Series Of Benches Research Articles

An Underwater Glider with Muscle—Actuated Buoyancy Control and Caudal Fin Turning

Underwater robotic gliders exploit gravity and buoyancy for long-distance cruising with ultra-low energy consumptions, making them ideal for open ocean surveying operations. However, the gliding-based motion generation principle also prevents their maneuverability, limiting their use in the short distances that are usually encountered in harbors or coastal scenarios. In this work, an innovative underwater glider robot is developed, enabling maneuverability through the introduction of an efficiently actuated caudal fin with bidirectional turning capabilities. In addition, modular actuator units, based on soft actuated materials, are integrated to control pitch angle by dynamically shifting the center of mass from the center of buoyancy. As a result, the high energy efficiency feature of the gliders is maintained, while high maneuverability is also achieved. The design concept, modeling of key components, and framework for control are presented, with the prototyped glider tested in a series of bench and field trials for validation of its motion performance.

Design and performance of SiPM-based readout of PbF2 crystals for high-rate, precision timing applications

We have developed a custom amplifier board coupled to a large-format 16-channel Hamamatsu silicon photomultiplier device for use as the light sensor for the electromagnetic calorimeters in the Muon g - 2 experiment at Fermilab. The calorimeter absorber is an array of lead-fluoride crystals, which produces short-duration Cherenkov light. The detector sits in the high magnetic field of the muon storage ring. The SiPMs selected, and their accompanying custom electronics, must preserve the short pulse shape, have high quantum efficiency, be non-magnetic, exhibit gain stability under varying rate conditions, and cover a fairly large fraction of the crystal exit surface area. We describe an optimized design that employs the new-generation of thru-silicon via devices. The performance is documented in a series of bench and beam tests.

Evaluation of sodium lignosulphonate for the remediation of chromium-contaminated soil and water

Commercial sodium lignosulphonate, a by–product of sulphite pulp leaching, was evaluated for the remediation of soil and water contaminated with hexavalent chromium. Two series of bench–scale tests were performed: (a) removal of chromium from water using reagent binding and membrane separation; and (b) stabilisation of chromium in the soil using chemical soil flushing. Water treatment tests were performed in a batch mode in stirred ultrafiltration cells. The test results revealed that lignosulphonates can bind hexavalent chromium and facilitate its removal from water when used in conjunction with ex–situ water treatment (membrane filtration). Soil treatment tests carried out in a column revealed that lignosulphonates reduced chromium mobility and helped stabilise it within the soil matrix. These tests showed that lignosulphonate fixation can be used to stabilise chromium in soil with in–situ treatment (soil flushing).

A technical and economical evaluation of CO2 capture from FCC units

The present work was focused on a technical and economical evaluation of two distinct CO2 capture technologies applied to an FCC unit, namely amine absorption and oxyfired FCC. All capital costs, utility requirements and chemical consumption of each technology were determined in order to allow the calculation of CO2 capture and avoided costs. The results showed a 45% decrease in CO2 capture cost for oxyfiring technology compared to the amine absorption alternative. As for the technical feasibility of oxyfiring in the FCC regenerator, a series of bench and pilot plant scale tests were performed. Product profile, stability of operation and the effectiveness of coke burn were evaluated. No significant changes from normal operation were observed.

Three-dimensional mapping of the Platreef at the Zwartfontein South mine: implications for the timing of magmatic events in the northern limb of the Bushveld Complex, South Africa

The Platreef is a pyroxenitic unit with Ni–Cu–PGE mineralisation that forms the base of the layered igneous succession in the northern limb of the Bushveld Complex. It rests upon sediments of the Transvaal Supergroup and Archaean granite/gneiss basement, and is overlain by norites and gabbronorites assigned to the Main Zone of the Complex. Detailed lithological mapping of a series of bench faces on bench 222 of the Zwartfontein South pit was undertaken to define a rectangular block. This information, coupled with drill chip data obtained during the drilling of the blast grids in the enclosing area, has allowed us to constrain with a high degree of confidence the three-dimensional nature of the lithological relationships on a local scale, not achieved by any previous study. The inter-connectivity of the mapped faces has allowed the first well constrained, three-dimensional representation of the Platreef–hangingwall contact to be generated. It has revealed finger-like intrusions of hangingwall gabbronorite which cut down into the Platreef along zones of low competency such as NE–SW and N–S trending shear zones. This relationship demonstrates that the emplacement of Main Zone type hangingwall magma occurred after a significant period of time that had allowed both crystallisation and deformation of the Platreef to take place.

Endoluminal fundoplication (ELF) – evolution of EsophyX™, a new surgical device for transoral surgery

A novel endoluminal fundoplication (ELF) technique using a trans‐oral and fastener‐deploying device (EsophyX™, EndoGastric Solutions) was developed and evaluated for feasibility, safety and the treatment of gastroesophageal reflux disease (GERD) in a series of bench, animal, human (phase 1, phase 2, commercial registry) studies. The studies verified biological compatibility, durability and non‐toxicity of the polypropylene fasteners as well as the feasibility of the ELF technique. The results of the preclinical testing indicated that the EsophyX™ device was shown to be safe, and capable of deploying fasteners directly into tissue and forming an interrupted suture line at the base of the gastro‐esophageal valve (GEV). Moreover, the studies demonstrated that the ELF technique performed using the EsophyX™ device resulted in the creation of new GEVs of 3–5 cm in length and a circumference of 200°–310°, which maintained their anatomical aspects at six months. The ELF‐created GEVs appeared similar to those created by laparoscopic anti‐reflux surgery (LARS). The ELF procedure also resulted in reduction of all small hiatal hernias (⩽2 cm in size) and restoration of the angle of His. The ELF procedure provides an anatomical approach similar to that of LARS for the treatment of GERD.

On-site mercury-contaminated soils remediation by using thermal desorption technology

In this study, the thermal desorption process was used to treat a mercury-contaminated soils in Taipei. A series of bench or pilot plant experiments were also performed the optimized operation condition. The results showed that the concentrations of residual mercury in all treated soils were below 2 mg/kg, some even lower than 0.05 mg/kg. The supernatant and exhaust gas stream of the condensed desorbed mercury vapor in the remediation site were also met with the effluent standard. The total fee was estimated to be US$ 3,557,000, when treating contaminated soil leading to a unit treatment cost of US$ 834/m 3 of soil.

Preliminary bench and pilot plant experiences for On-board wastewater treatment by ozone

This paper presents results obtained during a series of bench and pilot plant experiences on the utilization of ozone technology to treat sanitary wastewater coming from boats. Data on ozone solubility in soft water and sea water in a bench reactor were obtained. The analysis of the abatement of BOD, Total Coliforms, UV-absorbance and other parameters were performed on simulated saline and soft on-board wastewater considering increasing batch reactor retention time.The results indicated that the best abatement was obtained in saline wastewater with about 70% BOD and a 95% Total Coliform reduction in 30 minutes; further UV spectra have shown a sensible abatement of the absorbance readings.Pilot plant experiences on a saline wastewater confirm the potential possibility to treat hygienic on-board wastewater with ozone technology.

Observations on “cryoplanation” benches in Antarctica

A series of benches on nunataks of Alexander Island (Antarctica) are described. An increase in bench size with distance away from the retreating glacier suggests an age spectrum. The benches have thermal contraction cracks (in bedrock) on shallower, upper sections of the risers as well as salt encrusted runnels on the steeper lower section of the tread. The benches also show a distinct orientational preference (orientated to the north through to west) and, from first principles, these seem to be the aspects with optimal freeze-thaw cycles and temperatures conducive to thermal stress fatigue. The extensive dilatation associated with the retreating glaciers is thought to play a significant role in the origin and development of the benches as the combination of extensive jointing and optimal process conditions are thought to constrain where benches begin. The jointing, aided by the thermal contraction cracking, then facilitates extension and continued weathering of the treads. It would appear that these benches are examples of so called “cryoplanation terraces” that have been reported as fossil forms in Europe and North America. The study of such active forms in the Antarctic may provide good analogues for fossil features found in the Northern Hemisphere.

Evaluation of Activated Sludge Oxygen Uptake Rate Test Procedures

A series of bench- and pilot-scale experiments was conducted to evaluate the ability of biochemical oxygen demand (BOD) bottle-based oxygen uptake rate (OUR) analyses to represent accurately in situ OUR in complete mix-activated sludge systems. Aeration basin off-gas analyses indicated that, depending on system operating conditions, BOD bottle-based analyses could either underestimate in situ OUR rates by as much as 58% or overestimate in situ rates by up to 285%. The use of a continuous flow respirometer system was used to verify the off-gas analysis observations and assess better the rate of change in OUR after mixed liquor samples were suddenly isolated from their normally continuous source of feed. OUR rates for sludge samples maintained in the completely mixed bench-scale respirometer decreased by as much as 42% in less than two minutes after feeding was stopped. Based on these results, BOD bottle-based OUR results should not be used in any complete mix-activated sludge process operational control strategy, process mass balance, or system evaluation procedure requiring absolute accuracy of OUR values.

Monitoring of groundwater conditions at West Chevington opencast coal site, Northumberland

Abstract West Chevington opencast coal site is a productive mine situated near Widdrington, Northumberland and is operated on behalf of the National Coal Board Opencast Executive. Excavation of a multi-seam sequence of strata mainly within the upper Westphalian A of the Carboniferous is being carried out in a series of benches so that the excavation void proceeds eastwards with increasing depth. A number of piezometers have been installed along sections running across the site, both within the backfill, which follows the slowly migrating excavation void, and in advance of the excavation. The monitoring of groundwater levels has allowed a study of the drawdown and recovery due to the excavation to be carried out. A relationship between water level changes and the position of the excavation benches has been investigated. Rock samples were obtained from the excavation, as they were removed by faceshovel and dragline, and moisture contents and porosities determined in the laboratory. Estimates of volumes of water removed by earthmoving plant have been calculated to demonstrate the proportions that are mechanically extracted from the excavation.

Physiographic History of the Upper Arkansas River Valley and the Royal Gorge, Colorado

The physiographic history of the Arkansas River Valley between Leadville and Canon City is recorded in a descending series of benches, pediments, and alluvial plains flanking the present river. The highest of these seem to correspond to the Rocky Mountain peneplain which has been regarded as Miocene in age. Remnants of a later "broad-valley" stage lie above the flight of seven inner terraces developed in part on Pliocene sediments. Of these, two are preglacial in age, four correspond to glacial stages, and the lowest is postglacial.