Dielectric Coating of Cathodes for Microfabrication Using Electrochemical Method

Author(s):  
Anna Brusilovski

Pulse microelectrochemical machining (ECM) by bipolar current is a method allowing the manufacturing of microholes and micropatterns. In many cases, microholes with parallel walls and accurate micropatterns can only be manufactured with the application of an electrically isolating coating to the side surfaces of the cathode. The goal of this research was to find a durable coating for this process. Epoxy resins, Teflon, and diamond-like carbon are considered as dielectric cathode coatings. Different aspects of the working environment of these coatings in the pulse bipolar ECM process, such as electric field, chemical composition, and physical influences of the electrolyte, are analyzed. The main reasons for the low process durability of coatings are poor adhesion and harsh chemical and physical environments. The most promising coating for the process is diamond-like carbon, which shows significantly better performance than the other coatings. Improved adhesion of a coating to the cathode can dramatically improve its durability in the pulse bipolar ECM environment and therefore permits an efficient manufacturing process.

2017 ◽  
Vol 869 ◽  
pp. 226-233
Author(s):  
Patrick Ruediger ◽  
Hans Hagen

Uncertainty in manufacturing processes is as old as the manufacturing process itself. Simulationson the other hand are always certain in their outcome based on the chosen parameters. Nonethelessit makes sense to incorporate uncertainties in the simulation for validation and analysis of the realand simulated processes. This paper aims on highlighting the importance of an accurate understandingand measurement of uncertainty for simulation validation and thus to increase the significance andacceptance of simulation results in the working environment.


2019 ◽  
Vol 2 (4) ◽  
pp. 276-291
Author(s):  
Chatarina Natalia Putri

There are many factors that can lead to internship satisfaction. Working environment is one of the factors that will result to such outcome. However, many organizations discarded the fact of its importance. The purpose of this study is to determine whether there is a significant relationship between working environment and internship satisfaction level as well as to determine whether the dimensions of working environment significantly affect internship satisfaction. The said dimensions are, learning opportunities, supervisory support, career development opportunities, co-workers support, organization satisfaction, working hours and esteem needs. A total of 111 questionnaires were distributed to the respondents and were processed by SPSS program to obtain the result of this study. The results reveal that learning opportunities, career development opportunities, organization satisfaction and esteem needs are factors that contribute to internship satisfaction level. In the other hand, supervisory support, co-workers support and working hours are factors that lead to internship dissatisfaction. The result also shows that organization satisfaction is the strongest factor that affects internship satisfaction while co-workers support is the weakest.


Insects ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 340
Author(s):  
Kitherian Sahayaraj ◽  
Balakrishnan Saranya ◽  
Samy Sayed ◽  
Loko Yêyinou Laura Estelle ◽  
Koilraj Madasamy

The foam produced by nymphs of Poophilus costalis on eleven different host plants belonging to eight families on St. Xavier’s College campus in India was studied over five months. The chemical composition and antimicrobial activity of these biofoams were investigated. The results revealed that P. costalis preferred Theporsia purpurea and Mimosa pudica for laying their eggs and producing foam, over the other tested plants. P. costalis produce their foam on either nodes or internodes on monocotyledons (30%) (p < 0.05), whereas on dicotyledons, they produce more foam on the stems (63.8%) than on the leaves (6.2%) (p < 0.01). The number of nymphs in each piece of foam from P. costalis varied from 1 to 3 (mean = 1.8 per plant). They produced their foam (5.7 to 45.2 cm) from the ground level on a plant. The length and breadth of a piece of foam ranged from 1.0 to 3.9 cm and 0.6 to 4.7 cm, respectively. The foam tended to be cooler than the environment. Qualitative profiling showed that the foam consists of carbohydrates, including maltose; trypsin; amino acids; protease. The foam was also analyzed using a spectrophotometer, Fourier transform infrared spectroscopy (FT-IR), gas chromatography–mass spectroscopy (GC-MS), and high-performance liquid chromatography (HPLC). The antimicrobial activity of the biofoam was the greatest against Staphylococcus aureus, the growth of which was reduced by 55.9 ± 3.9%, suggesting that the foam could be used as an antimicrobial product. However, no activities were observed against Fusarium oxysporum and Candida albicans.


2016 ◽  
Vol 14 (4) ◽  
pp. 377-388 ◽  
Author(s):  
Maelle Amand ◽  
Zakaria Touhami

Studies on stop unrelease in second language acquisition have hitherto focused on the productions of Slavic learners of English (Šimačkova & Podlipsky, 2015) and experiments on Polish learners of English; the latter show the tendency to release stops on a more regular basis depending on the type of stop combinations (Rojczyk et al. 2013). In the present study, we aim to test the efficiency of audio-visual explanations as opposed to distracted imitation in pronunciation teaching amongst French learners of English. While unreleased stops are rather frequent in French and English - especially in plosives clusters (Byrd, 1993; Davidson, 2010), unreleased plosives in final positions are less common in French (Van Dommelen, 1983). During phase 1 of the experiment, three groups of 12 native French learners of English (level A1/A2, B1/B2 and C1/C2) were asked to read idiomatic expressions containing both homogeneous and heterogeneous sequences of voiceless stops straddled between words, namely, in sequences like “that cat” [dat˺ kat˺], and stops at the end of sentences like “I told him to speak” [tə spiːk˺]. In the second phase of the experiment, one half in each group was given a different task. The first group heard recorded versions of phase 1 sentences and before reading them out loud, counted up to five in their L1. Stimuli for imitation contained no release in the contexts under scrutiny. The other half had to watch a video explaining the phenomenon of unreleased stops with a production of phase-two expressions propped up by hand gestures. They were then asked to re-read the sentences given in phase 1. Based on these results the current study makes recommendations about what working environment should be prioritized in pronunciation teaching both in class and online (Kroger et al. 2010), and suggests ways to assess students and visually keep track of their progress.


2018 ◽  
Vol 11 (1) ◽  
pp. 69-77
Author(s):  
Fabrizio Perroni ◽  
Eric Mol ◽  
Anthony Walker ◽  
Calogero Alaimo ◽  
Laura Guidetti ◽  
...  

Background: In order to stay safe, and to successfully complete their work, firefighters have to constantly assess and process large numbers of sensory stimuli and adapt to the inherent risks present in the working environment. Objective: The purposes of the present preliminary study were to analyse the speed of Reaction Time responses (RT) of Italian Firefighters and to compare their cognitive responses with non-firefighting subjects. Methods: Anthropometric (weight, height and BMI) and RT (time-to-completion –TTC-, mean of reaction time –MRT-, and errors made -E-) evaluations were administered at 16 volunteers (Age: 40.3 ± 6.7 yrs; BMI: 23.8 ± 2.3 kg/m2) divided in Firefighters (FG) and Control (CG) groups. RT test consisted of 3 trials (T1 = 1s of stimulus duration and 1s interval between stimulus and the other; T2 = 0.5s of stimulus duration and 1s interval between stimulus and the other; T3 = 0.5s of stimulus duration and 0.5s interval between stimulus and the other). Mann Whitney U test between groups was applied to asses differences (p ≤ 0.05) in TTC, MRT, and E while Friedmann test and Dunn-Sidak post hoc were used to evaluate significant differences in the 3 trials in each variable of each group. Results: No significant differences based on anthropometric parameters were observed between groups. Despite no significant differences emerged for TTC and MRT between groups, we observed significant differences in E between groups (CG = 4; FG =12) and in the 3rd condition in each variable of each group. Conclusion: Workout programs that integrate reaction time training with job performance should be created to increase job performance.


2021 ◽  
Vol 5 (3) ◽  
Author(s):  
Marcel Biewendt ◽  
Florian Blaschke ◽  
Arno Böhnert

The presented paper gives an overview of the most important and most common theories and concepts from the economic field of organisational change and is also enriched with quantitative publication data, which underlines the relevance of the topic. In particular, the topic presented is interwoven in an interdisciplinary way with economic psychological models, which are underpinned within the models with content from leading scholars in the field. The pace of change in companies is accelerating, as is technological change in our society. Adaptations of the corporate structure, but also of management techniques and tasks, are therefore indispensable. This includes not only the right approaches to employee motivation, but also the correct use of intrinsic and extrinsic motivational factors. Based on the hypothesis put forward by the scientist and researcher Rollinson in his book “Organisational behaviour and analysis” that managers believe motivational resources are available at all times, socio-economic and economic psychological theories are contrasted here in order to critically examine this statement. In addition, a fictitious company was created as a model for this work in order to illustrate the effects of motivational deficits in practice. In this context, the theories presented are applied to concrete problems within the model and conclusions are drawn about their influence and applicability. This led to the conclusion that motivation is a very individual challenge for each employee, which requires adapted and personalised approaches. On the other hand, the recommendations for action for supervisors in the case of motivation deficits also cannot be answered in a blanket manner, but can only be solved with the help of professional, expert-supported processing due to the economic-psychological realities of motivation. Identifying, analysing and remedying individual employee motivation deficits is, according to the authors, a problem and a challenge of great importance, especially in the context of rapidly changing ecosystems in modern companies, as motivation also influences other factors such as individual productivity. The authors therefore conclude that good motivation through the individual and customised promotion and further training of employees is an important point for achieving important corporate goals in order to remain competitive on the one hand and to create a productive and pleasant working environment on the other.


2019 ◽  
Vol 70 (9) ◽  
pp. 3210-3212
Author(s):  
Oana Claudia Ciobotea Barbu ◽  
Ioana Alina Ciobotaru ◽  
Anca Cojocaru ◽  
Florin Mihai Benga ◽  
Danut Ionel Vaireanu

Nickel-Copper metallic layers were deposited onto a steel substrate by using the electrochemical method. The morphology and the chemical composition of the deposited layers were studied by scanning electron microscopy. The electrical capacitance was measured on a functional supercapacitor made of two Ni-Cu deposited layers and a Nafion 117� membrane hydrated with distilled water, which served as a dielectric separator.


1913 ◽  
Vol 18 (5) ◽  
pp. 584-590
Author(s):  
L. J. Gillespie

1. Pneumococci, when freshly isolated from the body, are able to live and multiply when a small number of them are inoculated into a small amount of broth. If, however, the inoculations are made in large amounts of broth, many more bacteria must be inoculated in order that they may grow. 2. It requires much smaller numbers of pneumococci to start a growth on agar than are required to start a growth in broth. 3. This predilection for solid medium disappears when the bacteria are grown for some time outside the body. 4. This phenomenon is not dependent on differences in chemical composition between the two media employed or on the presence of more available oxygen in one case than in the other. 5. It is probably dependent entirely on physical differences in the two kinds of media, and bears some relation to the differences in possibilities for diffusion in the two media.


2014 ◽  
Vol 60 (2) ◽  
pp. 7-17 ◽  
Author(s):  
Aneta Wesołowska ◽  
Monika Grzeszczuk ◽  
Dorota Jadczak

Abstract The aim of the studies conducted in 2012-2013 was to compare the chemical composition of essential oils isolated from wild thyme (Thymus serpyllum L.) by hydrodistillation in Deryng and Clevenger apparatus. GC-MS analysis of the isolated oils revealed that carvacrol (42.81-45.24%), γ-terpinene (7.68-9.04%), β-caryophyllene (5.28-9.10%), β-bisabolene (5.76-6.91%) and carvacrol methyl ether (4.92-6.09%) were the major components of all the samples. On the basis of the obtained data it was proved that the type of distillation apparatus had no significant effect on the content of the main essential oil constituents of wild thyme. However, based on the means for both years of the study it was proved that hydrodistillation in Deryng apparatus was more effective for carvacrol concentration, while in Clevenger apparatus - for y-terpinene and carvacrol methyl ether concentration. The type of distillation apparatus had no significant effect on the content of the other essential oil constituents.


2014 ◽  
Vol 609-610 ◽  
pp. 64-67
Author(s):  
Xiao Ni Ma ◽  
Li Hua Zhang ◽  
Li Xue Zheng ◽  
Zhan Hua Yang ◽  
Qing Gao ◽  
...  

Anodic spark deposition (ASD) is a novel technique to deposit bioceramic films on the surface of titanium (Ti) and its alloys, and the films prepared with nano/micro scale pores are characterized by high-quality performance for dental implant. Among the process parameters, electrolyte provides a leading role owing to its vital influence not only on the films chemistry but also on the electrical conductivity of the circuit, which affects the film properties. In this study, titania porous films were synthesized by ASD and the effect of electrolytic temperature on microstructure and chemical composition of the films was studied. The results show that the electrolytic temperature could significantly influence the surface topography, thickness and chemical composition of the oxidation films produced by ASD and, therefore, determined the layered hydroapatite (HA) deposition as the other process parameters were fixed.


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