Bottom Mount Research Articles

A Review on Design and Analysis of Multifunctional Seats used in Military Vehicle

This paper is based on the study of Design and Analysis of Multifunctional Seats Used in Military Vehicle. Border Security Technologies are being adopted by every country to ensure the safety and sovereignty of their nation. It is crucial to study and understand the latest advancements in security technologies to effectively protect against evolving threats. Just as countries are advancing in defence the threats, they face are also evolving necessitating the upgrading of defence system. Multifunctional Special Vehicles play a crucial role in ensuring the safety of their crew during operational tasks. These vehicles are equipped with specially designed seats that offer a high level of protection in the event of collisions or explosive detonations. The proposed modular structure of these seats brings numerous advantages, including cost reduction using repeatable elements and the ability to easily customize seats with different functions. Moreover, this modular structure enables a faster restoration process in case of any damage. It is essential for the modules to be versatile and adaptable to various seat configurations, considering factors such as their location within the vehicle (e.g., driver's seat, troops' seats, system operators' seats), installation method (e.g., wall, floor, ceiling), and assembly direction (e.g., side mount, rear mount, bottom mount). Key Words: Analysis of Multifunctional Seat, explosion proof seat, absorb explosion energy, Study of Vibration, Human body Impact and Safety in Transport.

Military special vehicle multifunctional seat as an element of vehicle passive safety

Road safety depends on the interaction in the human - vehicle - road system. The proper functioning or condition of each of these three elements is a prerequisite for ensuring the maximum possible level of safety. The most important requirement that is placed on special vehicles is to ensure crew protection during the implementation of operational tasks. Unfortunately, often when putting operational tasks overriding during designing vehicles, aspects related to driving comfort are ignored. The article presents a proposal for the description of light construction of seats for the crews of special vehicles, which, apart from the functions related to the ergonomic use of seats by the crew, in terms of safety ensure a high probability of protection of health and life of the crews during a collision or near detonation of an explosive charge. Proposed modular structure of the seats, in addition to the repeatability of elements, which reduces production costs and easy configuration of seats with various functions, will also contribute to a faster process of restoring their functionality in the event of damage. Modules should be selected and developed in such a way that they can be used in various configurations of seats, the functions of which can be determined due to: location in the vehicle, i.e. driver’s, troops, system operators’ seats, installation method, i.e. to the wall, floor, ceiling, direction assembly, i.e. side mount, rear mount, bottom mount.

Estimating propagation speed and direction, and vertical displacement of second-mode nonlinear internal waves from ADCP measurements

Propagation speed and direction, and vertical displacement of the second-mode nonlinear internal waves (NLIWs) over the continental shelf of the East China Sea are estimated by applying the iterative method, previously validated only for the first-mode NLIWs, to the along-beam velocities measured with the standard acoustic Doppler current profiler (ADCP). Two ADCPs mounted in trawl-resistance bottom mounts were deployed in upward looking configurations on the seabed at stations spaced 7.4 km apart, perpendicular to isobaths of the continental slope. During the observation period of two days, two wave trains arrived at an interval of approximately one day, whereas the flow was dominated by the semi-diurnal internal tide with a diurnal modulation. The results of the iteration show that the second-mode NLIWs of the convex type propagate shoreward at a speed of 0.44 (0.36) m s−1 at the offshore (onshore) station. The amplitude of the leading wave is estimated to be about 20 m at the offshore station, which is reduced to about 10 m at the onshore station. All the parameters agree remarkably well with those estimated independently from the backscatter signal of the ADCPs. The propagation time of 6.8 h estimated for the averaged propagation speed and direction is also consistent with a 6.9-h lag of the arrival time of the wave train between the two stations. In addition to the propagating features of the second-mode NLIWs, the iterative method reveals the wave-induced velocity associated with the radiation of short, small-amplitude first-mode waves from the second-mode NLIW, which has been observed only with shipboard echo sounders.

Seasonal variation of water transport through the Karimata Strait

Four trawl-resistant bottom mounts, with acoustic Doppler current profilers (ADCPs) embedded, were deployed in the Karimata Strait from November 2008 to June 2015 as part of the South China Sea-Indonesian Seas Transport/Exchange and Impact on Seasonal Fish Migration (SITE) Program, to estimate the volume and property transport between the South China Sea and Indonesian seas via the strait. The observed current data reveal that the volume transport through the Karimata Strait exhibits significant seasonal variation. The winteraveraged (from December to February) transport is–1.99 Sv (1 Sv=1×106 m3/s), while in the boreal summer (from June to August), the average transport is 0.69 Sv. Moreover, the average transport from January 2009 to December 2014 is–0.74 Sv (the positive/negative value indicates northward/southward transport). May and September are the transition period. In May, the currents in the Karimata Strait turn northward, consistent with the local monsoon. In September, the southeasterly trade wind is still present over the strait, driving surface water northward, whereas the bottom flow reverses direction, possibly because of the pressure gradient across the strait from north to south.

Toward Practical Powering of Oceanographic Sensors By Benthic Microbial Fuel Cells

Described here are the latest results from field tests of the Benthic Microbial Fuel Cell (BMFC). The BMFC sits on the sediment/water (benthic) interface of marine environments where it utilizes organic matter naturally residing in marine sediments as its fuel and oxygen in overlying water as its oxidant to generate electrical power. Both fuel and oxidant are used as found in the environment. The BMFC is expected to generate power indefinitely due to constant replenishment of organic matter and oxygen by naturally occurring mass transport (i.e., diffusion, advection, and tidal pumping); durability of its electrode catalysts consisting of self-forming biofilms comprised of microorganisms naturally inhabiting the benthic interface; and lack of moving, degrading, or depleting components. The BMFC is being developed to persistently power battery-powered oceanographic sensors presently limited in operational lifetime by battery depletion. During the past 10 years, we have successfully deployed small scale (< 0.1 Watt continuous output) BMFCs in coastal waters world wide ranging in depth from < 1 m to > 1000 m over for up to 2 years before being retrieved without any depletion in power output; and have powered a riverine metrological buoy with a radio transceiver link, a hydrophone with a radio transceiver link, and a surveillance camera with a cellular link. The highest power density we have thus far achieved is 0.39 Watt continuous power per square meter footprint area of sediment surface occupied by an early prototype that required extensive in-water manipulation by divers to deploy. This BMFC had a 29-liter volume, a 0.09-square meter footprint area (area of sediment surface occupied), and sustained 0.036 Watt continuously. Subsequently, by scaling up this BMFC we achieved the highest sustained power by a BMFC of 0.47 Watt continuous power (370 liter, 1.2 square meter footprint area, 0.39 Watt continuous power per square meter footprint area). Based on the 3.1 square meter footprint area of the oceanographic moorings we presently use to house battery-powered sensors, our long-term goal of a BMFC-equipped mooring capable of sustaining > 1 Watt is thought achievable. This amount of power, the equivalent of 440 alkaline D cells per year of operation based on optimal battery performance, is more than sufficient to operate complicated oceanographic instruments (e.g., an acoustic Doppler current profiler), including processing and transmitting data at least once a day either by acoustic telemetry or by radio to satellites. Practical considerations that limit the size of oceanographic battery packs (weight, cost, and size) compounded by poor battery performance at low temperatures encountered at the bottom of most marine environments limit the duration of most battery-powered sensors to 1 year. In contrast, the putative unlimited duration of BMFCs make them appealing for long-duration applications if BMFCs can be reliably deployed without in-water manipulation. Our current efforts to be reported on here center on iterative design and evaluation of full scale (targeting > 1 Watt continuous power) by BMFCS that do not require in-water manipulation by divers and/or remotely operated vehicles to deploy (i.e., drop and go). The challenge for deployment is the requirement that the anode be in contact with anoxic sediment and isolated from over lying oxic water. Our most recent design, to be described here, sustained 0.03 W continuous power when configured with a 1-m diameter bottom mount sensor mooring and was deployed without in-water manipulation. The power is intended to increase dramatically for each design-evaluation cycle and is projected to reach > 1 Watt continuous power as the mass-transport accessible surface area of the anode is increased. At this time 2 BMFC-equipped moorings are undergoing field testing. In addition to describing the results of these field tests, results of earlier deployments will be presented in which the dependency of BMFC power output vs sediment properties and environmental conditions was evaluated.

Virtual reality development and simulation of BMI nozzle inspection system for use during regular refueling outage of APR1400 family of reactors

Reactor vessel bottom mount instrumentation nozzle is J-groove welded to reactor vessel inside. This location has shown leaks in some NPPs in the past such as pinhole leaks at the South Texas Project in 2003 and a similar trace of leak at Palo Verde Unit 3 in 2013. Inspection of reactor vessel bottom mounted instrumentation nozzle weld crack requires removal of reactor internals in the case of APR1400 family of reactors without special tools. In Korea, the removal of reactor internals is prohibited during regular refueling outage following regulatory guidelines, hence the inspection of defects in reactor vessel bottom mounted instrumentation nozzle from inside of reactor vessel has not been performed during a regular refueling outage. In this study, a remote weld inspection system for reactor vessel bottom mounted instrumentation nozzles is developed in a virtual environment, and the operation of the inspection system was simulated to prove the validity of the system. The aim of the reactor vessel bottom mounted instrumentation nozzle inspection system was to inspect reactor vessel bottom mounted instrumentation nozzle during regular refueling outage without removing RI. This allows inspection of reactor vessel bottom mounted instrumentation nozzle weld for every refueling outage and allows finding defect at an early stage of defect formation and prevent reactor vessel crack caused by primary water stress corrosion cracking which lead to the bottom mounted instrumentation nozzle leak.

Estimation of composite hydraulic resistance in ice‐covered alluvial streams

AbstractFormation, propagation, and recession of ice cover introduce a dynamic boundary layer to the top of rivers during northern winters. Ice cover affects water velocity magnitude and distribution, water level and consequently conveyance capacity of the river. In this research, total resistance, i.e., “composite resistance,” is studied for a 4 month period including stable ice cover, breakup, and open water stages in Lower Nelson River (LNR), northern Manitoba, Canada. Flow and ice characteristics such as water velocity and depth and ice thickness and condition were measured continuously using acoustic techniques. An Acoustic Doppler Current Profiler (ADCP) and Shallow Water Ice Profiling Sonar (SWIPS) were installed simultaneously on a bottom mount and deployed for this purpose. Total resistance to the flow and boundary roughness are estimated using measured bulk hydraulic parameters. A novel method is developed to calculate composite resistance directly from measured under ice velocity profiles. The results of this method are compared to the measured total resistance and to the calculated composite resistance using formulae available in literature. The new technique is demonstrated to compare favorably to measured total resistance and to outperform previously available methods.

글로벌 무인해양관측 네트워크 현황과 전망

급격히 증가하고 있는 무인해양관측 체계들의 현황을 글로벌 관점에서 조명하고, 이를 범국가적 차원에서 통합, 조정, 관리하기 위한 네트워크에 대해 고찰하였다. 3차원 시공간적으로 변동이 심한 해양환경을 관측/감시하기 위해서 무인해양관측 플랫폼들은 점차 다양화되고 있는데, 여기서는 이동형(표층 뜰개, 중층 플로트, 수중 글라이더)과 고정형(표층 및 수중 계류선, 바닥장착형 관측)으로 구분하여 각각의 목적, 역사, 현황을 조사하고, 향후 변화를 전망했다. 이들을 활용하여 글로벌 해양관측체계에 기여하고 있는 대표적인 고정형과 이동형 무인해양관측 네트워크(ARGO와 OceanSITES) 프로그램들의 현황에 대해서 알아보고, 글로벌 해양관측/모니터링 체계를 위한 시너지 효과를 창출하기 위한 운용 및 활용 증가를 전망했다. 마지막으로 더욱 효과적인 해양관측/모니터링 체계를 설계하기 위해 다종의 플랫폼을 동시에 사용하는 것을 제안하였고, 그 대표적인 예로 미 국립과학재단의 OOI(Ocean Observatories Initiative) 프로그램을 소개하였다. 아울러 심해 및 남반구와 같이 글로벌 관점에서 존재하는 자료의 틈을 줄여나가기 위한 노력과 글로벌 경계류 관측 네트워크와 같은 새로운 해양관측 네트워크를 위한 노력, 그리고 생지화학/음향/광학 센서들을 포함한 센서 기술들의 개발 노력과, 자료의 표준화 및 센서 검/교정을 위한 노력에 대한 제언을 추가하였다. We introduce status and prospect of increasingly utilizing, unmanned, global ocean observing systems, and the global network to integrate, coordinate, and manage the systems. Platforms of the ocean observing system are diversified in order to resolve/monitor the variability occurring at multiple scales in both three-dimensional space and time. Here purpose, development history, and current status of the systems in two kinds - mobile (surface drifter, subsurface float, underwater glider) and fixed platforms (surface and subsurface moorings, bottom mounts), are examined and the increased future uses to produce synergies are envisioned. Simultaneous use of various mobile and fixed platforms is suggested to more effectively design the observing system, with an example of the NSF-funded OOI (Ocean Observations Initiative) program. Efforts are suggested 1) to fill the data gap existing in the deep sea and the Southern Ocean, and toward 2) new global network for oceanic boundary currents, 3) new technologies for existing and new sensors including biogeochemical, acoustic, and optical sensors, 3) data standardization, and 4) sensor calibration and data quality control.

Analysis of the temperature stratification of a no-frost domestic refrigerator with bottom mount configuration

The following paper presents the analysis of the temperatures stratification in the fresh food and freezer compartments from a forced-convection domestic refrigerator set in a bottom mount configuration. Initially the analysis is done through experimental tests measuring parameters like: temperature, cold air velocity and energy consumption. Thereafter, CFD is employed to model and simulate the refrigerator. The original model results reveal an inadequate thermal operational profile, which compared with a new design proposal shows a better distribution of air flow in the latter and therefore a more uniform temperature in the fresh food compartment. Experimentally, the new design proposal represents less ON stages for the compressor compared with those of the original refrigerator under the same operational conditions.

Observations of the Karimata Strait througflow from December 2007 to November 2008

In order to quantitatively estimate the volume and property transports between the South China Sea and Indonesian Seas via the Karimata Strait, two trawl-resistant bottom mounts, with ADCPs embedded, were deployed in the strait to measure the velocity profile as part of the South China Sea-Indonesian Seas transport/exchange (SITE) program. A pair of surface and bottom acoustic modems was employed to transfer the measured velocity without recovering the mooring. The advantage and problems of the instruments in this field work are reported and discussed. The field observations confirm the existence of the South China Sea branch of Indonesian throughflow via the Karimata Strait with a stronger southward flow in boreal winter and weaker southward bottom flow in boreal summer, beneath the upper layer northward (reversal) flow. The estimate of the averaged volume, heat and freshwater transports from December 2007 to March 2008 (winter) is (−2.7±1.1)×106 m3/s, (−0.30±0.11) PW, (−0.18±0.07)×106 m3/s and from May to September 2008 (summer) is (1.2±0.6)×106 m3/s, (0.14±0.03) PW, (0.12±0.04)×106 m3/s and for the entire record from December 2007 to October 2008 is (−0.5±1.9)×106 m3/s, (−0.05±0.22) PW, (−0.01±0.15)×106 m3/s (negative/positive represents southward/northward transport), respectively. The existence of southward bottom flow in boreal summer implies that the downward sea surface slope from north to south as found by Fang et al. (2010) for winter is a year-round phenomenon.

Effects of cold work and stress on oxidation and SCC behavior of stainless steels in PWR primary water environments

Recently intergranular stress corrosion cracking (IGSCC) in austenitic stainless steel 316L of Primary Loop Recirculation (PLR) piping and also a nozzle, and several core shrouds (CS) have been experienced in BWRs [1-4]. PWSCC incidences in nickel base alloys of Vessel Head Penetrations (VHP), Bottom Mount Instrumentation (BMI) nozzle and Steam Generator (SG) inlet nozzles in PWR were also reported [5-7]. Therefore, a great concern has been focused and an extensive research and development have been done on these SCC phenomena from a point of view of structural integrity of reactor components. In addition to those SCC incidences in BWR and PWR, there is one unique SCC incidence in 316 stainless steel in PWR plants [8-9]. The mode of this cracking is intergranular and cracks were found in weld HAZ of 316 stainless steel welded to a low alloy steel of SG nozzle with nickel base alloy 82 where PWSCC were also observed. Preliminary root cause analysis implied that the cracked 316 HAZ has a highly hardened not only at surface by machining but also at the region of a far distant from an inner surface of 316 pipe, probably due to a weld shrinkage strain as have been observed in PLR piping and Core shroud cracks in BWR. In laboratory tests [10, 11], there are many well-known evidences that strain hardened austenitic stainless steels such as 304, 304L, 316, 316L and 347, show SCC susceptibility without any sensitization of grain boundary when they are hardened by any sources during fabrication or under an operational condition. An extensive metallographic and TEM analysis has been performed on this cracked 316 HAZ sample as a part of failure analysis to characterize the microstructure and oxides morphology, compositional profiles as well as their crystal structures near the cracked surface of 316 HAZ [8, 9]. Typical strain hardening was measured on the sample due to weld shrinkage and also due to surface grinding. In addition to these analyses, an extensive surface oxides analysis has been performed by Raman Spectroscopy (RS) on a break-opened IGSCC surfaces and a cross-section sample where oxides can be observed in the cracks of concerns. In order to identify the oxides by RS, an extensive laboratory analysis of oxides formed in well-known environmental conditions in the laboratory was performed to generate a set of reference database of oxides by Raman spectroscopy. Based upon the observation of these oxides on/in the cracks, the crack growth history during the plant operation will be discussed in connection to a residual stress distribution at HAZ and oxides variation on/in the cracks. Possible time dependence of crack growth rate with crack growth in components will be discussed based upon the evidences observed about oxides. Finally, an importance of surface integrity assessment in SCC initiation and propagation will be emphasized from a point of view of oxidation localization which can be promoted by strain (dislocation density), straining and stress, which play an crucial role in an oxidation due to accelerated mass transfer in oxides as well as underlying metallic materials. Especially, preferential oxidation along slip bands suggests that oxygen diffusion in such a region with a high dislocation density is faster than the other region. This fact implies that grain boundary can also be a preferential path of oxidation as has been observed by TEM, TOFSIMS and 3D-APT. This localization of oxidation and acceleration will be discussed based upon an analysis of an profile development at an oxide/metal interface which is recently proposed by Y. Takeda et al. [12] based upon some statistical analysis of an oxide/metal interface profile and a concept of surface integrity will be emphasized for an quantitative prediction of SCC initiation.

Development of a Stress Corrosion Cracking Test Methodology Using Tube-shaped Specimens

Abstract Stress corrosion cracking (SCC) is one of the greatest concerns in nuclear aging and degradation, and studies on the measurement of stress corrosion crack growth rates (CGR) and the effects of environmental, material, and mechanical parameters on the CGR have been performed using mainly fracture mechanics specimens. However, the stress states for the fracture mechanics specimens are different from that of real field components and there is concern about the applicability of the data obtained from fracture mechanics specimens to the evaluation of SCC behaviors in real field components. In this study, in order to obtain SCC for specimens that have a similar shape of real field components under complicated stress states, an SCC test methodology using specimens in the shape of tubes was developed. Its effectiveness was verified by performing an SCC test using a mock-up of a bottom mount instrumentation tube of a pressurized water reactor (PWR) under a simulated PWR primary water environment. Intergranular SCC was created in the mock-up specimen using the developed SCC test methodology and SCC crack growth rate for the mock-up specimen was measured.

橋脚を利用した潮流発電について

There are several kinds of energy resources in the ocean but the utilization of the ocean energy is far behind the other natural energies such as solar and wind. A feasibility study on the tidal current power generation by making use of a bridge pier in the narrow strait is introduced in this report. There are several advantages to making use of a bridge pier for the tidal power generation. Current velocity increases near the pier, therefore the tidal power generation becomes more efficient because the power is proportional to the cubic of the current velocity. Furthermore, the pier is convenient for the maintenance of the hydraulic turbine and the power unit. The project is now underway at the Ikitsuki Bridge in Tatsuno-Seto Strait of Nagasaki Prefecture, where the tidal current was measured by the bottom mount ADCP for one month. The numerical simulations of the tidal current were conducted by the MEC Ocean Model, and the results were compared with the measurements. A long term estimation of the tidal current power is presented and the variation of the power by the lunar period is discussed. Lastly, the in-situ measurement results of the waves are presented.

The Barny Sentinel trawl-resistant ADCP bottom mount: design, testing, and application

A trawl-resistant bottom mount (TRBM) has been developed to meet the needs of long-term deployment of Acoustic Doppler Current Profilers (ADCPs) and Wave-Tide Gauges in water depths up to 300 m. This paper describes the unit's construction and operation together with practical lessons learned during development, testing, and use that can be applied to comparable platforms. The Barny Sentinel is derived from a larger version developed several years ago at SACLANT Center, now extensively redesigned to incorporate an RDI Sentinel ADCP and a Sea-Bird Wave-Tide Gauge. A concrete ring surrounding the fiberglass instrument housing serves as ballast and impact protection. Two independent recovery modes may be activated by acoustic commands, one of which can operate whether or not the platform is upright. Features have also been included to facilitate recovery by remotely operated underwater vehicle. A sending unit, temporarily attached during launch, provides real time information on platform depth and tilt, and confirms that the platform is properly positioned on the bottom before a launch commitment is made. A series of tests and applications have validated all basic functions and trawl resistance. Platform cost has been kept below that of the on-board instruments, while still maintaining the required high level of recoverability.

Method for continuously monitoring the weight and tension of filter bags in a fabric filter system

A technique has been devised to measure the weight of dust on filter bags inside a working filter. The output signals from load cells installed into the top and bottom bag mounts are combined with a ‘lift’ factor to correct for the effect of the pressure drop across the filter, and are then expressed as a bag weight. Monitoring of this bag weight parameter during several successive filtration cycles has provided filtration research with a clear view of dust cake build-up and release processes. Some initial observations of missed, or ineffective, shakes, as well as the timing of cake dislodgment and the behaviour of the bag tension during the shake cleaning, are reported.