31 research outputs found
Controlled electrochemical growth of ultra-long gold nanoribbons
No full textCitation: Basnet, G., Panta, K. R., Thapa, P. S., & Flanders, B. N. (2017). Controlled electrochemical growth of ultra-long gold nanoribbons. Applied Physics Letters, 110(7), 5. doi:10.1063/1.4976027This paper describes the electrochemical growth of branchless gold nanoribbons with similar to 40 nm x similar to 300 nm cross sections and >100 mu m lengths (giving length-to-thickness aspect ratios of > 10(3)). These structures are useful for opto-electronic studies and as nanoscale electrodes. The 0.75-1.0V voltage amplitude range is optimal for branchless ribbon growth. Reduced amplitudes induce no growth, possibly due to reversible redox chemistry of gold at reduced amplitudes, whereas elevated amplitudes, or excess electrical noise, induce significant side-branching. The inter-relatedness of voltage-amplitude, noise, and side-branching in electrochemical nanoribbon growth is demonstrated. Published by AIP Publishing
Fabrication of Tungsten Tips Suitable for Scanning Probe Microscopy by Electrochemical Etching Methods
No full textThe fabrication of metal tips is becoming an interesting field for scientists who are working in spectroscopy measurements. A significant amount of work has already been done in the tips fabrication process. Metal tips used to analyze the surface of materials play a key role in the scanning tunneling microscope (STM) technique. It\u27s remarkable quality that it is used to study the surface of material at the atomic level.
There are various methods used in the tips fabrication process. Of diverse methods, three different electrochemical etching methods: submerged method, single lamella drop-off method, and double lamella drop-off method are commonly used to make various tips\u27 shapes such as smaller cone shape, larger cone shape, sharp cone shape, and extremely sharp cone shape at room temperature are reported in this thesis. With submerged method, we made various tips in different etching parameters. The bulk surfaces of the etched tips were characterized using a simple optical microscope. Various tips shapes affected by etching parameters are discussed in this thesis. To better control tips\u27 shapes, a single lamella method was used. However, the tips still etched when the lower part of the etching wire dropped because there was no auto cutoff etching circuit at the end of the etching process. Sometimes, this method produced non-cone shapes tips. To overcome this problem, a double lamella drop-off method was finally used. In this method, the various tips\u27 shapes were made by the variation of the etchant height from the upper mark of the etch stop on the etching tungsten wire. The etch stop was enough to control the tips\u27 shapes. The fabricated tips through various etching methods are recommended to study the surface of material in the STM chamber
Assessment of the Required Subdivision Index for autonomous ships based on equivalent safety
No full textIn recent years, a significant amount of research has been conducted on autonomous ships. Since it is assumed that these ships will sail with a significantly reduced crew or even without people on board, the design of the ship needs reconsideration. The absence of people on board and the associated safety measures could result in a more efficient design. However, to achieve the required design freedom, the existing regulatory framework will have to be amended. In this article, we will focus on potential changes in the Convention for Safety Of Life At Sea (SOLAS) and in particular on the Required Subdivision Index. The evaluation is performed by using the principle of equivalent safety, which will ensure that unmanned ships will be at least as safe as manned ships. The index gives a requirement for the allowed probability of sinking when a ship is damaged due to collision or contact. The safety level is related to the safety of ship, cargo, environment and crew. If the crew is no longer present, the consequences of an incident will be less severe, since the probability of casualties is no longer present. If the principle of equivalent safety is applied, a lower subdivision index can be accepted for unmanned autonomous vessels. In this article, the level of risk that a manned ship is subjected to will be derived by means of a risk analysis. In this risk analysis all logical consequences of a collision will be taken into account, covering both the probability of losing the entire ship and the consequences of the cases where the ship will not sink. Thereafter, the Required Subdivision Index for unmanned ships, which ensures an equivalent safety level to an equivalent manned ship, is established. The sensitivity of the result to changes in the data is discussed as well.Ship Design, Production and Operation
Laser-Induced Electron Emission from Au Nanowires: A Probe for Orthogonal Polarizations
No full textPhotoelectron field emission, induced by femtosecond laser pulses focused on metallic nanotips, provides spatially coherent and temporally short electron pulses. The properties of the photoelectron yield give insight into both the material properties of the nanostructure and the exciting laser focus. Ultralong nanoribbons, grown as a single crystal attached to a metallic taper, are sources of electron field emission that have not yet been characterized. In this report, photoemission from gold nanoribbon samples is studied and compared to emission from tungsten and gold tips. We observe that the emission from sharp tips generally depends on one transverse component of the exciting laser field, while the emission of a blunted nanoribbon is found to be sensitive to both components. We propose that this property makes photoemission from nanoribbons a candidate for position-sensitive detection of the longitudinal field component in a tightly focused beam
OPTIMALISASI PERSEDIAAN BAHAN BAKU MULTI-ITEM MULTI-SUPPLIER DENGAN MENGGUNAKAN MODIFIED BASNET AND LEUNG FORMULATION (Studi Kasus: PT. Petrokimia Gresik)
No full textJika membutuhkan abstrak atau isi jurnal silahkan menghubungi author melalui email [email protected], [email protected], [email protected] Terima kasi
The measurement of internal supply chain integration
No full textPurpose: Internal supply chain refers to the chain of activities within a company that concludes with providing a product to the customer. This process involves multiple functions within companies such as sales, production, and distribution. It is obvious that a company's performance would be enhanced by the integration of these functions. However, there is no consensus yet on how integration is to be defined and measured. The purpose of this paper is to present research that was conducted with the goal of developing an instrument for the measurement of internal supply chain integration. Design/methodology/approach: Scale items were identified from current literature and the resulting survey instrument was sent out to a sample of New Zealand manufacturers. Statistical analysis was conducted to purify and validate the instrument. Findings: In total, three dimensions of integration were identified, labelled coordination, communication, and affective relationship. This paper makes a contribution towards developing a consensus in the understanding and measurement of the integration construct. Research limitations/implications: The selection and exclusion of measurement items for the survey have followed established principles of survey research, but may have been affected by the personal bias of the author. While every attempt has been made to comprehensively capture the state of the research up to the time of the study, there may be some omissions. The sample for the survey was drawn from a database of New Zealand businesses, thus the results are generalizable only to the extent that these businesses represent the population of all businesses. Another limitation is that no prior survey/case studies were carried out to collect practitioner's definitions/measures for integration. Practical implications: The authors hope to have made a contribution here towards building a consensus among practitioners and researchers in defining and measuring internal supply chain integration. For practitioners, the measurement instrument offers a self-assessment tool for internal supply chain integration. This should help them in identifying areas for improvement. Originality/value: The contribution of this paper consists of: development of an instrument for the measurement of integration, validating the instrument against a criterion, and the identification of three dimensions of integration - communication, coordination, and affective relationship. The unique contributions of this paper are the validation of the instrument against a criterion and the identification of "affective relationship" as a dimension of internal supply chain integration
Etch-stop method for reliably fabricating sharp yet mechanically stable scanning tunneling microscope tips
No full textResearch on risk, safety, and reliability of autonomous ships: A bibliometric review
No full textThe safety and reliability of autonomous ships are critical for the successful realization of an autonomous maritime ecosystem. Research and collaboration between governments, industry, and academia are vital in achieving this goal. This paper conducts a bibliometric review of the research on the risk, safety, and reliability of autonomous ships aiming to provide researchers and maritime stakeholders with a structured overview of the topics, development trends, and collaboration networks in this research field. 417 papers published between 2011 and 2022 were identified covering 940 authors, 31 countries, and 227 journals. Three main themes were determined in this research domain: “safety engineering and risk assessment for decision making”, “navigation safety and collision avoidance”, and “cybersecurity risk analysis”. Meanwhile, it was identified that research on cybersecurity in autonomous shipping is moving to overlap with safety, which requires future co-analysis methods. Additionally, the analysis of the most cited 30 papers suggests that further research is needed in the topics of unmanned machinery operation risks, online risk tools, system-theoretic safety analysis, human factor, and the determination of suitable risk acceptance criteria for safety assessment of autonomous ships. Furthermore, the analysis revealed that the development of unambiguous COLREGs regulation is crucial for the development of safe collision avoidance algorithms for MASS. It was identified that the publication by Fan et al., (2020) is a key publication in this research field, while the journals of Ocean Engineering, Reliability Engineering & System Safety, and Safety Science are the key journals publishing on autonomous ship safety and reliability.Safety and Security Scienc
