Development of Additional Freeboard Equations Considering Debris Accumulation in Bridge

Pericytes play an important role in the recovery process after ischemic injury of many tissues. Brain pericytes in the peri-infarct area express macrophage markers in response to injury stimuli and are involved in neovascularization. In the kidney, nerve/glial antigen 2 (NG2)+ pericytes have been found to accumulate after renal injury. These accumulated NG2+ cells are not involved in scar formation. However, the role of accumulated NG2+ cells in injured kidneys remains unknown. Here, using a reversible ischemic reperfusion model, we found that renal NG2+ cells were increased in injured kidneys and expressed macrophage markers (CD11b or F4/80) on day 3 after reperfusion. Isolated NG2+ cells from ischemia/reperfusion (I/R) kidneys also had phagocytic activity and expressed anti-inflammatory cytokine genes, including mannose receptor and IL-10. These macrophage-like NG2+ cells did not likely differentiate into myofibroblasts because they did not increase α-SMA expression. Intravenous transfusion of renal NG2+ cells isolated from donor mice on day 3 after reperfusion into recipient mice on day 1 after I/R surgery revealed that NG2+ cell-injected mice had lower plasma blood urea nitrogen, reduced KIM-1 mRNA expression, ameliorated renal damage, and reduced cellular debris accumulation than PBS-injected mice on day 5 after reperfusion. In conclusion, these data suggest that renal NG2+ cells have an M2 macrophage-like ability and play a novel role in facilitating the recovery process after renal I/R injury.

Download Full-text

A Model for Run-In and Other Transitions in Sliding Friction

Journal of Tribology ◽

10.1115/1.3261499 ◽

1987 ◽

Vol 109 (3) ◽

pp. 537-543 ◽

Cited By ~ 25

Author(s):

Peter J. Blau

Keyword(s):

Sliding Friction ◽

Friction Model ◽

Mathematical Framework ◽

Semiempirical Model ◽

System Parameters ◽

Debris Accumulation ◽

Scaling Parameters ◽

Coefficient Versus ◽

Specific Sliding ◽

Empirical System

The mathematical framework for a sliding friction model for run-in and other tribological transitions is presented. The semiempirical model was developed to portray the commonly observed shapes, durations, and variations in kinetic friction coefficient versus sliding time curves. Terms in the model involve material properties and physical interface conditions such as transfer, debris accumulation, and surface roughness. The forms of individual terms are adjustable through the use of systemspecific scaling parameters in order to provide enough modeling flexibility to treat a variety of possible tribological conditions. Effects of such conditions as lubrication efficiency loss over time, and temperature build-up can be incorporated by modification of appropriate terms. Illustrative plots using the framework with several combined contributions are compared with experimental data from previous work. The basic framework of the model can be further developed to incorporate sub-models for specific sliding friction contributions and, in so doing, reduce the number of empirical system parameters required to model actual tribosystem behavior.

Download Full-text

A Review on Protection Methods Against Debris Accumulation for Bridge in Mountain Areas

Lecture Notes in Civil Engineering - CIGOS 2019, Innovation for Sustainable Infrastructure ◽

10.1007/978-981-15-0802-8_34 ◽

2019 ◽

pp. 233-238

Author(s):

Huy Quang Mai ◽

Phong Dang Nguyen

Keyword(s):

Mountain Areas ◽

Debris Accumulation

Download Full-text

An Experimental Study on Head Loss of Prototypical Fibrous Debris Beds During Loss-of-Coolant Accident Conditions

Journal of Nuclear Engineering and Radiation Science ◽

10.1115/1.4032439 ◽

2016 ◽

Vol 2 (3) ◽

Cited By ~ 1

Author(s):

Amir Ali ◽

Edward D. Blandford

Keyword(s):

Safety Issue ◽

Nuclear Regulatory Commission ◽

The United States ◽

Head Loss ◽

Pressurized Water Reactor ◽

Pressurized Water ◽

Debris Accumulation ◽

Loss Of Coolant Accident ◽

Accident Conditions ◽

Regulatory Commission

The United States Nuclear Regulatory Commission (NRC) initiated a generic safety issue (GSI-191) assessing debris accumulation and resultant chemical effects on pressurized water reactor (PWR) sump performance. GSI-191 has been investigated using reduced-scale separate-effects testing and integral-effects testing facilities. These experiments focused on developing a procedure to generate prototypical debris beds that provide stable and reproducible conventional head loss (CHL). These beds also have the ability to filter out chemical precipitates resulting in chemical head loss. The newly developed procedure presented in this paper is used to generate debris beds with different particulate to fiber ratios (η). Results from this experimental investigation show that the prepared beds can provide reproducible CHL for different η in a single and multivertical loops facility within ±7% under the same flow conditions. The measured CHL values are consistent with the predicted values using the NUREG-6224 correlation. Also, the results showed that the prepared debris beds following the proposed procedure are capable of detecting standard aluminum and calcium precipitates, and the head loss increase (chemical head loss) was measured and reported in this paper.

Download Full-text

Initial Analysis of Plastic Debris Accumulation in the Estuary of Wonorejo River, Surabaya, Indonesia

E3S Web of Conferences ◽

10.1051/e3sconf/202014807001 ◽

2020 ◽

Vol 148 ◽

pp. 07001

Author(s):

Setyo Budi Kurniawan ◽

Muhammad Fauzul Imron

Keyword(s):

River Estuary ◽

Dry Weight ◽

Sampling Point ◽

Plastic Pollution ◽

Plastic Debris ◽

Debris Accumulation ◽

Plastic Bags ◽

Sampling Points ◽

Advance Research ◽

One Way Anova

The purpose of this research was to investigate the accumulation of plastic debris in the Wonorejo River Estuary, Surabaya, Indonesia. Visible plastic debris were collected from three (3) sampling points along the intertidal area of Wonorejo River Estuary. The correlation between sampling points (SPs) and the amount of the collected plastic debris (CPD) was analysed using one-way ANOVA. Result of one-way ANOVA showed that the sampling point was significantly affect the amount of the collected plastic debris (p<0.05). A further analysis using Tukey’s Significance Honest Test indicating a significantly higher CPD on SP2 compared to the SP1 and SP3 (p<0.05). The amount of CPD were 126.07±12.00 g dry weight/m2 from SP1, 375.97±16.72 g dry weight/m2 from SP2, and 291.13±36.28 g dry weight/m2 from SP3. The highest percentage of collected debris item was plastic bags (up to 57.90%), followed by bottle caps (up to 16.65%). The most identified plastic types were Low-Density Polyethylene (LDPE) (up to 73.13%), followed by Polypropylene (PP) (up to 17.22%). Understanding the accumulation of plastic debris in estuary is a fundamental requirement to conduct an advance research related to the marine plastic pollution and to determine further actions to solve this problem.

Download Full-text

Examinations on PEEK wear debris accumulation over counter surfaces in room and vacuum sliding environments

Polymer Testing ◽

10.1016/j.polymertesting.2019.04.027 ◽

2019 ◽

Vol 77 ◽

pp. 105880 ◽

Cited By ~ 2

Author(s):

Sandip Panda ◽

Mihir Sarangi ◽

S.K.Roy Chowdhury

Keyword(s):

Wear Debris ◽

Debris Accumulation

Download Full-text

Dynamic Responses of Ground-Dwelling Invertebrate Communities to Disturbance in Forest Ecosystems

Insects ◽

10.3390/insects10030061 ◽

2019 ◽

Vol 10 (3) ◽

pp. 61 ◽

Cited By ~ 1

Author(s):

Kayla Perry ◽

Daniel Herms

Keyword(s):

Forest Ecosystems ◽

Environmental Changes ◽

Woody Debris ◽

Canopy Structure ◽

Dynamic Responses ◽

Gap Formation ◽

Invasive Insects ◽

Salvage Logging ◽

Invertebrate Communities ◽

Debris Accumulation

In forest ecosystems, natural and anthropogenic disturbances alter canopy structure, understory vegetation, amount of woody debris, and the properties of litter and soil layers. The magnitude of these environmental changes is context-dependent and determined by the properties of the disturbance, such as the frequency, intensity, duration, and extent. Therefore, disturbances can dynamically impact forest communities over time, including populations of ground-dwelling invertebrates that regulate key ecosystem processes. We propose conceptual models that describe the dynamic temporal effects of canopy gap formation and coarse woody debris accumulation following disturbances caused by invasive insects, wind, and salvage logging, and their impacts on ground-dwelling invertebrate communities. Within this framework, predictions are generated, literature on ground-dwelling invertebrate communities is synthesized, and pertinent knowledge gaps identified.

Download Full-text

Comparison of Large Woody Debris Prototypes in a Large Scale Non-flume Physical Model

E3S Web of Conferences ◽

10.1051/e3sconf/20184005010 ◽

2018 ◽

Vol 40 ◽

pp. 05010

Author(s):

Brian Perry ◽

Colin Rennie ◽

Andrew Cornett ◽

Paul Knox

Keyword(s):

Physical Model ◽

Flood Control ◽

Large Scale ◽

Woody Debris ◽

Water Levels ◽

Mitigation Strategies ◽

Large Woody Debris ◽

Debris Accumulation ◽

The Impact ◽

The City

Due to excessive rainfall in June of 2013, several rivers located in and near the City of Calgary, Canada experienced significant flooding events. These events caused severe damage to infrastructure throughout the city, precipitating a renewed interest in flood control and mitigation strategies for the area. A major potential strategy involves partial diversion of Elbow River flood water to the proposed Springbank Off-Stream Storage Reservoir. A large scale physical model study was conducted to optimize and validate the design of a portion of the new project. The goals of the physical model were to investigate diversion system behaviors such as flow rates, water levels, sediment transport and, debris accumulation, and optimize the design of new flow control structures to be constructed on the Elbow River. In order to accurately represent the behavior of debris within the system due to flooding, large woody debris created from natural sources was utilized in the physical model and its performance was compared to that of debris of the same size fabricated from pressed cylindrical wood dowels. In addition to comparing the performance of these two debris types, the impact of root wads on debris damming was also investigated. Significant differences in damming behavior was shown to exist between the natural debris and the fabricated debris, while the impact of root wad on damming affected the dam structure and formation. The results of this experiment indicate that natural debris is preferred for studies involving debris accumulation.

Download Full-text

Prophylaxis protocols and their impact on bracket friction force

The Angle Orthodontist ◽

10.2319/020119-72.1 ◽

2019 ◽

Vol 89 (6) ◽

pp. 883-888

Author(s):

Sérgio Elias Neves Cury ◽

Silvio Augusto Bellini-Pereira ◽

Aron Aliaga-Del Castillo ◽

Sérgio Schneider ◽

Arnaldo Pinzan ◽

...

Keyword(s):

Sodium Bicarbonate ◽

Qualitative Analysis ◽

Friction Force ◽

Friction Forces ◽

Debris Accumulation ◽

Intergroup Comparison ◽

Group 3 ◽

Group 2 ◽

Sliding Mechanics

ABSTRACT Objective: To evaluate the effect of two different prophylaxis protocols on the friction force in sliding mechanics during in vivo leveling and alignment. Materials and Methods: The sample comprised 48 hemi-arches divided into three groups according to the prophylactic protocol adopted. Group 1 consisted of patients undergoing prophylaxis with sodium bicarbonate, group 2 consisted of patients submitted to prophylaxis with glycine, and group 3 consisted of patients without prophylaxis, as a control. All patients received hygiene instructions and, with the exception of group 3, prophylaxis was performed monthly. After 10 months, the brackets were removed from the oral cavity and submitted to friction force tests and qualitative analysis by scanning electron microscopy. Analysis of variance followed by Tukey tests was performed for intergroup comparison regarding the friction force. Results: The experimental groups presented significantly smaller friction forces than the group without prophylaxis. Accordingly, qualitative analysis showed greater debris accumulation in the group without the prophylactic procedures. Conclusions: Prophylactic blasting with sodium bicarbonate or glycine can significantly prevent an increase of the friction force during sliding mechanics.

Download Full-text