The Joining Environment

2004 ◽  
pp. 103-143
Keyword(s):  
Protective Atmosphere ◽  
Health Safety ◽  
Fluxless Soldering ◽  
Industrial Use ◽  
Materials Used

Abstract Materials used in joining, whether solders, fluxes, or atmospheres, are becoming increasingly subjected to restrictions on the grounds of health, safety, and pollution concerns. These regulations can limit the choice of materials and processes that are deemed acceptable for industrial use. This chapter addresses this issue in the context of soldering fluxes. It describes factors related to soldering under a protective atmosphere, provides information on chemical fluxes for soldering of various metals, and discusses the processes involved in fluxless soldering processes.

scholarly journals Characteristics of meat packaging materials and their environmental suitability assessment

2013 ◽  
Vol 67 (4) ◽  
pp. 615-620 ◽  
Author(s):  
Danijela Suput ◽  
Vera Lazic ◽  
Ljubinko Levic ◽  
Nevena Krkic ◽  
Vladimir Tomovic ◽  
...  
Keyword(s):  
Meat Products ◽  
Real Data ◽  
Barrier Properties ◽  
Protective Atmosphere ◽  
Product Packaging ◽  
Suitability Assessment ◽  
Meat Packaging ◽  
Materials Used ◽  
Characterization Of Materials

After functional phase, packaging becomes waste that is recycled or disposed of in landfills. Recently, numerus packages have been developed for assessing the packaging risk on the environment. We applied Gabi 4 Education software on polymer product packaging for meat products. The objective of first part of the paper was characterization of materials used for meat and meat products packaging in terms of mechanical and barrier properties. Results show that tested materials are able to keep protective atmosphere and contribute to the quality and sustainability of the product. Air permeability was 3.60 and 26.60 ml/m224h, and water vapor was 6.90 and 9.50 ml/m224h, respectively, for foils 1 and 2, as a result of different film composition. In second part, based on real data, Gabi 4 Education software is applied. The obtained results showed that organic compounds emissions have the highest impact on human health and the most damaging environmental impact observed was the emission of CO2.

scholarly journals Electrospun Nanofibrous Scaffolds: Review of Current Progress in the Properties and Manufacturing Process, and Possible Applications for COVID-19

Polymers ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 916
Author(s):  
Mohamed Kchaou ◽  
Mohammed Alquraish ◽  
Khaled Abuhasel ◽  
Ahmad Abdullah ◽  
Ashraf A. Ali
Keyword(s):  
Manufacturing Process ◽  
Tissue Repair ◽  
Electrospinning Technique ◽  
Tissue Repair And Regeneration ◽  
Nanofibrous Scaffolds ◽  
Proliferation And Differentiation ◽  
Potential Applications ◽  
Industrial Use ◽  
Materials Used ◽  
Review Current

Over the last twenty years, researchers have focused on the potential applications of electrospinning, especially its scalability and versatility. Specifically, electrospun nanofiber scaffolds are considered an emergent technology and a promising approach that can be applied to biosensing, drug delivery, soft and hard tissue repair and regeneration, and wound healing. Several parameters control the functional scaffolds, such as fiber geometrical characteristics and alignment, architecture, etc. As it is based on nanotechnology, the concept of this approach has shown a strong evolution in terms of the forms of the materials used (aerogels, microspheres, etc.), the incorporated microorganisms used to treat diseases (cells, proteins, nuclei acids, etc.), and the manufacturing process in relation to the control of adhesion, proliferation, and differentiation of the mimetic nanofibers. However, several difficulties are still considered as huge challenges for scientists to overcome in relation to scaffolds design and properties (hydrophilicity, biodegradability, and biocompatibility) but also in relation to transferring biological nanofibers products into practical industrial use by way of a highly efficient bio-solution. In this article, the authors review current progress in the materials and processes used by the electrospinning technique to develop novel fibrous scaffolds with suitable design and that more closely mimic structure. A specific interest will be given to the use of this approach as an emergent technology for the treatment of bacteria and viruses such as COVID-19.

scholarly journals Hardening of Additive Manufactured 316L Stainless Steel by Using Bimodal Powder Containing Nanoscale Fraction

Materials ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 115
Author(s):  
Aleksandr M. Filimonov ◽  
Oleg A. Rogozin ◽  
Denis G. Firsov ◽  
Yulia O. Kuzminova ◽  
Semen N. Sergeev ◽  
...  
Keyword(s):  
Stainless Steel ◽  
316L Stainless Steel ◽  
Steel Powder ◽  
Total Surface Area ◽  
Protective Atmosphere ◽  
Subgrain Structure ◽  
Protective Atmospheres ◽  
Powder Flowability ◽  
Materials Used ◽  
Porosity Analysis

The particle size distribution significantly affects the material properties of the additively manufactured parts. In this work, the influence of bimodal powder containing nano- and micro-scale particles on microstructure and materials properties is studied. Moreover, to study the effect of the protective atmosphere, the test samples were additively manufactured from 316L stainless steel powder in argon and nitrogen. The samples fabricated from the bimodal powder demonstrate a finer subgrain structure, regardless of protective atmospheres and an increase in the Vickers microhardness, which is in accordance with the Hall-Petch relation. The porosity analysis revealed the deterioration in the quality of as-built parts due to the poor powder flowability. The surface roughness of fabricated samples was the same regardless of the powder feedstock materials used and protective atmospheres. The results suggest that the improvement of mechanical properties is achieved by adding a nano-dispersed fraction, which dramatically increases the total surface area, thereby contributing to the nitrogen absorption by the material.

scholarly journals Development directions of packaging made from polymer materials

2011 ◽  
Vol 65 (6) ◽  
pp. 621-635 ◽  
Author(s):  
Slobodan Jovanovic ◽  
Jasna Dzunuzovic
Keyword(s):  
Product Quality ◽  
Market Share ◽  
Direct Contact ◽  
Production Costs ◽  
Polymer Materials ◽  
Protective Atmosphere ◽  
Intelligent Packaging ◽  
Packaging Technology ◽  
Materials Used ◽  
Made In

World packaging market achieves turnover of about $620 billion per year with one third of this amount being associated to packaging made from polymer materials. It is expected that this kind of packaging consumption will hold at least 3% of world packaging market share in the next five years and that it will surpass the consumption of all other materials used in the packaging production. This can be contributed to product quality, low production costs as well as significant investments made in the development of polymer materials, packaging technology and packaging. This paper presents some development directions for packaging made from polymer materials, such as: packaging in the protective atmosphere, the use of active and intelligent packaging, and the use of biopolymers and recycled polymers for packaging production that come into direct contact with the packed product.

Measurement of the Fineness of Powdered Materials

1938 ◽  
Vol 140 (1) ◽  
pp. 257-347 ◽  
Author(s):  
Harold Heywood
Keyword(s):  
Particle Size ◽  
Industrial Processes ◽  
Coarse Particles ◽  
Dilute Suspensions ◽  
Flow Round ◽  
Industrial Use ◽  
Particle Size And Shape ◽  
Materials Used ◽  
The Relationship ◽  
Size Grading

The paper describes in detail the methods of analysis at present available for measuring the fineness of powdered materials used in engineering and industrial processes. Definitions of particle size and shape are discussed, and examples are given of the size-distribution curves for typical industrial powders. Sieving or screening is used for the size grading of the comparatively coarse particles, and processes involving motion in a fluid for particles smaller than the limit of sieving. The theory of sieving and the relationship between particle size and sieve aperture are discussed. The equivalent sizes of round, square, and slotted apertures have been measured and results are given. The motion of irregularly shaped particles in a fluid is briefly described, and a method is given for calculating the falling velocity of such particles when the fluid flow round the particles is turbulent. The procedures used for the fineness analysis of sub-sieve particles are: elutriation by means of air or water, sedimentation, hydrometer readings, and the obscuring of a beam of light by dilute suspensions of the particles. Each of these processes is fully described, and the respective merits and disadvantages discussed. Tables of the nominal apertures of all the standard sieve series in industrial use, and a bibliography of about 150 references are included in the paper.

Deformation Replication

1970 ◽  
Vol 28 ◽  
pp. 280-281
Author(s):  
J. Temple Black
Keyword(s):  
Cutting Speed ◽  
Machining Process ◽  
Depth Of Cut ◽  
Rake Face ◽  
Orthogonal Machining ◽  
Aluminum Chips ◽  
Before And After ◽  
Materials Used ◽  
Glass Knife ◽  
Very High

Tool materials used in ultramicrotomy are glass, developed by Latta and Hartmann (1) and diamond, introduced by Fernandez-Moran (2). While diamonds produce more good sections per knife edge than glass, they are expensive; require careful mounting and handling; and are time consuming to clean before and after usage, purchase from vendors (3-6 months waiting time), and regrind. Glass offers an easily accessible, inexpensive material ($0.04 per knife) with very high compressive strength (3) that can be employed in microtomy of metals (4) as well as biological materials. When the orthogonal machining process is being studied, glass offers additional advantages. Sections of metal or plastic can be dried down on the rake face, coated with Au-Pd, and examined directly in the SEM with no additional handling (5). Figure 1 shows aluminum chips microtomed with a 75° glass knife at a cutting speed of 1 mm/sec with a depth of cut of 1000 Å lying on the rake face of the knife.

High Voltage Transmission Microscopy of Surveyor III Camera Shrouds

1971 ◽  
Vol 29 ◽  
pp. 138-139
Author(s):  
W. R. Duff ◽  
L. E. Thomas ◽  
R. M. Fisher ◽  
S. V. Radcliffe
Keyword(s):  
Alloy Sheet ◽  
Transmission Microscopy ◽  
Television Camera ◽  
Window Method ◽  
Transmission Electron ◽  
Microstructural Effects ◽  
Lunar Environment ◽  
Successful Retrieval ◽  
Materials Used ◽  
Abrasive Paper

Successful retrieval of the television camera and other components from the Surveyor III spacecraft by the Apollo 12 astronauts has provided a unique opportunity to study the effects of a known and relatively extensive exposure to the lunar environment. Microstructural effects including those produced by micro-meteorite impact, radiation damage (by both the solar wind and cosmic rays) and solar heating might be expected in the materials used to fabricate the spacecraft. Samples received were in the form of 1 cm2 of painted unpainted aluminum alloy sheet from the top of the camera visor (JPL Code 933) and the sides (935,936) and bottom (934) of the lower camera shroud. They were prepared for transmission electron microscopy by first hand-grinding with abrasive paper to a thickness of 0.006". The edges were lacquered and the sample electropolished in 10% perchloric methanol using the “window” method, to a thickness of ~0.001". Final thinning was accomplished by polishing 3 mm punched disks in an acetic-phosphoric-nitric acid solution.

Ultrastructure of mesotheliomas

1984 ◽  
Vol 42 ◽  
pp. 98-101
Author(s):  
Irving Dardick
Keyword(s):  
Electron Microscopy ◽  
Latent Period ◽  
Spindle Cell ◽  
Spindle Cell Sarcoma ◽  
Metastatic Adenocarcinoma ◽  
Cell Sarcoma ◽  
Cytological Features ◽  
Industrial Use ◽  
Degree Of Differentiation

With the extensive industrial use of asbestos in this century and the long latent period (20-50 years) between exposure and tumor presentation, the incidence of malignant mesothelioma is now increasing. Thus, surgical pathologists are more frequently faced with the dilemma of differentiating mesothelioma from metastatic adenocarcinoma and spindle-cell sarcoma involving serosal surfaces. Electron microscopy is amodality useful in clarifying this problem.In utilizing ultrastructural features in the diagnosis of mesothelioma, it is essential to appreciate that the classification of this tumor reflects a variety of morphologic forms of differing biologic behavior (Table 1). Furthermore, with the variable histology and degree of differentiation in mesotheliomas it might be expected that the ultrastructure of such tumors also reflects a range of cytological features. Such is the case.

Structure-property relationships of PE/PP sandwiched films

1987 ◽  
Vol 45 ◽  
pp. 454-455
Author(s):  
J. Petermann ◽  
G. Broza ◽  
U. Rieck ◽  
A. Jaballah ◽  
A. Kawaguchi
Keyword(s):  
Mechanical Tests ◽  
Polymer Materials ◽  
Ionic Crystals ◽  
Structure Property ◽  
Polymer Systems ◽  
Structure Property Relationships ◽  
Oriented Films ◽  
Materials Used ◽  
Polymer Laminates ◽  
Heated Glass

Oriented overgrowth of polymer materials onto ionic crystals is well known and recently it was demonstrated that this epitaxial crystallisation can also occur in polymer/polymer systems, under certain conditions. The morphologies and the resulting physical properties of such systems will be presented, especially the influence of epitaxial interfaces on the adhesion of polymer laminates and the mechanical properties of epitaxially crystallized sandwiched layers.Materials used were polyethylene, PE, Lupolen 6021 DX (HDPE) and 1810 D (LDPE) from BASF AG; polypropylene, PP, (PPN) provided by Höchst AG and polybutene-1, PB-1, Vestolen BT from Chemische Werke Hüls. Thin oriented films were prepared according to the method of Petermann and Gohil, by winding up two different polymer films from two separately heated glass-plates simultaneously with the help of a motor driven cylinder. One double layer was used for TEM investigations, while about 1000 sandwiched layers were taken for mechanical tests.

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