Tank Weight Research Articles

Design Study for a Superconducting High-Power Fan Drive for a Long-Range Aircraft

New aerodynamic aircraft concepts enable the storage of volumetric liquid hydrogen (LH2). Additionally, the low temperatures of LH2 enable technologies such as the superconductivity of electrical fan drives and power distribution components. An increased power density of the onboard wiring harness and the electrical machine can be expected. The highest system efficiency and the smallest fuel and tank weight will be achieved with a highly efficient energy conversion by the fuel cell from LH2 to electrical energy. This publication shows a comprehensive study for cryogenic fan drives based on experimental-driven tape superconductor investigations, mission profile-based considerations, design analyses of superconducting electrical machines, and studies of the cooling concepts. A cryogenic system cannot be considered without a feasible cooling concept. Here, an approach with a safe He-based cooling system is proposed, using the LH2 flow to the fuel cell as a heat sink for the losses in the electrical system.

Perancangan Rangka Tandon Air Berkapasitas 1200 Liter Untuk Kebutuhan Pelaku Usaha Rumah Kost

The increasing public interest in the need for adequate housing, especially the boarding house business, is one of the facilities that has great opportunities every year. The need for clean water in a boarding house environment is a factor that needs to be considered because clean water is an important need in human life. The water reservoir frame design with a capacity of 1200 liters is an optimized solution to meet the daily water needs of boarding house residents. The aim of this research is to design a water reservoir frame for water loads and carry out structural calculations of the water reservoir frame in accordance with applicable safety and strength standards. The research methodology explains in detail the research method which includes time and place of research, tools and materials, research procedures and research flow diagrams. Weight of load to be supported by the structure = weight of tank + weight of water Specify tank Type = Penguin TB, 120 uk Capacity = 1200 Liters = 1.2 m3 Tank mass (mT) = 29 kg Total mass of external load (mtot) = tank mass + water mass Mtot= 29 kg + 1200 kg = 1229 kg Total weight (Wtot) Wtot = (mtot) × g, g= acceleration due to gravity (9.8 m/s2) Kata kunci: Water discharge, Frame Strength, Structural Strength, Steel Selection, Water Reservoir

Exploring variations in the weight, size and shape of liquid hydrogen tanks for zero-emission fuel-cell vessels

We report an exploration of liquid hydrogen (LH2) tank technology, determining if improving LH2 tank weight, multiplicity or shape enables more hydrogen to be stored on hydrogen vessels. The improvements investigated are well beyond the current LH2 technology state-of-the-art. The platform for this study is a monohull H2 Baseline research vessel powered 100% by hydrogen.Regarding weight reductions, we found that the research vessel does not benefit significantly from large weight reductions of the LH2 tanks. A 50% reduction in mass of the inner pressure vessel led to a 3.1% reduction in the total research vessel weight. Reducing the LH2 tank weight to the asymptotic limit of zero results in a 7.1% reduction in the overall research vessel weight. This maritime application, while benefitting from a reduction in LH2 tank weight, is not a strong driver for LH2 tank weight improvements.The two large LH2 tanks of the H2 Baseline Vessel can be replaced with a multitude of smaller LH2 tanks. In two Multiplicity design variants, the total amount of stored LH2 was ∼5–9% less than that of the H2 Baseline Vessel, which does not motivate conducting the needed R&D that would drive the technology to smaller high-performing LH2 tanks.We did find a significant benefit to improving the shape of LH2 tanks, towards prismatic tanks that would better match the vessel hullform. Considering a “Shape Variant” that included space-consuming features such as tank connection spaces, manifolding and ventilation, we found a 26% improvement in stored LH2 compared to the H2 Baseline Vessel. The large improvement in storage capacity could warrant further LH2 tank R&D that can enable high performing prismatic LH2 tanks, such as pressure vessel steel developments allowing for higher strength/ductility at 20 K, improved insulation systems, methods for efficiently building prismatic tanks with insulation systems fit for 20 K service and flare-less techniques for managing heat leak (venting).The results are reviewed considering the current regulatory restrictions as well as prevailing limitations in LH2 tank manufacturing.

Implementation of Seismic Sensor to Detect Tank

This study aims to investigate seismic sensors in detecting ground vibrations caused by tank or military vehicle movements. Ground vibrations generated by tank movements have specific characteristics, where the produced frequency remains constant depending on the tank's weight and the area of the track's footprint. The amplitude of these vibrations provides information about the detection range, wherein the larger the amplitude, the closer the detection range to the tank. The method employed involves field experiments or the collection of quantitative data from field trials. Test results indicate that ground vibrations produced by tanks have an average frequency of 332 Hz, depending on the tank's weight and the area of the track's footprint. The average amplitude is 4.3 volts at a detection range of 1000 meters, 5.1 volts at 500 meters, 7.6 volts at 200 meters, 8.8 volts at 100 meters, and 12.1 volts at 50 meters. The implication of this research is that seismic sensors can be effectively used as tools to detect tank or military vehicle movements at different distances. These findings could be beneficial in the development of security systems or early detection in areas vulnerable to potential threats from tanks or military vehicles.

Progress of hydrogen subsonic commercial aircraft

Hydrogen may substitute traditional hydrocarbon fuels in propeller and jet aircraft. In the case of propeller propulsion, the use of combustion engines is preferable to fuel cells plus electric motors. The conversion efficiency from chemical to mechanical energy at the propeller is larger with fuel cells, but the propulsion system is also larger, in addition to heavier. Fuel cells have a better appeal for novel urban air mobility solutions. Hybridization of gas turbine engines is beneficial for propeller and jet propulsion. The hydrogen aircraft architecture is strongly modified to accept much larger fuel tanks, having hydrogen a larger mass-specific-energy, but a smaller volume-specific-energy, than jet fuels, stored onboard liquid or cold-cryo/compressed. Conformal tanks may reduce the total aircraft volume vs. spherical/cylindrical tanks, the same as the use of novel composite structures to improve strength and reduce the weight of tanks. With conventional designs, the maximum-take-off weight slightly reduces, but the operating-weight-empty largely increases with hydrogen, for an 8%–15% larger energy consumption per pax and nm compared to hydrocarbon fuels. Fuel cell propeller propulsion also suffers from the weight of batteries and fuel cell stack. Non-conventional designs such as Blended-Wing-Body and hybridization may help reduce energy consumption. Renewable-hydrogen-only aircraft necessitate further development of aircraft technology before full deployment by 2035, providing renewable hydrogen will be cheap and abundant at the time, and the airport infrastructure developed. The introduction of hypersonic renewable-hydrogen-only aircraft could also be possible, given the progress in hypersonic technologies and the synergy with subsonic commercial aviation.

LNG Type C, Cylindrical Weight Design Limitation Based on Shipbuiding Facilities

Supporting climate change mitigation and sustainable energy due to its ability to reduce CO2, Liquefied Natural Gas (LNG) considered as promising alternative fuel. In a particular small market with LNG demand between 2,500 m3 to 7,500 m3, utilization of LNG type-C, cylindrical tanks are compatible to use in small-scale LNG carrier. In order to overcome these challenges, Indonesian industry need to design the tank’s volume and weight requirements.while also taking into account the capabilities of the shipbuilding facilities. The weight of the tank, which comprises the weight of the outer tank and dished end, are the decision variable in the approach for weight estimation analysis, which carried by using using extrapolation to search optimum diameter and length of the tank The objective function is maximization of the tank capacity. The capability of the lifting equipment in the shipyard is the limitation used in this paper. This research data is based on the shipyard capability of PT. PAL Indonesia, PT. Dok dan Perkapalan Kodja Bahari (Persero), PT. Industri Kapal Indonesia, and PT. Batamec Shipyard. Result obtained that maximum volume of 5,663.369 m3 LNG type C, weight about 450.671 tons with maximum crane lifting capacity in shipyard are 500 tons

Stress response of juvenile rainbow trout reared at three densities

High rearing densities (kg of fish per rearing unit volume) can impact fish health and growth. This study evaluated the stress levels (as indicated by blood glucose) and growth of juvenile Shasta strain rainbow trout (Oncorhynchus mykiss) reared at three densities in 1.8-m diameter circular tanks for 111 days. Initial and final rearing densities for each treatment were: low (4.48 and 47.56 kg/m3), medium (5.96 and 60.60 kg/m3), and high (7.49 and 72.42 kg/m3). Throughout the experiment, blood glucose levels from individual fish were not significantly different among the three density treatments. At the end of the experiment, total tank weights and gain were significantly greater in the high-density treatment than the medium-density treatment, which in turn was significantly greater than the low-density treatment. However, percent gain was significantly greater in the low-density treatment. Feed conversion ratio was significantly lower in the high-density treatment compared to the low-density treatment, with the ratio in the medium-density treatment similar to the other two treatments. The results of this study indicate that higher rearing densities do not negatively impact juvenile Shasta strain rainbow trout stress or hatchery rearing performance.

Optimum Design of Oil Tank Foundation on Different Soil Conditions

Tank foundation is a base for the tank which is designed to support the weight of oil tank in order to ensure its stability. Failure of tank foundation usually occurred when the foundation system cannot support the weight of the tank or the soil bearing capacity of the area failed to resist the imposed stress from oil tank inclusive of foundation’s self-weight. Failure of tank foundation can lead to pivoting effect and cracking on the foundation slab. Hence, the right choice of foundation system with reference to the bearing capacity of foundation soil is important to ensure the stability of tank foundation. Thus, this study was carried out in order to determine the deformation characteristics of foundation slab of oil tank foundation on different soil conditions with the aim to determine optimum design of oil tank foundation. The dimensions and design of the models were based on a published case study. Series of analyses with finite element models were conducted using STAAD Foundation CONNECT Edition V9. The models were aimed to analyze the stability of foundation structure, and deformation characteristics of the foundation slabs on different soil conditions. Three types of foundation system (raft, pile raft and pile foundation) were modelled in STAAD Foundation CONNECT Edition V9. The findings showed that the most optimum design for foundation structure on stiff residual soil is raft foundation. Whereas pile raft foundation structure is the most appropriate to construct on unconsolidated marine sediment deposit while pile foundation structure is highly recommended on soft peaty soil.

Application of Reverse Electrodialysis Power for Oxygen Generation in Undersea Diving

With continued growth of marine exploration and underwater missions, there is a need to design new diving technologies. Currently, dive time is limited by scuba tank weight and volume. The use of an electrolysis system, powered by a battery, for driving chemical reactions could be introduced to produce a steady supply of oxygen during dives. However, batteries have a limited capacity, are heavy, and are detrimental to the environment when disposed. Developing an electrochemical technology that utilizes resources abundantly available to a diver (salt water) to drive the oxygen evolution reaction would expand the duration and sustainability of ocean dives. Reverse electrodialysis (RED) is a multi-membrane system that aims to convert salinity gradient energy into electrical energy. Redox mediators are typically used to convert ionic mixing into electricity at electrodes placed adjacent to a stack of membranes. However, replacing redox mediators with water splitting electrodes can enable the sustainable production of fuel (H2) and/or oxygen (O2). We aim to examine if a RED oxygen generation system could meet oxygen requirements for scuba diving. Evolving oxygen from water would enable the development of artificial gills, allowing for an inexhaustible supply of oxygen thus displacing the need to carry oxygen tanks. Here we propose a system where instead of an air tank, a diver carries a RED cell, a 2 L volume of dilute solution, and a cylinder of other compressed gases for breathing (Fig. 1a). A RED cell is comprised of a stack of alternating anion and cation exchange membranes separated by channels of high and low concentration solutions (HC and LC) (Fig. 1b). A stack is made up of repeating units, which consist of a pair of selective membranes and a pair of solution channels, between the anode and cathode chambers. Salt ions in solution migrate due to the concentration gradient and two redox based electrodes convert this ionic flux into electric flux. We show here that the oxygen evolution activation overpotentials are a significant fraction of internal resistance (77%) in a RED system with a small number of cell pairs (N=5). However, this resistance is nearly negligible (3.2%) as the number of cell pairs increases (N=500). We further compare the RED systems to four different battery-electrolysis systems (Li-ion, Ni-MH, Ni-Cd, and lead acid) to contextualize the performance of the RED oxygen generation system with competing technologies. For large (N=100+) systems and long (10 hr) dives, RED is comparable in size to a battery-electrolysis system. With 500 membrane pairs, a RED powered diving system is 10.8 L and weighs 29 kg. Typical 12 L scuba tanks weigh 16 kg, and the size of a Li-ion battery powered electrolysis system for a 1 hour dive is, 2.2 L and 3.5 kg (19.2 L and 32.6 kg for a 10 hour dive).Figure 1. (a) Configuration of a RED cell for scuba divers using the surrounding seawater, a fixed dilute volume, and a fixed volume of additional gases for breathing carried by the diver. (b) Schematic of RED cell. Oxygen and hydrogen are produced at the anode and cathode by redox reactions. Figure 1

A comparison of blue and silver vertically-suspended environmental enrichment during Chinook Salmon and Rainbow trout rearing

This study evaluated the use of either blue or silver vertically-suspended environmental enrichment in two experiments, with one rearing Chinook salmon (Oncorhynchus tshawytscha) for 29 days and the other rearing rainbow trout (Oncorhynchus mykiss) for 98 days. In both experiments, there were no significant differences in total tank weight, gain, percent gain, feed conversion ratio, or percent mortality between tanks with either silver (unpainted aluminum) or blue vertically-suspended environmental enrichment. Individual fish total length, weight, specific growth rate, and condition factor were also not significantly different between the two colors for both fish species. These results indicate that either silver (unpainted aluminum) or blue vertically-suspended environmental enrichment can be used during the hatchery rearing of juvenile Chinook salmon or rainbow trout.

Improving Embryologists’ Sleep Quality: Implementation of a Weight-Based Monitoring System for Gamete and Embryo Cryostorage

Background: Storage of gametes and embryos in our laboratories represents the highest concentration of risk for an ART clinic. A single storage tank may contain material of several hundred patients and vacuum failure is a scenario that haunts embryologists’ nightmares. Temperature sensors are currently the most prevalent mechanism for ‘alarming’ storage tanks, however, such approaches are akin to closing the gate after the horses have bolted. Aim: To assess the implementation of a fully redundant, weight-based monitoring system for ensuring the security of liquid nitrogen storage tanks in a high-capacity ART unit. Method: Forty flat-bed scales were fitted with alarm conversion units allowing a standard ‘open/closed’ alarm output to be relayed in the event a reading fell below the user defined weight limit. Output was routed through a security monitoring system via phone line and mobile-SIM, with no overlap of the existing, internet-based temperature probe system. Relationship between liquid nitrogen level (HC35 vessel), tank weight and temperature reading (probe positioned at top of canister), was established by sequential measurements. Results: Addition of the flat bed scales proved minimally disruptive to the space allocation per tank, requiring no additional ‘width’ but a slight increase in ‘depth’ behind tanks to accommodate the screen support. As expected, a clear, linear relationship was evident between liquid nitrogen level and tank weight, with every 1cm drop in liquid nitrogen equating to approximately 0.5kg weight loss. Concerningly, the temperature probe remained below -190∘ with just 0.5cm of liquid nitrogen remaining, only rising above the alarm trigger threshold once nitrogen had fully evaporated, resulting in a precipitous rise to above devitrification temperature in a matter of hours. Conclusion: Introducing a weight-based tank monitoring system is both feasible and effective. This system provides vastly superior performance in the timely identification of impending tank failure, allowing ample opportunity to ensure safe relocation of material.

Impact of tank gravimetric efficiency on propulsion system integration for a first-generation hydrogen civil airliner

AbstractCivil aircraft that fly long ranges consume a large fraction of civil aviation fuel, injecting an important amount of aviation carbon into the atmosphere. Decarbonising solutions must consider this sector. A philosophical-analytical feasibility of an airliner family to assist in the elimination of carbon dioxide emissions from civil aviation is proposed. It comprises four models based on the integration of the body of a large two-deck airliner with the engines, wings and flight surfaces of a long-range twin widebody jet. The objective of the investigation presented here is to evaluate the impact of liquid hydrogen tank technology in terms of gravimetric efficiency. A range of hydrogen storage gravimetric efficiencies was evaluated; from a pessimistic value of 0.30 to a futuristic value of 0.85. This parameter has a profound influence on the overall fuel system weight and an impact on the integrated performance. The resulting impact is relatively small for the short-range aircraft; it increases with range and is important for the longer-range aircraft. For shorter-range aircraft variants, the tanks needed to store the hydrogen are relatively small, so the impact of tank weight is not significant. Longer range aircraft are weight constrained and the influence of tank weight is important. In the case of the longest range, the deliverable distance increases from slightly over 4,000 nautical miles, with a gravimetric efficiency of 0.3, to nearly 7,000 with a gravimetric efficiency of 0.85.

Parametric study on tank integration for hydrogen civil aviation propulsion

Hydrogen powered gas turbine propulsion will play a central role in the decarbonisation of civil aviation. A key challenge is the integration of large liquid hydrogen tanks into the aircraft, given the low density of liquid hydrogen. Hydrogen offers a quarter of the energy content, per unit volume and one third of the fuel weight, when compared to a conventional fuel. Optimising tank weight is seen as key to aircraft usefulness. A detailed evaluation of tanks for civil aviation is presented here, covering a very wide range of sizes and design solutions.For passenger air transport, if the choice is made not to vent, dormancy time (the time the tank can be allowed to operate without vapour or important fuel extraction) becomes a key design parameter. This paper highlights the interdependence of Maximum Allowable Operating Pressure and the amount of insulation with heating and venting, considering the influence of dormancy time.The resulting tank gravimetric efficiency is presented for cylindrical tanks with hemispheric ends (a very likely choice for tank design). Notwithstanding conservative analysis, tank gravimetric efficiencies of 65–70% can be achieved. This permits combined fuel and tank weights that are less than half of those of current aircraft. The issue that then becomes critical is the resulting large tank and aircraft volume.

TO015INTRADIALYTIC ON-LINE MULTICOMPONENT TOTAL REMOVED SOLUTE MONITORING IN SPENT DIALYSATE BY A NOVEL MINIATURIZED OPTICAL SENSOR

Abstract Background and Aims Urea is the most commonly exploited marker of dialysis adequacy. Plenty of other uremic retention solutes with a deleterious effect on morbidity and mortality of uremic patients accumulate in ESKD patients [1]. Commonly, the uremic solutes are divided into three physicochemical types [2] with the representative markers urea, uric acid (UA),indoxyl sulfate (IS), and β2-Microglobulin (B2M). Optical monitoring of the uremic marker molecules has been proposed [3]. Despite being cumbersome as a clinical routine, direct dialysis quantification from total dialysate collection (TDC) is as the ‘gold standard’ for measuring the total amount of uremic solutes removed [4]. A robust and compact optical on-line dialysis monitoring device is a step closer to automatic assessment of removal of uremic toxins in dialysis. The aim of this study was to evaluate intradialytic on-line multicomponent Total Removed Solute (TRS) monitoring in the spent dialysate by a novel miniaturized optical sensor during hemodialysis (HD) and hemodiafiltration (HDF) with different settings. Method Ten ESKD patients (6 male and 4 female, 60.2±16.8 years) on chronic HDF were enrolled into the study (fistula N=9, graft N=1). For each patient 5 midweek dialysis sessions (length 240min, HD: N=1, Qb=200ml/min, Qd=300ml/min, 1,5m2; HDF: N=4, Qb≥300ml/min, Qd≥500ml/min, Vsubst≥15l, 1,8m2 and 2,2m2) were included. Spent dialysate from the drain was monitored on-line by a miniaturized sensor prototype (Optofluid Technologies OÜ, Estonia). For the reference, the samples from the spent dialysate drain tube of the HD machine were taken as 7, 60, 120 and 180min after the start and at the end of the session (240min). The concentrations of urea and B2M in dialysate were determined in the clinical laboratory. Concentration of IS and UA was determined utilizing the HPLC. TRS values were calculated using the tank weight and the lab or optical tank solute concentrations. t-test was used to determine significant differences between the methods (P≤0.05). Results The laboratory and optical TRS values were 489±112mM and 512±87mM for urea (R2=0.870), 4232±712µM and 4331±756µM for UA (R2=0.985), 230±47mg and 231±40mg for B2M (R2=0.906), 606±339µM and 616±321µM for IS (R2=0.969) (Fig. 1), being not statistically different for any uremic solutes. The reason for higher correlation for UA and IS is direct measurements of UA and IS by the optical sensor whereas urea and B2M are estimated indirectly. Conclusion Novel miniaturized optical sensor successfully carried out intradialytic on-line multicomponent TRS monitoring for the uremic solutes urea, UA, B2M and IS in the spent dialysate.

Use of Exercise and Structure during Rainbow Trout Rearing

A combination of two forms of environmental enrichment (in-tank structure and exercise) was evaluated during the hatchery rearing of juvenile rainbow trout Oncorhynchus mykiss. The study used four treatments: 1) neither exercise nor structure, 2) exercise without structure, 3) structure without exercise, and 4) both exercise and structure. Velocities in the unexercised tanks were a constant 12.2 cm-s-1. Velocities in the exercised tanks alternated weekly with one week at 12.2 cm-s-1 followed by a week at 30.5 cm-s-1. Structural enrichment consisted of an array of vertically-suspended aluminum angles. The use of either environmental enrichment technique significantly improved final tank weight, gain, percent gain, and specific growth rate. Feed conversion ratio was significantly and positively influenced only by structure, but fish on the exercise routine were overfed. There were no significant interactions between exercise and structure, indicating that each form of environmental enrichment operates independently. The results of this study indicate fish rearing performance can be improved with the addition of either vertically-suspended aluminum angles or an exercise routine, but the combination of the two techniques may not be needed to improve rainbow trout growth.

Vertically-Suspended Environmental Enrichment Improves Growth of Landlocked Fall Chinook Salmon during Initial Hatchery Rearing

Environmental enrichment has been shown to improve juvenile salmonid growth during hatchery rearing. This study examined the effects of vertically-suspended environmental enrichment starting seven days after feed training and continuing for the next 32 days of landlocked fall Chinook salmon (Oncorhynchus tshawytscha) rearing. At the end of this experiment, final tank weights, gain, percent gain, and feed conversion ratio were all significantly improved in the tanks of salmon with environmental enrichment compared to barren tanks, with a nearly 25% improvement in feed conversion ratio. Individual salmon in tanks with environmental enrichment were significantly longer and weighed significantly more than salmon from tanks without enrichment. Specific growth rate was also significantly improved with the use of enrichment. The use of vertically-suspended environmental enrichment to improve growth and rearing efficiency is recommended during the initial rearing of landlocked fall Chinook salmon.

Color of Vertically-Suspended Structure Does Not Impact the Growth of Rainbow Trout Reared in Circular Tanks

This study examined the effects of five different colors of vertically-suspended environmental enrichment on the growth of juvenile Shasta strain rainbow trout (Oncorhynchus mykiss) during hatchery rearing in circular tanks. The colors used were silver (unpainted aluminum—control), safety red, semi-gloss black, hunter green, and safety blue. After 86 days, total tank weight, weight gain, and feed conversion ration were not significantly different among any of the color treatments. Individual fish weights, lengths, and condition factors were also not significantly different among the treatments. The results of this study indicate that the relatively small amount of color present on the suspended structure did not affect rainbow trout growth. Thus, the inherent silver color of the aluminum angles does not need to be changed.

Influence of Water Velocity and Vertically-Suspended Structures on Rainbow Trout Rearing Performance

This study evaluated the effects of two water velocities and three types of vertically-suspended environmental enrichment during the rearing of juvenile rainbow trout (Oncorhynchus mykiss; mean ± SE, initial weight 4 ± 1 g and total length 71 ± 2 mm) in 1.8m diameter circular tanks. The 2 × 3 experimental design used two velocities (12.2 cm·s-1 and 30.5 cm·s-1) and three structural treatments (aluminum rod array, plastic spheres, or no structure). After 116 days, the fish reared without any structure (control) at 30.5 cm·s-1 had significantly lower total tank weight, gain, percent gain, feed conversion ratio, and specific growth rate compared to the other treatments. Similarly, the fish reared with a velocity of 30.5 cm·s-1 without structure were significantly shorter and lighter than those in the other treatments. There was no significant difference in condition factor and relative fin lengths among the treatments. These results indicate that vertically-suspended environmental enrichment may be impacting fish rearing performance by altering tank water velocities.

Early detection of cryostorage tank failure using a weight-based monitoring system.

To study the relationship between liquid nitrogen loss and temperature in cryostorage dewars and develop an early-warning alarm for impending tank failure. Cryostorage dewars were placed on custom-engineered scales, and weight and temperature data were continuously monitored in the setting of slow, medium, and fast rate-loss of LN2 to simulate three scenarios of tank failure. LN2 Tank weights and temperatures were continuously monitored and recorded, with a calculated alarm trigger set at 10% weight loss and temperature of - 185°C. With an intact tank, a 10% loss in LN2 occurred in 4.2-4.9days. Warming to - 185°C occurred in 37.8-43.7days, over 30days after the weight-based alarm was triggered. Full evaporation of LN2 required ~ 36.8days. For the medium rate-loss simulation, a 10% loss in LN2 occurred in 0.8h. Warming to - 185°C occurred in 3.7-4.8h, approximately 3h after the weight-based alarm was triggered. For the fast rate-loss simulation, a 10% weight loss occurred within 15s, and tanks were depleted in under 3min. Tank temperatures began to rise immediately and at a relatively constant rate of 43.9°C/h and 51.6°C/h. Temperature alarms would have sounded within 0.37 and 0.06h after the breech. This study demonstrates that a weight-based alarm system can detect tank failures prior to a temperature-based system. Weight-based monitoring could serve as a redundant safety mechanism for added protection of cryopreserved reproductive tissues.

Rearing Performance of Atlantic Salmon Grown in Circular Tanks with Vertically-Suspended Environmental Enrichment

Environmental enrichment is the incorporation of materials into hatchery tanks to simulate a more natural rearing environment. This study investigated the use of a vertically-suspended plastic conduit array as enrichment in 3.63 m circular tanks during Atlantic salmon (Salmo salar) rearing. After 168 days, feed conversion ratio was significantly improved for salmon reared in tanks with enrichment compared to the barren control tanks. Final tank weights and weight gain were not significantly different, although the difference in mean gain of 182.0 kg in the enriched tanks compared to 162.9 kg in the control tanks approached significance. There were no significant differences in individual fish length, weight, or condition factor between the treatments, likely because of large variances in body size due to sexual dimorphism and small sample sizes. The suspended array did not interfere with the hydraulic self-cleaning of the circular tanks. The results of this study support the use of vertically-suspended structures to improve the hatchery rearing performance of Atlantic salmon in circular tanks.