Comparison of long-term properties of laser sintered and injection molded polyamide 12 parts

2018 ◽  
Vol 38 (6) ◽  
pp. 573-582 ◽  
Author(s):  
Andreas Wörz ◽  
Katrin Wudy ◽  
Dietmar Drummer ◽  
Andreas Wegner ◽  
Gerd Witt

Abstract Selective laser sintering (SLS) of polymers is on the edge from a pure prototyping technique to a small-scale production. For this transition, characteristic values such as long-term properties, and thus the degradation mechanism, are crucial factors for enabling a series application. Due to the specific characteristics of SLS parts like porosity and rough surfaces, a direct transfer of known mechanisms and models for injection molded (IM) parts is not or just to a limited extent possible. This leads to the aim of this paper, which is to investigate and compare the degradation behavior of polyamide 12 parts produced by SLS and IM.

2021 ◽  
Vol 2115 (1) ◽  
pp. 012026
Author(s):  
Sonam Solanki ◽  
Gunendra Mahore

Abstract In the current process of producing vermicompost on a large-scale, the main challenge is to keep the worms alive. This is achieved by maintaining temperature and moisture in their living medium. It is a difficult task to maintain these parameters throughout the process. Currently, this is achieved by building infrastructure but this method requires a large initial investment and long-run maintenance. Also, these methods are limited to small-scale production. For large-scale production, a unit is developed which utilises natural airflow with water and automation. The main aim of this unit is to provide favourable conditions to worms in large-scale production with very low investment and minimum maintenance in long term. The key innovation of this research is that the technology used in the unit should be practical and easy to adopt by small farmers. For long-term maintenance of the technology lesser number of parts are used.


2021 ◽  
Author(s):  
Dzhumabek Dzhailov ◽  
Mardalieva Leila

The role and significance of the cluster competitive development of the agro-industrial complex are substantiated. The analysis of the development of priority sectors of the agro-industrial complex and the domestic food market is presented. Disproportions and factors of unbalanced development of related branches of the agro-industrial complex are revealed. The reasons for the low level of processing of agricultural products and the weak development of agricultural processing industries in the republic are determined. The factors of non-competitiveness of the agro-industrial complex sectors are determined - the development of small-scale production, the underdevelopment of economic and integration ties between adjacent agro-industrial complex enterprises. Measures are proposed to ensure import substitution of food, the growth of its exports and, on this basis, the competitive development of priority sectors of the agro-industrial complex. The mechanisms for improving economic relations in the agro-industrial complex and the advantages of developing long-term contractual contractual relations have been substantiated. A model for the development of an agricultural cluster has been developed in order to implement the import substitution policy for the consumption of food resources.


2020 ◽  
Vol 9 (2) ◽  
Author(s):  
Bùi Thị Bích Lan

In Vietnam, the construction of hydropower projects has contributed significantly in the cause of industrialization and modernization of the country. The place where hydropower projects are built is mostly inhabited by ethnic minorities - communities that rely primarily on land, a very important source of livelihood security. In the context of the lack of common productive land in resettlement areas, the orientation for agricultural production is to promote indigenous knowledge combined with increasing scientific and technical application; shifting from small-scale production practices to large-scale commodity production. However, the research results of this article show that many obstacles in the transition process are being posed such as limitations on natural resources, traditional production thinking or the suitability and effectiveness of scientific - technical application models. When agricultural production does not ensure food security, a number of implications for people’s lives are increasingly evident, such as poverty, preserving cultural identity, social relations and resource protection. Since then, it has set the role of the State in researching and building appropriate agricultural production models to exploit local strengths and ensure sustainability.


Author(s):  
Hariyadi DM ◽  
Athiyah U ◽  
Hendradi E ◽  
Rosita N ◽  
Erawati T ◽  
...  

The prevention of Diabetic Mellitus (DM) and its complications is the main aim of this study, in addition to the training of lotion foot care application and the development of small scale industry. The research team delivered knowledge in the form of training on Diabetic Mellitus, healthy food, treatment and prevention of complications, and small-scale production of cosmetic products. The aim of this study was to determine the correlation between training on diabetic and lotion foot care application as preventive measures against diabetic complications on the patient's blood glucose levels in the community of residents in Banyuurip Jaya, Surabaya. It was expected from this training that the knowledge of the residents increases and people living with diabetic undergo lifestyle changes and therefore blood sugar levels can be controlled. The parameters measured in this research were blood glucose levels, the anti diabetic drug types consumed, and compliance on diabetics. This study used the data taken from 60 patients with DM over a period of one month. Questionnaires and log books was used to retrieve data and changes in blood glucose levels in diabetic patients. The results showed the demographic data of patients with type 2 diabetic of 85% female and 15% male, with the range of patients aged of 61-70 years of 46.67% and had history of diabetic (90%). The history of drugs consumed by respondents was anti diabetic drugs such as metformin (40%), glimepiride (33.37%) and insulin (6.67%). In addition, the increased knowledge of DM patients after being given the training compared to before training was shown in several questions in the questionnaire. A statistical analysis using t-test analyzed a correlation between training provided in order to enhance understanding of the patient, as well as correlation with blood glucose levels. A paired T-test showed that there was a relationship between the knowledge of trainees before and after training (p less than 0.05). An interesting result was that there was no relationship between blood glucose levels before and after training provided (p> 0.05).


2019 ◽  
Vol 9 (7) ◽  
pp. 1308 ◽  
Author(s):  
Rob Kleijnen ◽  
Manfred Schmid ◽  
Konrad Wegener

This work describes the production of a spherical polybutylene terephthalate (PBT) powder and its processing with selective laser sintering (SLS). The powder was produced via melt emulsification, a continuous extrusion-based process. PBT was melt blended with polyethylene glycol (PEG), creating an emulsion of spherical PBT droplets in a PEG matrix. Powder could be extracted after dissolving the PEG matrix phase in water. The extrusion settings were adjusted to optimize the size and yield of PBT particles. After classification, 79 vol. % of particles fell within a range of 10–100 µm. Owing to its spherical shape, the powder exhibited excellent flowability and packing properties. After powder production, the width of the thermal processing (sintering) window was reduced by 7.6 °C. Processing of the powder on a laser sintering machine was only possible with difficulties. The parts exhibited mechanical properties inferior to injection-molded specimens. The main reason lied in the PBT being prone to thermal degradation and hydrolysis during the powder production process. Melt emulsification in general is a process well suited to produce a large variety of SLS powders with exceptional flowability.


2021 ◽  
Vol 4 ◽  
pp. 100153
Author(s):  
Armel Gougbedji ◽  
Pamphile Agbohessou ◽  
Philippe A. Lalèyè ◽  
Frédéric Francis ◽  
Rudy Caparros Megido

2021 ◽  
pp. 003232172110072
Author(s):  
Ramon van der Does ◽  
Vincent Jacquet

Deliberative minipublics are popular tools to address the current crisis in democracy. However, it remains ambiguous to what degree these small-scale forums matter for mass democracy. In this study, we ask the question to what extent minipublics have “spillover effects” on lay citizens—that is, long-term effects on participating citizens and effects on non-participating citizens. We answer this question by means of a systematic review of the empirical research on minipublics’ spillover effects published before 2019. We identify 60 eligible studies published between 1999 and 2018 and provide a synthesis of the empirical results. We show that the evidence for most spillover effects remains tentative because the relevant body of empirical evidence is still small. Based on the review, we discuss the implications for democratic theory and outline several trajectories for future research.


2021 ◽  
Author(s):  
Dongsheng Xia ◽  
Chenchen Yu ◽  
Yinghao Zhao ◽  
Yinping Wei ◽  
Haiyan Wu ◽  
...  

The severe degradation of Fe-N-C electrocatalysts during long-term oxygen reduction reaction (ORR) has become a major obstacle for application in proton-exchange membrane fuel cells. Understanding the degradation mechanism and regeneration...


2020 ◽  
Vol 32 (S1) ◽  
pp. 15-16
Author(s):  
William E. Reichman ◽  
L. Bradford Perkins ◽  
Hilde Verbeek

This symposium will review the latest data on the influence of environmental design and its attributes on the cognitive and psychological wellbeing of older adults living with dementia. The presenters will cover the myriad ways in which the physical environment of care can adapt to the changing demands of older adults with sensory, motor and cognitive deficits and foster optimal functioning and quality of life. The role of emerging technologies will also be reviewed as they complement the contribution of the design of the physical environment to the wellbeing of older adults with cognitive impairment. Information will be offered through a review of the existing research literature as well as case studies that illustrate the impact of environmental modification on fostering wellbeing and minimizing the emergence of the behavioral and psychological symptoms of dementia. The presenters will represent and integrate sensibilities that have emerged from the fields of architecture, cognitive neuroscience and psychology.How the Principles of the Culture Change Movement Inform Environmental Design and the Application of Technology in the Care of Older Adults Living with DementiaWilliam E. ReichmanThe culture change movement informs a number of principles that have been applied to more contemporary design concepts for the congregate care of older adults living with dementia. This talk will review the core tenets of the Culture Change Movement as exemplified by the Greenhouse, Dementia Village and other innovative models of congregate long-term care. Specific reference will be made to how these tenets have been operationalized around the world into the design of programming and the creation of residential care environments that foster a better quality of life for older adults and an enhanced work environment for care providers. This talk will also include the emerging role of technologies that complement innovative design of the environment and which foster optimized social and recreational functioning of older adults living with dementia.A Better Life Through a Better Nursing Home DesignL. Bradford PerkinsOver the last 20 years there has been extensive experimentation related to the role of the environment in the housing, care and treatment of persons with Alzheimer’s and other age related dementias. Prior to that time the typical housing and care environment was a locked unit in a skilled nursing or other restrictive senior living facility. In 1991 the Presbyterian Association on Aging in Western Pennsylvania opened Woodside Place on its Oakmont campus. This small 36 bed facility was designed to incorporate the latest research and care experience with persons suffering from these issues. This one small project, as well as the long post occupancy research led by Carnegie Mellon University, clearly demonstrated that individuals with Alzheimer’s and related forms of dementia could lead a healthier, happier, higher quality of life in a more residential, less restrictive environment. Not everything in this pioneering project worked, and five generations of living and care models have followed that have refined the ideas first demonstrated by Woodside Place. Bradford Perkins, whose firm designed Woodside Place and over 100 other related projects, will discuss what was learned from Woodside Place as well as the five generations of projects (and post occupancy research) that followed.Innovative dementia care environments as alternatives for traditional nursing homes: evidence and experiences from the NetherlandsHilde VerbeekKey goals of the dementia care environment focus on increasing autonomy, supporting independence and trying to enable one’s own lifestyle for as long as possible. To meet these goals, innovative, small-scale and homelike care environments have been developed that have radically changed the physical, social and organizational aspects of long-term care in the Netherlands. This presentation discusses various Dutch models that have implemented small-scale and homelike care environments, including green care farms, dementia village and citizen initiatives. The models reflect a common care concept, focusing on residents’ remaining strengths, providing opportunity for choice and aiming to sustain a sense of self and control. A small number of residents (usually 6 to 8) live together in a homelike environment and nursing staff are part of the household. Residents are encouraged to participate in daily household activities, emphasizing normalization of daily life with person-centred care. The physical environment resembles an archetypal home. This talk presents the scientific evidence on the impact and effects of these small-scale, homelike models on residents, their family caregivers and staff. Furthermore, the presentation will highlight working approaches and how these initiatives have positively influenced routine care across the long-term care spectrum.


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