Research on Computer Controlled Optical Surfacing (CCOS) Working Function at Wear State

2013 ◽  
Vol 457-458 ◽  
pp. 1386-1389
Author(s):  
Wen Long Liu ◽  
Bin Lin ◽  
Xiao Feng Zhang ◽  
Bo Wang
Keyword(s):  
Removal Rate ◽  
Convex Curve ◽  
Planetary Motion ◽  
Wear Loss ◽  
Working Pressure ◽  
Initial Stage ◽  
Computer Controlled Optical Surfacing ◽  
The Impact ◽  
Processing Stability ◽  
Function Peak

The distribution of working pressure in CCOS has been studied when the polishing disc frayed. Combined with the planetary motion, the working functions at wear and ideal states were calculated separately, the result shows that the function peak is higher at wear state and it is a convex curve instead of a concave curve at ideal state. The impact of different wear loss on the working function has been also studied in this paper, one preliminary conclusion has been obtained that with the increasing of the wear loss, the working function peak will get higher and sharper, and the effective range of processing will decrease meanwhile. It can be predicted that although the removal rate may not change obviously at the initial stage of wear, the processing quality may decrease and the processing stability will be worse since the variation of the removal distribution.

scholarly journals Effect of Plating Current Density on the Ball-On-Disc Wear of Sn-Plated Ni Coatings on Cu Foils

Coatings ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 56
Author(s):  
Ashutosh Sharma ◽  
Byungmin Ahn
Keyword(s):  
Current Density ◽  
Wear Loss ◽  
Wear Properties ◽  
Friction Behavior ◽  
Track Geometry ◽  
Cu Substrates ◽  
Current Densities ◽  
The Impact ◽  
Sliding Distance ◽  
Ball On Disc

Metallic and alloyed coatings are used widely in several decorative and technology-based applications. In this work, we selected Sn coatings plated on Cu substrates for joining applications. We employed two different plating baths for the fabrication of Sn and Ni coatings: acidic stannous sulfate for Sn and Watts bath for Ni layer. The plating current densities were varied from 100–500 mA/cm2. Further, the wear and friction behavior of the coatings were studied using a ball-on-disc apparatus under dry sliding conditions. The impact of current density was studied on the morphology, wear, and coefficient of friction (COF) of the resultant coatings. The wear experiments were done at various loads from 2–10 N. The sliding distance was fixed to 7 m. The wear loss was quantified in terms of the volume of the track geometry (width and depth of the tracks). The results indicate that current density has an important role in tailoring the composition and morphology of coatings, which affects the wear properties. At higher loads (8–10 N), Sn coatings on Ni/Cu had higher volume loss with a stable COF due to a mixed adhesive and oxidative type of wear mechanism.

scholarly journals Monitoring of the Impact of Lithium Nitrate on the Alkali–aggregate Reaction Using Acoustic Emission Methods

Materials ◽  
2018 ◽  
Vol 12 (1) ◽  
pp. 20
Author(s):  
Justyna Zapała-Sławeta ◽  
Grzegorz Świt
Keyword(s):  
Acoustic Emission ◽  
Initial Reaction ◽  
Lithium Nitrate ◽  
Acoustic Emission Method ◽  
Emission Method ◽  
Acoustic Activity ◽  
Initial Stage ◽  
Chemical Admixture ◽  
Different Characteristics ◽  
The Impact

The study analyzed the possibility of using the acoustic emission method to analyse the reaction of alkali with aggregate in the presence of lithium nitrate. Lithium nitrate is a chemical admixture used to reduce adverse effects of corrosion. The tests were carried out using mortars with reactive opal aggregate, stored under the conditions defined by ASTM C227. The acoustic activity of mortars with a corrosion inhibitor was referred to linear changes and microstructure of specimens in the initial reaction stages. The study found a low acoustic activity of mortars with lithium nitrate. Analysis of characteristic parameters of acoustic emission signals, combined with the observation of changes in the microstructure, made it possible to describe the corrosion processes. As the reaction progressed, signals with different characteristics were recorded, indicating aggregate cracking at the initial stage of the reaction, followed by cracking of the cement paste. The results, which were referred to the acoustic activity of reference mortars, confirmed that the reaction of opal aggregate with alkali was mitigated in mortars with lithium nitrate, and the applied acoustic emission method enabled the detection and monitoring of ASR progress.

scholarly journals Atypical start-up experiments on pump as turbine

2021 ◽  
Vol 13 (11) ◽  
pp. 168781402110627
Author(s):  
Yu-Liang Zhang ◽  
Yan-Juan Zhao
Keyword(s):  
Static Pressure ◽  
Power Coefficient ◽  
Transient Performance ◽  
Test Rig ◽  
Transient Characteristics ◽  
Maximum Value ◽  
Start Up ◽  
Initial Stage ◽  
Evolution Characteristics ◽  
The Impact

At present, research on the characteristics of pumps as turbine (PATs) during the start-up process is still insufficient. To reveal the transient characteristics of a centrifugal PAT during the atypical start-up process, a test rig for the transient performance of the PAT was built; in addition, experiments on the transient hydraulic performance of three kinds of steady speed and three kinds of steady flow were conducted. Through these experiments, the evolution characteristics of the transient performance parameters of the PAT during the atypical start-up process were analyzed over time. Moreover, three dimensionless coefficients were employed to deeply reveal the transient characteristics of the PAT during atypical start-up. Results showed that the rise curves of flow rate and outlet static pressure exhibited shock phenomena. With the increase in the stable running speed after start-up, the impact phenomenon of the outlet static pressure presented a delayed trend. The dimensionless head and flow coefficients reached the maximum value at the initial stage of the atypical start-up process and then rapidly dropped to the minimum value before slowly rising to the final stable value. The dimensionless power coefficient had a maximum value at the initial stage of atypical start-up and then rapidly dropped to the final stable value.

scholarly journals Solidification Enhancement in a Multi-Tube Latent Heat Storage System for Efficient and Economical Production: Effect of Number, Position and Temperature of the Tubes

Nanomaterials ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 3211
Author(s):  
Min Li ◽  
Jasim M. Mahdi ◽  
Hayder I. Mohammed ◽  
Dmitry Olegovich Bokov ◽  
Mustafa Z. Mahmoud ◽  
...  
Keyword(s):  
Free Convection ◽  
Heat Storage ◽  
Liquid Fraction ◽  
Removal Rate ◽  
Heat Removal ◽  
Vertical Direction ◽  
Heat Transfer Fluid ◽  
Latent Heat Storage ◽  
Solidification Mode ◽  
The Impact

Thermal energy storage is an important component in energy units to decrease the gap between energy supply and demand. Free convection and the locations of the tubes carrying the heat-transfer fluid (HTF) have a significant influence on both the energy discharging potential and the buoyancy effect during the solidification mode. In the present study, the impact of the tube position was examined during the discharging process. Liquid-fraction evolution and energy removal rate with thermo-fluid contour profiles were used to examine the performance of the unit. Heat exchanger tubes are proposed with different numbers and positions in the unit for various cases including uniform and non-uniform tubes distribution. The results show that moving the HTF tubes to medium positions along the vertical direction is relatively better for enhancing the solidification of PCM with multiple HTF tubes. Repositioning of the HTF tubes on the left side of the unit can slightly improve the heat removal rate by about 0.2 in the case of p5-u-1 and decreases by 1.6% in the case of p5-u-2. It was found also that increasing the distance between the tubes in the vertical direction has a detrimental effect on the PCM solidification mode. Replacing the HTF tubes on the left side of the unit negatively reduces the heat removal rate by about 1.2 and 4.4%, respectively. Further, decreasing the HTF temperature from 15 °C to 10 and 5 °C can increase the heat removal rate by around 7 and 16%, respectively. This paper indicates that the specific concern to the HTF tube arrangement should be made to improve the discharging process attending free convection impact in phase change heat storage.

scholarly journals Impact Size and Determinants of Indirect Cost of Financial Distress: Role of Receivable and Inventory Management

2020 ◽  
Vol 16 (2) ◽  
pp. 179-207
Author(s):  
Umar Farooq ◽  
Muhammad Ali Jibran Qamar ◽  
Krishna Reddy
Keyword(s):  
Indirect Cost ◽  
Inventory Management ◽  
Financial Distress ◽  
Multi Stage ◽  
Initial Stage ◽  
Non Linear ◽  
Management Policies ◽  
Internal Operations ◽  
The Impact

This research investigates the opportunity cost as an indirect cost of financial distress from two perspectives. First, indirect cost is estimated using multi-stage financial distress and non-linear proxy of debt. Second, receivable and inventory management are studied as determinants of indirect cost. The sample includes ongoing Pakistani firms that were healthy in the previous year and documenting positive gross profit. Results showed that firms bear opportunity loss primarily due to leverage rather than multistage financial distress. However, a non-linear relationship is found between leverage and indirect cost. Results further explored the impact of multistage financial distress on internal operations, i.e., working capital policies. It is found that firms manage receivable and inventory simultaneously during the multistage financial distress. Results revealed that increasing receivables and decreasing inventory is suitable during the transition of healthy firms to initial stage of financial distress, i.e., profit reduction. However, decreasing receivables, along with holding more inventory, is recommended for healthy firms that face liquidity problems subsequently. It is concluded that managers can reduce the indirect cost after deploying the optimal debt ratio and recommended receivable and inventory management policies.

Wear Based Lifetime Estimation of a Clutch Facing using Coupled Field Analysis

2021 ◽  
Vol 18 (4) ◽  
Author(s):  
A. Kulkarni ◽  
R. Mahale ◽  
C. Kannan
Keyword(s):  
Working Life ◽  
Element Model ◽  
Friction Material ◽  
Inorganic Materials ◽  
Field Analysis ◽  
Frictional Heat ◽  
Ride Quality ◽  
Wear Loss ◽  
Limiting Factor ◽  
The Impact

Repetitive use of the clutch, over a period of time, causes the friction material at the contact surfaces (clutch facing and flywheel/pressure plate) to wear, thus deteriorating its performance and usable life. The working life of a rigid clutch is the limiting factor when it comes to extracting maximum performance from a dual mass flywheel system, which is used in a lot of modern vehicles nowadays to lower fuel consumption and improve ride quality. In this study, we investigate the influence of different groove patterns on wear in rigid clutch facings and estimate their life using a comprehensive finite element model. The wear is calculated and analysed for five different groove patterns across two different inorganic materials, namely FTL180 and TF1600-MC2, using Archard’s Adhesive Wear Model. Coupled multi-physics elements are employed in the analysis to capture the effect of frictional heat generation on wear. We found that the Waffle pattern offered a decrease of 10.4% in volumetric wear loss, a 5.78% decrease in maximum wear thickness and an increase of 11.51% in the average working life is used in city like conditions with frequent engagements. This work sheds light on the impact of groove patterns on clutch facing wear and opens a new path for the design and development of more resilient rigid clutches.

Rock Movement in Tectonic Zones. Mining Activities and Rock Pressure Management in the Norilsk-Kharaelakh Fault Area

2020 ◽  
pp. 148-151
Author(s):  
S.G. Kirillov ◽  
Z.G. Ufatova ◽  
I.F. Khrushchev ◽  
K.A. Bashirov
Keyword(s):  
Rock Mass ◽  
High Mobility ◽  
Mining Operations ◽  
Profile Line ◽  
Initial Stage ◽  
Tectonic Zones ◽  
Rock Movement ◽  
Hazard Level ◽  
And Control ◽  
The Impact

The article describes the rock mass state within the boundaries of the Skalistiy mining allotment. The ore mass within the mine field was found to preserve its rock-bump hazard and show high mobility in the impact zone of the Norilsk-Kharaelakh Fault and the associated high failure potential manifested as roof cavings. Based on the monitoring results along underground profile lines, it was concluded that the displacement process is currently at its initial stage. Moreover, the maximum subsidence in the central part of the profile line is about 3 times higher (up to 35 mm) than in other areas. This is caused by immediate proximity of this zone to the Norilsk-Kharaelakh Fault. Assessment of the bump hazard level of this rock mass with the help of the Prognoz-2 instrument that was performed by the rock-bump forecasting and control teams of the mine and the Norilskshakhtstroy company, showed the 'Not Hazardous' category in all cases. However, the progress of mining operations towards the Norilsk-Kharaelakh Fault may lead to deterioration in the condition of mine workings. This can be manifested through rock exfoliation from the walls of the advance workings of the safety layer in highly and extremely faulted rocks. In addition, permanent workings, which are one of the most critical structures of the production level and which will be used until the development of the deposit area adjacent to the Norilsk-Kharaelakh Fault is completed, will be maintained in increasingly difficult conditions. The article describes recommendations for mining operations in the fault area with account for the current mining and geomechanical situation and the potential for its change.

The Impact of New Technology on Society and Workforce in Production in the Era of Industry 4.0

2021 ◽  
pp. 1202-1218
Author(s):  
Cem Zafer ◽  
Pelin Vardarlier
Keyword(s):  
Human Resources ◽  
Social Structure ◽  
20Th Century ◽  
Industry 4.0 ◽  
Industrial Revolution ◽  
New Technology ◽  
The Internet ◽  
Initial Stage ◽  
The Social ◽  
The Impact

The industrial revolution, which took place in the 20th century, is the first step of similar developments in the ongoing centuries. In the first steps of this century, the use of steam machines in production is the first steps of a more serial and systematic production structure. With the advancing developments up to the industrial revolution or Industry 4.0, a structure quite different from the initial stage was formed. In the most general sense, the Industry 4.0 structure, defined as the internet of objects, emerges with a more systematic and self-functioning structure discourse in its production activities, but its effects are not only related to production activities. As a matter of fact, the use of Industry 4.0 at the point reached, human resources, employment, social classes, communities, and so on. It is thought to be effective on the structures. In this context, in this study, the effects of the social impacts of these processes and the ways in which Industry 4.0 can create a social structure have been explained.

Engineering the Interaction Forces to Optimize CMP Performance

2002 ◽  
Vol 732 ◽  
Author(s):  
G. B. Basim ◽  
I. Vakarelski ◽  
P. Singh ◽  
B. M. Moudgil
Keyword(s):  
Material Removal ◽  
Surface Deformation ◽  
Defect Density ◽  
Removal Rate ◽  
Particle Interactions ◽  
Interaction Forces ◽  
High Performing ◽  
Optimal Material ◽  
Slurry Stability ◽  
The Impact

AbstractThe main objective of Chemical Mechanical Polishing (CMP) process is to planarize the metal or dielectric layers deposited on the wafer surfaces in microelectronics device manufacturing. In CMP, slurries containing submicrometer size particles and chemicals are used to achieve planarization. An effective polishing requires an optimal material removal rate with minimal surface deformation. Therefore, it is important to control the particle-substrate interactions that are responsible for the material removal and the particle-particle interactions, which control the slurry stability and consequently the defect density. This paper discusses the impact of interaction forces on polishing, and underlines the scientific guidelines to formulate consistently high performing CMP slurries.

scholarly journals A Contribution to a UHS-Based Seismic Risk Assessment in Croatia—A Case Study for the City of Osijek

2020 ◽  
Vol 12 (5) ◽  
pp. 1796 ◽  
Author(s):  
Gordana Pavić ◽  
Marijana Hadzima-Nyarko ◽  
Borko Bulajić
Keyword(s):  
Risk Assessment ◽  
Seismic Risk ◽  
Seismic Vulnerability ◽  
Modern Society ◽  
Seismic Risk Assessment ◽  
Hazard Exposure ◽  
Initial Stage ◽  
Vulnerability Of Buildings ◽  
The Many ◽  
The Impact

Due to increases in the number of inhabitants and their concentrations in densely populated areas, there is a growing need in modern society to be cautious towards the impact of catastrophic natural events. An earthquake is a particularly major example of this. Knowledge of the seismic vulnerability of buildings in Europe and around the world has deepened and expanded over the last 20 years, as a result of the many devastating earthquakes. In this study, a review of seismic risk assessment methods in Croatia was presented with respect to the hazard, exposure, and vulnerability of buildings in the fourth largest city (Osijek) in Croatia. The proposed algorithm for a detailed risk assessment was applied to a database and is currently in its initial stage.

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