scholarly journals Development of an autonomous flow-proportional water sampler for the estimation of pollutant loads in urban runoff

2020 ◽  
Vol 192 (9) ◽  
Author(s):  
Péter Budai ◽  
Máté Krisztián Kardos ◽  
Marcell Knolmár ◽  
Gábor Szemán ◽  
József Turczel ◽  
...  

Abstract Implementation of an extensive urban runoff monitoring program, targeting the quantification of heavy metal and organic micropollutant loads, necessitated the development of an autonomous water sampler. The design requirements for the device were to fulfill flow-proportional continuous composite sampling of urban runoff events in a widely customizable, relatively inexpensive, and simple way. In this paper, we introduce the concept along with the experiences gained from the first several months of field tests at seven pilot areas in Hungary that represent a wide range of urban environments. During the test period, prototype samplers were placed in natural (urban) streams as well as stormwater drainage pipes, resulting in a total of 97 automatic composite runoff samples. At two sites, an additional 28 manual grab samples were collected to represent time series from five distinct runoff events. Sampling efficiency was checked by comparing collected volumes with the theoretical ones (derived from pump mileage data). Ranges and ratios of concentrations measured from composite and grab samples were graphically interpreted in order to evaluate their representativeness. It has been shown that the concept is suitable for conducting cost-effective urban runoff characterization surveys targeting inter-event variability.

1981 ◽  
Vol 54 (2) ◽  
pp. 311-330 ◽  
Author(s):  
B. G. Willoughby ◽  
G. Lawson

Abstract The pollution problems of the rubber industry are complex and the pollutants arise from a variety of sources. Prior knowledge of the nature of these pollutants is invaluable to the successful execution of a factory monitoring program. Such a knowledge enables the most appropriate monitoring equipment to be preselected and provides for cost effective analysis. The collection and analysis of hitherto unidentified compounds requires a degree of control which is most easily achieved with a laboratory vulcanization. The results presented here show that this control enables a wide range of volatile species to be captured and permits yields to be optimized for the purposes of identification. Examples of the control that may be achieved in a laboratory vulcanization include the ability to handle samples without loss and to carry out this work with ready access to the most sophisticated analytical equipment. A knowledge of the chemical nature of the fumes from a vulcanizing rubber is not only of value to the industrial hygienist but also provides an insight into the chemical processes of vulcanization. For example, evidence for the free radical contribution to a sulfenamide cure can be obtained. Of special note is the fact that these data can be obtained from fully compounded rubber stocks.


2020 ◽  
Vol 2020 ◽  
pp. 1-20
Author(s):  
Domenico Suriano ◽  
Gennaro Cassano ◽  
Michele Penza

Atmospheric pollution is one of the biggest concerns for public health. Air quality monitoring is currently performed by expensive and cumbersome monitoring stations. For this reason, they are sparse, and therefore, inadequate to provide enough accurate information on the personal exposure to pollutant gases. The current worldwide trend to address this issue consists in the use of low-cost small gas sensors, already available on the market, with a wide range of costs and performances. However, the performance of these sensors is heavily affected by the environmental conditions of the specific location used for their deployment. For this reason, it is of fundamental importance to test them in real-world scenarios. Field evaluation of sensor performance could be a challenging task because, on the one hand, they have heterogeneous output signals, and on the other hand, there is no widely shared evaluation protocol. The SentinAir system has been designed and developed to facilitate this task. It can carry out performance evaluations for any type of sensor thanks to its configurable and adaptable sensing capability, multiple wireless sensor network compatibility, flexibility, and usability. In order to evaluate SentinAir capabilities and functionalities, the performances of CO2, NO2, and O3 sensors were tested in real-world scenarios against reference instruments. To the best of our knowledge, there is no previous study providing information about the performance of SP-61 (O3 sensor), IRC-A1 (CO2 sensor), and TDS5008 (CO2 sensor) achieved during on-field tests. On the contrary, results obtained by OXB431 (O3 sensor) and NO2B43F (NO2 sensor) are consistent with the ones shown in previous studies carried out in similar conditions. During validation tests, we have found R2=0.507 for the best performing NO2 sensor, and R2=0.668 for the best O3 sensor. Concerning the indoor experiment, the best CO2 sensor performance showed an excellent R2=0.995. In conclusion, the effectiveness of this tool in evaluating the performance of heterogeneous gas sensors in different real-world scenarios has been demonstrated. Therefore, we anticipate that the use of SentinAir will facilitate researchers to carry out these challenging tasks.


Author(s):  
T. K. Houghtaling ◽  
G. A. Abramczyk ◽  
D. S. Hoang ◽  
D. R. Leduc ◽  
R. N. Lutz ◽  
...  

In general, the design process involves envisioning and developing concepts for a component or system, combining these fractions into an integrated whole and evaluating the final design against functional requirements. A major challenge is developing components or systems to a level of maturity that permits feasibility evaluation of the integrated whole while optimizing opposing performance functions (e.g., thick for strength, but thin for heat transfer). Economic pressure often drives design concepts to conservative bases early in the process. The approach presented in this paper is a highly cost-effective means of developing alternative design solutions for given set of design requirements — in this case a radioactive materials transportation package. In response to planned phase-out of the Department of Transportation 6M specification package, an internal competition was held at the Savannah River Site to develop design proposals for the 6M replacement. Two teams were provided with design requirements, design evaluation criteria, a limited budget and short time frame to develop proposals for a General Purpose Fissile Package (GPFP). Resulting GPFP designs, while quite different, met the performance requirements, were economical, operator friendly, light weight, certifiable, and able to accommodate a wide range of radioactive materials. The methodology of an in-house design competition proved to be a very cost effective way of advancing design alternatives from design requirements to practical design proposals. Estimated fabrication costs for each of the designs are significantly less than other packages currently available for the proposed service.


2020 ◽  
pp. 1192-1198
Author(s):  
M.S. Mohammad ◽  
Tibebe Tesfaye ◽  
Kim Ki-Seong

Ultrasonic thickness gauges are easy to operate and reliable, and can be used to measure a wide range of thicknesses and inspect all engineering materials. Supplementing the simple ultrasonic thickness gauges that present results in either a digital readout or as an A-scan with systems that enable correlating the measured values to their positions on the inspected surface to produce a two-dimensional (2D) thickness representation can extend their benefits and provide a cost-effective alternative to expensive advanced C-scan machines. In previous work, the authors introduced a system for the positioning and mapping of the values measured by the ultrasonic thickness gauges and flaw detectors (Tesfaye et al. 2019). The system is an alternative to the systems that use mechanical scanners, encoders, and sophisticated UT machines. It used a camera to record the probe’s movement and a projected laser grid obtained by a laser pattern generator to locate the probe on the inspected surface. In this paper, a novel system is proposed to be applied to flat surfaces, in addition to overcoming the other limitations posed due to the use of the laser projection. The proposed system uses two video cameras, one to monitor the probe’s movement on the inspected surface and the other to capture the corresponding digital readout of the thickness gauge. The acquired images of the probe’s position and thickness gauge readout are processed to plot the measured data in a 2D color-coded map. The system is meant to be simpler and more effective than the previous development.


Weed Science ◽  
1979 ◽  
Vol 27 (5) ◽  
pp. 497-501 ◽  
Author(s):  
C. D. Boyette ◽  
G. E. Templeton ◽  
R. J. Smith

An indigenous, host-specific, pathogenic fungus that parasitizes winged waterprimrose [Jussiaea decurrens(Walt.) DC.] is endemic in the rice growing region of Arkansas. The fungus was isolated and identified asColletotrichum gloeosporioides(Penz.) Sacc. f.sp. jussiaeae(CGJ). It is highly specific for parasitism of winged waterprimrose and not parasitic on creeping waterprimrose (J. repensL. var.glabrescensKtze.), rice (Oryza sativaL.), soybeans [Glycine max(L.) Merr.], cotton (Gossypium hirsutumL.), or 4 other crops and 13 other weeds. The fungus was physiologically distinct from C.gloeosporioides(Penz.) Sacc. f. sp.aeschynomene(CGA), an endemic anthracnose pathogen of northern jointvetch[Aeschynomene virginica(L.) B.S.P.], as indicated by cross inoculations of both weeds. Culture in the laboratory and inoculation of winged waterprimrose in greenhouse, growth chamber and field experiments indicated that the pathogen was stable, specific, and virulent in a wide range of environments. The pathogen yielded large quantities of spores in liquid culture. It is suitable for control of winged waterprimrose. Winged waterprimrose and northern jointvetch were controlled in greenhouse and field tests by application of spore mixtures of CGJ and CGA at concentrations of 1 to 2 million spores/ml of each fungus in 94 L/ha of water; the fungi did not damage rice or nontarget crops.


Author(s):  
Allan Matthews ◽  
Adrian Leyland

Over the past twenty years or so, there have been major steps forward both in the understanding of tribological mechanisms and in the development of new coating and treatment techniques to better “engineer” surfaces to achieve reductions in wear and friction. Particularly in the coatings tribology field, improved techniques and theories which enable us to study and understand the mechanisms occurring at the “nano”, “micro” and “macro” scale have allowed considerable progress to be made in (for example) understanding contact mechanisms and the influence of “third bodies” [1–5]. Over the same period, we have seen the emergence of the discipline which we now call “Surface Engineering”, by which, ideally, a bulk material (the ‘substrate’) and a coating are combined in a way that provides a cost-effective performance enhancement of which neither would be capable without the presence of the other. It is probably fair to say that the emergence and recognition of Surface Engineering as a field in its own right has been driven largely by the availability of “plasma”-based coating and treatment processes, which can provide surface properties which were previously unachievable. In particular, plasma-assisted (PA) physical vapour deposition (PVD) techniques, allowing wear-resistant ceramic thin films such as titanium nitride (TiN) to be deposited on a wide range of industrial tooling, gave a step-change in industrial productivity and manufactured product quality, and caught the attention of engineers due to the remarkable cost savings and performance improvements obtained. Subsequently, so-called 2nd- and 3rd-generation ceramic coatings (with multilayered or nanocomposite structures) have recently been developed [6–9], to further extend tool performance — the objective typically being to increase coating hardness further, or extend hardness capabilities to higher temperatures.


Biostatistics ◽  
2019 ◽  
Author(s):  
Dane R Van Domelen ◽  
Emily M Mitchell ◽  
Neil J Perkins ◽  
Enrique F Schisterman ◽  
Amita K Manatunga ◽  
...  

SUMMARYMeasuring a biomarker in pooled samples from multiple cases or controls can lead to cost-effective estimation of a covariate-adjusted odds ratio, particularly for expensive assays. But pooled measurements may be affected by assay-related measurement error (ME) and/or pooling-related processing error (PE), which can induce bias if ignored. Building on recently developed methods for a normal biomarker subject to additive errors, we present two related estimators for a right-skewed biomarker subject to multiplicative errors: one based on logistic regression and the other based on a Gamma discriminant function model. Applied to a reproductive health dataset with a right-skewed cytokine measured in pools of size 1 and 2, both methods suggest no association with spontaneous abortion. The fitted models indicate little ME but fairly severe PE, the latter of which is much too large to ignore. Simulations mimicking these data with a non-unity odds ratio confirm validity of the estimators and illustrate how PE can detract from pooling-related gains in statistical efficiency. These methods address a key issue associated with the homogeneous pools study design and should facilitate valid odds ratio estimation at a lower cost in a wide range of scenarios.


Author(s):  
Mamou Diallo ◽  
Servé W. M. Kengen ◽  
Ana M. López-Contreras

AbstractThe Clostridium genus harbors compelling organisms for biotechnological production processes; while acetogenic clostridia can fix C1-compounds to produce acetate and ethanol, solventogenic clostridia can utilize a wide range of carbon sources to produce commercially valuable carboxylic acids, alcohols, and ketones by fermentation. Despite their potential, the conversion by these bacteria of carbohydrates or C1 compounds to alcohols is not cost-effective enough to result in economically viable processes. Engineering solventogenic clostridia by impairing sporulation is one of the investigated approaches to improve solvent productivity. Sporulation is a cell differentiation process triggered in bacteria in response to exposure to environmental stressors. The generated spores are metabolically inactive but resistant to harsh conditions (UV, chemicals, heat, oxygen). In Firmicutes, sporulation has been mainly studied in bacilli and pathogenic clostridia, and our knowledge of sporulation in solvent-producing or acetogenic clostridia is limited. Still, sporulation is an integral part of the cellular physiology of clostridia; thus, understanding the regulation of sporulation and its connection to solvent production may give clues to improve the performance of solventogenic clostridia. This review aims to provide an overview of the triggers, characteristics, and regulatory mechanism of sporulation in solventogenic clostridia. Those are further compared to the current knowledge on sporulation in the industrially relevant acetogenic clostridia. Finally, the potential applications of spores for process improvement are discussed.Key Points• The regulatory network governing sporulation initiation varies in solventogenic clostridia.• Media composition and cell density are the main triggers of sporulation.• Spores can be used to improve the fermentation process.


2021 ◽  
Vol 13 (11) ◽  
pp. 6506
Author(s):  
Roberto Fanigliulo ◽  
Daniele Pochi ◽  
Pieranna Servadio

Conventional seedbed preparation is based on deep ploughing followed by lighter and finer secondary tillage of the superficial layer, normally performed by machines powered by the tractor’s Power Take-Off (PTO), which prepares the seedbed in a single pass. Conservation methods are based on a wide range of interventions, such as minimum or no-tillage, by means of machines with passive action working tools which require two or more passes The aim of this study was to assess both the power-energy requirements of conventional (power harrows and rotary tillers with different working width) and conservation implements (disks harrow and combined cultivator) and the soil tillage quality parameters, with reference to the capability of preparing an optimal seedbed for wheat planting. Field tests were carried out on flat, silty-clay soil, using instrumented tractors. The test results showed significant differences among the operative performances of the two typologies of machines powered by the tractor’s PTO: the fuel consumption, the power and the energy requirements of the rotary tillers are strongly higher than power harrows. However, the results also showed a decrease of these parameters proceeding from conventional to more conservation tillage implements. The better quality of seedbed was provided by the rotary tillers.


2018 ◽  
Vol 66 (10) ◽  
pp. 1487-1491 ◽  
Author(s):  
Jean B Nachega ◽  
Nadia A Sam-Agudu ◽  
Lynne M Mofenson ◽  
Mauro Schechter ◽  
John W Mellors

Abstract Although significant progress has been made, the latest data from low- and middle-income countries show substantial gaps in reaching the third “90%” (viral suppression) of the UNAIDS 90-90-90 goals, especially among vulnerable and key populations. This article discusses critical gaps and promising, evidence-based solutions. There is no simple and/or single approach to achieve the last 90%. This will require multifaceted, scalable strategies that engage people living with human immunodeficiency virus, motivate long-term treatment adherence, and are community-entrenched and ‑supported, cost-effective, and tailored to a wide range of global communities.


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