Short Operational Life Research Articles

Some Observations on the Strength of Viking Ship Rudders

Technical papers which attempt to analyse historic and ancient ship structures using modern techniques appear only spasmodically in today’s learned engineering journals. There could be many good reasons for this; the lack of commercial incentives, the paucity of accurate engineering data and perhaps a certain reluctance to cross into an area which is rightly the province of the nautical archaeologist. This, in the author’s view is a pity since simplified analytical techniques of the type routinely used in design offices can offer useful cost-effective insights into the physical behaviour of historic ships and craft, without endangering the physical reconstruction or its crew. In addition as the input data are often only loosely defined, less sophisticated methods are ideal for conducting “data-sensitivity” investigations. One such paper (Loscombe, 2022) described efforts to apply modern local and global structural design methods to Viking-age ships with a view to establishing plausible operational factors of safety for comparison with modern requirements. This follow-up contribution continues with the theme by focusing on the rudder. Rudder failure can endanger any ship, ancient, medieval or modern but the Viking ship rudder has a number of structural features not found on modern vessels which invite retrospective stress analyses. One component in particular, the lower bearing in modern terminology, appears to have a very short operational life, measured in days rather than years as is the expectation for today’s marine vehicles and hence the Viking ship rudder is a good candidate for such simplified numerical analyses.

ЗНАЧЕННЯ СТАРТАПІВ У ПІДПРИЄМНИЦЬКІЙ ДІЯЛЬНОСТІ

With the existing complexity and variability of the modern market, the question of the expediency of further development and support of entrepreneurial activity remains relevant. In a reality where large funds are earned from the sale of information, communication, gadgets and computer entertainment, for a successful and rapidly growing business, you need to create your own startup. The main purpose of this work is to study the content analysis of the term "start-up", the specifics of the development of start-ups in entrepreneurial activity and the development of proposals for their activation. The article contains a content analysis of theoretical and semantic constructions in the definition of the term "startup". The author's vision of the term "startup" is provided, by which it is proposed to understand a new promising form of doing business, offering an innovative product or service, the purpose of which is rapid growth and scaling. The distinctive features of startups are considered, which include: short operational life cycle; unique idea; development of a high-tech product and innovative technology; scaling and high investment risks. The main stages of start-up development are revealed, namely: the seed stage; launch; early growth; extensions; exit. Certain problems in the development of startups have been identified. The types and characteristics of information technology startups are investigated separately: financial technology startups; medical technology startups; legal technology startups; educational technology startups. Complex process of development of startups in business should be: increased investment in intellectual potential; state support of domestic technological startups; information support for startups. Within the framework of the study, startups are recognized as key players in the venture capital market and are the main driver of innovative development of entrepreneurial activity, which increases interest in its unambiguous definition and research. It is the development of start-ups that contributes to the development of entrepreneurial activity, since with the emergence of an opportunity to embody ideas, innovations are introduced into business, science and other spheres of life.

Length of Operational Life and Its Impact on Life-Cycle Costs of a Tractor in Switzerland

Assuming full exhaustion of their estimated service life—also referred to as estimated technical working life—the low annual utilisation of agricultural machines in Switzerland leads to a long operational life. To determine the costs of an additional year’s service, we calculate the life-cycle costs (LCCs), which encompass all costs for an 82 kW four-wheel-drive tractor over its entire operational life. Assuming full utilisation of the estimated service life of 10,000 h, five operating versions are compared, each with an operational life of between 10 and 30 years and matched annual utilisations between 1000 h and 333 h. A key finding is that an additional year in service increases LCCs by 4.5% of the tractor’s purchase price. In addition, we carry out a sensitivity analysis by applying discount rates of between 0% and 4%, finding that a comparatively high discount rate of 3% leads to almost identical LCCs for all operating versions. We conclude that the annual utilisation and the resulting duration of operational life have a strong impact on LCCs. A short operational life associated with high annual utilisation is a promising strategy for substantially cutting machinery costs.

Invited: Bio-Inspired Electrocatalysts for Electrochemical Processes

Enzymes can be highly efficient and selective catalysts for important electrochemical processes such as Oxygen Reduction Reaction (ORR), Hydrogen Oxidation Reaction (HOR) or oxidation of alcohols incluting polyvalent alcohols (polyols) and complex organic acids such as malic or oxalic acid for example. At the same time enzymes (due to their size) have low active site density (one or two active sites per molecule is a norm), they have short operational life spans, and are limited to a relatively narrow pH and temperature operating conditions. We have made efforts to synthesize transition metal-nitrogen-carbon catalysts that resemble Mn-containing active site for oxalate oxidation. This materials were made by pyrolysis and then evalauted with multple spectroscopic techniques and modeled by DFT. We have found that the atomivally dispersed transitin metal coordinates with 3 N moeities in the carboanteous backbone structire of the ctalysts. This resemled closely the structure of the active site of the enzyme oxalate oxidase [1]. This paper will present an overview of our bio-mimietic strtaegies and will include also new results on ORR bio-inspired catalysts. In an effort to capitalize on the excellent selectivity and inexpensive materials content of enzymes while improving site density, stability, and durability we used “Materials data-mining” approach in order to identify copper-based mixed metal oxides that closely match the geometric and electronic structure of copper-center enzymes for catalysis of oxygen reduction reaction ORR. We have imposed the requirements on the conformation of the tri-Cu oxygen binding centers (T2/T3) from the native 3D structures of multi-copper oxidases and relaxed the requirement of the singular Cu site for the primary electron donation (the substrate oxidation active site T1). After screening geological and materials databases we have identified a list of mixed metal oxides that have the motive present as a part (segment) of their elementary cell. The Ln2CuO4 group materials, where Ln is the lanthanide series, most closely matches the geometric requirements of an ORR enzyme and can be tuned for electronic and bonding configuration while also offering the electronic conductivity and stability needed for an efficient ORR catalyst. A range of pure Copper Lanthanide Oxides was made using La/Pr/Nd and copper-like metals doped into the copper positions. These Ln-mixed oxide catalysts were synthesized, characterized, the tested for ORR and OER using RDE in alkaline environment. Catalysts were characterized for surface area, composition, crystal structure, nano-structure, and surface chemical state using XRD, BET, SEM/EDS HRTEM/STEM/EDS, and XPS. We will report on the meso and nano-scale phase purity of these Copper Lanthanides. The materials made were then tested as ORR catalysts. It was found that the La and Pr -based materials performed best. Doping of the Lanthanide and Copper components changes the ORR performance. For nickel doping, the performance of mixed Cu/Ni-lanthanum oxide showed a linear activity trend where Nickel reduced activity. The reactivity trends observed demonstrate a successful synthesis of copper-based mixed oxides which structurally mimic enzymes active for oxygen reduction reaction, and that these bio-mimetic oxides are catalytically active. Further, this work demonstrates a successful “materials genomics” approach to creating biomimetic electrocatalysts. [1] I. Matanovic, S. Babanova, A. Perry, A. Serov, K. Artyushkova and P. Atanassov, Bio-inspired Design of Electrocatalysts for Oxalate Oxidation: a Combined Experimental and Computational Study of Mn-N-C Catalyst, Phys. Chem. Chem. Phys., 17 (2015) 13235-13244

Human bone ingrowth into a porous tantalum acetabular cup

Porous Tantalum is increasingly used as a structural scaffold in orthopaedic applications. Information on the mechanisms of human bone ingrowth into trabecular metal implants is rather limited. In this work we have studied, qualitatively, human bone ingrowth into a retrieved porous tantalum monoblock acetabular cup using optical microscopy, scanning electron microscopy and energy dispersive X-ray analysis. According to the results and taking into account the short operational life (4 years) of the implant, bone ingrowth on the acetabular cup took place in the first two-rows of porous tantalum cells to an estimated depth of 1.5 to 2 mm. The bone material, grown inside the first raw of cells, had almost identical composition with the attached bone on the cup surface, as verified by the same Ca:P ratio. Bone ingrowth has been a gradual process starting with Ca deposition on the tantalum struts, followed by bone formation into the tantalum cells, with gradual densification of the bone tissue into hydroxyapatite. A critical step in this process has been the attachment of bone material to the tantalum struts following the topology of the porous tantalum scaffold. These results provide insight to the human bone ingrowth process into porous tantalum implants.

An Active Voltage Doubling Rectifier with Unbalanced-Biased Comparators for Piezoelectric Energy Harvesters

For wearable health monitoring systems, a fundamental problem is the limited space for storing energy, which can be translated into a short operational life. In this paper, a highly efficient active voltage doubling rectifier with a wide input range for micro-piezoelectric energy harvesting systems is proposed. To obtain a higher output voltage, the Dickson charge pump topology is chosen in this design. By replacing the passive diodes with unbalanced-biased comparator-controlled active counterparts, the proposed rectifier minimizes the voltage losses along the conduction path and solves the reverse leakage problem caused by conventional comparator-controlled active diodes. To improve the rectifier input voltage sensitivity and decrease the minimum operational input voltage, two low power common-gate comparators are introduced in the proposed design. To keep the comparator from oscillating, a positive feedback loop formed by the capacitor C is added to it. Based on the SMIC 0.18-μm standard CMOS process, the proposed rectifier is simulated and implemented. The area of the whole chip is 0.91×0.97 mm², while the rectifier core occupies only 13% of this area. The measured results show that the proposed rectifier can operate properly with input amplitudes ranging from 0.2 to 1.0V and with frequencies ranging from 20 to 3000 Hz. The proposed rectifier can achieve a 92.5% power conversion efficiency (PCE) with input amplitudes equal to 0.6 V at 200 Hz. The voltage conversion efficiency (VCE) is around 93% for input amplitudes greater than 0.3 V and load resistances larger than 20kΩ.

A 2-$\mu$m BiCMOS Rectifier-Free AC–DC Piezoelectric Energy Harvester-Charger IC

A fundamental problem that miniaturized systems, such as biomedical implants, face is limited space for storing energy, which translates to short operational life. Harvesting energy from the surrounding environment, which is virtually a boundless source at these scales, can overcome this restriction, if losses in the system are sufficiently low. To that end, the 2-μm bi-complementary metal-oxide semiconductor switched-inductor piezoelectric harvester prototype evaluated and presented in this paper eliminates the restrictions associated with a rectifier to produce and channel 30 μW from a periodic 72- μW piezoelectric source into a battery directly. In doing so, the circuit also increases the system's electrical damping force to draw more power and energy from the transducer, effectively increasing its mechanical-electrical efficiency by up to 78%. The system also harnesses up to 659 nJ from nonperiodic mechanical vibrations, which are more prevalent in the environment, with 6.1±1.5% to 8.8±6.9% of end-to-end mechanical-electrical efficiency.

EQUATOR-S: The mission and first coordinated measurements with GEOTAIL

An overview of the origin of the EQUATOR-S mission, the spacecraft development and the mission history is given. In spite of its short operational life of only five months, the major goals were fulfilled, except that its contribution to IASTP science is restricted to the morning sector of the outer magnetosphere. A few data sets illustrating the satellite's capability are presented.

<i>Introduction</i>: The Equator-S mission

Abstract. In spite of its short operational life of only five months, the major goals of the Equator-S mission were fulfilled, except that its contribution to the ISTP science is restricted to the morning sector of the outer magnetosphere. A set of twelve papers following this introduction is a first documentation of the achievements. They span from the successful testing and operation of the most advanced and complex way of measuring electric fields in a hot plasma environment by means of electron beams, to various investigations at or near the equatorial magnetopause and in the plasma sheet.

The Equator-S mission

In spite of its short operational life of only five months, the major goals of the Equator-S mission were fulfilled, except that its contribution to the ISTP science is restricted to the morning sector of the outer magnetosphere. A set of twelve papers following this introduction is a first documentation of the achievements. They span from the successful testing and operation of the most advanced and complex way of measuring electric fields in a hot plasma environment by means of electron beams, to various investigations at or near the equatorial magnetopause and in the plasma sheet.

Replica grating radiation damage in a normal incidence monochromator

Experience with the Synchrotron Radiation Center 4 meter normal incidence monochromator has revealed short operational life for the high energy gratings. Within periods as short as 6 months, the resolution of the gratings degraded sufficiently to limit the resolution to values expected with 80 micron slits. This decrease in resolution occurs without any noticeable changes in the efficiency or throughput of the grating. The resolution degradation has been shown to have been caused by light between 100 and 200 eV, which was transmitted through the gold layer of the replica grating and caused shrinkage of the epoxy. This resulted in distortion of the surface. The problem was solved by ordering a special replica grating with a double layer of gold. Calculations indicate that a thicker gold layer should decrease the flux penetrating the epoxy layer by a factor of ten slowing down the deterioration of the grating figure. A grating with a double thickness gold layer has been operating in the monochromator for more than one year with no noticeable decrease in the resolution.

Diphenylphosphin-substituiertes, chirales Polyepichlorhydrin, ein Träger für die heterogene, asymmetrische Katalyse / Diphenylphosphine-Substituted, Chiral Polyepichlorohydrin, a Support for the Heterogeneous, Asymmetric Catalysis

Chiral polyepichlorohydrin was obtained as a crystalline, optically active powder by coordinative polymerization of S(+)-epichlorohydrin. Subsequent reaction with lithium diphenylphosphide in THF resulted in substitution of about 90% of the chlorine atoms by the P(C6H5)2 group to give an insoluble polymer, which was characterized by elemental analysis, 31P CP MAS NMR, and IR spectroscopy. On addition of solutions of bis(1.5-cyclooctadiene)-rhodium tetrafluoroborate to the polymer “heterogenization” of the complex occurred. The reason for the as yet short operational life time during the hydrogenation of α-acetamido cinnamic acid is the leaching of the metal complex moiety. The rhodium atom is coordinated to only one phosphorus atom of the polymer in the side group and rather weakly to one oxygen atom of the polymer chain.

Development of long-life BF3 counters.

In order to improve the well-known short operational life time of BF3 counters, three potential adsorbents for impurity gases (graphite, activated charcoal and a zirconium-aluminum mixture) were introduced into BF3 counters in the form of coating on the aluminum cathode surface. Tests in γ fields revealed that a partial coating of activated charcoal provides the best result. The improvement of their operational life in γ fields was about three orders of magnitude in terms of tolerable exposure. Many counters with a partial coating of activated charcoal were further tested from the following viewpoints: background noise, vibration and shock, γ pulse discrimination, operational life in a neutron field and non-operational in-reactor exposure life. The results were satisfactory for reactor control and protection usage.

Remote Reading Bottom-Hole Pressure Gauges- An Evaluation of Installation Techniques And Practical Applications

Abstract Since 1959, 50 field installations of remote reading bottom-hole pressure gauges have been made on the Cedar Creek anticline in Eastern Montana. The installations were made in wells 9,000 ft deep with bottom-hole temperatures as high as 200F, and included both taut wire and bourdon tube bottom-hole pressure transducers. The initial installations had short periods of operational life because of cable and instrument failures. Continued investigation of installation techniques and types of cable have resulted in operational periods in excess of one year with an expected life of two years or more. Eleven types of cables were tested with various types of insulation and protective sheaths, various outside diameters, and solid and stranded conductors. Several methods of splicing were evaluated for mechanical strength and insulating qualities; a new cable clamp had to be designed; dawn-hole and surface conductor pack-offs were revised; and surface handling techniques had to be developed. Several case histories of practical applications are cited, which include bottom-hale pressure build-up surveys, water flood observation well surveillance and performances of producing wells. The installation cost figures included demonstrate that, although the use of remote bottom-hole pressure gauges cannot be justified in every producing well of this depth, installation in most key observation wells can be justified, depending upon the volume and importance of the data required. Practical installations of remote reading bottom-hole pressure gauges can now be made and have resulted in another valuable tool available to the petroleum engineer. Introduction Accurate and current down-hole pressure data are desirable to produce oil and gas wells at their optimum rate and by the most economical means. A permanently installed bottom-hole pressure gauge is an instrument which can provide such data for production personnel and engineers. The installation of remote reading bottom-hole pressure gauges in every producing well would be ideal from the standpoint of determining producing and static pressures and for detecting subtle equipment malfunctions. However, limited life expectancy and the existence of other indirect methods for determining bottom-hole pressure data have previously limited these installations to specialized cases. The development of the German-produced bottom-hole pressure transmitting system and its widespread use in the Schoonebeek and other fields in Europe prompted the investigation of practical applications in various Shell areas in the United States in 1958. Initial installations in the Pacific Coast, Texas and Rocky Mountain areas resulted in varying degrees of success. Fairly successful installations were made in relatively shallow wells, but the results were disappointing in wells ranging in depth from 6,000 to 9,000 ft. Short operational life and consequent expense were experienced in these wells. In view of the potential application of a direct reading and permanently installed pressure gauge, the development of practical installation techniques was classified as a General Development and Evaluation Project by Shell Oil and a sum of money was granted to the Rocky Mountain area for investigation and development of installation procedures and equipment evaluation. From these investigations, installation techniques have been refined and operating expenses have been reduced, permitting greater utilization and justification for these instruments. The remote reading bottom-hole pressure gauge has become an operational and a practical tool for wells producing highly aromatic hydrocarbons at depths to 9,000 ft, temperatures to 220F (104C) and pressures to 3,500 psi. Presently installed instruments have operated for an average duration of one year or more, and two year runs have been quite common. Installations in wells having less severe conditions should operate for significantly longer periods. This paper presents the experience obtained to date with these gauges and includes recommended installation and operating practices and materials. Theory of Operation of Existing Instruments To date two operational gauges are available for measuring bottomhole pressures on a remote reading basis. They are the German-produced taut wire gauge and the United States- produced bourdon tube-type gauge. The taut wire gauge was developed in 1948 and tested in German oil fields during 1950. JPT P. 1303^

Failure of Type 316 Stainless Steel Autoclave Components

Abstract A short account is given of an investigation into the cause of failure of a number of Type 316 stainless steel autoclave components that failed in service after an extremely short operational life. Failure of these components situated in the vapor phase was attributed to stress-corrosion cracking. The active corrodant was probably chloride while the stresses that initiated failure were predominantly residual. There is evidence that the components suffered some degree of cold working prior to installation, the latter probably resulting from machining or fabrication. The failure was in no way due to the use at any time of excessive operating temperatures or pressures. 7.6.3