Plastic Cover Research Articles

Time reduction in changing of plastic injection mold part bottom cover injection machine size 380 ton

This study focuses on enhancing efficiency by reducing the time required to adjust plastic injection molds on a 380-ton machine. The setup time for mold change was 61 minutes, exceeding the company's target of 30 minutes. The research employed a quasi-experimental approach, capturing pre-improvement data, measuring the time for each mold change, and documenting sub-work steps using a Flow Process Chart and a Man-Machine Chart. The main activities identified were mold change and Jig robot adjustment using the Quick changeover technique, involving internal and external activities. The study revealed that some mold-changing steps could be prepared in advance, and applying SMED (Single Minute Exchange of Die) and ECRS (Eliminate, Combine, Rearrange, Simplify) principles led to the identification of seven external adjustment steps. Assigning another employee to assist in these steps significantly reduced the average mold adjustment time to 28 minutes, representing a 54.09% improvement.

Brassinosteroids enhance the tolerance, production, and fruit quality of covered table grape vines

ABSTRACT Plastic covering (PC) is used to speed up the ripening and harvesting of grapes while also shielding grapevines from unfavourable climatic conditions. This study aimed to determine how PC induced abiotic stress on covered vines and assess the role of brassinosteroids (Brs) in alleviating these impacts. The results showed that PC caused a substantial rise in soluble sugar, MDA, proline, total phenol, and antioxidant enzymes (catalase and ascorbate peroxidase) and decreased insoluble sugars and carbohydrates in ‘Superior' seedless grape leaves. Applying Brs at concentrations of 0, 1, 2, and 3 mg/l twice during the berry development stages (pea and veraison) enhanced the plants’ ability to withstand PC-induced stress. The concentration of 3 mg/l Brs elevated some metabolic activities, including insoluble sugar, total carbohydrates, proline, and total phenol. Additionally, it increased the antioxidant enzyme activity. Meanwhile, 2 mg/l appeared to be the most effective concentration in achieving the highest cluster and berry weight, enhanced total soluble solids (TSS) and firmness, and reduced weight loss over shelf life. In conclusion, applying Brs could be a promising strategy to alleviate the adverse effect of abiotic stress on table grapes.

First Report of Basal Stem Rot of Achnatherum inebrians Caused by Fusarium pseudograminearum in China.

Drunken horse grass (Achnatherum inebrians) is a perennial bunchgrass that is widely distributed in arid and semi-arid grasslands in northwest China (Zhang et al., 2021). In July 2023, Basal stem rot was found in artificially grown drunken horse grass plots in Yuzhong County (35.85° N, 104.12° E), Gansu Province, China, with an average incidence of 5.2%. Diseased plants showed crown and basal stem rot with chocolate brown discoloration at the base of the stem and slight constriction of some basal stems. Five field's foci were surveyed and at least 6 basal stems per focus were collected. Infected basal stems were surface-sterilized (75% ethanol for 30 s and 1% NaClO for 90 s), rinsed three times with sterilized water, placed on potato dextrose agar (PDA), and incubated at 22°C in the dark for 3 days. Isolates were purified by single spore cultures (Leslie and Summerell, 2006). The average mycelial growth rate was 4.8 to 7.5 mm/day at 25°C on PDA, and the colonies produced aerial mycelium varying from rose to yellow white, and rose to burgundy pigment diffused into the agar. Macroconidia of the isolates were produced on carnation leaf agar (CLA) incubated under black light and observed to be abundant, but no microconidia were found. Macroconidia were relatively slender, curved to almost straight, commonly 3-6 septate, averaging 30.1 × 3.8 μm (n=50). The morphological characteristics of this fungus fully fit the description of F. pseudograminearum (Aoki and O'Donnell, 1999). To obtain the phylogenetic support, DNA of three representative isolates YZ-Y-1, YZ-Y-2 and YZ-Y-3 was extracted by using an HP Fungal DNA Kit (D3195), and a portion of the RNA polymerase II second largest subunit (RPB2) gene and elongation factor 1 alpha (EF1-α) gene were amplified using primers RPB2-5f2 and RPB2-7cr (O'Donnell et al. 2010) and EF1 and EF2 (O'Donnell et al. 1998), respectively. Results of sequences were deposited in GenBank (accession nos. PP179044 to PP179049). A nucleotide BLAST search revealed RPB2 and EF1-α sequences to be 99.8 and 100% similar to the corresponding sequences of the ex-type strain NRRL 28062 F. pseudograminearum accessions numbers MW233433 and MW233090, respectively. For pathogenicity tests, 15 μl of conidia suspension (1×106 conidia/ml) was inoculated into the stem bases of 10 healthy drunken horse grass seedlings (around 3 weeks old) using a sterile syringe, then wrapped with moistened sterile gauze, while the other 10 drunken horse grass seedlings were injected with sterile water as a control. All seedlings were placed in a greenhouse with a plastic cover at 15-22°C and 90-100% relative humidity. All inoculated drunken horse grass seedlings showed symptoms similar to those of natural infection with stem basal rot, whereas uninoculated drunken horse grass seedlings remained healthy after 15 days. Fungi re-isolated from the basal stems of inoculated plants were confirmed phenotypically and molecularly as F. pseudograminearum. To our knowledge, this is the first report of F. pseudograminearum causing crown rot of drunken horse grass in China. The disease has become a potential threat to the growth of drunken horse grass in China.

Influence of Fruit Load Regulation on Harvest and Postharvest Fruit Quality and Antioxidant-Related Parameters in Sweet Cherry (Prunus avium L.) cv. Regina Cultivated under Plastic Covers in Southern Chile.

Plastic covers have been used to prevent environmental constraints negatively affecting sweet cherry production in Southern Chile. However, less information is available on agronomic practices and their effects on fruit quality in sweet cherry covered orchards. Thus, in this study, we evaluated the impact of fruit load regulation on cherries' antioxidant-related parameters and the quality and condition at harvest and postharvest in sweet cherry (Prunus avium) cv. Regina that was cultivated under a plastic cover in Southern Chile. For this, four fruit load treatments were manually applied-(i) 100% fruit load (the control), (ii) 80% fruit load, (iii) 60% fruit load, and (iv) 40% fruit load-in a commercial sweet cherry orchard for two seasons (2021/2022 and 2022/2023). The results revealed that the yield and fruit load were not significantly different between the treatments. Interestingly, the 60% and 40% fruit loads increased the fresh weight, fruit size, and firmness (20.3%) compared to the control (the 100% fruit load) during both seasons. Likewise, the 60% and 40% fruit load treatments exhibited the highest fruit size distribution of 30 mm, while the 100 and 80% fruit load treatments showed the highest fruit distribution with fruit sizes between 28 mm and 24 mm. The total soluble solids (TSSs) did not vary among the fruit load treatments, while a significant increase was found in the titratable acidity (TA) in the 60 and 40% fruit load treatments during both seasons. No significant differences in antioxidant activity (AA) and total phenols (TPHs) among the treatments were observed during both seasons. Overall, the results revealed that the fruit load treatments, mainly 40%, increased the fruit weight and firmness and reduced pitting in fruits by 39.4% at postharvest. Thus, fruit thinning might be an important agronomical practice to regulate fruit load, positively affecting fruit quality at harvest and during postharvest storage in sweet cherry cv. Regina cultivated under a plastic cover. However, more biochemical and molecular studies are needed to elucidate the mechanism involved in this improvement.

Precise soil coverage in potato planting through plastic film using real-time image recognition with YOLOv4-tiny

Planting potatoes through plastic film with incomplete or excessive soil coverage over seed holes significantly impairs yield. Existing covering methods rely solely on mechanical transmissions, leading to bulky and inconsistent soil coverage of the seed holes. This paper reports an innovative method using a precise soil covering device based on the YOLOv4-tiny real-time object detection system to accurately identify potato plastic film holes and cover them with soil. The system adopts a lightweight and high-precision detection scheme, balancing increased network depth with reduced computation. It can identify holes in the plastic film in real-time and with high accuracy. To verify the effectiveness of YOLOv4-tiny real-time object detection system, a precise soil covering device based on this detection system has been designed and applied to a double crank multi-rod hill-drop planter. Field tests revealed that the system's average accuracy rate for detecting holes is approximately 98%, with an average processing time of 15.15 ms per frame. This fast and accurate performance, combined with the device's robust real-time operation and anti-interference capabilities during soil covering, effectively reduce the problems of soil cover omission and repeated covering caused by existing mechanical transmission methods. The findings reported in this paper are valuable for the development of autonomous potato plastic film precise soil covering devices for commercial use.

Digital Documentation and Architectural Heritage Restoration with 3-D Geometry: The Ambulatory of the Cathedral of Santiago de Compostela

ABSTRACT The SFM photogrammetry (Structure from Motion) is a technique developed in the field of computer vision that allows obtaining 3D models from images taken from different angles. Despite its extensive development, this technique faces methodological challenges when applied to complex heritage environments. Typically, heritage restoration documentation focuses on the initial and final stages when works have not yet begun or have already concluded, and the object of study is free of obstacles and workers, with its use in intermediate stages being uncommon. The aim of this article is to present geometric documentation using SFM-MVS photogrammetry across multiple stages of the roof restoration of the Cathedral of Santiago de Compostela (Spain), showcasing an expert application of this technique in a real working scenario with multiple challenges, adapting to complex scenes without interfering with project timelines and providing high-quality outcomes at a low cost, even in areas temporarily obscured by scaffolding or plastic coverings. It provides essential data for geometric assistance in restoration design, adaptation, and stakeout. Moreover, continuous 3D documentation enables the creation of 3D stop-motion models, offering an innovative perspective for understanding and communicating a wide range of restoration and construction projects.

Novel Low Tunnel Coverings and Plant Type Affect Productivity of Day-neutral Strawberries

Growers producing day-neutral strawberries (Fragaria ×ananassa) in temperate climates face challenges when attempting to extend the season and mitigate the effects of rain. Conventional plastic coverings over low tunnels have been used for these purposes, but they often exacerbate heat-induced problems in summer. We examined two approaches for addressing this challenge. The first was to start dormant bare root ‘Albion’ strawberry plants in small pots in the greenhouse, then plant them into the field in spring so they could begin production before the onset of consistently high temperatures. Plants set in small pots on 26 Feb in the greenhouse and field planted on 6 May were compared with bare root plants set directly into the field on 6 May. The second approach used various low tunnel coverings to modify the light and temperature environment around the plants. Three coverings were woven nets embedded with reflective strips at various densities that allowed 50%, 60%, and 70% light transmission, and these were intended to lower temperatures under the covers by reflecting infrared radiation. A fourth covering was a polyethylene plastic embedded with optically active additives that shift incident light into wavelengths that are more photosynthetically active. Two other covers were standard commercial polyethylene plastics, and the final treatment was an uncovered control. Over the 2020 and 2021 growing seasons (hot and dry vs. moderate and wet, respectively), plots were harvested once or twice a week from June through October and fruit yield, size, and marketability were assessed. In both years, strawberry plants started in the greenhouse produced significantly higher yields than bare root plants over the season (30.5% and 43.7%). Bare root plants were less responsive to cover type than greenhouse plants. In 2020, yields tended to be higher in the middle of summer in plots with reflective coverings that reduced temperature and higher later in the season with coverings of wavelength-shifting film. Polyethylene covers that increased temperature without shifting the light spectrum had lower yields. Under the cooler conditions of 2021, plants under covers that increased temperature tended to have higher yields. In a third year (2023), bare root plants were covered with a reflective covering from 29 Jun until 1 Sep, then this cover was replaced with polyethylene with optical additives as the weather cooled and light levels dropped. This sequenced treatment was compared with uncovered plots and plots covered with standard commercial polyethylene plastic. Plants under the two-phase sequential covering performed significantly better than uncovered plots or those covered with standard polyethylene plastic alone.

Measurement of Light Interception by Crops under Solar Panels using PARbars

To analyse agrivoltaics systems and understand crop responses to shading, measurements of available light for the crop and light interception by the crop are important. Especially in row crops, there is a lot of variation in the amount of light at different heights, different positions relative to the row and over time. This spatial and temporal variation in light is difficult to capture with standard point measurement technology. Commercially available line quantum sensors are not long enough to cover the desired width within an agrivoltaics system and come at high cost. Therefore, custom made PARbars were used: bars of 1.5 m long having light sensors every 5 cm facing the sky and giving a total (line) irradiance value per time step. PARbars were installed above and below a raspberry crop row in both the agrivoltaics system and the control with a plastic foil cover, and a point sensor was installed in the open field. The difference between open field radiation and the top PARbar gives the light interception by the panel construction or the foil cover, the difference between the top and bottom PARbar gives the light interception by the crop. This information can be used in conjunction with destructive crop measurements to analyse impacts on leaf area and light interception, dry matter production and derived efficiency of photosynthesis. The crop in the current agrivoltaics system received half of the amount of light compared to the control system, but total biomass production was less reduced because of compensation by increasing specific leaf area and photosynthesis efficiency. Further analysis is needed to evaluate the agrivoltaics system and the impact of increasing shade on the crop, and to assess the trade-off between electricity production and crop production.

Recognition of Plastic Film in Terrain-Fragmented Areas Based on Drone Visible Light Images

In order to meet the growing demand for food and achieve food security development goals, contemporary agriculture increasingly depends on plastic coverings such as agricultural plastic films. The remote sensing-based identification of these plastic films has gradually become a necessary tool for agricultural production management and soil pollution prevention. Addressing the challenges posed by the complex terrain and fragmented land parcels in karst mountainous regions, as well as the frequent presence of cloudy and foggy weather conditions, the extraction efficacy of mulching films is compromised. This study utilized a DJI Mavic 2 Pro UAV to capture visible light images in an area with complex terrain features such as peaks and valleys. A plastic film sample dataset was constructed, and the U-Net deep learning model parameters integrated into ArcGIS Pro were continuously modified and optimized to achieve precise plastic film identification. The results are as follows: (1) Sample quantity significantly affects recognition performance. When the sample size is 800, the accuracy of plastic film extraction notably improves, with area accuracy reaching 91%, a patch quantity accuracy of 96.38%, and an IOU and F1-score of 85.89% and 94.20%, respectively, compared to the precision achieved with a sample size of 300; (2) Different learning rates, batch sizes, and iteration numbers have a certain impact on the training effectiveness of the U-Net model. The most suitable model parameters improved the training effectiveness, with the highest training accuracy achieved at a learning rate of 0.001, a batch size of 10, and 25 iterations; (3) Comparative experiments with the Support Vector Machine (SVM) model validate the suitability of U-Net model parameters and sample datasets for precise identification in rugged terrains with fragmented spatial distribution, particularly in karst mountainous regions. This underscores the applicability of the U-Net model in recognizing plastic film coverings in karst mountainous regions, offering valuable insights for agricultural environmental health assessment and green planting management in farmlands.

Drying Performance and Economic Analysis of a Greenhouse Solar Dryer for Tomatoes

Purpose: The purpose of this study was to assess the drying performance and economic feasibility of a Greenhouse Solar Dryer for Tomatoes. With a focus on small-scale tomato drying, the study aimed to evaluate the effectiveness of the greenhouse in comparison to traditional sun drying methods. Additionally, the economic analysis sought to determine the investment attractiveness of the greenhouse dryer by considering the initial investment, operational costs, and potential revenue generation. Methodology: The methodology involved conducting drying experiments using the Greenhouse Solar Dryer for Tomatoes under existing weather conditions. The dryer's components include the steel frame, greenhouse plastic cover, and concrete floor. The temperature and relative humidity contributed to the environment inside the greenhouse that facilitated the drying process. Moisture content measurements were taken at regular intervals to assess the drying kinetics and effectiveness of the greenhouse. Economic analysis was conducted to evaluate the project's financial viability, considering initial investment, revenue generation, and operational costs. Findings: The findings revealed that the Greenhouse Solar Dryer outperformed sun drying methods, achieving higher temperatures and faster drying times for tomatoes. Specifically, the greenhouse reached maximum temperatures of 38.4 °C and 45.5 °C on the first and second days, respectively, leading to a moisture content of 14.9% wet basis within 11 hours on the second day. In contrast, sun drying resulted in a significantly higher moisture content of 37.9% at the same time, highlighting the effectiveness of the greenhouse. Economic analysis demonstrated that the project had a payback period of 1.6 years, indicating its attractiveness as an investment opportunity for farmers. Unique Contribution to theory, practice and policy: This study makes a unique contribution to knowledge by providing empirical evidence of the drying performance and economic viability of a Greenhouse Solar Dryer for Tomatoes. By demonstrating the effectiveness of the greenhouse in achieving faster drying times and lower moisture content compared to sun drying methods, the study underscores the potential of solar drying technologies in small-scale agricultural settings. Additionally, the economic analysis offers valuable insights into the financial feasibility of adopting greenhouse dryers, particularly for farmers seeking to enhance their income through value-added tomato products.

Estimation of Intercepted Solar Radiation and Stem Water Potential in a Table Grape Vineyard Covered by Plastic Film Using Sentinel-2 Data: A Comparison of OLS-, MLR-, and ML-Based Methods.

In the framework of precision viticulture, satellite data have been demonstrated to significantly support many tasks. Specifically, they enable the rapid, large-scale estimation of some viticultural parameters like vine stem water potential (Ψstem) and intercepted solar radiation (ISR) that traditionally require time-consuming ground surveys. The practice of covering table grape vineyards with plastic films introduces an additional challenge for estimation, potentially affecting vine spectral responses and, consequently, the accuracy of estimations from satellites. This study aimed to address these challenges with a special focus on the exploitation of Sentinel-2 Level 2A and meteorological data to monitor a plastic-covered vineyard in Southern Italy. Estimates of Ψstem and ISR were obtained using different algorithms, namely, Ordinary Least Square (OLS), Multivariate Linear Regression (MLR), and machine learning (ML) techniques, which rely on Random Forest Regression, Support Vector Regression, and Partial Least Squares. The results proved that, despite the potential spectral interference from the plastic coverings, ISR and Ψstem can be locally estimated with a satisfying accuracy. In particular, (i) the OLS regression-based approach showed a good performance in providing accurate ISR estimates using the near-infrared spectral bands (RMSE < 8%), and (ii) the MLR and ML algorithms could estimate both the ISR and vine water status with a higher accuracy (RMSE < 7 for ISR and RMSE < 0.14 MPa for Ψstem). These results encourage the adoption of medium-high resolution multispectral satellite imagery for deriving satisfying estimates of key crop parameters even in anomalous situations like the ones where plastic films cover the monitored vineyard, thus marking a significant advancement in precision viticulture.

Periodical alternation between precipitation and dissolution of camphor solid film on an ethanol solution.

Rhythmic behaviors are generally observed in nonlinear chemical reactions such as the Belousov-Zhabotinsky reaction and enzymatic reactions. Similarly, a simple phase change can also lead to rhythmic behavior. It has been reported previously that camphor solid films alternate between generation and disappearance on ethanol (EtOH) solution, and a phenomenological mechanism has been suggested for this. The evaporation of EtOH decreases the temperature on the surface of the solution via vaporization heat and induces precipitation in the camphor solid film. At this time, the film prevents evaporation, and thus, the surface temperature increases due to thermal diffusion from the atmosphere, resulting in dissolution of the solid film. To verify the previously suggested phenomenological mechanism, we controlled the evaporation rate of EtOH using a porous plastic cover. As a result, the period of oscillation increased with decreasing pore diameter, and finally, the oscillation did not occur without pore in the cover, where the camphor solid film was not observed. Additionally, a new mathematical model was proposed, and the numerical calculations agreed well with experimental observations. Linear stability and bifurcation analyses revealed the detailed mechanism of this phenomenon, which agreed well with the phenomenological explanation mentioned above.

Winter Rye Cover Crops Shelter Competent Squash Phyllosphere Bacteria to Reduce Pseudomonas syringae pv. lachrymans Growth and Angular Leaf Spot Symptoms.

Cover crops, a soil conservation practice, can contribute to reducing disease pressure caused by Pseudomonas syringae, considered one of the most important bacterial plant pathogens. We recently demonstrated that the phyllosphere (leaf surface) bacterial community structure changed when squash (Cucurbita pepo) was grown with a rye (Secale cereale) cover crop treatment, followed by a decrease of angular leaf spot disease symptoms on squash caused by P. syringae pv.lachrymans. Application of biocontrol agents is a known agricultural practice to mitigate crop losses due to microbial disease. In this study, we tested the hypothesis that some phyllosphere bacteria promoted when squash is grown on cover crops could be isolated and used as a biocontrol agent to decrease angular leaf spot symptoms. We grew squash during a 2-year field experiment using four agricultural practices: bare soil, cover crops, chemically terminated cover crops, and plastic cover. We sampled squash leaves at three different dates each year and constructed a collection of cultivable bacterial strains isolated from squash leaves and rye cover crop material. Each isolated strain was identified by 16S rRNA gene sequencing and used in in vitro (Petri dish) pathogen growth and in vivo (greenhouse) symptom control assays. Four bacterial isolates belonging to the genera Pseudarthrobacter, Pseudomonas, Delftia, and Rhizobium were shown to inhibit P. syringae pv. lachrymans growth and angular leaf spot symptom development. Strikingly, the symptom control efficacy of all strains was stronger on older leaves. This study sheds light on the importance of bacterial isolation from cover crop sources to promote disease control. [Formula: see text] Copyright © 2024 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.

Understanding urban expansion and shrinkage via green plastic cover mapping based on GEE cloud platform: A case study of Shandong, China

Green Plastic Cover (GPC) has been widely used in construction sites of China as the main measure for dust suppression. As a unique land cover in China, GPC could be viewed as a sign for evaluating the intensity of urban construction. Therefore, time series GPC maps could provide a new perspective to understand the pattern of urban development, including both urban expansion and urban shrinkage. The objective of this study is to present a novel framework for detection of urban development patterns based on high resolution GPC maps generated from Google Earth Engine (GEE) cloud platform. Specifically, we first generated the GPC maps of 137 districts and counties in Shandong Province of China from 2018 to 2022 by combining time series spectral features and textural features derived from Sentinel-1 and Sentinel-2 images provided by GEE cloud platform. Afterwards, we designed a GPC-based urban development vigor index (GPC-UDVI) to evaluate the vitality of each city, which offers a novel perspective to identify shrinking cities. Experimental results demonstrated that the average overall accuracy of GPC maps is 89.696 %, which is accurate enough for the following analysis. Besides, the proposed GPC-UDVI exhibits a consistent trend with statistical data and could reveal urban development patterns with a high performance. Above all, dynamic monitoring of urban GPC through remote sensing is significant for understanding urban expansion modes and aiding in urban reconstruction management.

Variations Among Crop Seasons and Inoculum Availability Have a Higher Impact on Grapevine Rust Epidemics than Training Systems or Plastic Cover.

Canopy management practices can be effective as part of the integrated management of grapevine diseases. This study aimed to determine whether training systems and plastic covers can contribute to prevent Asian grapevine leaf rust (AGLR) development. Additionally, the influence of crop season and inoculum availability on AGLR development was investigated. Six-season experiments were carried out to characterize 16 epidemics that developed from natural inoculum (NI) or artificial inoculum (AI) sources (NI + AI), conducted in different training systems and with or without the plastic cover. The Richards model was fitted to each AGLR disease progress curve to estimate and compare the onsets and intensities of epidemics using eight curve elements. Principal components analysis (PCA) identified the incidence progress rate, the area under the severity progress curve, final disease severity, time to disease onset, and time to reach the inflection point as the main descriptors for AGLR epidemics. The results showed that AGLR epidemic development was related mainly to differences in inoculum availability and climatic conditions throughout the seasons and to a lower extent to the training system and plastic cover. The earliest disease onset was observed in epidemics when the NI was supplemented with an AI source. Differences in AGRL intensity were correlated to accumulated precipitation, being less severe in autumn-winter than in the spring-summer season. The present findings provided a better understanding of the structure and the seasonal variation of AGLR in cultivar 'Niagara Rosada'. The strategies for reducing and/or delaying inoculum buildup among seasons are discussed.

Phthalate ester levels in agricultural soils of greenhouses, their potential sources, the role of plastic cover material, and dietary exposure calculated from modeled concentrations in tomato

Soil samples collected from 50 greenhouses (GHs) cultivated with tomatoes (plastic-covered:24, glass-covered:26), 5 open-area tomato growing farmlands, and 5 non-agricultural areas were analyzed in summer and winter seasons for 13 PAEs. The total concentrations (Σ13PAEs) in the GHs ranged from 212 to 2484 ng/g, wheeas the concentrations in open-area farm soils were between 240 and 1248 ng/g. Σ13PAE in non-agricultural areas was lower (35.0 - 585 ng/g). PAE exposure through the ingestion of tomatoes cultivated in GH soils and associated risks were estimated with Monte Carlo simulations after calculating the PAE concentrations in tomatoes using a partition-limited model. DEHP was estimated to have the highest concentrations in the tomatoes grown in both types of GHs. The mean carcinogenic risk caused by DEHP for tomato grown in plastic-covered GHs, glass-covered GHs, and open-area soils were 2.4 × 10−5, 1.7 × 10−5 and 1.1 × 10−5, respectively. Based on Positive Matrix Factorization results, plastic material usage in GHs (including plastic cover material source for plastic-GHs) was found to be the highest contributing source in both types of GHs. Microplastic analysis indicated that the ropes and irrigation pipes inside the GHs are important sources of PAE pollution. Pesticide application is the second highest contributing source.

Broadband sub-wavelength terahertz subsurface imaging using a solid-immersion lens

We demonstrate a broadband sub-wavelength terahertz (THz) imaging system by combining a solid-immersion lens (SIL) with a THz time-domain spectrometer (TDS). The imaging resolution of the system is enhanced in a wide spectral range (from 0.3 to 2.0 THz) with the aid of the SIL. The beam size is within 120–280 μm (0.28–0.8 λ) in the measured frequency range. Experimentally achieved imaging resolution enhancement results are consistent with the numerical simulation results. Unlike the previous reports on imaging systems using SIL, the beam size reduction by the SIL is more than a factor of nSIL (3.42) for all frequencies near the focal spot. An analytical calculation is employed to obtain insights into the beam size reduction mechanism and estimate the beam size in a given experimental condition. THz image of the WR1.9 waveguide is measured to highlight the broadband sub-wavelength imaging capability. The increased reflection from the waveguide near the cutoff frequency for TE10 and TE01 modes, inaccessible with other THz-TDS-based or continuous wave (CW) source-based THz imaging systems, is experimentally observed. In addition, we show the multispectral sub-wavelength images of subsurface structures by selecting the appropriate measurement time window of the temporal THz signal. THz images of a credit card show the sub-wavelength details of the card, including an IC chip, invisible due to the plastic cover. The experimental results highlight the potential applications of the imaging system in non-contact, non-destructive testing of the sub-wavelength scale structures in various fields.

Produção e qualidade da uva Niágara rosada (Vitis labrusca L.) produzida com e sem cobertura plástica

The objective of this work was to evaluate the productivity and quality of Niagara rosada grape grown without and with plastic cover. Analyzed variables: leaf area (af), sprouting index (Ib) and fertility (If), bunch mass, bunches per plant and yield, bunch quality (Type 1 and 2), total soluble solids (ºBrix). The experiment was carried out in the 2022/2023 harvest, in a 5-year-old vineyard, with spacing of 1.5 between plants by 2.5 m in the row, located in the municipality of Bento Gonçalves/RS, Serra Gaúcha, with two treatments, T1 - environment without cover, T2 - environment with impermeable plastic cover, a randomized block design was used, with 6 plants per treatment. Treatments did not differ for ºBrix, Ib, If, bunch mass, bunches per plant and estimated production per ha. Harvesting the grapes in the plastic cover delayed the harvest by two weeks. As for the qualitative factor, T1 obtained for Type 1 grapes, 81% of the production/ha and treatment T2, 98.5%, grapes that have superior quality. The production of Niagara rosada under the plastic cover did not differ in terms of the production of T1, but presented a higher added value due to the higher % of production of superior quality grapes.

Agronomic Performance, Oil Yield and Hydrolate Quality of Patchouli Cultivated in Different Soil Covers.

This study describes the evaluation of the effectiveness of different soil covers on the development, productivity, yield and metabolic content of patchouli oil (Pogostemon cablin) and its hydrolate. The agronomic experiments were carried out in the field, including four types of soil cover and six replications (4 x 6), using green cover (peanut), straw (crotalaria and millet straw), white plastic cover, and no mulch (weeding). After transplanting, the initial growth of seedlings was analyzed through weekly monitoring of plant height, stem diameter, and the number of leaves. At harvest time, the harvest yield (green mass) was performed. After drying the leaves, the oil and hydrolate were extracted by steam distillation and then the yield of patchouli oil was determined. Regarding the agronomic analyses, white plastic and straw coverage was superior to the other treatments, with higher plant heights, number of leaves, whereas the plastic and straw coverage was superior to the other treatments, with higher plant heights, number of leaves and green mass yield. The metabolic content was evaluated using High Resolution Mass Spectrometry (HRMS), and the chemical markers were identified through the analysis of the MS/MS fragmentation spectra and chemotaxonomic data. No significant differences were observed in the essential oils yields and their hydrolates and the intensities of the major ions found in the samples identified as chemical markers for the quality control of P. cablin.

The Role of the Relative Humidity on the Development of Downy Mildew Infection of Cucumber in the Greenhouse in Baghdad

This study conducted at the Dujail, north of Baghdad, aims to control the downy mildew disease of cucumber based on the ventilation of greenhouses by making three ventilation holes in the plastic cover, in comparison to cultivation into a regular greenhouse (without ventilation holes). Three approved cucumber hybrid were included in this study; Mustaqbal, Jamilah, and Faris. The infection percentage and disease severity rates were calculated since the onset of the disease on March 21st, 2022 until May 18th, 2022. The results showed that the average temperatures (minimum and maximum) and relative humidity were 5-25 ºC and 97% inside the regular greenhouse were suitable for the Pseudoperonospora cubensis natural infection. The highest percentage of infection and disease severity were 30.81 and 23.33%, respectively, reported into the regular greenhouse (without ventilation), compared with the infection percentage and disease severity in the ventilated greenhouses, which were 1.28 and 6.99%, respectively. The percentages of infection of Mustaqbal, Faris and Jamila in the regular greenhouse (without ventilation) were 31.69, 31.40 and 29.35%, respectively, compared to 1.47, 1.17 and 1.21% noticed in the greenhouses with three ventilation holes for the same cucumber varieties, respectively. This study found that three ventilation holes in plastic cover of the greenhouse reduced the percentage infection and disease severity in cucumber plants, by 95.8 and 70% respectively.