Rancang Bangun Mesin Electromechanical Grinding dengan Proses Silindris

Dalam pembuatan suatu profil yang mudah pada benda kerja, umumnya terdapat penggunaan mesin gerindakonvensional. Jika penggunaan mesin gerinda konvensional saat pengerjaannya bisa memakan waktu yang relatif lama,bisa terjadi distorsi pada permukaannya, dll.Proses ECG memiliki kelebihan dari gerinda konvensional seperti teganganinduksi rendah, kedalaman potongan, proses pengerjaannya lebih cepat dibandingkan dengan proses pengerjaanlainnya, bisa digunakan untuk segala jenis benda kerja yang bersifat konduktif, dll.ECG menggabungkan prosespenggerindaan konvensional dan proses ECM secara bersamaan antara proses pemesinan dengan gerak mekanispartikel abrasif dan reaksi elektrokimia. Dipasaran mesin ECG memiliki harga yang tinggi maka disini penulis mencobamerancang bangun alat Electrochemical Grinding sederhana agar dapat digunakan oleh mahasiswa Teknik MesinIndustri. Untuk perancangan mesin ECG memerlukan perancangan (struktur, penggerindaankonvensional,ECM),pembuatan mesin ECG dan pengujian. Hasil pengujian dari pembuatan mesin yang telah dilakukanmenunjukkan MRR penggerindaan konvensional 138,57 mm3/min dan MRR ECG 330 mm3/mi

Different factors limit early‐ and late‐season windows of opportunity for monarch development

Abstract Seasonal windows of opportunity are intervals within a year that provide improved prospects for growth, survival, or reproduction. However, few studies have sufficient temporal resolution to examine how multiple factors combine to constrain the seasonal timing and extent of developmental opportunities. Here, we document seasonal changes in milkweed (Asclepias fascicularis)–monarch (Danaus plexippus) interactions with high resolution throughout the last three breeding seasons prior to a precipitous single‐year decline in the western monarch population. Our results show early‐ and late‐season windows of opportunity for monarch recruitment that were constrained by different combinations of factors. Early‐season windows of opportunity were characterized by high egg densities and low survival on a select subset of host plants, consistent with the hypothesis that early‐spring migrant female monarchs select earlier‐emerging plants to balance a seasonal trade‐off between increasing host plant quantity and decreasing host plant quality. Late‐season windows of opportunity were coincident with the initiation of host plant senescence, and caterpillar success was negatively correlated with heatwave exposure, consistent with the hypothesis that late‐season windows were constrained by plant defense traits and thermal stress. Throughout this study, climatic and microclimatic variations played a foundational role in the timing and success of monarch developmental windows by affecting bottom‐up, top‐down, and abiotic limitations. More exposed microclimates were associated with higher developmental success during cooler conditions, and more shaded microclimates were associated with higher developmental success during warmer conditions, suggesting that habitat heterogeneity could buffer the effects of climatic variation. Together, these findings show an important dimension of seasonal change in milkweed–monarch interactions and illustrate how different biotic and abiotic factors can limit the developmental success of monarchs across the breeding season. These results also suggest the potential for seasonal sequences of favorable or unfavorable conditions across the breeding range to strongly affect monarch population dynamics

Different factors limit early- and late-season windows of opportunity for monarch development.

Seasonal windows of opportunity are intervals within a year that provide improved prospects for growth, survival, or reproduction. However, few studies have sufficient temporal resolution to examine how multiple factors combine to constrain the seasonal timing and extent of developmental opportunities. Here, we document seasonal changes in milkweed (Asclepias fascicularis)-monarch (Danaus plexippus) interactions with high resolution throughout the last three breeding seasons prior to a precipitous single-year decline in the western monarch population. Our results show early- and late-season windows of opportunity for monarch recruitment that were constrained by different combinations of factors. Early-season windows of opportunity were characterized by high egg densities and low survival on a select subset of host plants, consistent with the hypothesis that early-spring migrant female monarchs select earlier-emerging plants to balance a seasonal trade-off between increasing host plant quantity and decreasing host plant quality. Late-season windows of opportunity were coincident with the initiation of host plant senescence, and caterpillar success was negatively correlated with heatwave exposure, consistent with the hypothesis that late-season windows were constrained by plant defense traits and thermal stress. Throughout this study, climatic and microclimatic variations played a foundational role in the timing and success of monarch developmental windows by affecting bottom-up, top-down, and abiotic limitations. More exposed microclimates were associated with higher developmental success during cooler conditions, and more shaded microclimates were associated with higher developmental success during warmer conditions, suggesting that habitat heterogeneity could buffer the effects of climatic variation. Together, these findings show an important dimension of seasonal change in milkweed-monarch interactions and illustrate how different biotic and abiotic factors can limit the developmental success of monarchs across the breeding season. These results also suggest the potential for seasonal sequences of favorable or unfavorable conditions across the breeding range to strongly affect monarch population dynamics