Effects of Extrusion Methods and Powder Carriers on Powder Forming and Precursor Foaming Behavior in the Preparation Process of Aluminum Foam

2013 ◽  
Vol 634-638 ◽  
pp. 1734-1739 ◽  
Author(s):  
Zhi Qiang Guo ◽  
Xiang Li ◽  
Xiao Guang Yuan ◽  
Hong Jun Huang
Keyword(s):  
Aluminum Foam ◽  
Whole Body ◽  
Preparation Process ◽  
Aluminum Foams ◽  
Minimum Density ◽  
Pore Structures ◽  
Foaming Behavior ◽  
New Type ◽  
Powder Forming

Aluminum foam is a new type of material that can be used in many fields. Compaction conditions are the most important parameters that have influence on foam preparation process. So in this paper, detailed researches about extrusion methods and powder carriers are conducted. The results show that: compare with direct extrusion, pre-pressing can effectively eliminate the influences of hydrogen, obtain high density precursors. However, when the flank of the precursor is wrapped with copper, H2 can escape from the combination parts of Al and Cu, in early foaming stage. The minimum density is only 0.75g/cm3, pore structures are almost round and nearly no plateau borders exist, so the quality of aluminum foam is still poor. When there is no copper wrapped, an oxide layer can be formed in the whole body of the precursor and limit the escaping of H2. The minimum density can reach 0.45g/cm3, pore structures are polygonal with thin cell walls about 0.08mm. Thus high quality aluminum foams can be obtained by using pre-pressing and then extruding method and precursor sheet powder carrier.

scholarly journals Shaping of Aluminum Foam During Foaming of Precursor Using Steel Mesh with Various Opening Ratios

Metals ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 223 ◽  
Author(s):  
Yoshihiko Hangai ◽  
Ryohei Nagahiro ◽  
Masataka Ohashi ◽  
Kenji Amagai ◽  
Takao Utsunomiya ◽  
...  
Keyword(s):  
Heating Rate ◽  
Aluminum Foam ◽  
Aluminum Foams ◽  
Steel Mesh ◽  
Pore Structures ◽  
Foaming Time

In this study, steel meshes with various opening ratios φ were used to shape aluminum foams during precursor foaming. The effect of φ on the heating rate and shape of the obtained aluminum foams was investigated. It was found that steel meshes with various opening ratios can be used to shape aluminum foam. There is no significant effect on the pore structures of the obtained aluminum foams when upward expansion is restricted during foaming, regardless of the value of φ. The meshes with higher φ clearly transfer the mesh pattern onto the surface of the aluminum foam but require a shorter foaming time. In contrast, the lower-φ meshes produce aluminum foams with a smoother surface but a longer foaming time is required.

scholarly journals Microstructural and corrosion study of aluminum foams obtained by space holder process using low-cost removable preforms

2021 ◽  
Vol 19 (3) ◽  
pp. 202-216
Author(s):  
P. Fernández Morales ◽  
L. Marulanda Zapata ◽  
M. Vásquez Rendón
Keyword(s):  
Aluminum Foam ◽  
Low Cost ◽  
Morphological Structure ◽  
Metal Foams ◽  
Aluminum Foams ◽  
Space Holder ◽  
Common Technique ◽  
A356 Aluminum ◽  
Metal Microstructure

The space holder process (SHP) is a useful and common technique to obtain metal foams. However, an important question remains unsolved: Would the quality of the salt affect the properties of the aluminum foam obtained? In this paper, removable preforms of two types of salt (refined and unrefined) were infiltrated with A356 aluminum alloy to obtain metal foams with different pore sizes. The interaction preform-metal was studied from analyzing the morphological structure of the foams, the metal microstructure, and the corrosion resistance of the Al356 alloy. It was observed that, although the two types of salt exhibited some differences, they did not show variations in relation to the porous structure and metal microstructure in the aluminum foams obtained. Additionally, the electrochemical analyses did not show significant effects on the corrosion behavior of aluminum foams caused by the interaction with the salt preforms.

scholarly journals A Comparison of the Effect of Two Types of Whole Body Vibration Platforms on Fibromyalgia. A Randomized Controlled Trial

2021 ◽  
Vol 18 (6) ◽  
pp. 3007
Author(s):  
José Antonio Mingorance ◽  
Pedro Montoya ◽  
José García Vivas Miranda ◽  
Inmaculada Riquelme
Keyword(s):  
Quality Of Life ◽  
Motor Function ◽  
Whole Body Vibration ◽  
Whole Body ◽  
Control Group ◽  
Body Vibration ◽  
Positive Effects ◽  
Therapy Program

Whole body vibration has been proven to improve the health status of patients with fibromyalgia, providing an activation of the neuromuscular spindles, which are responsible for muscle contraction. The present study aimed to compare the effectiveness of two types of whole body vibrating platforms (vertical and rotational) during a 12-week training program. Sixty fibromyalgia patients (90% were women) were randomly assigned to one of the following groups: group A (n = 20), who performed the vibration training with a vertical platform; group B (n = 20), who did rotational platform training; or a control group C (n = 20), who did not do any training. Sensitivity measures (pressure pain and vibration thresholds), quality of life (Quality of Life Index), motor function tasks (Berg Scale, six-minute walking test, isometric back muscle strength), and static and dynamic balance (Romberg test and gait analysis) were assessed before, immediately after, and three months after the therapy program. Although both types of vibration appeared to have beneficial effects with respect to the control group, the training was more effective with the rotational than with vertical platform in some parameters, such as vibration thresholds (p < 0.001), motor function tasks (p < 0.001), mediolateral sway (p < 0.001), and gait speed (p < 0.05). Nevertheless, improvements disappeared in the follow-up in both types of vibration. Our study points out greater benefits with the use of rotational rather than vertical whole body vibration. The use of the rotational modality is recommended in the standard therapy program for patients with fibromyalgia. Due to the fact that the positive effects of both types of vibration disappeared during the follow-up, continuous or intermittent use is recommended.

scholarly journals The Interplay between Mitochondrial Morphology and Myomitokines in Aging Sarcopenia

2020 ◽  
Vol 22 (1) ◽  
pp. 91
Author(s):  
Vanina Romanello
Keyword(s):  
Mitochondrial Dysfunction ◽  
Poor Quality ◽  
Whole Body ◽  
Fibroblast Growth Factor 21 ◽  
Mitochondrial Morphology ◽  
Mass Force ◽  
Major Mechanism ◽  
Muscle Aging ◽  
And Function

Sarcopenia is a chronic disease characterized by the progressive loss of skeletal muscle mass, force, and function during aging. It is an emerging public problem associated with poor quality of life, disability, frailty, and high mortality. A decline in mitochondria quality control pathways constitutes a major mechanism driving aging sarcopenia, causing abnormal organelle accumulation over a lifetime. The resulting mitochondrial dysfunction in sarcopenic muscles feedbacks systemically by releasing the myomitokines fibroblast growth factor 21 (FGF21) and growth and differentiation factor 15 (GDF15), influencing the whole-body homeostasis and dictating healthy or unhealthy aging. This review describes the principal pathways controlling mitochondrial quality, many of which are potential therapeutic targets against muscle aging, and the connection between mitochondrial dysfunction and the myomitokines FGF21 and GDF15 in the pathogenesis of aging sarcopenia.

scholarly journals Publication by association: how the COVID-19 pandemic has shown relationships between authors and editorial board members in the field of infectious diseases

2021 ◽  
pp. bmjebm-2021-111670
Author(s):  
Clara Locher ◽  
David Moher ◽  
Ioana Alina Cristea ◽  
Florian Naudet
Keyword(s):  
Infectious Diseases ◽  
Evidence Based Medicine ◽  
Medical Community ◽  
Board Members ◽  
Evidence Based ◽  
Ripple Effect ◽  
New Type ◽  
Based Medicine

During the COVID-19 pandemic, the rush to scientific and political judgements on the merits of hydroxychloroquine was fuelled by dubious papers which may have been published because the authors were not independent from the practices of the journals in which they appeared. This example leads us to consider a new type of illegitimate publishing entity, ‘self-promotion journals’ which could be deployed to serve the instrumentalisation of productivity-based metrics, with a ripple effect on decisions about promotion, tenure and grant funding, but also on the quality of manuscripts that are disseminated to the medical community and form the foundation of evidence-based medicine.

scholarly journals Whole Body Vibration Exercises and the Improvement of the Flexibility in Patient with Metabolic Syndrome

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Danúbia da Cunha Sá-Caputo ◽  
Pedro Ronikeili-Costa ◽  
Rafaelle Pacheco Carvalho-Lima ◽  
Luciana Camargo Bernardo ◽  
Milena Oliveira Bravo-Monteiro ◽  
...  
Keyword(s):  
Metabolic Syndrome ◽  
Muscle Power ◽  
Whole Body Vibration ◽  
Whole Body ◽  
Mineral Density ◽  
Level Of Evidence ◽  
Body Vibration ◽  
Pubmed Database ◽  
Number Of Publications

Vibrations produced in oscillating/vibratory platform generate whole body vibration (WBV) exercises, which are important in sports, as well as in treating diseases, promoting rehabilitation, and improving the quality of life. WBV exercises relevantly increase the muscle strength, muscle power, and the bone mineral density, as well as improving the postural control, the balance, and the gait. An important number of publications are found in the PubMed database with the keyword “flexibility” and eight of the analyzed papers involving WBV and flexibility reached a level of evidence II. The biggest distance between the third finger of the hand to the floor (DBTFF) of a patient with metabolic syndrome (MS) was found before the first session and was considered to be 100%. The percentages to the other measurements in the different sessions were determined to be related to the 100%. It is possible to see an immediate improvement after each session with a decrease of the %DBTFF. As the presence of MS is associated with poorer physical performance, a simple and safe protocol using WBV exercises promoted an improvement of the flexibility in a patient with MS.

The Design of Home Intelligent Power Node Based on ZigBee

2015 ◽  
Vol 719-720 ◽  
pp. 561-566
Author(s):  
Yong Qing Gao ◽  
Dan Shanng
Keyword(s):  
Network Node ◽  
Power Parameter ◽  
Home Gateway ◽  
The Core ◽  
Intelligent Home ◽  
Overload Protection ◽  
Zigbee Protocol ◽  
New Type ◽  
Parameter Monitoring

Firstly, this paper analyzes the significance and demand of intelligent power. Then a solution of home intelligent power system based on ZigBee is proposed. Hardware components of the solution proposed in this work mainly consists of AT91SAM9G20 as the core of the home gateway controller, CC430F6137 as the core of the network node of intelligent power and construction of intelligent home network system. This paper mainly introduces a new type of home intelligent power consumption network node, which realizes the measurement of electric power parameter, monitoring, overload protection and timing control, the communication between home gateway and network node through ZigBee protocol, the intelligent household electricity. By testing and using, it can meet the aspects of everyday life needs of user in convenient life, intelligent life and energy-saving, etc. It brings great commercial return and technical value to the development and application of intelligent home in future, as well as far-reaching impact to improving the quality of intelligent home services.

Reteaua de licee: cum o optimizam din punct de vedere numeric si în profil teritorial

2019 ◽  
Author(s):  
Serafim Florea ◽  
Keyword(s):  
High School ◽  
High Schools ◽  
Negative Impact ◽  
Boarding Schools ◽  
Qualified Teachers ◽  
Republic Of Moldova ◽  
School Network ◽  
New Type ◽  
The Republic

There are over 300 high schools in the Republic of Moldova, most of which do not have 10-12th parallel classes, many of which also lead to the lack of qualified teachers in some subjects, which has a negative impact on the quality of students education. The optimization of the high school network can be achieved by keeping only about 100 of their existing number, planning them in new type institutions: district high-schools, boarding schools and mixed high schools of both these categories.

Dista nce learning as a new challenge to the educati on system

2021 ◽  
pp. 16-21
Author(s):  
A. V. Loginov ◽  
O. V. Panisheva
Keyword(s):  
Higher Education ◽  
Distance Learning ◽  
Education System ◽  
Information Technologies ◽  
Social Problems ◽  
Quality Of Education ◽  
New Type

Distance learning is currently one of the most topical problems at the intersection of technical and pedagogical disciplines. The widespread introduction of distance learning in secondary and higher education has revealed a significant layer of problems that should be addressed by information technologies specialists, teachers, scientists, psychologists in cooperation with officials. The article discusses the main problems that arose during the transition to distance learning, the solution of which will raise the quality of education to a new level, including after the end of the new type of coronavirus pandemic. The authors highlight the organizational, technical and social problems in the process of organizing distance learning, the totality of which can be considered as a challenge to the education system.

Designing the Profile of a Student of a General Education School in the Context of the System-Activity and Outcome-Based Approach

2021 ◽  
pp. 10-15
Author(s):  
V. Nikolaev
Keyword(s):  
General Education ◽  
Adult Life ◽  
Education Development ◽  
System Activity ◽  
Global Competitiveness ◽  
Modern School ◽  
New Type ◽  
Production Economic ◽  
Goals And Objectives

At present goals and objectives of the education development are associated with ensuring the global competitiveness of the Russian education in general and guaranteeing the entry of the Russian Federation into the top 10 countries in the world in terms of the quality of general education, in particular. To achieve these national goals and objectives aimed at the development of education, the purposeful activity of general education institutions is required. They should focus on the design of modern school models to transform them into a new type of schools that will be able to improve the quality of education and ensure the school graduates’ training and preparation for their future adult life in the context of sustainable technological changes in the production, economic and social spheres. The article presents the approaches used by the staff of the Educational Complex "Nasha Shkola" in Novosibirsk to the construction of the Student’s Profile as a target reference point for the educational content standard of the System "Nasha Shkola" in the context of the system-activity and outcome-based approaches. The paper also considers the list of universal competencies and literacy groups that are formed by the educational and technological environment of the school and allow creating conditions for the personal and professional success of each student.

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