On the effect of acoustic coupling on random and harmonic plate vibrations

The effect of acoustic coupling on random and harmonic plate vibrations is studied using two numerical models. In the coupled model, the plate response is obtained by integration of the nonlinear plate equation coupled with the nonlinear Euler equations for the surrounding acoustic fluid. In the uncoupled model, the nonlinear plate equation with an equivalent linear viscous damping term is integrated to obtain the response of the plate subject to the same excitation field. For a low-level, narrow-band excitation, the two models predict the same plate response spectra. As the excitation level is increased, the response power spectrum predicted by the uncoupled model becomes broader and more shifted towards the high frequencies than that obtained by the coupled model. In addition, the difference in response between the coupled and uncoupled models at high frequencies becomes larger. When a high intensity harmonic excitation is used, causing a nonlinear plate response, both models predict the same frequency content of the response. However, the level of the harmonics and subharmonics are higher for the uncoupled model. Comparisons to earlier experimental and numerical results show that acoustic coupling has a significant effect on the plate response at high excitation levels. Its absence in previous models may explain the discrepancy between predicted and measured responses

Pembuatan Aplikasi Pencatatan Penjualan Helm di Toko Suoyo Laris Berbasis Desktop Menggunakan Database SQL Server

Toko Suoyo Laris adalah toko yang bergerak dalam bidang penjualan helm. Dalam proses transaksinya menggunakan nota secara manual dan pencatatan transaksi setiap harinya maupun stok barangnya masih menggunakan buku. Namun dari nota transaksi dan buku pencatatan transaksi yang telah digunakan masih banyak kekurangan. Sehingga pendokumentasian data transaksi dan stok barang masih sering kurang akurat. Sehubungan dengan hal tersebut, maka penulis membuat suatu aplikasi pencatatan penjualan helm berbasis komputer yang dapat menggantikan nota transaksi dan pencatatan transaksi maupun stok barang. Aplikasi ini nantinya bertujuan untuk memperlancar dan mempermudah dalam melakukan transaksi harian maupun pencatatan stok barang. Metode yang digunakan dalam penelitian ini menggunakan metode wawancara, observasi, dan kepustakaan dalam pengumpulan datanya. Dalam metode ini, penulis melakukan pengumpulan data secara langsung ke tempat toko Suoyo Laris dengan menggunakan metode tersebut. Sehingga untuk mempermudah dalam pembuatan aplikasi ini. Dengan adanya penelitian dalam pembuatan aplikasi pencatatan penjualan helm ini, akan diimplementasikan pada toko Suoyo Laris. Sehingga program yang di buat natinya diharapkan dapat mempermudah dalam melakukan proses transaksi dan pencatatan stok barang

Development of Measuring Device for Non-Invasive Blood Sugar Levels Using Photodiode Sensor

Diabetes mellitus is one of the deadliest diseases faced by Indonesian people. The number of sufferers of this disease in Indonesia is 10 million according to the International Diabetes Federation (IDF). Indonesia is included in five countries with the number of people with diabetes mellitus. This disease is caused by high levels of glucose in the blood. Patients are usually not controlled for sugar consumption in everyday life. For measuring blood sugar levels so far, the most widely used device is invasive, namely by injuring the patient's body. Techniques like this make people reluctant to take measurements of glucose levels in their blood routinely. Though it is recommended to take measurements regularly to be able to control the intake of nutrients in the body. The method used in this experiment is to design and build a blood sugar measuring device using a photodiode sensor. As well as collecting data on several patients related to blood to obtain patient data. Based on the results of the identification of the problems mentioned above, the authors make a non-invasive measuring tool entitled "Design of a Non-invasive Blood Sugar Measuring Instrument (TFT Display)". Results that have been obtained from this study are there are error values in the voltage measurement circuit voltage distribution with the calculation of the resistance value to get the voltage value. The error value obtained is 5%. The results of the linear regression value of 0.996