Term Field Tests Research Articles

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Simplified approach for quantitative inspections of concrete structures using digital image correlation

Periodic visual inspections are typically the primary means by which the existing condition of most infrastructure assets is assessed. The results of these inspections are inherently qualitative and subjective, and unfortunately, the recent catastrophic collapse of structures such as De La Concorde overpass in Canada have underscored the need for quantitative assessment tools to monitor crack growth and deformations over time. Conventional measurement methods present several limitations, including cost, need for a priori knowledge of critical crack locations and orientation, and exposure of sensors to harsh environmental conditions. Digital image correlation (DIC) is an optical full-field non-contact measurement technique that has been shown to be highly accurate for laboratory studies under controlled conditions and has also been successfully used for short term field tests of bridges and other structures. In this study, a simple low-cost approach is proposed to supplement periodic visual inspections with quantitative measurements using images from a handheld digital camera processed with a free DIC software. A method is introduced to correct measurement errors associated with the inevitable camera movements between photographs taken during different inspections. The approach was validated by tracking the shear crack kinematics of seven push-off specimens tested in the laboratory. After correcting for errors due to movement of the handheld camera, 98% of the 462 measurements made during the tests were within the selected tolerance limit of ± 0.1 mm compared with reference measurements made with a stationary camera equipped with a long focal length lens. These results represent a first step towards the use of the DIC technique for quantitative structural inspections for improved infrastructure management.

Arsenic Removal from Groundwater by Solar Driven Inline-Electrolytic Induced Co-Precipitation and Filtration-A Long Term Field Test Conducted in West Bengal.

Arsenic contamination in drinking water resources is of major concern in the Ganga delta plains of West Bengal in India and Bangladesh. Here, several laboratory and field studies on arsenic removal from drinking water resources were conducted in the past and the application of strong-oxidant-induced co-precipitation of arsenic on iron hydroxides is still considered as the most promising mechanism. This paper suggests an autonomous, solar driven arsenic removal setting and presents the findings of a long term field test conducted in West Bengal. The system applies an inline-electrolytic cell for in situ chlorine production using the natural chloride content of the water and by that substituting the external dosing of strong oxidants. Co-precipitation of As(V) occurs on freshly formed iron hydroxide, which is removed by Manganese Greensand Plus® filtration. The test was conducted for ten months under changing source water conditions considering arsenic (187 ± 45 µg/L), iron (5.5 ± 0.8 mg/L), manganese (1.5 ± 0.4 mg/L), phosphate (2.4 ± 1.3 mg/L) and ammonium (1.4 ± 0.5 mg/L) concentrations. Depending on the system setting removal rates of 94% for arsenic (10 ± 4 µg/L), >99% for iron (0.03 ± 0.03 mg/L), 96% for manganese (0.06 ± 0.05 mg/L), 72% for phosphate (0.7 ± 0.3 mg/L) and 84% for ammonium (0.18 ± 0.12 mg/L) were achieved—without the addition of any chemicals/adsorbents. Loading densities of arsenic on iron hydroxides averaged to 31 µgAs/mgFe. As the test was performed under field conditions and the here proposed removal mechanisms work fully autonomously, it poses a technically feasible treatment alternative, especially for rural areas.

Antibiofilm and antifouling activities of extracellular polymeric substances isolated from the bacteria associated with marine gastropod Turbo sp

Abstract The extracellular polymeric substances (EPS) produced by the bacteria associated with the gastropod Turbo sp. were isolated and screened for antibacterial activity against biofilm-forming bacteria. EPS of five out of 13 strains showed inhibitory activities in the antibacterial assay. Furthermore, the antibiofilm and antifouling activity of the most active EPS isolated from the strain KT1 was studied using various in vitro and in vivo bioassays. Results revealed that EPS significantly inhibited the growth and biofilm formation of bacteria. Furthermore, the antifouling coating developed with bacterial EPS considerably reduced the recruitment of fouling organisms on coated surfaces submerged in the seawater. The functional groups present in EPS, characterized by strong activity, were analyzed using FT-IR and the spectrum showed the presence of alcohol, amines, carboxylic acid and esters. The bacterium responsible for the production of bioactive EPS was identified as Pseudomonas aeruginosa, using the 16S rRNA gene. Since the findings of this study revealed the antibiofilm and antifouling activities of EPS, further long term field tests and characterization of the bioactive compound of the EPS could lead to the development of eco-friendly antifouling coating.

Long Term Field Test on Structure Forces of Sheet-Pile Wharf with Barrier Piles

Tan, H.; Jiao, Z., and Cai, Z., 2015. Long term field test on structure forces of sheet-pile wharf with barrier piles.Based on the first engineering application of new-type sheet-pile wharf with barrier piles, the field test has been conducted for 7 years. According to the long term field testing results, the structure forces of the wharf front wall and barrier piles have been obtained in different periods. The results have showed that the new wharf structure was effective for a large harbor basin, the maximum positive bending moments for both front wall and barrier piles appeared in dredging period, and the maximum negative bending moment appeared in operation period. The rebar stress of front wall was about twice larger than that of barrier piles. In order to make full use of the potential bearing capacity of front wall and barrier piles, the optimal design was to make them in the same stress level. The modified bending moment calculation method has been proposed based on the field testing data.

도시 지하역사 미세먼지제어를 위한 이중여과장치의 현장적용 연구

This study attempted to find an alternative method for fine dust control in the pre-exiting facilities of metro-subway stations. A new double-layer design was proposed for the MVAC (mechanical ventilation and air control) system. Several filter lay-outs were combined a pre-filter with electret filter (EF), electret bundle filter (EBF), or electret pleated filter (EPF), and were then examined focusing on the collection efficiency of particulate matters and pressure drop across the filter layers. The experimental results from the lab and field tests showed the best collection efficiency with EPF, which achieved 85% for and 55% for . It was also found from the long term field test that the new filter lay-out could provide quite consistent dust level particularly in underground platform regardless of external condition.

Functionality and performance of customized sole inlays for various sports applications

To increase product value and consumer satisfaction customization has become a major aspect in product development. From the consumers’ perspective this trend towards individual fitting is certainly positive as long as it does not negatively influence other sports specific functionality parameters. The current study is dealing with this interaction heading towards customizing effects in footwear. A long term field test was conducted to determine which design parameters of a customized insole embodies the highest benefit for the athlete perceived performance. A test assembly of 20 athletes evaluated a traditional and a customized insole under three different sport conditions 1) indoor sports, 2) outdoor sports, and 3) running). A questionnaire was designed that asked for nine functions at six decisive foot segments (heel, metatarsal, forefoot; lateral, medial); 1) optimal roll off, 2) cushioning, 3) force transmission, 4) feet support, 5) bedding, 6) secure step, 7) avoid slipping 8) avoid pressure and 9) avoid pain. These items were subjectively evaluated by our test persons and finally correlated with initially collected objective measures. Static and dynamic plantar pressure measurements provided data for individual foot sole profiles. Results showed four important outcomes. Firstly, different sports applications require different functional insoles to ensure optimal athlete perception and performance. Secondly the grade of customization increases their perceived performance. Thirdly objective and subjective data are both required to ensure optimal insole supply. And fourthly subjects are rather limited in their ability to distinguish effects of insole design modifications. Especially the last finding raises the question how far customization should be expanded and where it unnecessarily goes beyond practical relevance.

Host range of Gonatocerus sp. near tuberculifemur ‘Clade 1’ in Argentina, an egg parasitoid newly associated to the glassy-winged sharpshooter, Homalodisca vitripennis (Hemiptera: Cicadellidae), and candidate for its biological control in California, USA

The South American egg parasitoid Gonatocerus sp. near tuberculifemur “Clade 1” (G. sp. “Clade 1”) (Hymenoptera: Mymaridae) is a new association of the glassy-winged sharpshooter (GWSS), Homalodiscavitripennis (Germar) (Cicadellidae) and a candidate for its biological control in California, USA. In Argentina, G. sp. “Clade 1” was screened in the laboratory (no-choice tests) and in the field (multiple choice tests) against eggs of 32 Auchenorrhyncha host species and other four potential hosts unrelated to sharpshooters. In no-choice assays, it parasitized only eggs within the leafhopper tribe Proconiini. In contrast, in the long term field tests, it emerged not only from eggs of the Proconiini but also from two species of Cicadellini at low numbers (five wasps out of 698 exposed eggs). Two interpretations arise from the results: (1) Host associations of G. sp. “Clade 1” are restricted to the Proconiini whereas field parasitization of the Cicadellini species were false positive, or (2) G. sp. “Clade 1” parasitizes also some Cicadellini species and its rejection in the laboratory was a false negative. Both interpretations are discussed. Insect motivation could be the explanation for the negative results in the no-choice tests. On the other hand, in the more natural field situations, the host selection process and oviposition behavior should not have been affected and host range would be more realistic. The parasitism of the Cicadellini species would be indicative of a potential non-target effect on the sharpshooters in the USA.

Long Term Field Test of Polymer Insulator on 77kV Transmission Line

As an anti-Vandalism measure, polymer insulator which is light and shows good performance in contamination withstand voltage is already adopted to many new power transmission lines mainly in U.S.A. However, it is said that aging deterioration is promoted by ultraviolet rays, ozone, leakage current and partial discharge because polymer insulator is made of organic materials. It is important that we seize the characteristics of aging deterioration to maintain power transmission lines. As polymer insulator for power transmission lines is more expensive than ceramic one, it is scarely used in Japan, and there is no data in the field.In this study, we installed polymer insulator to 77kV power transmission line and carried out field test for nine years from 1997 to 2006 and investigated electrical and mechanical characteristics of them.

Gas Turbine Compressor Washing State of the Art: Field Experiences1

Technology development in gas turbine compressor washing over the last 10 years and today’s state of the art technology is presented in this paper. Based on various long term field tests and observations, correlation between rate of power degradation and atmospheric conditions can be established. Questions about compressor on line washing with water alone against the use of detergents, as well as washing frequencies are also addressed in this paper. Performance degradation behavior between gas turbines of different sizes and models can be explained with an index of sensitivity to fouling. The implementation of an optimized regime of on line and off line washing in the preventive turbine maintenance program is important. It will improve the plant profitability by reducing the costs of energy production and contribute to a cleaner environment.

Complementary short term and seasonal field tests of several orchard pesticides to measure their impact on the beneficial arthropod fauna

The impact of three insecticides (diazinon, phosphamidon and azinphosmethyl) and one acaricide (bromopropylate) applied for the control of fruit pests on beneficial arthropod populations was determined in four short term and one seasonal test in the field. Arthropod populations on apple trees were not affected by bromopropylate in the short term tests of 24 hours duration except for a slight reduction of spiders and tiny hymenopterous parasites. However, beneficial arthropod populations were reduced significantly after application of diazinon, and in descending order by phosphamidon, which demonstrated acceptable selectivity on anthocorids and mirids, and azinphosmethyl, which in addition was also soft onChrysopa larvae. Coccinellid adults, hymenopterous parasites and spiders were affected by these three organophosphates to the same degree.

RO desalting of brackish water oversaturated with CaSO 4

The possibility of recovery increase in the commercial (10,000 m 3/d) RO plant, desalting brackish feed of 5,000 PPM TDS salinity, was tested in a pilot plant, equipped with 4′' spiral wound and hollow fiber modules. The pilot plant desalted the reject stream from the commercial plant. Long term (up to 4,000 hr) field tests of membrane performance were conducted. During the tests the ratio of the calcium and sulfate ion concentrations product;(Ca ++) × (SO = 4), to the formal solubilities of CaSO 4(Ksp), at the corresponding ionic strength was maintained in the range of 1.2–2.3. Stable membrane performances, in respect to productivity and salt rejection, were obtained. Based on the field results, a 900 m 3/d unit for reject desalting was constructed. The unit, operative since October 1982, enabled an increase of the product recovery in the commercial plant to 65% from a design value of 53%.

Practical Use of "Siolap" Insulated Oil-Filled Cables

SIOLAP is the laminated paper composed of high density crosslinked polyethelene film and kraft paper. Using this SIOLAP as insulating paper 275kV self-contained oil-filled cable (OF cable) has been manufactured and also its physical, dielectric and mechanical performance has been examined for practical use. Furthermore, a long term field test of the cable and its accessories has been carried out. As the result of the test, the firm prospect of practical use of the cable and its accessories has been obtained. In addition, we have now gained a hopeful outlook for practicability of SIOLAP insulated 500kV OF cables.

Newly Developed FM Current-Differential Carrier Relaying System and its Field Experiences

This paper presents the theoretical and experimental studies on the newly developed FM current- differential carrier relaying system ( FM relay). FM relay, with outstanding facility compared with any types of conventional relays, can be applied to multiterminal lines as well as two-terminal lines where conventional types of relays may not be considered satisfactory. The principle of this system lies in the current-differential protection in which the instantaneous current values at each terminal are frequency- modulated and transferred via microwave communication system. The results of a long term field test which was successfully performed on a three-terminal tapped transmission line showed the excellent performances of the FM relay.

Reverse osmosis desalting plant for industrial water at Kashima, in Japan

In early 1975, the first PERMASEP B-9 Reverse Osmosis plant with a capacity of 1500 T/D commenced operation at the Kashima industrial complex in Japan, where industrial water is supplied from Kitaura Lake which contains 1600 ppm or higher TDS, due to the inflow of sea water. In addition to the high salinity, it contains a great deal of organic matter, bacteria and algae. Therefore the most important factor of successful operation is elimination of bacteria growth in the pretreatment system as well as in the permeator. Before installation of the actual plant, a long term field test was carried, out and the best process flow arrangement was determined based on this experimental data. The actual plant is composed Of a 4000 T/D pretreatment system, a 1500 T/D R.O. and a 1000 T/D Ion Exchange unit.

A method of using irrigation drainage water for power plant cooling

The accumulation of large quantities of saline water collected from irrigated fields by underground tile drainage systems presents environmental problems in the South-Western U.S. and Mexico. A major project conducted in this Laboratory indicates technical and economic feasibility for using such wastewaters for power plant cooling. A novel process sequence is employed comprising (a) ion-exchange resin softening whereby nearly all the calcium is removed, followed by (b) using this softened water as feed to the power plant cooling tower, concentrating it by a factor of 5 to 15; this cooling tower blowdown is subsequently (c) further concentrated by vertical tube foam evaporation (VTFE) to provide a 20-fold concentrate of the initially softened wastewater which is then adequate to (d) serve as the sole regenerant for the ion-exchange resin used in the initial softening step. Step (d) is carried out in an upflow fluidized bed mode which ensures favorable reaction kinetics by the formation and removal of calcium sulphate precipitate from the resin bed. A new pilot plant facility of 2,000 gpd capacity is described including a softening and regeneration facility, a cooling tower operating under realistic process conditions and a complete VTFE facility; test data are presented indicating technical feasibility. Long term field tests with this facility are planned in the San Joaquin Valley to determine the viability of this approach for the beneficial use and simultaneous disposal of irrigation drainage. This project is sponsored by several major U.S. power utilities, the Electric Power Research Institute and the California Department of Water Resources.