157 research outputs found
Tribological properties of diamond-like-carbon coating doped with tungsten
This paper presents the tribological properties of diamond-like-carbon coatings (DLC) doped with tungsten. The hardness of the DLC coating was determined using a micro-hardness tester. Friction tests were carried out on a tribometer in rotational motion in a 100Cr6 steel ball-disk association with a-C-H:W tungsten doped hydrogenated DLC coating. Tests were carried out with loads of 10 N, 25 N and 50 N under technically dry friction conditions. Using a scanning electron microscopy (SEM), the surface morphology was observed, and with a confocal microscope, the geometric structure of the surface was observed before and after the friction tests. The wetting angle of the samples was examined on an optical tensiometer for distilled water and diiodomethane. The results indicated that DLC coatings of the a-C:H:W type obtained by the PVD technique can be used in unlubricated high-load tribological systems
Object oriented programming environment for reconfigurable applications implemented in FPGA chips
One of the methods to control and manage multichannel, distributed measurement systems (as the ones used in High Energy Physics experiments) is described in this paper. These systems are based on FPGA chips. The method fulfills requirements for system configurability and efficiency. The method is based on a new way of address space management called the Component Internal Interface (CII). Creation of a stable link between the hardware and software is the purpose of the designed and realized programing environment. Practical implementation and usage example of suggested application in the Muon Trigger RPC detector at CMS experiment is discussed. The work was realized with strong participation of Ph.D. students
Glycerin as a factor for moderating quality changes in table eggs during storage
Glycerol, a by-product of biodiesel production, is non-toxic to humans and
the environment. With the current increase in the demand for fuels obtained from
biomass, the amount of glycerine waste production is increasing. There are many ways to
dispose this substance (in pharmaceuticals, cosmetics, and in chemical industry),
but its utilization is still insufficient. Therefore, the aim of this study was to assess
the possibility of limiting quality changes in table eggs during
storage by coating the shells with a glycerol solution. The material used in this research consisted
of 270 table chicken eggs collected on the same day. On the first day of the
experiment, quality traits of 30 eggs were evaluated (initial control group). The
remaining 240 eggs were divided into two equal groups: control (eggs that
were not subjected to any treatment) and experimental (eggs that were coated with a
5 % aqueous solution of glycerol). The eggs were placed on transport
trays and stored at 14 °C and 70 % humidity. Quality
evaluations were carried out after 14 and 28 days of storage. The depth of the air cell,
mass and specific gravity of the egg, the shell characteristics (water vapour
conductance, strength, mass, thickness, and density), and the content traits (pH
of the albumen and yolk, Haugh units, and colour and weight of the yolk) were evaluated.
The results obtained suggest that the use of glycerine may contribute to
slowing adverse changes in egg quality during storage by limiting
CO2 removal from the egg content, which allows the egg to maintain albumen
structure. Due to the fact that glycerine is a safe, cheap, and easy-to-apply
substance, its large-scale use in poultry raw material storage seems to be a very real possibility.</p
Luminescence based temperature bio-imaging: Status, challenges, and perspectives
The only way to get thermal images of living organisms without perturbing them is to use luminescent probes with temperature-dependent spectral properties. The acquisition of such thermal images becomes essential to distinguish various states of cells, to monitor thermogenesis, to study cellular activity, and to control hyperthermia therapy. Current efforts are focused on the development and optimization of luminescent reporters such as small molecules, proteins, quantum dots, and lanthanide-doped nanoparticles. However, much less attention is devoted to the methods and technologies that are required to image temperature distribution at both in vitro or in vivo levels. Indeed, rare examples can be found in the scientific literature showing technologies and materials capable of providing reliable 2D thermal images of living organisms. In this review article, examples of 2D luminescence thermometry are presented alongside new possibilities and directions that should be followed to achieve the required level of simplicity and reliability that ensure their future implementation at the clinical level. This review will inspire specialists in chemistry, physics, biology, medicine, and engineering to collaborate with materials scientists to jointly develop novel more accurate temperature probes and enable mapping of temperature with simplified technical mean
Preparing the Next Generation of Sustainability Scientists
Graduate programs emerging in universities over recent decades support the advanced study of sustainability issues in complex socio-environmental systems. Constructing the problem-scope to address these issues requires graduate students to integrate across disciplines and synthesize the social and natural dimensions of sustainability. Graduate programs that are designed to foster inter- and transdisciplinary research acknowledge the importance of training students to use integrative research approaches. However, this training is not available in all graduate programs that support integrative research, often requiring students to seek external training opportunities. We present perspectives from a group of doctoral students with diverse disciplinary backgrounds conducting integrative research in universities across the United States who participated in a 10-day, National Science Foundation-funded integrative research training workshop to learn and develop socio-environmental research skills. Following the workshop, students conducted a collaborative autoethnographic study to share pre- and postworkshop research experiences and discuss ways to increase integrative research training opportunities. Results reveal that students, regardless of disciplinary background, face common barriers conducting integrative research that include: (1) lack of exposure to epistemological frameworks and team-science skills, (2) challenges to effectively include stakeholder perspectives in his/her research, and (3) variable levels of committee support to conduct integrative research. To overcome the identified barriers and advance integrative research, students recommend how training opportunities can be embedded within existing graduate programs. Students advocate that both internal and external training opportunities are necessary to support the next generation of sustainability scientists
Right Heart Pulmonary Circulation Unit Response to Exercise in Patients with Controlled Systemic Arterial Hypertension: Insights from the RIGHT Heart International NETwork (RIGHT-NET)
Background. Systemic arterial hypertension (HTN) is the main risk factor for the development of heart failure with preserved ejection fraction (HFpEF). The aim of the study was was to assess the trends in PASP, E/E’ and TAPSE during exercise Doppler echocardiography (EDE) in hypertensive (HTN) patients vs. healthy subjects stratified by age. Methods. EDE was performed in 155 hypertensive patients and in 145 healthy subjects (mean age 62 ± 12.0 vs. 54 ± 14.9 years respectively, p < 0.0001). EDE was undertaken on a semi-recumbent cycle ergometer with load increasing by 25 watts every 2 min. Left ventricular (LV) and right ventricular (RV) dimensions, function and hemodynamics were evaluated. Results. Echo-Doppler parameters of LV and RV function were lower, both at rest and at peak exercise in hypertensives, while pulmonary hemodynamics were higher as compared to healthy subjects. The entire cohort was then divided into tertiles of age: at rest, no significant differences were recorded for each age group between hypertensives and normotensives except for E/E’ that was higher in hypertensives. At peak exercise, hypertensives had higher pulmonary artery systolic pressure (PASP) and E/E’ but lower tricuspid annular plane systolic excursion (TAPSE) as age increased, compared to normotensives. Differences in E/E’ and TAPSE between the 2 groups at peak exercise were explained by the interaction between HTN and age even after adjustment for baseline values (p < 0.001 for E/E’, p = 0.011 for TAPSE). At peak exercise, the oldest group of hypertensive patients had a mean E/E’ of 13.0, suggesting a significant increase in LV diastolic pressure combined with increased PASP. Conclusion. Age and HTN have a synergic negative effect on E/E’ and TAPSE at peak exercise in hypertensive subjects
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