scholarly journals A Binder Jet Printed, Stainless Steel Preconcentrator as an In-Line Injector of Volatile Organic Compounds

Sensors ◽  
2019 ◽  
Vol 19 (12) ◽  
pp. 2748 ◽  
Author(s):  
Xiaolu Huang ◽  
Tyler Bauder ◽  
Truong Do ◽  
Hawke Suen ◽  
Connor Boss ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Base Material ◽  
Liquidus Line ◽  
High Yield ◽  
Full Density ◽  
Small Scale ◽  
Shape Distortion ◽  
Sensor Applications ◽  
Temperature Detector ◽  
Gaseous Analytes

A conventional approach to making miniature or microscale gas chromatography (GC) components relies on silicon as a base material and MEMS fabrication as manufacturing processes. However, these devices often fail in medium-to-high temperature applications due to a lack of robust fluidic interconnects and a high-yield bonding process. This paper explores the feasibility of using metal additive manufacturing (AM), which is also known as metal 3D printing, as an alternative platform to produce small-scale microfluidic devices that can operate at a temperature higher than that which polymers can withstand. Binder jet printing (BJP), one of the metal AM processes, was utilized to make stainless steel (SS) preconcentrators (PCs) with submillimeter internal features. PCs can increase the concentration of gaseous analytes or serve as an inline injector for GC or gas sensor applications. Normally, parts printed by BJP are highly porous and thus often infiltrated with low melting point metal. By adding to SS316 powder sintering additives such as boron nitride (BN), which reduces the liquidus line temperature, we produce near full-density SS PCs at sintering temperatures much lower than the SS melting temperature, and importantly without any measurable shape distortion. Conversely, the SS PC without BN remains porous after the sintering process and unsuitable for fluidic applications. Since the SS parts, unlike Si, are compatible with machining, they can be modified to work with commercial compression fitting. The PC structures as well as the connection with the fitting are leak-free with relatively high operating pressures. A flexible membrane heater along with a resistance-temperature detector is integrated with the SS PCs for thermal desorption. The proof-of-concept experiment demonstrates that the SS PC can preconcentrate and inject 0.6% headspace toluene to enhance the detector’s response.

Fatigue Crack Growth Properties of a Cryogenic Structural Steel at Liquid Helium Temperature

1996 ◽  
Vol 118 (1) ◽  
pp. 109-113 ◽  
Author(s):  
Shinji Konosu ◽  
Tomohiro Kishiro ◽  
Ogi Ivano ◽  
Yoshihiko Nunoya ◽  
Hideo Nakajima ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Fatigue Crack ◽  
Austenitic Stainless Steel ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Liquid Helium ◽  
Liquid Helium Temperature ◽  
Small Scale ◽  
Helium Temperature ◽  
Growth Properties

The structural materials of the coils of superconducting magnets utilized in thermonuclear fusion reactors are used at liquid helium (4.2 K) temperatures and are subjected to repeated thermal stresses and electromagnetic forces. A high strength, high toughness austenitic stainless steel (12Cr-12Ni-10Mn-5Mo-0.2N) has recently been developed for large, thick-walled components used in such environments. This material is non-magnetic even when subjected to processing and, because it is a forging material, it is advantageous as a structural material for large components. In the current research, a large forging of 12Cr-12Ni-10Mn-5Mo-0.2N austenitic stainless steel, was fabricated to a thickness of 250 mm, which is typical of section thicknesses encountered in actual equipment. The tensile fatigue crack growth properties of the forging were examined at liquid helium temperature as function of specimen location across the thickness of the forging. There was virtually no evidence of variation in tensile strength or fatigue crack growth properties attributable to different sampling locations in the thickness direction and no effect of thickness due to the forging or solution treatment associated with large forgings was observed. It has been clarified that there are cases in which small scale yielding (SSY) conditions are not fulfilled when stress ratios are large. ΔJ was introduced in order to achieve unified expression inclusive of these regions and, by expressing crack growth rate accordingly, the following formula was obtained at the second stage (middle range). da/dN = CJ ΔJmJ, CJ = AJ/(ΔJ0)mJ, where, AJ = 1.47 × 10−5 mm/cycle, ΔJ0 = 2.42 × 103N/m.

scholarly journals Simplified Orange (Citrus spp.) Production Guide for Small-scale Farmers

2020 ◽  
pp. 23-27
Author(s):  
Hillary M. O. Otieno
Keyword(s):  
Soil Analysis ◽  
Fruit Fly ◽  
Codling Moth ◽  
Water Infiltration ◽  
High Yield ◽  
Small Scale ◽  
Leaf Miners ◽  
Land Preparation ◽  
False Codling Moth ◽  
Small Scale Farmers

Orange production provides both nutritional and financial benefits to farmers across Africa. However, these farmers do not realize the full benefits due to low yields caused by poor agronomic practices currently applied in the region. This guide, therefore, highlights key practices that farmers need to adopt for better yields. Farmers should always follow the best practices right from the selection of a variety to harvesting practices for high yield and better quality fruits to be achieved. Proper land preparation helps in early weed control and improves water infiltration and growth of roots. Weeds should always be kept below economic thresholds to ensure efficiencies in the use of water and nutrient. Like other plants, oranges require proper nutrition for growth and development of big fruits. Both manure and inorganic fertilizers should be applied depending on the availability and cost. Soil analysis helps in determining the rates of application. During production, farmers should scout for pests such as aphids, false codling moth, whiteflies, leaf miners, thrips, fruit fly and common spiral nematode and diseases like Pseudocercospora leaf and fruit spot, Phytophthora spp. and orange fruit scab which are common in the area. These pests cause significant yield losses if not timely controlled. When ready, harvesting of fruits should be careful and gentle without causing injuries.

scholarly journals The anaerobic digestion of sheep manure in self-designed low-cost biogas reactor

2018 ◽  
Vol 12 (2) ◽  
pp. 13-23 ◽  
Author(s):  
Gábor Nagy ◽  
Alexandra Takács ◽  
András Arnold Kállay ◽  
Dóra Mentes
Keyword(s):  
Main Product ◽  
Low Cost ◽  
Base Material ◽  
Solid Material ◽  
Gas Production ◽  
Small Scale ◽  
Fluid Displacement ◽  
Data Collector ◽  
Sheep Manure ◽  
Biogas Reactor

One of the possible utilisation methods for organic wastes is anaerobe decomposition (fermentation). The main product of this process is biogas which is usually used for energy purposes due to its composition (mainly methane and carbon dioxide). The residual solid material after fermentation can be used as soil conditioner. Lab-scale fermentation can be carried out using the “VDI 4630 – Fermentation of organic materials Characterisation of the substrate, sampling, collection of material data, fermentation tests” standard. Based on the conditions described in the standard, a small-scale low-budget reactor system were prepared. The temperature during the holding time was controlled with water bath and the gas production was determined with fluid displacement method. A peristaltic pump was used for the recirculation of the gas to mix the base material. Furthermore, the temperatures of the environment, the water baths and the inside of each reactor was automatically registered on a data collector.

scholarly journals Investigating the Type of Gene Action Conditioning Tolerance to Aluminum (Al) Toxicity in Tropical Maize

2019 ◽  
pp. 1-8
Author(s):  
Victoria Ndeke ◽  
Langa Tembo
Keyword(s):  
Root Length ◽  
Aluminum Toxicity ◽  
Gene Action ◽  
Abiotic Factors ◽  
Al Toxicity ◽  
High Yield ◽  
Small Scale ◽  
Tropical Maize ◽  
Maize Varieties ◽  
Small Scale Farmers

Maize is a third important cereal crop in the world after wheat and rice. In Zambia, it is an important staple crop. Its production is however hampered by both biotic and abiotic factors. Among the abiotic factors, Aluminum (Al) toxicity causes high yield losses and is directly linked to acidic soils. Application of lime can ameliorate this problem, but it is expensive for small scale farmers. Developing maize varieties that are tolerant to Al toxicity is cheaper and feasible for small scale farmers. The purpose of this research was to investigate the type of gene action conditioning tolerance to aluminum toxicity in tropical maize.  Eleven inbred lines were mated in an 8 male (4 moderately tolerant and 4 susceptible) x 3 female (resistant) North Carolina Design II. Results revealed that general combining ability (GCA) effects due to both males and females were highly significant (P≤ 0.001) for root biomass. The shoot length GCA effects due to both male and female respectively were significant (P≤ 0.01). Similarly, the GCA effects due to females and males for root length were significant, P≤ 0.01 and P≤ 0.05 respectively. The genotype CML 511 had the most desirable significant GCA effect value (1.40) for root length among the male lines while CML 538 had the most desirable significant GCA effect value (0.92) among the female lines. The baker’s ratio for root length was found to be 0.49 implying that both additive and non-additive gene action were important in conditioning aluminum toxicity tolerance in tropical maize.

scholarly journals Pengaruh Perlakuan Panas Quenching dan Tempering terhadap Laju Korosi pada Baja AISI 420

2017 ◽  
Vol 1 (2) ◽  
pp. 19
Author(s):  
Sotya Anggoro
Keyword(s):  
Heat Treatment ◽  
Stainless Steel ◽  
Corrosion Rate ◽  
Base Material ◽  
Air Cooling ◽  
Corrosion Resistant ◽  
A Value ◽  
Aisi 420 ◽  
Quenching Process ◽  
Cooling Media

<p>Corrosion occurs in almost all metals. Even corrosion-resistant metals are corroded, but their corrosion rate is different from ordinary or non-corrosion resistant metals. This study examines the corrosion rate that occurs in stainless steel that is stainless steel. Stainless steel contains high enough chromium levels that can reduce the rate of corrosion that occurs. The metal material to be studied is the AISI 420 steel, which belongs to the Martensitic Stainless Steel class. This study examined the effect of heat treatment on corrosion rate and hardness level of AISI 420 steel. The heat treatment carried out was Quenching at 1020<sup>o</sup>C with a holding time of 60minutes with an oil cooling medium. After quenching the subsequent heat treatment is tempering with temperature variations of temperature 200<sup>o</sup>C and 300<sup>o</sup>C with a resistance time of 45 minutes and air cooling media. The results of this study showed that the base material specimens had the highest corrosion rate of 0.569 mm/y. The lowest corrosion rate is in specimens with quenching process with a value of 0.267 mm/y. The highest Vickers hardness values were found in specimens with quenching process with a value of 551 kg/mm<sup>2</sup>. The lowest hardness value is in the specimen with tempering process at 300<sup>o</sup>C with 405 kg/mm<sup>2</sup>.</p>

Yb:YAG Disc Laser Welding of Austenitic Stainless Steel Without Filler Material

2009 ◽  
Vol 410-411 ◽  
pp. 87-96 ◽  
Author(s):  
Markku Keskitalo ◽  
Kari Mäntyjärvi
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Cross Sections ◽  
Base Material ◽  
Tensile Tests ◽  
Solidification Cracking ◽  
Filler Material ◽  
Test Material ◽  
Butt Weld

The laser weldability of austenitic stainless steel (ASS) is good because of the material’s high absorptivity and favourable microstructure. There can be a slight possibility of solidification cracking at high welding speeds and low Crekv/Niekv ratios. Test welds were welded with a Yb:YAG disc laser. The test material was 3.2 mm EN 1.4404 2H C700 type stainless steel plate which was work hardened by cold rolling. The test materials were welded with different heat inputs ranging from 0.024 kJ/mm to 0.12 kJ/mm and with 300 mm and 200 mm focal lengths. The weld seams were square-groove welded as butt weld without filler material. The edges of the groove were made by mechanical or laser cutting. The hardness profiles from cross-sections of the welds were measured with a Vickers microhardness tester using 200 g weight. The mechanical properties were tested with tensile tests. The welds were classified with radiographic verification by an accredited laboratory. A number of the welds were fatigue tested with a bending fatigue tester. The mechanical properties (Rp 0.2%, Rm) of the laser welds were almost the same as in the base material except at the highest heat input. In the radiographic classification, the welds which were welded to the laser-cut edge were classified as class B (accepted). The other welds were classified as class D or C (rejected). The main reasons for the rejection of welds made on mechanically cut edges were lack of penetration or undercut of the weld. A problem with mechanically cut edges, and hence the welds, is that they can be non-square and bent edge. Fatigue tests and tensile tests gave no evidence of solidification cracking in the microstructure of the solidified parts of the welds.

Comparing Nuclear and Chemical Power Sources for MEMS/NEMS Applications

2021 ◽  
Author(s):  
Oliver M. Barham
Keyword(s):  
Energy Density ◽  
Lithium Battery ◽  
Radioactive Isotopes ◽  
Small Scale ◽  
Implantable Medical Devices ◽  
Power Sources ◽  
Chemical Power Sources ◽  
Sensor Applications ◽  
Power And Energy ◽  
Nuclear Batteries

Abstract Nuclear batteries are a class of power sources that harvest energy from decaying radioactive isotopes to generate electricity for powering sensors and electronics. They are well known in the fields of space exploration and implantable medical devices, but are not widely known to micro or nano-technologists in general. Nuclear batteries are compared against chemical sources of energy applicable to small-scale systems, including energy harvesting prototypes and a mm-scale commercial lithium battery, utilizing the metrics of volumetric power and energy density. Nuclear batteries benefit from orders of magnitude more energy density than power sources derived from chemical reactions, however they also have orders smaller power density. For some sensor applications, nuclear batteries enable capabilities not possible with chemical energy sources, and examples are discussed.

Comparing Environmental Impacts of Additive Manufacturing vs. Investment Casting for the Production of a Shroud for Gas Turbine

2021 ◽  
Author(s):  
Angela Serra ◽  
Martina Malarco ◽  
Alessandro Musacchio ◽  
Giulio Buia ◽  
Pietro Bartocci ◽  
...  
Keyword(s):  
Life Cycle ◽  
Additive Manufacturing ◽  
Environmental Impact ◽  
Investment Casting ◽  
Gas Turbines ◽  
Raw Materials ◽  
Base Material ◽  
Small Scale ◽  
Atomization Process ◽  
Traditional Manufacturing

Abstract Additive manufacturing (AM hereinafter) is revolutionizing prototyping production and even small-scale manufacturing. Usually it is assumed that AM has lower environmental impact, compared to traditional manufacturing processes, but there have been no comprehensive environmental life-cycle assessment studies confirming this, especially for the gas turbines (GT hereinafter) and turbomachinery sector. In this study the core processes performed at Baker Hughes site in Florence are considered, together with the powder production via atomization process to describe the overall environmental impact of a GT shroud produced through additive manufacturing and comparing it with traditional investment casting production process. Particular attention is given to materials production and logistics. The full component life cycle starts from the extraction of raw materials during mining, their fusion and, as said, the atomization process, the powders are transported to the gas turbines production site where they are used as base material in additive manufacturing, also machining and finishing processes are analyzed as they differ for a component produced by AM respect to one produced by traditional investment casting. From the analysis of the data obtained, it emerges that the AM process has better performances in terms of sustainability than the Investment casting (IC hereinafter), highlighted above all by a decrease in greenhouse gas emissions (GHG hereinafter) of over 40%.

scholarly journals Effect of Hot Isostatic Pressing on Porosity and Mechanical Properties of 316 L Stainless Steel Prepared by the Selective Laser Melting Method

Materials ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 4377
Author(s):  
Tomas Cegan ◽  
Marek Pagac ◽  
Jan Jurica ◽  
Katerina Skotnicova ◽  
Jiri Hajnys ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Hot Isostatic Pressing ◽  
Microstructural Analysis ◽  
Scanning Speed ◽  
High Yield ◽  
Laser Method ◽  
Preparation Conditions ◽  
Lower Porosity ◽  
316 L Stainless Steel

The manufacturing route primarily determines the properties of materials prepared by additive manufacturing methods. In this work, the microstructural features and mechanical properties of 316 L stainless steel prepared by the selective laser method have been determined. Three types of samples, (i) selective laser melted (SLM), (ii) selective laser melted and hot isostatic pressed (HIP) and (iii) selective laser melted and heat treated (HT), were characterized. Microstructural analysis revealed that SLM samples were formed by melt pool boundaries with fine cellular–dendritic-type microstructure. This type of microstructure disappeared after HT or HIP and material were formed by larger grains and sharply defined grain boundaries. The SLM-prepared samples contained different levels of porosity depending on the preparation conditions. The open interconnected LOF (lack of fusion) pores were observed in the samples, which were prepared with using of scanning speed 1200 mm/s. The blowhole and keyhole type of porosity were observed in the samples prepared by lower scanning speeds. The HIP caused a significant decrease in internal closed porosity to 0.1%, and a higher pressure of 190 MPa was more effective than the usually used pressure of 140 MPa, but for samples with open porosity, HIP was not effective. The relatively high yield strength of 570 MPa, tensile strength of 650 MPa and low ductility of 30–34% were determined for SLM samples with the lower porosity content than 1.3%. The samples after HIP showed lower yield strengths than after SLM (from 290 to 325 MPa) and relatively high ductility of 47.8–48.5%, regardless of the used SLM conditions.

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