Long-term Field Evaluation Research Articles

Seasonally optimized calibrations improve low-cost sensor performance: long-term field evaluation of PurpleAir sensors in urban and rural India

Abstract. Lower-cost air pollution sensors can fill critical air quality data gaps in India, which experiences very high fine particulate matter (PM2.5) air pollution but has sparse regulatory air monitoring. Challenges for low-cost PM2.5 sensors in India include high-aerosol mass concentrations and pronounced regional and seasonal gradients in aerosol composition. Here, we report on a detailed long-time performance evaluation of a popular sensor, the Purple Air PA-II, at multiple sites in India. We established three distinct sites in India across land use categories and population density extremes (in urban Delhi and rural Hamirpur in north India and urban Bengaluru in south India), where we collocated the PA-II model with reference beta attenuation monitors. We evaluated the performance of uncalibrated sensor data, and then developed, optimized, and evaluated calibration models using a comprehensive feature selection process with a view to reproducibility in the Indian context. We assessed the seasonal and spatial transferability of sensor calibration schemes, which is especially important in India because of the paucity of reference instrumentation. Without calibration, the PA-II was moderately correlated with the reference signal (R2 = 0.55–0.74) but was inaccurate (NRMSE ≥ 40 %). Relative to uncalibrated data, parsimonious annual calibration models improved the PurpleAir (PA) model performance at all sites (cross-validated NRMSE 20 %–30 %; R2 = 0.82–0.95), and greatly reduced seasonal and diurnal biases. Because aerosol properties and meteorology vary regionally, the form of these long-term models differed among our sites, suggesting that local calibrations are desirable when possible. Using a moving-window calibration, we found that using seasonally specific information improves performance relative to a static annual calibration model, while a short-term calibration model generally does not transfer reliably to other seasons. Overall, we find that the PA-II model can provide reliable PM2.5 data with better than ±25 % precision and accuracy when paired with a rigorous calibration scheme that accounts for seasonality and local aerosol composition.

Long-term field evaluation of Pera sweet orange selections under the Brazilian humid subtropical climate

Currently, a low number of citrus varieties are commercially planted to supply the Brazilian citrus industry demand. The diversification of citrus scion and rootstock varieties is an important strategy to prevent disease outbreaks and to obtain higher off-season profits, as well as to extend fruit supply for the citrus processing industry. The aim of this study was to evaluate 16 Pera sweet orange selections (Citrus ×sinensis Osbeck) under a humid subtropical climate in the northwest region of the state of Paraná, Brazil regarding tree development, production, and disease incidence. The experimental orchard was planted in December 2012 in a randomized block design with three replications and five trees per plot. All scions were grafted on Rangpur lime rootstock (C. ×limonia Osbeck). The evaluations were performed from 2016 through 2022, and included vegetative growth, yield, fruit quality, estimated tree density and productivity for new plantings, and incidence of diseases as citrus canker, huanglongbing (HLB), and citrus tristeza virus (CTV). All data was submitted to ANOVA and means grouped by the Scott Knott’s test (p ≤ 0.05). Pera Perão was the most vigorous variety, with the heaviest and largest fruit, and was among the selections with the highest content of soluble solids (SS), titratable acidity (TA) and juice. However, this variety showed a light-yellow juice color, and one of the lowest SS·TA−1 ratio. This selection had the lowest percentage of fruits with citrus canker but was among the selections with the highest HLB incidence. The selections Ovale, Clone 9, and Clone 42 also showed higher vegetative growth and fruit length, but lower SS content, juice yield and technological indices. All other Pera selections had lower tree height and canopy volume than Ovale, Clone 9, and Clone 42, and adequate overall fruit quality. Conversely, Pera Comprida, Dibbern, Morretes, and Seleç ão 12 scored lower cumulative fruit yield. Pera Pirangi and Comprida had the highest citrus canker incidence on fruits, while Morretes, Ovo, Pirangi, Seleç ão 12, and Seleç ão 27 had the highest HLB incidence alongside Perão. Low severity level of stem pitting was observed within the evaluated selections. The scores ranged from one (absence of stem pitting) to two (sparse surface stem pitting). IAC, Olímpia, Mel, Bianchi, and IPR 159 revealed to be the most suitable for new plantings under humid subtropical edaphoclimatic conditions, as trees had small vegetative growth, high yield performance and fruit quality, in addition to showing lower incidences of citrus canker, HLB and CTV.

On the forecast control of heating system as an easily applicable measure to increase energy efficiency in existing buildings: Long term field evaluation

The priority for reaching carbon neutral buildings by 2050 is to first increase energy efficiency in existing buildings by use of easily and widely applicable measures that are verified based on long-term field research. One such solution is a forecast control of heating systems, which can be quickly and easily integrated to existing weather based controls. However, there are still no long-term field evaluation and detailed analyses of the main features of such a system, which would provide a clear picture about the system’s energetical and economical features and thus increase their wide application in existing buildings. This paper provides the data from a long term field evaluation of an innovative forecast control of heating systems (forHEAT), which can be easily installed (in less than 2 h) and integrated with existing installations in millions of existing buildings in Europe and throughout the world. The energy consumption for heating was evaluated in seven residential buildings and three public office buildings before and after the installation and use of the forecast control. The resulting energy savings averaged 13.4% in the residential and 10.7% in the public buildings located in continental European climate, with very cold winters. The payback time averaged a 0.6 heating season and in most case studies does not exceed a single heating season.

Long-Term Field Evaluation of Conventional vs. Micropropagated Plants of Chrysanthemum cinerariifolium

Pyrethrum is a perennial herbaceous plant endemic to the eastern coast of the Adriatic Sea, and introduced in large areas of nearly all continents, where it is cultivated for the industrial extraction of pyrethrins. Pyrethrins are a group of six closely related monoterpene esters, widely used as natural insecticides. The world production of natural pyrethrins is lower than the market demand, and a wider introduction of this crop within the Mediterranean agrosystems could be an appealing opportunity for farmers and manufacturers. The availability of adequate amounts of selected plant material to bring into cultivation is, however, one of the major issues. Therefore, the in vitro propagation of elite pyrethrum genotypes could be a suitable alternative to conventional propagation methods. In this paper, we present the results of a 9-year field comparison between pyrethrum plants coming from an in vitro propagation protocol and plants obtained by cutting from the same mother plants. Furthermore, since plantlets derived from in vitro regeneration may experience ploidy changes, we evaluated the stability of the ploidy level of pyrethrum-micropropagated plants by flow cytometry (FCM) analysis. FCM screening revealed no differences among the morphotypes and between them and the mother plant. Likewise, the field evaluation of plants gave no significant differences between flower yields in both groups. Hence, micropropagation was confirmed as an easy, efficient and reproducible method to obtain large quantities of selected pyrethrum genotypes.

Discussion of “Long-Term Field Evaluation of a Geosynthetic-Stabilized Roadway Founded on Expansive Clays’’ by Gholam H. Roodi and Jorge G. Zornberg

Discussion of “Long-Term Field Evaluation of a Geosynthetic-Stabilized Roadway Founded on Expansive Clays’’ by Gholam H. Roodi and Jorge G. Zornberg

Closure to “Long-Term Field Evaluation of a Geosynthetic-Stabilized Roadway Founded on Expansive Clays” by Gholam H. Roodi and Jorge G. Zornberg

Closure to “Long-Term Field Evaluation of a Geosynthetic-Stabilized Roadway Founded on Expansive Clays” by Gholam H. Roodi and Jorge G. Zornberg

Usability and user acceptance of an arm-support exoskeleton in automotive assembly: Results of a long-term field evaluation

Usability and user acceptance of an arm-support exoskeleton in automotive assembly: Results of a long-term field evaluation

Energy Efficient Wireless Sink Node for Monitoring of Snow Environment

Conventionally, sink node is considered to have large hardware and energy resources; however, many times sink node is working in same conditions as source nodes, especially when deployed for monitoring of the snow environment. In this paper, an effort has been made to practically realize a sink node which is energy efficient and cost effective for monitoring applications. To save energy, the Main Power Module is designed to provide controlled powers to sensors and sub-modules. The paper discusses design aspects of the sink node and its long-term field evaluation with environmental sensors, especially the Snow Depth Sensor of MaxBotix. Field performance of Snow Depth Sensor has been enhanced by Euclidean Minimum Distance filter which improved the correlation of data to 0.997. The proposed design helps to achieve energy consumption of 42.72mWh which is significantly lower than the previous work. The reliable working of the sink node in the long-term field evaluation indicates that snow environment can be monitored at less expense of energy by employing proposed sensors and the specially designed sink node.

Long-term field evaluation and large-scale application of a Metarhizium anisopliae strain for controlling major rice pests

There is increasing concern about the toxic effects of chemical pesticides on human health and the environment. Many alternatives, however, are viewed as impracticable or inefficient for agricultural needs. Here, a sustainable, environmentally friendly strategy was designed for the control of major rice insect pests (i.e. Nilaparvata lugens, Cnaphalocrocis medinalis and Chilo suppressalis) with minimal impact on natural enemies via selection of a specific entomopathogenic fungal strain for use as a biological control agent. In large-scale multiyear field applications, Metarhizium anisopliae CQMa421 was shown to act as effectively as chemical pesticides for pest control. Rice pest control applications in all major rice-producing provinces in China covering > 6000 hectares, performed over a period of 8 years (2011–2018), showed equal rice harvest yields between the use of the fungal pathogen versus chemical pesticides. More importantly, the use of the specific fungal pathogen isolated by this strategy resulted in an increase in beneficial insects and other animals. These long-term field evaluation data and large-scale application results demonstrated the feasibility of shifting from chemical dependency to more nuanced approaches for pest control for maintaining agricultural productivity while protecting natural enemies. With this strategy, new specific fungal strains can also be isolated to control the main pests of other crops.

Long-Term Field Evaluation of a Geosynthetic-Stabilized Roadway Founded on Expansive Clays

AbstractThis paper presents an evaluation of the long-term field performance of Farm-to-Market Road 2, the construction of which involved geosynthetic stabilization to address concerns related to t...

Long-term field Evaluation of Low-cost Particulate Matter Sensors in Nanjing

ABSTRACT Low-cost particulate matter (PM) sensors can be widely deployed to measure aerosol concentrations at higher spatial and temporal resolutions than traditional instruments, but they need to be carefully calibrated under ambient conditions. In this study, a long-term field experiment was conducted from December 2015 to May 2017 at a site in Nanjing to evaluate the capabilities of in-house built low-cost PM monitors using the Shinyei PPD42NS sensor for ambient PM2.5 monitoring. A BAM-1020 particulate monitor was co-located with the low-cost sensors to provide reference readings. Least-square regressions with linear and power-law functions, and an artificial neural network (ANN) technique were used to convert electrical instrument readings to ambient aerosol concentrations. Applying the ANN technique resulted in the best estimation of the hourly PM2.5 (R2 = 0.84; mean normalized bias = 12.7% and mean normalized error (MNE) = 29.7%). The low-cost sensors displayed relatively good performance with high aerosol concentrations but larger errors with concentrations below 35 µg m–3. High humidity (RH > 75%) can cause a larger MNE for these sensors, but the impact of temperature was negligible in this study. A clear sensor deterioration trend was observed during the 18-month field calibration. High correlations were found between the data from a single low-cost sensor and the data from the BAM-1020 when the low-cost sensor was individually calibrated, but the correlations between measurements taken by different low-cost sensor units were only moderate, possibly due to internal sensor variations. The results suggest that these low-cost sensors can measure ambient PM2.5 concentrations with an acceptable level of accuracy, which can and should be improved by calibrating each sensor individually. Special attention should be paid to the accuracy of these sensors after long-term application and in highly humid environments.

Long-term field evaluation of the Plantower PMS low-cost particulate matter sensors

The low-cost and compact size of light-scattering-based particulate matter (PM) sensors provide an opportunity for improved spatiotemporally resolved PM measurements. However, these inexpensive sensors have limitations and need to be characterized under realistic conditions. This study evaluated two Plantower PMS (particulate matter sensor) 1003s and two PMS 5003s outdoors in Salt Lake City, Utah over 320 days (1/2016–2/2016 and 12/2016–10/2017) through multiple seasons and a variety of elevated PM2.5 events including wintertime cold-air pools (CAPs), fireworks, and wildfires. The PMS 1003/5003 sensors generally tracked PM2.5 concentrations compared to co-located reference air monitors (one tapered element oscillating microbalance, TEOM, and one gravimetric federal reference method, FRM). The different PMS sensor models and sets of the same sensor model exhibited some intra-sensor variability. During winter 2017, the two PMS 1003s consistently overestimated PM2.5 by a factor of 1.89 (TEOM PM2.5<40 μg/m3). However, compared to the TEOM, one PMS 5003 overestimated PM2.5 concentrations by a factor of 1.47 while the other roughly agreed with the TEOM. The PMS sensor response also differed by season. In two consecutive winters, the PMS PM2.5 measurements correlated with the hourly TEOM measurements (R2 > 0.87) and 24-h FRM measurements (R2 > 0.88) while in spring (March–June) and wildfire season (June–October) 2017, the correlations were poorer (R2 of 0.18–0.32 and 0.48–0.72, respectively). The PMS 1003s maintained high intra-sensor agreement after one year of deployment during the winter seasons, however, one PMS 1003 sensor exhibited a significant drift beginning in March 2017 and continued to deteriorate through the end of the study. Overall, this study demonstrated good correlations between the PMS sensors and reference monitors in the winter season, seasonal differences in sensor performance, some intra-sensor variability, and drift in one sensor. These types of factors should be considered when using measurements from a network of low-cost PM sensors.

Field evaluation of performance of HVAC optimization system in commercial buildings

New smart building technologies that offer continuous dynamic optimization of Heating, Ventilation, and Air Conditioning (HVAC) control hold promise to advance building operations for efficiency and grid response. These technologies use data from the control system to determine the analytically optimal setpoints, and then write back the optimal setpoints into the control system to minimize system energy consumption or costs. There are limited studies documenting field validations of these technologies. This paper presents the results from a long-term field evaluation of a model-predictive HVAC optimization system that installed in four commercial buildings.Energy savings analysis was conducted based on pre/post submetered energy use. Across the cohort of evaluation sites, HVAC savings following the implementation of the optimization system were mixed, ranging from 0–9%. Analysis of site operational data showed that occupant comfort was neither positively nor negatively impacted. Key technology adoption considerations and recommendations are summarized in the paper. The technology performs best when HVAC systems are in good working condition, and can be exercised to achieve the full range of its optimized setpoints–however it may not provide extensive additional savings over cases where best practice sequences of operation and reset strategies are already comprehensively implemented.

Assessment of the ‘Gasaway’ source of resistance to eastern filbert blight in New Jersey

Abstract The disease eastern filbert blight (EFB), caused by Anisogramma anomala, severely limits hazelnut (Corylus avellana) production in North America. In the 1970s, ‘Gasaway’, a late-flowering pollenizer, was found to be resistant to EFB in the Pacific northwestern U.S., and to transmit its resistance in a predictable Mendelian pattern. Its subsequent use in breeding at Oregon State University led to the release of a number of EFB-resistant cultivars, including Jefferson, Yamhill, Dorris, Wepster, and McDonald, which are now being widely planted across the Willamette Valley of Oregon. However, some cultivars carrying the ‘Gasaway’ R-gene develop EFB in New Jersey. Thus, the utility of this resistance source for breeding plants adapted to the eastern U.S has not been fully evaluated. In this study, we examined the EFB response of seedlings from 31 different full-sib progenies expected to segregate for the ‘Gasaway’ R-gene. Trees were exposed to the disease over at least 5 years and evaluated on a scale of 0 to 5 (0 = resistant, 5 = highly susceptible). In general, we found the number of seedlings free of EFB (class 0) to be less than expected based on prior work in Oregon, but resistant individuals were identified in each progeny, indicating the presence of heritable resistance. When disease response classes 0, 1, and 2 were combined (resistant through highly tolerant) and considered as “resistant”, the expected ratio of resistant to susceptible trees was recovered, signifying that the single dominant allele alone continues to provide a predictable level of at least tolerance. Modifying genes/factors appear to play a role in the final disease response of the individual seedling. It is thus hypothesized that some cultivars selected as resistant in Oregon that develop cankers in New Jersey may lack the necessary modifying genetic factors for full protection in the east. Until these modifying genes are elucidated, long-term field evaluation remains necessary to identify selections that carry the ‘Gasaway’ R-gene and express a high level of resistance to EFB in the eastern U.S.

Long-term field evaluation of the changes in fruit and olive oil chemical compositions after agronomic application of olive mill wastewater with rock phosphate

The objectives of this study were to determine the long-term effects of agronomic application of olive mill wastewater (OMW) with rock phosphate (RP) in a field of olive trees, on olive fruits and oil quality. The results revealed that olive fruits of OMW-RP amended plants had higher contents of polyphenols and mannitol indicating that agronomic application of OMW with RP generated an oxidative stress. Land spreading of OMW with RP altered the relative proportions of individual sugars in leaves and fruits. Consequently, the oil content decreased significantly, and a marked decrease in the contents of carotenoids and chlorophylls was also observed. Changes also took place in the composition of fatty acids, particularly by the increase of linoleic acid and the decrease of oleic acid. Our results suggested that the use of OMW in combination with RP is expected to have a major negative impact on olive fruit and oil quality.

Pulsed marker method for real-time detection of reverse osmosis membrane integrity loss

Real-time membrane integrity monitoring is critically needed in order to ensure that reverse osmosis (RO) treatment and desalination processes provide a reliable barrier against the passage of pathogens for potable reuse applications. A pulsed marker membrane integrity monitoring (PM-MIM) method was developed for real-time assessment of RO membrane integrity. The sensitivity of the PM-MIM method was evaluated, using a fluorescent molecular marker, in a plate-and-frame RO (PFRO) membrane system with intact and compromised membranes (induced mechanically and via chemical oxidation). Analysis of the marker permeate concentration–time profiles, in response to a controlled marker feed pulse, allowed unambiguous detection of marker enhanced passage, which was indicative of membrane integrity loss. The PM-MIM approach, which is capable of demonstrating log removal value (LRV) above 4 for a fluorescent molecular marker (smaller in size than pathogens) should be suitable for providing a conservative estimate of pathogens LRV. However, regulatory acceptability of the present real-time PM-MIM approach will undoubtedly require long-term field evaluation in RO plants in order to establish the level of confidence to satisfy regulatory requirements for RO use in potable water reuse applications.

Different vegetable crop rotations affect soil microbial communities and soilborne diseases of potato and onion: literature review and a long-term field evaluation

A major concern in potato and onion production worldwide is the sustainability of crop production systems using short-term rotations. Although rotation crops are known to influence soil microbial communities, few long-term field studies have investigated effects of potato and onion crop rotations on soil microflora and soilborne diseases. A long-term trial (10 years) was established in New Zealand in the 2004–05 season to determine changes in soil characteristics, soil biological communities, plant productivity and soilborne diseases resulting from different crop rotations. Six different crop rotation ‘treatments’ were used: three were onion-focused and three were potato-focused. For both the onion- and potato-focused rotations, one treatment was continual monoculture, one was biennial alternating onion and potato (‘conventional’ rotation, common local commercial practice) and one was a 4-year cycle where the onion or potato crops were grown every fourth season with different crops in the intervening seasons (‘sustainable’ rotation). The results of the rotations were evaluated at the end of 2012–13, nine growing seasons after the trial began. Soils from the three potato-focused rotations had similar microbial biomass carbon (C) and nitrogen (N), total C and N, and enzyme activity, but had different microbial activity parameters. Soils from the three onion rotations differed in organic matter content, total C and N, enzyme activity and carbohydrate utilization. The main factor correlated with potato diseases (stem canker, black scurf) and crop yields was the amount of Rhizoctonia inoculum in the soil. Onion yields in 2012–13 were correlated with the severity of pink root during the growing season. Total microbial activity in soil gave better relationships to soilborne disease incidence (Rhizoctonia stem canker of potato or pink root of onion) and to crop yields, than soil chemical parameters (pH, nutrient status, C:N ratio) or other microbiological parameters (microbial biomass, total culturable bacteria and fungi, and microbial diversity). This research has broadened understanding of effects of crop rotations on soil microbial community characteristics, soilborne diseases and crop productivity of potatoes and onions grown in a soil and an area where intensive vegetable production is common. This knowledge will assist growers to increase crop yields and reduce soilborne pathogens in a sustainable manner. Based on the results from this study, intensive potato and onion production should require these crops to be grown within 4-year crop rotations in order to foster sustainable yields and minimize soilborne diseases.

Long-term field evaluation and analysis of top-down cracking for Superpave projects

A field evaluation of cracking performance was undertaken for 10 pavement sections as part of a long-term Superpave monitoring project. It was found that top-down cracking was the major type of cracking. Also, moisture damage was identified in four of these sections. An analysis based on the energy ratio (ER) parameter showed that the mixtures that were affected by moisture generally exhibited a much faster reduction in the ER (indicating reduced fracture resistance) than those that were not. Further analysis of cracking performance was conducted using the enhanced hot mix asphalt fracture mechanics-based pavement performance model (HMA-FM-E). The HMA-FM-E is capable of predicting the entire process of top-down cracking from the onset of cracking until pavement failure, and thus provides more valuable information that may better assist material and pavement engineers to optimise their designs. The results showed that the predictions for sections not affected by moisture generally agreed well with field observations. More importantly, it was identified that the key to further improve the accuracy of the performance model is to more accurately predict changes of mixture properties affected by moisture in addition to oxidative ageing.

Long-term field evaluation of phosphate rock and superphosphate use strategies in acid soils of Hungary: Two comparative field trials

The effect of two P-forms and the P fertilization system were studied in field trials set up on two moderately acidic Hungarian soils. Reactive Algerian rock phosphate and Kola superphosphate doses were based on the phosphorus equivalence. The experimental design makes it possible to compare the effect of annual 35 kg/ha P doses with initial one-time application of the 175 kg/ha P level in a five-year interval. Ammonium-lactate (AL)-, NaHCO3 (Olsen)- and DW-P contents as well as Lakanen- Ervio (LE)- soluble Cd, Cr and Sr contents were also determined. The results of the first five-year period are reported in the paper. Responses to P fertilization were related to the original P supply of the soils. There was no significant difference between the two P forms and between the P fertilization systems on both grain yield and P-uptake. While AL- method overestimated, and Olsen-method – on the other hand – underestimated the P supply of reactive Algerian rock phosphate, distilled water (DW)-soluble P contents indicated the soil P status more accurately. Phosphorus balances were positive after the fifth year of the trials in the P treated plots. The soluble Cd and Cr contents did not increase in the Algerian rock phosphate treated plots. On the other hand, Kola superphosphate application at 175 kg/ha P level resulted in higher LE-Sr contents in soils. The Algerian rock phosphate is an economic alternative P source on the moderately or strongly acidic Hungarian soils.

Community surveillance of cardiovascular diseases in the Stanford Five-City Project. Methods and initial experience.

The Stanford Five-City Project is a long-term field evaluation of the effects of community health education on cardiovascular disease risk factors and event rates. One major end point of the project is the difference between treatment and control group trends in morbidity and mortality rates ascertained through community-wide surveillance of deaths and hospital discharges. This surveillance system includes continuous review of death certificates and hospital discharge records, interviews with the families and physicians of decedents who died outside the hospital, abstraction of the hospital records of possible myocardial infarction and stroke cases (fatal and nonfatal), and systematic validation of diagnosis by the use of standard criteria. Initial experience with information access, availability of diagnostic information, costs, and reliability are described. This standardized approach to community surveillance of cardiovascular disease events rates, both fatal and nonfatal, is a feasible method for evaluating large-scale intervention programs and may be applicable to monitoring secular trends in the absence of intervention.