Voltage induced spreading and liquid optical devices

An experimental investigation has been carried out into Liquid dielectrophoresis (LDEP), in which dielectric forces are used to actuate bulk liquid spreading and to imprint a deformation pattern at a liquid air surface. Our basic conguration uses a set of co-planar stripe interdigital electrodes to create a non-uniform A.C. electric field that exponentially decays in amplitude and penetrates above the structure into a dielectric liquid droplet. Dielectric forces drive a voltage-induced spreading of the droplet into a low contact angle droplet/film, an effect which will be referred to here as "dielectrowetting". Further application of the A.C. voltage to the electrodes results in a static sinusoidal wrinkle forming at the oil-air interface on the spread film. Three main areas of investigations are reported, the first of which is a study of the statics and dynamics of the voltage induced spreading of a stripe of the material 1,2 propylene glycol. In the limit of thick droplets, a theoretical prediction has been derived that the cosine of the static equilibrium contact angle is proportional to the square of the amplitude of the voltage applied to the inter-digital electrodes. This relationship is analogous to that found for electrowetting-on-dielectric (EWOD). Experimental observations confirm this predicted dielectrowetting behavior for the advancing static contact angle of the voltage induced spreading of a stripe of the material 1,2 propylene glycol

INTENSITAS SERANGAN HAMA ULAT GRAYAK SPODOPTERA FRUGIPERDA PADA TANAMAN JAGUNG DI KABUPATEN TAKALAR

Spodoptera frugiperda is an invasive insect and includes a highly polyphagous insect that can attack various types of plants. Armyworm attacks can be a severe threat to corn farmers. It can cause significant yield loss. This study aims to determine the attack intensity and distribution of the S. frugiperda armyworm in several sub-districts on several varieties of maize in Takalar Regency, South Sulawesi, as the first step in determining an appropriate control strategy. The results showed that from the five sub-districts where the observations were made, there were symptoms of S. frugiperda attack, namely in the sub-districts of South Polongbangkeng, North Polongbangkeng, Sanrobone, South Galesong, and Pattallassang. The highest attack intensity was around 97.33% of 4 weeks in Pallantikang Village, Pattallassang District. The lowest attack intensity, namely 46.44% of 3 weeks, was found in Kadatong Village, South Galesong District.Spodoptera frugiperda merupakan serangga invasif dan termasuk serangga polifag tinggi yang dapat menyerang berbagai jenis tanaman. Serangan hama ulat grayak dapat menjadi ancaman serius bagi petani jagung, karena dapat menyebabkan kehilangan hasil yang signifikan. Penelitian ini bertujuan untuk mengetahui intensitas serangan dan distribusi penyebaran ulat grayak S. frugiperda dibeberapa kecamatan pada beberapa varietas tanaman jagung di Kabupaten Takalar sebagai langkah awal dalam menentukan strategi pengendalian yang tepat. Hasil penelitian menunjukkan bahwa dari lima kecamatan tempat dilakukan pengamatan, kelima kecamatan tersebut terdapat gejala serangan S. frugiperda yaitu di Kecamatan Polongbangkeng Selatan, Polongbangkeng Utara, Sanrobone, Galesong Selatan dan Patallassang, intensitas serangan tertinggi sekitar 97,33% dengan umur 4 minggu di Kelurahan Pallantikang, Kecamatan Patalassang, sedangkan intensitas serangan terendah sekitar 46,44% umur tanaman 3 minggu di Desa Kadatong, Kecamatan Galesong Selatan. Kata Kunci:   Spodoptera frugiperda; intensitas serangan; tanaman jagung; polifag, varietas

INTENSITAS SERANGAN HAMA ULAT GRAYAK SPODOPTERA FRUGIPERDA PADA TANAMAN JAGUNG DI KABUPATEN TAKALAR

Spodoptera frugiperda is an invasive insect and includes a highly polyphagous insect that can attack various types of plants. Armyworm attacks can be a severe threat to corn farmers. It can cause significant yield loss. This study aims to determine the attack intensity and distribution of the S. frugiperda armyworm in several sub-districts on several varieties of maize in Takalar Regency, South Sulawesi, as the first step in determining an appropriate control strategy. The results showed that from the five sub-districts where the observations were made, there were symptoms of S. frugiperda attack, namely in the sub-districts of South Polongbangkeng, North Polongbangkeng, Sanrobone, South Galesong, and Pattallassang. The highest attack intensity was around 97.33% of 4 weeks in Pallantikang Village, Pattallassang District. The lowest attack intensity, namely 46.44% of 3 weeks, was found in Kadatong Village, South Galesong District.Spodoptera frugiperda merupakan serangga invasif dan termasuk serangga polifag tinggi yang dapat menyerang berbagai jenis tanaman. Serangan hama ulat grayak dapat menjadi ancaman serius bagi petani jagung, karena dapat menyebabkan kehilangan hasil yang signifikan. Penelitian ini bertujuan untuk mengetahui intensitas serangan dan distribusi penyebaran ulat grayak S. frugiperda dibeberapa kecamatan pada beberapa varietas tanaman jagung di Kabupaten Takalar sebagai langkah awal dalam menentukan strategi pengendalian yang tepat. Hasil penelitian menunjukkan bahwa dari lima kecamatan tempat dilakukan pengamatan, kelima kecamatan tersebut terdapat gejala serangan S. frugiperda yaitu di Kecamatan Polongbangkeng Selatan, Polongbangkeng Utara, Sanrobone, Galesong Selatan dan Patallassang, intensitas serangan tertinggi sekitar 97,33% dengan umur 4 minggu di Kelurahan Pallantikang, Kecamatan Patalassang, sedangkan intensitas serangan terendah sekitar 46,44% umur tanaman 3 minggu di Desa Kadatong, Kecamatan Galesong Selatan. Kata Kunci:   Spodoptera frugiperda; intensitas serangan; tanaman jagung; polifag, varietas