mathematical modeling and simulation. Furthermore, the main system parameters are identified and corresponding basic dimensioning rules are presented. In a second step, the influence of finite switching times of the valves, the hydraulic impedances of the various flow channels and of the dead volumes and the dynamical properties of the hydraulic cylinder attached to the device, are discussed.
Advanced Hydraulically Actuated Patient Transfer Assist Device
Authors: Humphreys Heather C. , Book Wayne J. 
Published: October 2014

A new, advanced patient transfer device is being developed for moving mobility limited patients, for example, from a wheelchair to a bed or a floor into a chair. Current market patient lift devices are antiquated and insufficient for customer needs, with only one actuated degree of freedom. The high power to size ratio of hydraulic actuation makes it suitable for moving larger, heavier patients. We have developed a prototype pump-controlled hydraulically actuated patient transfer device that is more maneuverable and agile, using multiple actuated degrees of freedom. We are also working toward developing a more intuitive and safe caretaker interface and control strategy.
We have performed an extensive needs assessment; these are a few associated key design requirements relevant to this presented work. A compact package is needed for ease of maneuvering the patient around obstacles in an uncertain environment. The device is capable of producing large forces, so it is desirable for the controller to minimize any unintentional large external contact forces, or provide force feedback. In this system, the caretaker and device work together to maneuver a complex payload, a human body; the operator’s mental workload must be minimized. With humans in the device workspace, safety and stability are necessary, including environment interactions.
This new application presents several challenges related to the hydraulic control. First, we are using a separate bidirectional fixed displacement pump with a reversible brushed DC motor for each degree of freedom. The low level control involves obtaining desirable response from each motor-pump-actuator system, while compensating for significant static friction. At a higher level, we are testing several approaches to attain the desired intuitive control and desired dynamics, and minimize the operator workload. First, we are developing a coordinated control using a force input, such that the operator simply pushes on the device in the desired direction of motion. We are testing several different controllers to attain the desired dynamics. This paper presents the design of the machine, the proposed control structures as applied to this application, operator interface options, some preliminary results, and future work.
A Numerical Procedure to Design the Optimal Axial Balance of Pressure Compensated Gear Machines
Authors: Thiagarajan Divya , Vacca Andrea 
Published: October 2014

This paper presents an innovative numerical procedure to determine the optimal balancing area of lateral bushes in external gear pumps or motors. In pressure compensated designs of external gear machines, the lateral bushes perform the important functions of sealing the tooth space volumes while they transfer fluid from the inlet to the outlet port. In normal operating conditions, a lubricating gap exists between the lateral bush and the gear permitting to minimize losses due to shear stress and leakage. These conditions are found by determining proper balancing areas at the side of the bushes not facing the gears, in which the pressure of the high pressure port is properly established. This problem is also known as “axial balance” of external gear machines.
To determine the optimal axial balance which minimizes the power losses associated with the lubricating gap in all operating conditions, all the static and hydrodynamic forces acting on the lateral bushes have to be considered. This delicate aspect of external gear units design is usually addressed through empirical procedures; while in this paper an automatic numerical procedure is presented. The proposed method is based on the solution of the force balance of the lateral bushes, taking into account all force components, including the hydrodynamic terms due to the relative inclination between bushes and gears and material deformation.
After detailing the procedure, the paper describes its potentials by showing the advantages arising from the optimization of the axial balance of a particular external gear pump for fluid power applications.
Combined Air Supply at Fuel Pump Entrance
Authors: Gafurov Salimzhan , Rodionov Leonid , Gimadiev Asgat 
Published: October 2014

Previous research has shown that aviation fuel pumps, which consist of a screw and centrifugal wheels are the most loaded units of the gas turbine engines. Thus a fuel pump is the key component that limits the reliability and endurance of the fuel system and, as a result, of the whole engine.
This paper describes the results of CFD simulations of the process getting free gas to enter the combined pump. The CFD analysis has been used to calculate an unsteady three-dimensional viscous flow of multi-component fluid in the fuel pump. The calculations have been used to determine unsteady loads of fuel pump in different operating modes. To examine the efficiency of the CFD analysis, we conducted a series of experiments. The experimental results proved the accuracy of the numerical model. The results can help to develop measures for the reduction of dynamic loads in aviation fuel pumps in case where combined air is at entrance to pump.
Energy Saving Potential of a Hydrostatic Drivetrain With Variable Charge Pump
Authors: Zavadinka Peter , Grepl Robert 
Published: October 2014

This paper deals with the power saving prediction of hydrostatic drivetrains achieved with a variable roller charge pump. Focusing on the charge pump in a hydrostatic transmission, shows, that fixed pumps don’t act in all operating conditions very efficient. The charge pump delivers in some conditions a higher flow than required. The unused energy is dissipated into heat. According to this assumption, using variable charge pump is another possible way to save energy. In the end it means reduce fuel consumption.
Generally, the power saving potential is depending on the application, but two main factors can be highlighted: the first one is the charge pump size and the second is the application of an intelligent loop flushing system. The standard loop flushing system demands more cooling flow than required in some conditions, but a variable charge pump is able to more efficiently cover demands of intelligent loop flushing system.
The power saving potential will be analyzed for two different example systems/vehicles in their typical operation conditions. All analyses are made with simulation models, which include simplified thermal behavior of the hydraulic circuit, also. The results in this paper confirmed the power saving potential for different applications with bigger charge pumps with an intelligent loop flushing function could be the most interesting applications.
Boom Motion Control Using Pressure Control Valve
Authors: Sørensen Jesper K. , Hansen Michael R. , Ebbensen Morten K. 
Published: October 2014

This paper focuses on the reduction in oscillations created by counterbalance valves by using a proportional pressure control valve. The motion control of a cylinder boom is presented using this valve, which is a 4/3-way directional control valve with the main spool in series with an upstream compensator. The input to the valve control is a main spool position reference and, indirectly, the compensator downstream pressure. This gives a different flow gain and, therefore, a different feedforward scheme as compared to applications with the more common pressure compensated flow control valve.
The theory behind the pressure control valve is presented and applied to both a theoretical and experimental implementation of closed loop motion control of the jib boom of a commercial vehicle loader crane.
A General Auto-Tuning Method for Active Vibration Damping of Mobile Hydraulic Machines
Authors: Ritelli Guido Francesco , Vacca Andrea 
Published: October 2014

This paper presents an innovative approach towards the active vibration damping of mobile hydraulic machines. The authors’ research group recently introduced a novel control strategy based on pressure feedback and on an optimization procedure. The success of the optimization lies on the efficient quantification of the vibration extend which is the objective to be minimized. This paper addresses the definition of the objective function introducing a new method which does not require a priori knowledge of the working cycle. This approach enables the control strategy to be potentially applied to any kind of working scenario and does not require the intervention of a control designer.
The results presented in this paper show that the novel method is able to effectively attenuate the undesired oscillations while not affecting the actuator velocity.
The Effects of Walking on Gastrocnemius Cooling During an Ice Bag Treatment
Authors: Guzzo Stephanie J. , Yeargin Susan W. , Carr Jeffery S. , Demchak Timothy J. , Edwards Jeffrey E. 
Published: October 2014

Context:Many athletic trainers use “ice to go” to treat their athletes. However, researchers have reported that icing a working muscle may negate intramuscular (IM) cooling.Objective:The purpose of our study was to determine the length of time needed to cool the gastrocnemius while walking followed by rest.Design:A randomized crossover study design was used.Setting:Exercise Physiology Laboratory.Patients or Other Participants:Nine healthy, physically active males and females (males 5, females 4; age 24.0 ± 2.0 years; height 174.0 ± 8.0 cm; weight 86.3 ± 6.5 kg; skinfold taken at center of gastrocnemius greatest girth, R leg 20.3 ± 4.4 mm, L leg 19.6 ± 4.1 mm) without lower extremity injury or cold allergy volunteered to complete the study.Intervention:Participants randomly experienced three treatment conditions on separate days: rest (R), walk for 15 minutes followed by rest (W15R), or walk for 30 minutes followed by rest (W30R). During each treatment, participants wore a 1 kg ice bag secured to their right gastrocnemius muscle. Participants walked at a 4.5km/hr pace on a treadmill during the W15R and W30R trials.Main Outcome Measures:A 1 × 3 within groups ANOVA was used to determine the effect of activity on cooling time needed for the gastrocnemius temperature to decrease 6 °C below baseline.Results:The R condition cooled faster (25.9 ± 5.5 min) than both W15R (33.7 ± 9.3 min; P = .002) and W30R (49.4 ± 8.4 min; P < .001). Average time to decrease 6 °C after W15R was 18.7 ± 9.3 minutes and after W30R was 19.4 ± 8.4 minutes.Conclusions:Clinicians should instruct their patients to stay and ice or to keep the ice on for an additional 20 minutes after they stop walking and begin to rest.
Operative Elbow Injuries Among Hungarian Elite Wrestlers
Authors: Molnár Szabolcs Lajos , Hidas Péter , Kocsis György , Rögler Gábor , Balogh Péter , Farkasházi Miklós , Lang Péter 
Published: October 2014

Background:Upper extremity injuries are common in wrestling, most of which do not require surgery.Methods:We retrospectively documented the case histories of six elite wrestlers who sustained elbow injuries that required surgical treatment, three of which involved reinjury and another surgical procedure.Results:All but one of the six initial injuries were associated with a defensive maneuver. Reinjury was more common for freestyle wrestling than for Greco-Roman style. The average time between the initial elbow injury and surgical intervention was 22 months. One-half of the wrestlers with elbow injuries that required surgery were reinjured and underwent revision surgery.Conclusions:All of the elite wrestlers waited for a long period of time before receiving surgery for the initial injury, and the reinjury rate was high.
Thermostable Cross-Protective Subunit Vaccine against Brucella Species
Authors: Cherwonogrodzky John W. , Barabé Nicole D. , Grigat Michelle L. , Lee William E. , Poirier Robert T. , Jager Scott J. , Berger Bradley J. 
Published: October 2014

ABSTRACTA subunit vaccine candidate was produced fromBrucella suis145 (biovar 4; expressing both the A antigen ofBrucella abortusand the M antigen ofBrucella melitensis). The preparation consisted mostly of polysaccharide (PS; >90% [wt/wt]; both cell-associated PS and exo-PS were combined) and a small amount of protein (1 to 3%) with no apparent nucleic acids. Vaccinated mice were protected (these had a statistically significant reduction in bacterial colonization compared to that of unvaccinated controls) when challenged with representative strains of threeBrucellaspecies most pathogenic for humans, i.e.,B. abortus,B. melitensis, andB. suis. As little as 1 ng of the vaccine, without added adjuvant, protected mice againstB. suis145 infection (5 × 105CFU), and a single injection of 1 μg of this subunit vaccine protected mice fromB. suis145 challenge for at least 14 months. A single immunization induced a serum IgG response toBrucellaantigens that remained elevated for up to 9 weeks. The use of heat (i.e., boiling-water bath, autoclaving) in the vaccine preparation showed that it was thermostable. This method also ensured safety and security. The vaccine produced was immunogenic and highly protective against multiple strains ofBrucellaand represents a promising candidate for further evaluation.
Establishment of Quantitative PCR (qPCR) and Culture Laboratory Facilities in a Field Hospital in Benin: 1-Year Results
Authors: Marion Estelle , Ganlonon Line , Claco Eric , Blanchard Simon , Kempf Marie , Adeye Ambroise , Chauty Annick 
Published: October 2014

ABSTRACT

No simple diagnostic tool is available to confirm
Mycobacterium ulcerans
infection, which is an emerging disease reported in many rural areas of Africa. Here, we report the 1-year results of a hospital laboratory that was created in an area of endemicity of Benin to facilitate the diagnosis of
M. ulcerans
infection.
Screening Rectal Swabs for Carbapenemase Genes
Authors: van der Zee Anneke , Roorda Lieuwe , Bosman Gerda , Ossewaarde Jacobus M. 
Published: October 2014

ABSTRACT

In an outbreak setting, we screened 16,296 samples from 3,644 patients by PCR for the presence of
bla
OXA-48
,
bla
VIM
,
bla
IMP
,
bla
NDM
, and
bla
KPC
. The
bla
OXA-48
gene was found in samples from 43 patients infected with 9 different species of
Enterobacteriaceae
. Five patients had
Pseudomonas aeruginosa
isolates containing
bla
VIM
. The negative predictive value of screening was 100%, and the positive predictive value was 86%.
Acid Exposure Induces Multiplication of Salmonella enterica Serovar Typhi
Authors: Ahirwar Suneel Kumar , Pratap Chandra Bhan , Patel Saurabh Kumar , Shukla Vijay K. , Singh Indarjeet Gambhir , Mishra Om Prakash , Kumar Kailash , Singh Tej Bali , Nath Gopal 
Published: October 2014

ABSTRACT

Salmonella enterica
serovar Typhi faces several environmental stresses while going through the stomach (acidic pH) to the small intestine (basic pH) and intracellularly in macrophages (acidic pH) in humans. The acidic pH followed by alkaline pH in the small intestine might be responsible for expression of certain stress-induced genes, resulting in not only better survival but also induction of multiplication and invasion of the bacterium in the small intestine. Based on this hypothesis, we developed a process wherein we exposed the blood, urine, and stool specimens from 90 acute typhoid fever patients and 36 chronic typhoid carriers to acidic pH to see the effect on isolation rate of
S
. Typhi. About 5 g of freshly passed unpreserved stool, a centrifuged deposit of 15 ml of urine, and 5 ml of blood clot were subjected to 5 ml of Luria-Bertani (LB) broth (pH 3.5) for 20 min, followed by enrichment in bile broth-selenite F broth. When the combined isolation from all 3 specimens, i.e., blood, urine, and stool, after acid exposure was considered, a total of 77.7% of the acute typhoid patients were observed to be positive for the isolation of the
S
. Typhi serotype, compared to 8.8% by the conventional method. Similarly, 42% (15/36) of chronic carriers yielded positive for
S
. Typhi growth after acid exposure, compared to 5.5% (2/36) by the conventional method. It therefore can be concluded that acid shock triggers the multiplication of the bacteria, resulting in better isolation rates from blood clot, stool, and urine specimens.
Proinflammatory Effects of Interferon Gamma in Mouse Adenovirus 1 Myocarditis
Authors: McCarthy Mary K. , Procario Megan C. , Twisselmann Nele , Wilkinson J. Erby , Archambeau Ashley J. , Michele Daniel E. , Day Sharlene M. , Weinberg Jason B. 
Published: October 2014

ABSTRACTAdenoviruses are frequent causes of pediatric myocarditis. Little is known about the pathogenesis of adenovirus myocarditis, and the species specificity of human adenoviruses has limited the development of animal models, which is a significant barrier to strategies for prevention or treatment. We have developed a mouse model of myocarditis following mouse adenovirus 1 (MAV-1) infection to study the pathogenic mechanisms of this important cause of pediatric myocarditis. Following intranasal infection of neonatal C57BL/6 mice, we detected viral replication and induction of interferon gamma (IFN-γ) in the hearts of infected mice. MAV-1 caused myocyte necrosis and induced substantial cellular inflammation that was composed predominantly of CD3+T lymphocytes. Depletion of IFN-γ during acute infection reduced cardiac inflammation in MAV-1-infected mice without affecting viral replication. We observed decreased contractility during acute infection of neonatal mice, and persistent viral infection in the heart was associated with cardiac remodeling and hypertrophy in adulthood. IFN-γ is a proinflammatory mediator during adenovirus-induced myocarditis, and persistent adenovirus infection may contribute to ongoing cardiac dysfunction.IMPORTANCEStudying the pathogenesis of myocarditis caused by different viruses is essential in order to characterize both virus-specific and generalized factors that contribute to disease. Very little is known about the pathogenesis of adenovirus myocarditis, which is a significant impediment to the development of treatment or prevention strategies. We used MAV-1 to establish a mouse model of human adenovirus myocarditis, providing the means to study host and pathogen factors contributing to adenovirus-induced cardiac disease during acute and persistent infection. The MAV-1 model will enable fundamental studies of viral myocarditis, including IFN-γ modulation as a therapeutic strategy.
The Human CD8
+
T Cell Responses Induced by a Live Attenuated Tetravalent Dengue Vaccine Are Directed against Highly Conserved Epitopes
Authors: Weiskopf Daniela , Angelo Michael A. , Bangs Derek J. , Sidney John , Paul Sinu , Peters Bjoern , de Silva Aruna D. , Lindow Janet C. , Diehl Sean A. , Whitehead Stephen , Durbin Anna , Kirkpatrick Beth , Sette Alessandro 
Published: October 2014

ABSTRACT

The incidence of infection with any of the four dengue virus serotypes (DENV1 to -4) has increased dramatically in the last few decades, and the lack of a treatment or vaccine has contributed to significant morbidity and mortality worldwide. A recent comprehensive analysis of the human T cell response against wild-type DENV suggested an human lymphocyte antigen (HLA)-linked protective role for CD8
+
T cells. We have collected one-unit blood donations from study participants receiving the monovalent or tetravalent live attenuated DENV vaccine (DLAV), developed by the U.S. National Institutes of Health. Peripheral blood mononuclear cells from these donors were screened in gamma interferon enzyme-linked immunosorbent spot assays with pools of predicted, HLA-matched, class I binding peptides covering the entire DENV proteome. Here, we characterize for the first time CD8
+
T cell responses after live attenuated dengue vaccination and show that CD8
+
T cell responses in vaccinees were readily detectable and comparable to natural dengue infection. Interestingly, whereas broad responses to structural and nonstructural (NS) proteins were observed after monovalent vaccination, T cell responses following tetravalent vaccination were, dramatically, focused toward the highly conserved NS proteins. Epitopes were highly conserved in a vast variety of field isolates and able to elicit multifunctional T cell responses. Detailed knowledge of the T cell response will contribute to the identification of robust correlates of protection in natural immunity and following vaccination against DENV.

IMPORTANCE
The development of effective vaccination strategies against dengue virus (DENV) infection and clinically significant disease is a task of high global public health value and significance, while also being a challenge of significant complexity. A recent efficacy trial of the most advanced dengue vaccine candidate, demonstrated only partial protection against all four DENV serotypes, despite three subsequent immunizations and detection of measurable neutralizing antibodies to each serotype in most subjects. These results challenge the hypothesis that seroconversion is the only reliable correlate of protection. Here, we show that CD8
+
T cell responses in vaccinees were readily detectable and comparable to natural dengue virus infection. Detailed knowledge of the T cell response may further contribute to the identification of robust correlates of protection in natural immunity and vaccination against DENV.