Development of an automatic monitoring system for rice light-trap pests based on machine vision

Monitring pest populations in paddy fields is important to effectively implement integrated pest management.Light traps are widely used to monitor field pests all over the world.Most conventional light traps still involve manual identification of target pests from lots of trapped insects,which is time-consuming,labor-intensive and error-prone,especially in pest peak periods.In this paper,we developed an automatic monitoring system for rice light-trap pests based on machine vision.This system is composed of an itelligent light trap,a computer or mobile phone client platform and a cloud server.The light trap firstly traps,kills and disperses insects,then collects images of trapped insects and sends each image to the cloud server.Five target pests in images are automatically identifed and counted by pest identification models loaded in the server.To avoid light-trap insects piling up,a vibration plate and a moving rotation conveyor belt are adopted to disperse these trapped insects.There was a close correlation(r=0.92)between our automatic and manual identification methods based on the daily pest number of one-year images from one light trap.Field experiments demonstrated the effectiveness and accuracy of our automatic light trap monitoring system.

Light trapping characteristics of glass substrate with hemisphere pit arrays in thin film Si solar cells

In this paper, the light trapping characteristics of glass substrate with hemisphere pit （HP） arrays in thin film Si solar cells are theoretically studied via a numerical approach. It is found that the HP glass substrate has good antireflection properties. Its surface reflectance can be reduced by - 50% compared with planar glass. The HP arrays can make the unabsorbed light return to the absorbing layer of solar cells, and the ratio of second absorption approximately equals 30%. Thus, the glass substrate with the hemisphere pit arrays （HP glass） can effectively reduce the total reflectivity of a solar celt from 20% to 13%. The lip glass can also prolong the optical path length. The numerical results show that the total optical path length of the thin film Si solar cell covered with the HP glass increases from 2ω to 409. These results are basically consistent with the experimental results.

Beyond Lambertian light trapping for large-area silicon solar cells:fabrication methods

Light trapping photonic crystal(PhC)patterns on the surface of Si solar cells provides a novel opportunity to approach the theoretical efficiency limit of 32.3%,for light-to-electrical power conversion with a single junction cell.This is beyond the efficiency limit implied by the Lambertian limit of ray trapping~29%.The interference and slow light effects are harnessed for collecting light even at the long wavelengths near the Si band-gap.We compare two different methods for surface patterning,that can be extended to large area surface patterning:1)laser direct write and 2)step-&-repeat 5×reduction projection lithography.Large area throughput limitations of these methods are compared with the established elec-tron beam lithography(EBL)route,which is conventionally utilised but much slower than the presented methods.Spec-tral characterisation of the PhC light trapping is compared for samples fabricated by different methods.Reflectance of Si etched via laser patterned mask was~7%at visible wavelengths and was comparable with Si patterned via EBL made mask.The later pattern showed a stronger absorbance than the Lambertian limit6.

Improving light trapping and conversion efficiency of amorphous silicon solar cell by modified and randomly distributed ZnO nanorods

Three-dimensional （3D） nanostructures in thin film solar cells have attracted significant attention due to their appli- cations in enhancing light trapping. Enhanced light trapping can result in more effective absorption in solar cells, thus leading to higher short-circuit current density and conversion efficiency. We develop randomly distributed and modified ZnO nanorods, which are designed and fabricated by the following processes： the deposition of a ZnO seed layer on sub- strate with sputtering, the wet chemical etching of the seed layer to form isolated islands for nanorod growth, the chemical bath deposition of the ZnO nanorods, and the sputtering deposition of a thin Al-doped ZnO （ZnO：Al） layer to improve the ZnO/Si interface. Solar cells employing the modified ZnO nanorod substrate show a considerable increase in solar energy conversion efficiency.

Solar trough receiver with V-grooved light traps for efficiency improvement

Parabolic trough collector is a promising technology for both domestic and industrial heat supplies.To enhance the collector efficiency,a modified trough receiver with dozens of V-grooved light traps incorporated into its lower-half absorber was introduced.For assessing the performance of this receiver,a solar-thermal-stress coupled model was established.Using this model,firstly,the effects of the V-grooved light traps were investigated.The results reveal that,compared to the conventional trough receiver,the modified trough receivers equipped with different traps can reduce their optical losses by 81.9-138.0 Wm^(-1)(i.e.,15.0%-25.2%),improving their optical efficiencies by 1.60%-2.69%.However,these traps also result in increased thermal loss from the receiver.Therefore,there is no single optimal modified trough receiver that consistently outperforms all other receivers across all possible conditions.Nonetheless,the MTR30-3 and MTR60-3 receivers emerge as the optimized choices due to their better solar-thermal performance.Subsequently,performance evaluation reveals that the two optimized receivers can enhance the receiver efficiencies within the typical solar irradiance range by 0.02%-2.65%and 0.05%-1.70%when the inlet fluid temperatures are below 488 and 523 K,respectively.Consequently,the collector efficiencies can be improved by 0.02%-2.49%and 0.05%-1.60%,respectively.Additionally,thermal stress analysis verifies that the two optimized receivers remain within safe limits under all typical conditions.Given that the heating temperature of a typical solar collector for domestic or industrial heat supply is typically below 523 K,the integration of the two optimized receivers has the capability to effectively enhance the overall collector efficiency.

Comparative Human Landing Catch and CDC Light Trap in Mosquito Sampling in Knowlesi Malaria Endemic Areas in Peninsula Malaysia

Adult mosquito sampling techniques are essential for monitoring transmission of malaria and other mosquito borne infections. Preference for any sampling technique depends on both its field efficiency and the characteristics of local vector populations. Surveys on adult mosquitoes using Human Landing Catch (HLC) and CO2-baited CDC light trap (CDC-LT) techniques were conducted in several knowlesi malaria endemic areas between the months of March to December 2012 in several states of Peninsula Malaysia. These two techniques were relatively compared to determine the preferences of anopheline mosquitoes towards CO2-baited CDC-LT technique using HLC technique as the reference method. Cx. gelidus, An. maculates and An. introlatus were the main three species collected by HLC technique, whereas the species collected by CO2-baited CDC-LT technique were mostly An. cracens, Ar. durhami and Coquillettidia species. Most of the Anopheles species were collected almost exclusively by the human collectors except for An. cracens and An. introlatus which were collected using both techniques. Anopheles cracens was the most dominant species captured using CO2-baited CDC-LT technique. This is the first report showing An. cracens was caught using CO2-baited CDC-LT technique in Malaysia.

Ecological Sound Control Strategies for Population Suppression of Date Palm Borers Oryctes spp.

Cultural practices, hand collection of larvae, light traps and entomopathogenic fungi were investigated to manage of palm borers Oryctes spp. in date palm orchards during the years 2010-2015. Cultural practices, such as sanitation and pruning frond bases, hand collection of larvae during regular annual service work and light traps with solar energy were practiced annually in one orchard for five years. In the second orchard, cultural practices were applied for two years, light trap for one year only, and no hand collection of larvae was done during the period. The third orchard was used as a control treatment. Results showed reduction in population density of larvae （91.6% and 53.0%） and adult （76.1% and 41.1%） ofOryects spp. in the 1st and 2nd orchard, respectively The results also demonstrated the impact of moon light phases on the number of Oryctes spp. adults caught by light trap and the existence of an inverse relation between moon light and flight activity of adults. Biological experiments also revealed that entomopathogenic fungi can cause high mortality rate reaching 100% after 29 d. Beauveria bassiana scored higher mortality rate in short time, especially at concentration of 1 × 10^11 conidia/mL with LT50 = 12.75 and LT90 = 20; while, Metarhizium anisopliae caused the higher percentage of malformed adults. The results depicted the effectiveness of some integrated ecological sound control methods for monitoring and population suppression of Oryects spp. in date palm orchards.

Influence of Trap Construction on Mosquito Capture

During 2009 and 2010, 23 night-time mosquito captures were made at Kanci obora in south-eastern Moravia, Czech Republic. It was used in the Centers for Disease Control and Prevention （CDCP） miniature light traps with CO2 （dry ice） and baited lard-can traps in which sentinel animals were replaced with a container filled with CO2 （dry ice）. In the observed period, a total of 31,882 female mosquitoes were captured by CDC miniature light traps with CO2. Lard-can traps baited with CO2 captured 995 females under the same conditions, which is just 3.12% of the quantity from the CDC traps. At the same time, there were significant differences in the proportional captures of various species. Compared to CDC miniature light traps, baited lard-can traps much more often captured Aedes cinereus （16.58% of total versus 1.93% in CDC traps）, Culex modestus （15.48% versus 4.62%）, and Ae. rossicus （6.13% versus 2.67%）. On the other hand, capture of female Ae. vexans was proportionally much lower （15.38% versus 36.41%）. Capture of Cx. pipiens was more or less the same 14.77% （miniature light traps） and 15.76% （baited lard-can traps）. The occurrence of the calamity species Ae. sticticus was proportionally very high in both trap types （30.05% in lard-can traps baited with CO2, 33.58% in CDC miniature light traps）. The findings prove that a trap＇s design itself significantly affects not only the overall capture of mosquitoes but also the proportional representation of individual species.

Invertebrates Diversity in Arabuko-Sokoke Forest and Nearby Farm­land at Gede,Kilifi County,Kenya

Insectivorous bats mainly feed on various types of invertebrates.The authors studied the abundance and diversity of invertebrates in the farmland in the eastern part of Arabuko-Sokoke Forest,mainly to assess their availability to insectivorous bats occurring in the two study sites.Solar powered light traps were used to attract aerial invertebrates to a white suspended cloth sheet used as a landing surface.The sampling was conducted for four hours in one trapping station each night,and in twelve different stations both in the ASF and farmland.A total of 6,557 invertebrates individuals were trapped,which included 48%in ASF and 52%in the farmland.The two most common invertebrate orders were Hymenoptera(ants,bees,wasps and sawflies)represented by 38.1%,and Coleoptera(beetles,28.1%).The interior of ASF had higher invertebrate species diversity(Shannon-Weiner index 1.72±0.1),than the farmland(1.41±0.1).Although the farmland(260.5±52.9,N=12)had higher mean number of invertebrates trapped per night,than the interior of ASF(200.3±36.4,N=12),there was no significant difference between the medians of invertebrates captured in the two study areas(Mann-Whitney U-Test,U=61:P>0.544).Thus,the farmland and the interior of ASF had the same invertebrate abundance.This study indicates the value of human-modified areas(agricultural and human settlements)landscapes,always ignored in biodiversity surveys,in sustaining diverse invertebrates that are preyed by different species of insectivorous bats that occur in the two study areas.

Analysis of phototactic responses in Spodoptera frugiperda using Helicoverpa armigera as control

Light traps are widely utilized to monitor and manage insect pest populations.In late 2018,the fall armyworm(FAW),Spodoptera frugiperda,invaded China through Yunnan Province representing a huge threat to grain production.To estimate the efficiency of light traps on FAW moths,we first identified the opsin genes from FAW by using the transcriptome.Phylogenetic analysis indicated that the four opsins of FAW were clustered with those of other Noctuidae species.The expressed levels of opsins in S.frugiperda were lower than in Helicoverpa armigera,suggesting a different phototactic response between the two species.Then,we determined the phototactic behavior of FAW using H.armigera as a control,which is widely monitored and managed using light traps in China.Our results indicated that the two moths species showed significantly different phototactic behavior and both female and male FAW displayed faster flight-to-light speed than H.armigera.This may be due to a faster flight capacity in FAW compared to H.armigera.However,the capture rate of both female and male of S.frugiperda was significantly lower than that of H.armigera,which was consistent with the expression levels of opsins.These results support the positive phototaxis of S.frugiperda moths and suggest light traps could be used for monitoring and managing the pests,but with a lower efficiency than H.armigera.

The Role of Mineral and Natural Oils in Integration with Inorganic Salts and Some Insecticides in Suppressing the Invasion of the Red Palm Weevil Rhynchophorus ferrugineus (RPW) Affecting Date Palms with Estimation of Its Residues in the Resulting Date Fruits

Applied experiments were conducted in the palm orchard in the Nubaria region. The orchard includes the varieties of Al-Barhi (imported) and Zaghloul (local) to examine the efficacy of some natural materials alone and in combination with some pesticides against the Red Palm Weevil Rhynchophorus ferrugineus (RPW) that infects palm trees in Egypt. Most insects caught by light traps, which have a role in the spread of the red palm weevil in palm groves, appear in early February and March. Peak numbers for the month of May until September namely Phyllgnathus excavatus. Pseudophilus testaceus, Phonapata frontalis, and Oryctes elegans. The neglected gardens of date palms are more compensating for insect infestation than those maintained in terms of agricultural and pest control services. Individual injection of insecticide (Mosspilan) was the most potent against RPW-infested Barhi var. with a recovery rate of 91.7%, followed by Selikron at 80%, and finally Saydon at 37.5%. Injection of the car oil used with Mosspilan followed by Selikron was effective against RPW. No significant difference between treatments of injection (F-value: 1.2). Mixing injection of mineral oils with chemical pesticides is effective against red palm weevil after two successive seasons. As a result, the pesticide was poured around the affected palm root, with a low recovery rate. There is no effect of palm spray. The best way to control the red palm weevil is the method of injecting the tested material (single or mixed) with the pure pesticide into the trunk of the infected palm tree. The tested pesticide residues gradually decrease as the period after application is prolonged with an average loss of 0.12, 0.02 and 0.07 ppm after 90 consecutive days. .

Absorption enhancement in thin film a-Si solar cells with double-sided SiO_2 particle layers

Light absorption enhancement is very important for improving the power conversion efficiency of a thin film a-Si solar cell. In this paper, a thin-film a-Si solar cell model with double-sided SiO2 particle layers is designed, and then the underlying mechanism of absorption enhancement is investigated by finite difference time domain（FDTD） simulation;finally the feasible experimental scheme for preparing the SiO2 particle layer is discussed. It is found that the top and bottom SiO2 particle layers play an important role in anti-reflection and light trapping, respectively. The light absorption of the cell with double-sided SiO2 layers greatly increases in a wavelength range of 300 nm-800 nm, and the ultimate efficiency increases more than 22% compared with that of the flat device. The cell model with double-sided SiO2 particle layers reported here can be used in varieties of thin film solar cells to further improve their performances.

Optical management in organic photovoltaic devices

Due to their potentials in light‐weight,flexible,and semitransparent devices,organic photovoltaics are of great significance in the field of renewable energy.However,the narrow intrinsic absorption spectrum of organic materials hinders the full utilization of solar energy.To fabricate a highly efficient opaque solar cell,it is greatly necessary to modify the optical properties of the device to improve light absorption.In addition,the growing interest in building‐integrated photovoltaics drives the development of semitransparent devices.The preparation of semitransparent solar cells with excellent performance imposes high requirements on the high efficiency and appropriate visible light transmittance of effective optical management.In this review,the recent research progress of optical management in organic photovoltaics is reviewed,including the design of light‐absorbing materials,the modification of different layers,adding a lighttrapping structure,and changing the light absorption capabilities of specific materials,so as to provide strategies of how to improve the performance of organic photovoltaic devices and present the prospect of the area.

ISOTROPIC TEXTURING OF POLYCRYSTALLINE SILICON WAFERS

An isotropic etching technique of texturing silicon solar cells has been applied to polycrystalline silicon wafers with different acid concentrations. Optimal e tching conditions have been determined by etching rate calculation, scanning ele ctron microscope (SEM) image and reflectance measurement. The surface morphology of the textured wafers varies in accordance with the different etchant concentr ation which in turn leads to the dissimilarity of etching speed. Textured polycr ystalline silicon wafer surfaces display randomly located etched pits which can reduce the surface reflection and enhance the light absorption. The special rela tionship between reflectivity and etching rate was studied. Reflectance measurem ents show that isotropic texturing is one of the suitable techniques for texturi ng polycrystalline silicon wafers and benefits solar cells performances.

Improved uniformity of deposited metallic layer on hybrid micro/nano-structured Si substrates fabricated by two-step laser ablation for SERS application

Surface-enhanced Raman scattering(SERS) has been widely used as an effective technique for lowconcentration molecules detections in the past decades. This work proposes a rapid and accessible process to fabricate SERS-active substrates with high uniformity and controllability based on two-step laser ablation. Laser beams directly ablate the surface of Si, concurrently creating microstructures and ejecting molten materials caused by the thermal effect that nucleate in ambient air. The nuclei grow into nanoparticles and deposit over the surface. These nanoparticles,together with microstructures, improve the light collection efficiency of the SERS-active substrates. Especially after Au thin film deposition, these nanoparticles can provide nanogaps as hotspots for SERS. By orthogonal experiment design,laser processing parameters for better performances are determined. Compared with substrates fabricated by single 1064 nm master oscillator power amplifier(MOPA) laser ablation, substrates ablated by the primary 1064 nm MOPA laser and secondary UV pulsed laser show more uniform nanoparticles’ deposition over the surface. The optimized largearea substrate has a SERS detection limit of 10^(-8)mol/L for 4-aminothiophenol(4-ATP), indicating the potential realworld applications for trace detection.

Some Aspects of Biology and Control Methods of Fruit Stalk Borer Oryctes elegans Prell （Coleoptera： Scarabaeidae）

Laboratory and field studies were conducted on some aspects of biology and control methods of fruit stalk borer Oryctes elegans Prell., the study was conducted in date palm orchards in south Baghdad during the years 2009 and 2010. The laboratory rearing result ofO. elegans indicated that the larval stage period was very long reached 6 months, the body weight of the mature larva was 7.61 gm, the length and body circumference were 7.58 and 5.23 cm respectively. The period of pupa stage was 19 day and 2.97 gm body weight, while the length and body circumference were 3.74 and 3.21 cm respectively .While the weight of adult stage was 1.67 gm and 3.14 cm, 2.71 cm for the length and circumference body respectively. Results of hand collection larvae in palm trees during the regular annual service, showed reduction in population density of adults to 1.4 adult/trap per week compared with 3.3 and 14.0 adult/trap per week in the orchards were larvae collected partially and without hand collection by using the light traps with solar energy （Magna Traps, Russell IPM） respectively. Also, the study proved the existence of an inverse relation between the moon light and adult activity, which affected on the adult number cough in light traps. These results indicated that the hand collection of larvae works during months January, February, March and April at synchronized with the larval stage on palm trees, and use Magna Traps as an effective method to control O. elegans through IPM programs in palm orchards.

Determination of Effective Degree-Day for Supporting Chemical Control Against Cutworms （Lep. Noctuinae） in the Sugar Beet

The aim of the research was to connect two methods of the chemical control. The first chemical treatments were applied according to the signalling method. The second method was applied according to the phonological criterion i.e., on the basis of the values of effective temperatures sums or heat sums for cutworms. The studies on cutworms infesting sugar beet crops were carried out in the years 2005-2008. The observation performed during the moth flights from May to September included two species, turnip moth （Agrotis segetum Den. ＆ Schiff.） and heart-and-dart moth （A. exclamationis L.）. The dynamics of moth flights was recorded in reference to readings of climatic conditions registered with the field meteorological stations set up near the light traps. Observations on cutworm occurrence during the vegetation season were done every 5-7 days. Moreover, additional studies were conducted under control conditions in the growth chambers at three programmed temperatures （17°C, 20 °C, 24 °C） and relative humidity （50%-70%）. Based on the results the values for the heat sum of 501.1 °C and effective temperatures sum of 230.0 °C were determined for the developmental stages of cutworm. On the base of the results obtained it can be stated that the improved method of short-term forecasting can be an alternative solution in the integrated protection management against pest.

Activity of Insect Fauna during the Night in the Pa Orchards of Central Iraq

The study was carried out at three palm orchards, each of 2.5 hectare in AI-Madain palm orchards （30 km, South Baghdad） contains the palm varieties （Prem, Osta omran, Zahdi, Berhee, Khadrawi, Khastawi, Oueedi and Tebarzel） in 2010 season aiming to determine the population density of palm borers and to know other insect occurring in date palm orchards. Three light traps with solar energy （Magna Traps with lamps of 320-420 nm wavelength are produced by Russell IPM） were used as one trap in each orchard. The number of fruit stalk borer, Oryctes elegans and frond borer, Phonapate frontalis adults were calculated per week in each trap aiming to determine the population density of adults in the three orchards under this study. Results of using light traps （Magna Traps） indicated that the number of O. elegans adults catch per trap during the period from April to December 2010 were 254, 217 and 240 adult/trap in orchards No. l, 2 and 3, respectively, the higher population densities were 87,79 and 81 adult/trap per month, respectively reported in July. Also, the study indicated that the population density of frond borer, Phonapatefrontalis catch per trap during the period from April to December 2010 were 34, 58 and 54 adult/trap for orchards No. 1, 2 and 3, respectively, the higher population densities were 10, 21 and 15 adult/trap per month, respectively reported in June. Many insect groups were caught in light traps, the insect fauna composed of nineteen insect groups, 12 are coleoptera, 1 hemiptera, 1 hymenoptera, 1 homoptera, 2 dermaptera, and 2 orthoptera, the numbers of this insect were recorded per month a year round in palm orchards.

Investigation on Open-Circuit Voltage of an Efficiency-Boosting Solar Cell Technique Featuring V-Configuration

The V-Shaped Module (VSM) solar cell technology, which breaks the traditional concept of solar cell system, has been proven to enhance power conversion efficiency of some solar cells and has offered opportunities to increase generation power densities in area-limited applications. Compared to a planar cell system, the VSM has an additional opportunity to absorb photons and taps the potential of solar cells. In this study, the VSM, the proposed common technique enhancing efficiencies of various solar cells, was investigated by using commercially available multi-crystalline silicon solar cells. The VSM technique enables the efficiencies of the multi-crystalline silicon cells to increase from 13.4% to 20.2%, giving an efficiency boost of 51%. Though the efficiency of the cells increases, the open-circuit voltage of the cells decreases owing to the VSM technique. Furthermore, the obvious reduction in open-circuit voltage in the VSM was found and the phenomenon is explained for the first time.

Metallic nanostructures for light trapping in energy-harvesting devices

Solar energy is abundant and environmentally friendly.Light trapping in solar-energy-harvesting devices or structures is of critical importance.This article reviews light trapping with metallic nanostructures for thin film solar cells and selective solar absorbers.The metallic nanostructures can either be used in reducing material thickness and device cost or in improving light absorbance and thereby improving conversion efficiency.The metallic nanostructures can contribute to light trapping by scattering and increasing the path length of light,by generating strong electromagnetic field in the active layer,or by multiple reflections/absorptions.We have also discussed the adverse effect of metallic nanostructures and how to solve these problems and take full advantage of the light-trapping effect.