ASSESSMENT OF THE SURFACE CONDITIONS OF GAS-LUBRICATED FACE-SEAL SEALING RINGS

Tribologia ◽  
2017 ◽  
pp. 11-21
Author(s):  
Jakub GACEK ◽  
Łukasz NORYMBERCZYK ◽  
Stanisław PŁONKA
Keyword(s):  
Silicon Carbide ◽  
Surface Condition ◽  
Face Seal ◽  
Roughness Parameters ◽  
Surface Conditions ◽  
Before And After ◽  
The Face ◽  
Almost All ◽  
2D And 3D ◽  
Sintered Silicon

The paper presents a study of surface condition of stationary and rotary rings of a gas-lubricated face seal before and after 25 hours of operation on a test bench, with 75 cycles of start-ups and stops of the drive. For evaluation of surface conditions, flatness deviation and a selected 2D and 3D roughness parameters were measured. Profiles of the roughness, material ratio curves, topography, and surface maps in colour before and after 25 hours of operations were presented. It has been found that wear of the end faces of the saling rings differs between sintered silicon carbide and carbon graphite. In the case of the stationary ring made of sintered silicon carbide with a hardness of 3000 HV, there is a slight increase in values of almost all (except Sp) measured 3D amplitude parameters: Sa, Sq, Sv, St. In the case of the rotary ring made of carbon graphite with hardness of about 115 HR a noticeable reduction in values of these parameters was found. Changes In 2D and 3D roughness parameters of end faces of the stationary and rotary rings allow confirming the al most contact-free character of the face seal operation.

scholarly journals Reduction in Ocular Hypotensive Eyedrops by Ab Interno Trabeculotomy Improves Not Only Ocular Surface Condition But Also Quality of Vision

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Kenji Kashiwagi ◽  
Mio Matsubara
Keyword(s):  
Visual Acuity ◽  
Ocular Surface ◽  
Surface Condition ◽  
Tear Film ◽  
Film Stability ◽  
Corneal Epithelial ◽  
Surface Conditions ◽  
Trabectome Surgery ◽  
Before And After ◽  
Ab Interno

Purpose. To investigate the effect of ab interno trabeculotomy using the Trabectome surgical system on tear film stability and functional visual acuity (FVA). Patients and Methods. Adult glaucoma patients who underwent Trabectome surgery alone or Trabectome surgery combined with phacoemulsification with intraocular lens insertion were included in this study. Corneal epithelial defects, tear film breakup time (TBUT), tear meniscus height, tear film spreading grade, tear interferometry grade, and FVA were assessed before and after surgery in addition to routine ophthalmic examinations. Changes in ocular surface conditions and visual acuity as a result of the Trabectome surgery were investigated. Results. Thirty eyes of 22 patients with a mean age of 72.2 ± 7.9 years, including 8 males and 14 females, were enrolled. The Trabectome surgery significantly reduced the intraocular pressure (IOP) from 20.3 ± 5.2 to 15.0 ± 3.3 mmHg (P<0.001) and the number of different types of ocular hypotensive eyedrops used from 3.2 ± 0.7 to 1.1 ± 0.7 types (P<0.001). The surgery significantly improved corneal epithelial defects, the tear spreading grade, the tear interferometry grade, and FVA. The surgery also improved the visual maintenance ratio among all enrolled patients, including those who underwent Trabectome surgery only. Conclusion. Trabectome surgery may be beneficial not only for IOP reduction but also for improving ocular surface conditions and FVA.

scholarly journals Is Deterioration of Surface Properties of Resin Composites Affected by Filler Size?

2020 ◽  
Vol 2020 ◽  
pp. 1-6 ◽  
Author(s):  
H. Elbishari ◽  
N. Silikas ◽  
J. D. Satterthwaite
Keyword(s):  
Resin Composite ◽  
Tooth Brushing ◽  
Resin Composites ◽  
Strongly Correlated ◽  
Roughness Parameters ◽  
Filler Size ◽  
Before And After ◽  
Post Hoc ◽  
2D And 3D ◽  
Surface Gloss

Statement of the problem. Resin composite restorations can lose their aesthetic properties in clinical service. Purpose. To investigate the effect of filler size on surface gloss and roughness of resin composites using a glossmeter and 3D noncontact surface topography, respectively, before and after tooth-brushing abrasion. Materials and Methods. Seven model resin composites and one commercial were tested in the study. All materials were first polished, and then the surface gloss and 2D and 3D roughness parameters were recorded. Materials are then subjected to abrasion in a tooth-brushing simulator. Roughness parameters were recorded after 10,000 cycles, and after 20,000 cycles, both roughness and gloss were recorded. One-way ANOVA and Bonferroni post hoc test (p<0.05) were used to analyze data. Conclusion. Filler size is strongly correlated to gloss and surface roughness retention.

Copper-Zinc-Titania Nanocomposite as Catalyst for CO2 Photo-Reduction: A Surface Deactivation Study

2014 ◽  
Vol 896 ◽  
pp. 134-140 ◽  
Author(s):  
Oman Zuas ◽  
Yuni Krisyuningsih Krisnandi ◽  
Widayanti Wibowo ◽  
Jin Seog Kim ◽  
Jarnuzi Gunlazuardi
Keyword(s):  
Aqueous Solution ◽  
Photoelectron Spectroscopy ◽  
Electron Spectroscopy ◽  
Surface Condition ◽  
Surface Conditions ◽  
X Ray ◽  
Before And After ◽  
Copper Zinc ◽  
Deactivation Process ◽  
Scanning Electron

In this paper, a surface deactivation study of Cu1.0-Zn0.5-Ti98.5 oxide nanocomposite (CZT-ONC) as catalyst for photo-reduction of CO2 in aqueous solution is reported. The photo-reduction experiments were conducted through five experimental cycles. The results demonstrated that the activity of the CZT-ONC decreased by increasing the number of testing cycle. The causes for declining the activity of the CZT-ONC catalyst was studied by investigating the surface condition of the catalyst before and after used by mean X-ray photoelectron spectroscopy (XPS) and field emission-scanning electron spectroscopy (FE-SEM) techniques and the results are discussed. It was found that the surface conditions (chemical state of the elements and morphology) of the CZT-ONC catalyst have been critically altered. Change in surface condition pointed that the deactivation process on the surface of the CZT-ONC was occurred and it could be considered to be the reasons for declining of the activity.

A Review Paper on Cloud Computing

2018 ◽  
Vol 8 (6) ◽  
pp. 17 ◽  
Author(s):  
Priyanshu Srivastava ◽  
Rizwan Khan
Keyword(s):  
Cloud Computing ◽  
Grid Computing ◽  
Review Paper ◽  
Computing Technology ◽  
Internet Infrastructure ◽  
Before And After ◽  
The Face

Today is the era of Cloud Computing Technology in IT Industries. Cloud computing which is based on Internet has the most powerful architecture of computation. It reckons in of a compilation of integrated and networked hardware, software and internet infrastructure. It has various avails atop grid computing and other computing. In this paper, I have given a brief of evaluation of cloud computing by reviewing more than 30 articles on cloud computing. The outcome of this review signalizes the face of the IT industries before and after the cloud computing.

Effects of Vickers Cracks on the Mechanical Properties of Solid-phase-sintered Silicon Carbide Ceramics

2012 ◽  
Vol 27 (9) ◽  
pp. 965-969
Author(s):  
Xiao YANG ◽  
Xue-Jian LIU ◽  
Zheng-Ren HUANG ◽  
Gui-Ling LIU ◽  
Xiu-Min YAO
Keyword(s):  
Mechanical Properties ◽  
Silicon Carbide ◽  
Solid Phase ◽  
Carbide Ceramics ◽  
Silicon Carbide Ceramics ◽  
Sintered Silicon

scholarly journals Effect of Integrated Neuromuscular Exercise in Physical Education Class on Health-Related Fitness in Female Children

Healthcare ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 312
Author(s):  
Marijana Sinđić ◽  
Draženka Mačak ◽  
Nikola Todorović ◽  
Bianka Purda ◽  
Maja Batez
Keyword(s):  
Physical Education ◽  
Muscular Fitness ◽  
Female Children ◽  
Before And After ◽  
Health Related ◽  
The Republic ◽  
Almost All ◽  
And Control ◽  
Cardiorespiratory Endurance ◽  
Health Related Fitness

Integrated neuromuscular training (INT) showed benefits for improving fundamental movement skills (FMS). However, the INT health-related fitness (HRF) effects are lacking. The current study aimed to determine the effects of INT implemented during physical education (PE) in a primary school in the Republic of Serbia on HRF in female children. The sample consisted of 72 healthy girls who were divided into the intervention (EG: n = 37; mean ± SD: age = 8.17 ± 0.31) and control (CG: n = 35; age = 8.11 ± 0.31) groups. The EG and CG performed the INT program and traditional PE activities two times per week within the first ~15 min of PE class, respectively. The Fitnessgram battery tests assessed the HRF (body composition, cardiorespiratory endurance, muscular fitness, and flexibility) before and after the program. After eight weeks, the EG significantly reduced all fat measures, while the CG decreased only triceps skinfold but to a smaller extent (F = 5.92, p < 0.02, ŋ2 = 0.09). Both groups significantly improved the performance of almost all muscular fitness tests (curl-ups, trunk lift, push-ups); however, the EG increased the push-ups more than the CG (F = 9.01, p < 0.01, ŋ2 = 0.14). The EG additionally improved the modified pull-ups (F = 14.09, p < 0.01, ŋ2 = 0.19) and flexed arm hang (F = 28.82, p < 0.01, ŋ2 = 0.33) tests. The flexibility and cardiorespiratory endurance of both groups did not significantly change after eight weeks. This approach of exercise showed positive acceptance and relatively good results after only eight weeks.

scholarly journals Directional Hydraulic Fracturing (DHF) of the Roof, as an Element of Rock Burst Prevention in the Light of Underground Observations and Numerical Modelling

Energies ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 562
Author(s):  
Marek Jendryś ◽  
Andrzej Hadam ◽  
Mateusz Ćwiękała
Keyword(s):  
Rock Mass ◽  
Hydraulic Fracturing ◽  
Coal Mining ◽  
Rock Burst ◽  
Coal Mine ◽  
Seismic Activity ◽  
Black Coal ◽  
Directional Hydraulic Fracturing ◽  
Before And After ◽  
The Face

The following article analyzes the effectiveness of directional hydraulic fracturing (DHF) as a method of rock burst prevention, used in black coal mining with a longwall system. In order to define changes in seismic activity due to DHF at the “Rydułtowy” Black Coal Mine (Upper Silesia, Poland), observations were made regarding the seismic activity of the rock mass during coal mining with a longwall system using roof layers collapse. The seismic activity was recorded in the area of the longwall itself, where, on a part of the runway, the rock mass was expanded before the face of the wall by interrupting the continuity of the rock layers using DHF. The following article presents measurements in the form of the number and the shock energy in the area of the observed longwall, which took place before and after the use of DHF. The second part of the article unveils the results of numerical modeling using the discrete element method, allowing to track the formation of goafs for the variant that does not take DHF into consideration, as well as with modeled fractures tracing DHF carried out in accordance with the technology used at “Rydułtowy” coal mine.

scholarly journals The Demerger Impact upon Sustainable Development of Economic Entities: Evidence from Romania

2021 ◽  
Vol 13 (15) ◽  
pp. 8316
Author(s):  
Camelia Mirela Baba ◽  
Constantin Duguleană ◽  
Marius Sorin Dincă ◽  
Liliana Duguleană ◽  
Gheorghița Dincă
Keyword(s):  
Sustainable Development ◽  
Business Strategies ◽  
The Sustainable Development ◽  
Ex Post ◽  
Before And After ◽  
Almost All ◽  
The Impact ◽  
Profitability Ratios ◽  
Positive Effect

The Covid-19 induced economic crisis has significantly affected almost all businesses from nearly every sector, causing severe financial problems, lack of cash assets, and decrease of revenues. In this context, the economic entities were forced to look for adjustment and rescue solutions of their activities. One possible solution for the recovery and reorganization of economic entities’ activities is demerger. This paper evaluates the impact of demerger upon the sustainable development of economic entities in terms of economic efficiency and financial performances. To achieve this goal, a statistical analysis of profitability ratios before and after the demerger, as well as a structural analysis of 268 demerger projects for the April 2012–April 2021 period, were performed. The results attest there are no significant differences between the ex-ante and ex-post financial performances. However, demerger seems to have a positive effect upon analyzed companies helping them to overcome economic hardships, rethink their business strategies, and continue their activity in the medium and long-term time horizon.

Labor Productivity and Managerial Efficiency against a Static Technology: The Pennsylvania Iron Industry, 1750–1800

1980 ◽  
Vol 40 (1) ◽  
pp. 129-136 ◽  
Author(s):  
Paul F. Paskoff
Keyword(s):  
Eighteenth Century ◽  
Fuel Consumption ◽  
Labor Productivity ◽  
Learning By Doing ◽  
Iron Industry ◽  
Managerial Efficiency ◽  
Before And After ◽  
Consumption Rates ◽  
The Face

An increase in labor productivity and a reduction of fuel consumption rates were two notable and closely related achievements of the management of Hopewell Forge, an ironworks in eighteenth-century Pennsylvania. Significantly, these economies were realized in the face of technological stasis through learning by doing. The analysis of this accomplishment is cast in the larger context of the performance of the iron industry before and after 1800.

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