Real-time multi ISFET/FIA soil analysis system with automatic sample extraction

Successful implementation of site-specific crop management relies on accurate quantification of spatial variation of important factors. Therefore, there is a tremendous need for the development of sensing technologies that will allow automated collection of soil, crop and pest data, to more accurately characterize within-field variability. The objective of this work was to develop an integrated multi-sensor soil analysis system. Ion-selective field effect transistor (ISFET) technology was coupled with flow injection analysis (FIA) to produce a real-time soil analysis system. Testing of the ISFET/ FIA system for soil analysis was carried out in two stages: (1) using manually extracted samples, and (2) the soil to be analysed was placed in the automated soil extraction system, and the extracted solution fed directly into the FIA system. The sensor was successful in measuring soil nitrates in manually extracted soil solutions (r2\u3e0.9). The rapid response of the system allowed a sample to be analysed in 1.25 s, which is satisfactory for real-time soil sensing. Precision and accuracy of the system were highly dependent on maintaining precise, repetitive injection times and maintaining constant flow parameters during the calibration and testing cycle. The progress toward an automated soil extraction system was notable, but considerable effort will be necessary before commercialization can be realized. However, the concept of using ISFETs for the real-time analysis of soil nitrates is sound. The rapid response and low sample volumes required by the multi-sensor ISFET/FIA system make it a viable candidate for use in real-time soil nutrient sensing

Membrane Selection and ISFET Configuration Evaluation for Soil Nitrate Sensing

Successful implementation of site-specific crop management relies on accurate quantification of spatial variation of important factors. Data collection on a finer spatial resolution than is feasible with manual and/or laboratory methods is often required but cost prohibitive. Therefore, there is a need for the development of sensors to more accurately characterize within-field variability. The objective of this research was to investigate matrix membranes produced from different combinations of ligand and plasticizer materials using ion-selective electrode (ISE) technology, and to use selected membranes to develop a nitrate ion-selective field effect transistor (ISFET) which might be integrated with a flow injection analysis (FIA) system for real-time soil analysis. Several ion-selective membranes were tested, and all of the evaluated membranes proved to be viable candidates for the development of a nitrate ISFET. Membranes using methyltridodecylammonium chloride (MTDA) as the ligand showed a better response to nitrates at low concentrations while those using tetradodecylammonium nitrate (TDDA) ligand showed superior selectivity for the nitrate ion. A multi- ISFET nitrate sensor was successfully developed. The electrical responses of the ISFETs were consistent and predictable. While significant difficulty was found in preparing a multi-ISFET chip with all four sensors operational, once prepared, the multi-ISFET chips were reliable and performed through extensive tests without failure. The sensitivities of the nitrate ISFETs (38-46 mV/decade) were lower than the theoretical Nernst sensitivity. The nitrate ISFETs proved to be viable sensors for the development of a real-time soil nitrate analysis system, under the conditions of our tests

The theatre of destruction: anarchism, nihilism & the avant-garde, 1909-1945

This thesis argues that theatricalization is an appropriate paradigm to employ in a political reassessment of the historical avant-garde moments of Futurism, Dada and Surrealism. Through an analysis of the performativity and theatricality of the manifestos and manifestations of these successive avant-garde, it is suggested that each avant-garde moment self-dramatizes a destructive character. An argument is then developed that the destructive character of the avant-garde demonstrates and displays a libertarian-barbarian dialectic which emerges from within the discourses of anarchism and nihilism, in particular from Michael Bakunin’s maxim: ‘the passion for destruction is a creative passion, too’. The destructive character of the avant-garde is manifest most clearly in the manifestos which announce and perform a desire for the destruction of the institution of art and the re-integration of art and life, as advanced by Peter Bürger. Identifying a parallel between the discourses of theatricalization and aestheticization in Symbolist drama, I argue that the paradigm of theatricalization necessitates a critical re-assessment of the polarity which Walter Benjamin advances, between the aestheticization of politics and the politicization of art. Further, it is suggested, we must also re-examine the polarity which Bürger asserts between Aestheticism and the avant-garde with respect to the question of autonomy in art. Thus, from Bakunin’s initial breakdown of the opposition between destruction/creation we embark upon a re-examination of the polarity between key terms of the avant-garde: libertarian/barbarian; incarnation/integration; aestheticization/politicization; theatricality/performativity. The theatricalization of avant-garde manifesto is then articulated in the context of Habermas’ study of the structural transformation of the public sphere from feudalism (theatricalization) to capitalism (literalization)

Laboratory Evaluation of an Electro-Pneumatic Sampling Method for Real-Time Soil Sensing

An automated electro-pneumatic soil sampling method based on pressurized air for real-time soil analysis was developed and tested under laboratory conditions. Pressurized air was applied for 36 ms across a 2.5 cm diameter cylinder to cut a sample from a soil column and convey the sample along a delivery pipe into a container. An electro-pneumatic regulator valve was used to regulate the air pressure at 550, 690, and 830 kPa (80, 100, and 120 psi) using an analog electrical signal. A two-position solenoid valve controlled by a stand-alone microprocessor was used to control pulse duration. Laboratory tests were conducted to determine the effectiveness of positive high-pressure air as a cutting force for different soil conditions. The effects of air pressure level, soil moisture content, soil compaction, and soil type on the quantity of soil sample obtained were investigated. Moisture content and air pressure level were the most significant factors, while compaction was not significant (. = 0.05) in terms of mass of soil obtained. Laboratory test results proved that pressurized air was effective in cutting and transporting a soil sample in a short time period (36 ms) for all different soils studied in this experiment. The electro-pneumatic method was also capable of obtaining a consistent amount of soil sample with a coefficient of variation of less than 20% for any individual treatments in the experimental design. The electro-pneumatic soil sampling method is a viable candidate as a soil sampling system for on-the-go soil analysis

An investigation into the literature regarding nasal allergy with special reference to the therapeutic value of Zinc ionisation - a report on 120 personal cases

1. A review of the literature on nasal allergy has been made with special reference to zinc ionisation therapy.2. Mention has been made of the methods of investigating a case of nasal allergy and the results of various forms of treatment are liven.3. The technique of zinc ionisation is described and the details requirin`, particular attention are mentioned.4. Zinc ionisation acts by coagulating the surface epithelium with a subsequent regeneration of healthy epithelium, and by reducing oedema in the nose as a result of fibrosis in the submucosa.5. Zinc ionisation may be used for any form of nasal allergy. The results of 120 cases treated are given in full. These show 30.92% personally 3 cures , 42.73; great improvements , 15.45 %, improvements ,and 10.90% failures.6. No untoward effects have been noted in a total of 492 ionisations.7. The cases which have failed to respond to zinc ionisation are described and commented upon.8. Zinc ionisation has no effect at all upon purulent nasal discharge.9. An outline of the treatment to be adopted. in any particular case of nasal allergy is given

Evaluation of Nitrate and Potassium Ion-Selective Membranes for Soil Macronutrient Sensing

On-the-go, real-time soil nutrient analysis would be useful in site-specific management of soil fertility. The rapid response and low sample volume associated with ion-selective field-effect transistors (ISFETs) make them good soil fertility sensor candidates. Ion-selective microelectrode technology requires an ion-selective membrane that responds selectively to one analyte in the presence of other ions in a solution. This article describes: (1) the evaluation of nitrate and potassium ion-selective membranes, and (2) the investigation of the interaction between the ion-selective membranes and soil extractants to identify membranes and extracting solutions that are compatible for use with a real-time ISFET sensor to measure nitrate and potassium ions in soil. The responses of the nitrate membranes with tetradodecylammonium nitrate (TDDA) or methlytridodecylammonium chloride (MTDA) and potassium membranes with valinomycin were affected by both membrane type and soil extractant. A TDDA-based nitrate membrane would be capable of detecting low concentrations in soils to about 10-5 mole/L NO3 -. The valinomycin-based potassium membranes showed satisfactory selectivity performance in measuring potassium in the presence of interfering cations such as Na+, Mg2+, Ca2+, Al3+, and Li+ as well as provided a consistent sensitivity when DI water, Kelowna, or Bray P1 solutions were used as base solutions. The TDDA-based nitrate membrane and the valinomycin-based potassium membrane, used in conjunction with Kelowna extractant, would allow determination of nitrate and potassium levels, respectively, for site-specific control of fertilizer application

Corn Stover Harvest, Tillage, and Cover Crop Effects on Soil Health Indicators

Monitoring soil health indicators (SHI) will help ensure that corn (Zea mays L.) stover harvest is sustainable. This study examines SHI changes after 5 yr of growing continuous corn with either chisel plow or no-tillage practices and harvesting 0, ∼35, or ∼60% of the stover. Two no-tillage treatments with a cereal rye (Secale cereale L.) cover crop and stover harvest rates of ∼35 or ∼60% were evaluated. All eight treatments were replicated four times in a randomized complete block design at an 11-ha site in Boone County, IA. Soil samples were collected following grain and stover harvest from 0- to 5- and 5- to 15-cm depth increments. Particulate organic matter C (POM-C) decreased when stover was removed or the soil was chisel plowed. No-till with 0% stover removal had 10 mg g–1 POM-C in the 0- to 5-cm soil layer, which was 1.9-fold higher than in other treatments. Potentially mineralizable N (PMN) was greater under cover crop treatments. Average PMN values were 56.9 and 45.5 µg g–1 PMN for no-till with cereal rye at 0- to 5- and 5- to 15-cm depths, respectively, compared with 17.5 and -3.7 µg g–1 PMN for the same no-till treatments without cereal rye. Other soil properties did not respond to increasing levels of stover removal. At this location and at the studied removal rates, 5 yr of harvesting corn stover did not decrease soil health, but POM-C data suggest that changes may be occurring. Long-term monitoring should continue to assess corn stover harvest sustainability

Rapid Nitrate Analysis of Soil Cores Using ISFETs

An intact core extraction procedure was tested that might be used in the field for real–time prediction of soil nitrates. An extraction solution was pushed through a soil core held between two filters, and an ion–selective field–effect transistor/flow injection analysis (ISFET/FIA) system was used to sense soil nitrates in real time. Laboratory tests were conducted using four soil types and two levels of nitrate concentration, soil moisture, core density, core length, core diameter, and extraction solution flow rate. The extraction solution flow was sampled at the exit face of the core and routed to the ISFET/FIA system. The ISFET output voltage was sampled at 100 Hz. Results of the test indicate that nitrate extraction of the soil cores was successful, and that data descriptors based on response curve peak and slope of the ISFET nitrate response curve might be used in tandem in a real–time prediction system

Corn Stover Nutrient Removal Estimates for Central Iowa, USA

One of the most frequent producer-asked questions to those persons striving to secure sustainable corn (Zea mays L.) stover feedstock supplies for Iowa’s new bioenergy conversion or other bio-product facilities is “what quantity of nutrients will be removed if I harvest my stover?” Our objective is to summarize six years of field research from central Iowa, U.S.A. where more than 600, 1.5 m2 samples were collected by hand and divided into four plant fractions: vegetative material from the ear shank upward (top), vegetative material from approximately 10 cm above the soil surface to just below the ear (bottom), cobs, and grain. Another 400 stover samples, representing the vegetative material collected directly from a single-pass combine harvesting system or from stover bales were also collected and analyzed. All samples were dried, ground, and analyzed to determine C, N, P, K, Ca, Mg, S, Al, B, Cu, Fe, Mn, and Zn concentrations. Mean concentration and dry matter estimates for each sample were used to calculate nutrient removal and estimate fertilizer replacement costs which averaged $25.06,$20.04, $16.62,$19.40, and $27.41 Mg−1 for top, bottom, cob, stover, and grain fractions, respectively. We then used the plant fraction estimates to compare various stover harvest scenarios and provide an answer to the producer question posed above

Evaluation of Phosphate Ion-Selective Membranes for Real-time Soil Nutrient Sensing

A real-time soil nutrient sensor would allow the efficient collection of data with a fine spatial resolution, to accurately characterize within-field variability for site-specific nutrient application. Our goal was to evaluate the applicability of a phosphate membrane to the measurement of phosphate levels in soil extractants and to determine how previously developed nitrate and potassium membranes would be affected by the presence of phosphate. A type of PVC-based phosphate membrane containing an organotin compound, bis(p-chlorobenzyl)tin dichloride, was evaluated, along with the nitrate and potassium membranes, in pH 7 Tris buffer solution and Kelowna soil extractant for sensitivity and long-term stability. The phosphate membranes in the Tris buffer solution of pH 7 exhibited a response over a range of 10-5 to 10-1 mol/L phosphate concentrations with an average slope of -28.2 +1.5 mV per activity decade of dibasic phosphate. The response speed of tested electrodes containing phosphate, nitrate and potassium membranes was rapid, reaching an equilibrium response in less than 15 s. However, the phosphate membrane in the Kelowna solution of pH 8.5 was almost insensitive to different phosphate levels from 10-6 to 10-2 mol/L due to the presence of a high concentration of fluoride in the solution. In addition, the tin compound-based phosphate membranes had limited lifetimes of less than 14 days. It is not expected that the tested phosphate membranes could be used for phosphate detection in other soil extractants, such as Bray P1 and Mehlich III solutions, because they also contain high concentrations of fluoride