scholarly journals A Review on Existing Methods to Assess Hydraulic Erodibility Downstream of Dam Spillways

Water ◽  
2021 ◽  
Vol 13 (22) ◽  
pp. 3205
Author(s):  
Yavar Jalili Kashtiban ◽  
Ali Saeidi ◽  
Marie-Isabelle Farinas ◽  
Marco Quirion
Keyword(s):  
Rock Mass ◽  
Numerical Methods ◽  
Safety Concern ◽  
Hydraulic Structures ◽  
Future Research ◽  
Advantages And Disadvantages ◽  
In Situ Data ◽  
Plunge Pool ◽  
Theoretical Approaches ◽  
Mass Erosion

In recent years, rock scouring or erosion downstream of dams has become an increasing dam safety concern. Several theoretical, semi-theoretical, semi-analytical and numerical methods can be used to assess the rock erosion in hydraulic structures. Semi-theoretical approaches determine the correlation between the erosive intensity of fluid flow and the resistive capacity of rock. Such approaches establish the scour thresholds as a function of erosive intensity of water and several rock mass indices by using in situ data and a curve-fitting approach. In some studies, the excavatability index, initially developed for rock mass stability analysis, was used to analyse the rock mass resistance in hydraulic erodibility analysis. The effectivity and weight of the geomechanical parameters used are yet to be determined on the basis of the erodibility phenomenon. The semi-analytical methods are developed on the basis of the mechanical and hydraulic interaction of rock mass and water. Four methods developed by Bollaert et al. are important in determining the erodibility in the plunge pool, but they are not applicable in the case of spillways. They used the comprehensive fracture mechanics for closed-end joints, quasi-steady impulsion, and dynamic impulsion (DI) for blocky rock erosion. The application of these methods to each site is necessary to identify constants that are difficult to determine. Few numerical methods are available to assess the rock mass erosion in hydraulic structures. In the case of numerical methods, the erosive agent is indistinct, and the hydraulic hazard parameter on the spillway surface is almost challenging to apply. This study comprehensively reviews the mechanism of erosion and the methods for assessing the risk of potential rock mass erosion downstream of dams and hydraulic structures. The advantages and disadvantages of all methods are discussed and the potential future research directions in this domain are proposed.

Numerical simulation of parachute inflation: A methodological review

2017 ◽  
Vol 233 (2) ◽  
pp. 736-766 ◽  
Author(s):  
Yihua Cao ◽  
Shuai Nie ◽  
Zhenlong Wu
Keyword(s):  
Numerical Methods ◽  
Bluff Body ◽  
Moving Boundary ◽  
Structural Models ◽  
Future Research ◽  
Advantages And Disadvantages ◽  
Parachute Inflation ◽  
Dependent Flow ◽  
Coupling Algorithms ◽  
The Impact

The parachute inflation process involves fluid–structure interaction problems posing several mathematical and engineering challenges, e.g. accurate aerodynamics calculations for bluff-body geometries involving with moving boundary, appropriate structural models in predicting the behavior of canopy, and realization of the coupling between the fluid and structure. These challenges attract the attention of scholars worldwide, and considerable achievements have been obtained in applying numerical methods and simulations to design multifarious parachutes. In this paper, the authors highlight the advances in the following fields: the methods suitable for time-dependent flow around bluff-body geometries, the accurate structural models in consideration of the under-constrained and no-compression nature of the canopy, and the advantages and disadvantages of different coupling algorithms in terms of numerical stability and computational economics. Moreover, in order to simulate the parachute inflation more realistically, we focus on accurate representation of three physical phenomena, as follows: an appropriate model of the flow through porous media, an accurate treatment of the wrinkling phenomenon of the canopy, and a consistent representation of the impact-contact problem associated with the inflation process. Finally, based on a review of existing literature, we offer recommendations for future research on the application of numerical methods for simulating the inflation process.

A Review of Drug Side Effect Identification Methods

2020 ◽  
Vol 26 (26) ◽  
pp. 3096-3104 ◽  
Author(s):  
Shuai Deng ◽  
Yige Sun ◽  
Tianyi Zhao ◽  
Yang Hu ◽  
Tianyi Zang
Keyword(s):  
Side Effects ◽  
Future Research ◽  
Drug Side Effects ◽  
Important Indicator ◽  
Advantages And Disadvantages ◽  
Key Points ◽  
Network Methods ◽  
Future Research Directions ◽  
The One ◽  
Approved Drugs

Drug side effects have become an important indicator for evaluating the safety of drugs. There are two main factors in the frequent occurrence of drug safety problems; on the one hand, the clinical understanding of drug side effects is insufficient, leading to frequent adverse drug reactions, while on the other hand, due to the long-term period and complexity of clinical trials, side effects of approved drugs on the market cannot be reported in a timely manner. Therefore, many researchers have focused on developing methods to identify drug side effects. In this review, we summarize the methods of identifying drug side effects and common databases in this field. We classified methods of identifying side effects into four categories: biological experimental, machine learning, text mining and network methods. We point out the key points of each kind of method. In addition, we also explain the advantages and disadvantages of each method. Finally, we propose future research directions.

scholarly journals A Review of Dynamic Balancing for Robotic Mechanisms

Robotica ◽  
2020 ◽  
Vol 39 (1) ◽  
pp. 55-71 ◽  
Author(s):  
Bin Wei ◽  
Dan Zhang
Keyword(s):  
Future Research ◽  
Dynamic Balancing ◽  
Advantages And Disadvantages

SUMMARYThe authors summarize the main dynamic balancing methods of robotic mechanisms in this paper. The majority of dynamic balancing methods have been presented, and there may be other dynamic balancing methods that are not included in this paper. Each of the balancing methods is reviewed and discussed. The advantages and disadvantages of each method are presented and compared. The goal of this paper is to provide an overview of recent research in balancing. The authors hope that this study can provide an informative reference for future research in the direction of dynamic balancing of robotic mechanisms.

scholarly journals Validity of the Gender Dysphoria diagnosis and incidence trends in Sweden: a nationwide register study

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Malin Indremo ◽  
Richard White ◽  
Thomas Frisell ◽  
Sven Cnattingius ◽  
Alkistis Skalkidou ◽  
...  
Keyword(s):  
Gender Dysphoria ◽  
Age Groups ◽  
Medical Intervention ◽  
Future Research ◽  
Advantages And Disadvantages ◽  
Incidence Trends ◽  
Interaction Terms ◽  
Definition Of ◽  
The Individual ◽  
Nationwide Register Study

AbstractThe aim of this study was to examine the validity of the Gender Dysphoria (GD) diagnoses in the Swedish National Patient Register (NPR), to discuss different register-based definitions of GD and to investigate incidence trends. We collected data on all individuals with registered GD diagnoses between 2001 and 2016 as well as data on the coverage in the NPR. We regarded gender confirming medical intervention (GCMI) as one proxy for a clinically valid diagnosis and calculated the positive predictive value (PPV) for receiving GCMI for increasing number of registered GD diagnoses. We assessed crude and coverage-adjusted time trends of GD during 2004–2015 with a Poisson regression, using assigned sex and age as interaction terms. The PPV for receiving GCMI was 68% for ≥ 1 and 79% for ≥ 4 GD-diagnoses. The incidence of GD was on average 35% higher with the definition of ≥ 1 compared to the definition of ≥ 4 diagnoses. The incidence of GD, defined as ≥ 4 diagnoses increased significantly during the study period and mostly in the age categories 10–17 and 18–30 years, even after adjusting for register coverage. We concluded that the validity of a single ICD code denoting clinical GD in the Swedish NPR can be questioned. For future research, we propose to carefully weight the advantages and disadvantages of different register-based definitions according to the individual study’s needs, the time periods involved and the age-groups under study.

scholarly journals Involvement of Probiotics and Postbiotics in the Immune System Modulation

Biologics ◽  
2021 ◽  
Vol 1 (2) ◽  
pp. 89-110
Author(s):  
Neslihan Yeşilyurt ◽  
Birsen Yılmaz ◽  
Duygu Ağagündüz ◽  
Raffaele Capasso
Keyword(s):  
Immune System ◽  
Pharmaceutical Industry ◽  
Intestinal Microbiota ◽  
Health Benefits ◽  
The Body ◽  
Future Research ◽  
Immune Systems ◽  
Advantages And Disadvantages ◽  
Immune System Modulation ◽  
Molecular Patterns

Intestinal microbiota interacts with other systems, especially the immune system, which is responsible for protecting the body by recognizing “stranger” (pathogen associated molecular patterns-PAMPs) and “danger” (damage-associated molecular patterns-DAMPs) molecular motifs. In this manner, it plays an important role in the pathogenesis of various diseases and health. Despite the use of probiotics that modulate the intestinal microbiota in providing health benefits and in the treatment of diseases, there are some possible concerns about the possibility of developing adverse effects, especially in people with suppressed immune systems. Since probiotics provide health benefits with bioactive compounds, studies are carried out on the use of products containing non-living probiotic microorganisms (paraprobiotics) and/or their metabolites (postbiotics) instead of probiotic products. It is even reported that these microbial compounds have more immunomodulatory activities than living microorganisms via some possible mechanism and eliminates some disadvantages of probiotics. Considering the increasing use of functional foods in health and disease, further studies are needed with respect to the benefits and advantages of parabiotic and/or postbiotic use in the food and pharmaceutical industry as well as immune system modulation. Although probiotics have been extensive studied for a long time, it seems that postbiotics are promising tools for future research and applications according to the recent literature. This review aimed to evaluate the interaction of probiotics and postbiotics with the immune systems and also their advantages and disadvantages in the area of food-pharmaceutical industry and immune system modulation.

scholarly journals A Systematic Literature Review of Multi-Criteria Decision-Making Methods for Sustainable Selection of Insulation Materials in Buildings

2021 ◽  
Vol 13 (2) ◽  
pp. 737
Author(s):  
Indre Siksnelyte-Butkiene ◽  
Dalia Streimikiene ◽  
Tomas Balezentis ◽  
Virgilijus Skulskis
Keyword(s):  
Decision Making ◽  
Literature Review ◽  
Systematic Literature Review ◽  
Energy Demand ◽  
Energy Performance ◽  
Future Research ◽  
Multi Criteria Decision Making ◽  
Insulation Materials ◽  
Advantages And Disadvantages ◽  
Selection Of

The European Commission has recently adopted the Renovation Wave Strategy, aiming at the improvement of the energy performance of buildings. The strategy aims to at least double renovation rates in the next ten years and make sure that renovations lead to higher energy and resource efficiency. The choice of appropriate thermal insulation materials is one of the simplest and, at the same time, the most popular strategies that effectively reduce the energy demand of buildings. Today, the spectrum of insulation materials is quite wide, and each material has its own specific characteristics. It is recognized that the selection of materials is one of the most challenging and difficult steps of a building project. This paper aims to give an in-depth view of existing multi-criteria decision-making (MCDM) applications for the selection of insulation materials and to provide major insights in order to simplify the process of methods and criteria selection for future research. A systematic literature review is performed based on the Search, Appraisal, Synthesis and Analysis (SALSA) framework and the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. In order to determine which MCDM method is the most appropriate for different questions, the main advantages and disadvantages of different methods are provided.

scholarly journals Analysis of High-Friction Surface Texture with Respect to Friction and Wear

Coatings ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 758
Author(s):  
Cibi Pranav ◽  
Minh-Tan Do ◽  
Yi-Chang Tsai
Keyword(s):  
Friction Coefficient ◽  
Surface Texture ◽  
Safety Concern ◽  
Future Research ◽  
Scanning System ◽  
Novel Approach ◽  
Texture Parameters ◽  
Aggregate Loss ◽  
Friction Surfaces ◽  
The Impact

High Friction Surfaces (HFS) are applied to increase friction capacity on critical roadway sections, such as horizontal curves. HFS friction deterioration on these sections is a safety concern. This study deals with characterization of the aggregate loss, one of the main failure mechanisms of HFS, using texture parameters to study its relationship with friction. Tests are conducted on selected HFS spots with different aggregate loss severity levels at the National Center for Asphalt Technology (NCAT) Test Track. Friction tests are performed using a Dynamic Friction Tester (DFT). The surface texture is measured by means of a high-resolution 3D pavement scanning system (0.025 mm vertical resolution). Texture data are processed and analyzed by means of the MountainsMap software. The correlations between the DFT friction coefficient and the texture parameters confirm the impact of change in aggregates’ characteristics (including height, shape, and material volume) on friction. A novel approach to detect the HFS friction coefficient transition based on aggregate loss, inspired by previous works on the tribology of coatings, is proposed. Using the proposed approach, preliminary outcomes show it is possible to observe the rapid friction coefficient transition, similar to observations at NCAT. Perspectives for future research are presented and discussed.

scholarly journals Going virtual: youth attitudes toward and experiences of virtual mental health and substance use services during the COVID-19 pandemic

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Lisa D. Hawke ◽  
Natasha Y. Sheikhan ◽  
Karen MacCon ◽  
Joanna Henderson
Keyword(s):  
Mental Health ◽  
Substance Use ◽  
Youth Mental Health ◽  
Research Process ◽  
Clinical Samples ◽  
Future Research ◽  
Advantages And Disadvantages ◽  
Substance Use Services ◽  
Youth Attitudes ◽  
Virtual Services

Abstract Background During the COVID-19 pandemic, youth mental health and substance use services rapidly moved to virtual modalities to meet social distancing requirements. It is important to understand youth attitudes toward and experience of virtual services. Objective This study examined the attitudes toward and experiences of virtual mental health and substance use services among youth drawn from clinical and non-clinical samples. Method Four hundred nine youth completed a survey including questions about their attitudes toward and experience of virtual services. The survey included quantitative and open-ended questions on virtual care, as well as a mental health and substance use screener. Results The majority of youth with mental health or substance use challenges would be willing to consider individual virtual services, but fewer would consider group virtual services. However, many have not received virtual services. Youth are interested in accessing a wide variety of virtual services and other supportive wellness services. Advantages and disadvantages of virtual services are discussed, including accessibility benefits and technological barriers. Discussion As youth mental health and substance use services have rapidly gone virtual during the COVID-19 pandemic, it is essential that we hear the perspectives of youth to promote service utilization among those in need. Diverse, accessible, technologically stable virtual services are required to meet the needs of different youth, possibly with in-person options for some youth. Future research, engaging youth in the research process, is needed to evaluate the efficacy of virtual services to plan for the sustainability of some virtual service gains beyond the pandemic period.

scholarly journals A Review of Remote Sensing Image Dehazing

Sensors ◽  
2021 ◽  
Vol 21 (11) ◽  
pp. 3926
Author(s):  
Juping Liu ◽  
Shiju Wang ◽  
Xin Wang ◽  
Mingye Ju ◽  
Dengyin Zhang
Keyword(s):  
Remote Sensing ◽  
Data Driven ◽  
Future Research ◽  
Research Focus ◽  
Image Dehazing ◽  
Surface Information ◽  
Haze Removal ◽  
Advantages And Disadvantages ◽  
Extra Information ◽  
Removal Technique

Remote sensing (RS) is one of the data collection technologies that help explore more earth surface information. However, RS data captured by satellite are susceptible to particles suspended during the imaging process, especially for data with visible light band. To make up for such deficiency, numerous dehazing work and efforts have been made recently, whose strategy is to directly restore single hazy data without the need for using any extra information. In this paper, we first classify the current available algorithm into three categories, i.e., image enhancement, physical dehazing, and data-driven. The advantages and disadvantages of each type of algorithm are then summarized in detail. Finally, the evaluation indicators used to rank the recovery performance and the application scenario of the RS data haze removal technique are discussed, respectively. In addition, some common deficiencies of current available methods and future research focus are elaborated.

A Comprehensive Synthesis of Theories of Mobile Shopping Adoption and Narrative Review

2021 ◽  
Vol 11 (2) ◽  
pp. 52-74
Author(s):  
Rajat Gera ◽  
Priyanka Chadha ◽  
Shirin Alavi
Keyword(s):  
Distribution Channel ◽  
Narrative Review ◽  
Advanced Technology ◽  
Future Research ◽  
Theoretic Approach ◽  
Individual Level ◽  
Theoretical Approaches ◽  
Mobile Shopping ◽  
Future Research Directions ◽  
The Individual

This paper aims to synthesize and integrate the existing literature on MSA adoption and provide directions for future research through narrative review by classifying and organizing the accumulated knowledge into a thematic framework. The paper's theoretical, conceptual approaches, and results were organized into three themes: online distribution channel (theoretical approaches and antecedent factors of MSA adoption, consumer characteristics), advanced technology for in-store shopping (marketing aspects of MSA), and technology perspectives (technology aspects of MSA). The 25 theories of mobile shopping app (MSA) adoption and usage (at the individual level) from 22 reviewed papers were summarized, defined, and mapped with authors. Research questions have been proposed for theories used in reviewed papers and new theories. MSA adoption is at an emergent stage of evolution with fragmentation of theoretical and methodological approaches. While theories of technology adoption and behavioral intentions have been used predominantly, most studies have adopted a multi-theoretic approach or have extended/modified the model with hedonic, situational, and behavioral constructs. The findings related to consumer characteristics of MSA adoption, anchor constructs, moderator and mediator variables, and marketing and technology features of MSA are synthesized and organized according to the themes. Theoretical and practical implications are drawn, research limitations are identified, and future research directions are suggested.

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