Micro heat exchanger by using MEMS impinging jets

A micro impinging-jet heat exchanger is presented here. Heat transfer is studied for single jet, slot arrays and jet arrays. In order to facilitate micro heat transfer measurements with these devices, a MEMS sensor chip, which has an 8 x 8 temperature-sensor array on one side, and an integrated heater on the other side has been designed and fabricated. This sensor chip allows 2-D surface temperature measurement with various jets impinging on it. It is found that micro impinging jets can be highly efficient when compared to existing macro impinging-jet microelectronics packages such as IBM 4381. For example, using a single nozzle jet (500-μm diameter driven by 5 psig pressure), the sensor chip (2 x 2 cm^2) temperature can be cooled down from 70 to 33°C. The cooling becomes more efficient when nozzle arrays (4x5 over 1 cm^2 area) are used under the same driving pressure. Interestingly, although higher driving pressure gives better cooling (lower surface temperature), the cooling efficiency, defined as h/0.5pv^2, is actually higher for lower driving pressure

A suspended microchannel with integrated temperature sensors for high-pressure flow studies

A freestanding microchannel, with integrated temperature sensors, has been developed for high-pressure flow studies. These microchannels are approximately 20μm x 2μm x 4400μm, and are suspended above 80 μm deep cavities, bulk micromachined using BrF3 dry etch. The calibration of the lightly boron-doped thermistor-type sensors shows that the resistance sensitivity of these integrated sensors is parabolic with respect to temperature and linear with respect to pressure. Volumetric flow rates of N2 in the microchannel were measured at inlet pressures up to 578 psig. The discrepancy between the data and theory results from the flow acceleration in a channel, the non-parabolic velocity profile, and the bulging of the channel. Bulging effects were evaluated by using incompressible water flow measurements, which also measures 1.045x10^-3N-s/m^2 for the viscosity of DI water. The temperature data from sensors on the channel shows the heating of the channel due to the friction generated by the high-pressure flow inside

Marketing Strategy Of Dodol Singkong Malayan

Penelitian ini dilaksanakan pada kelompok USAha karya Mandiri Sepakat di Kp. Melayu jorong sungai jernih Talu Kabupaten Pasaman Barat. Tujuan dari penelitian in adalah untuk mengetahui strategi pemasaran yang tepat pada USAha dodol ubi kayu dikenagarian Talu. Metode analisis data yang digunakan pada penelitian ini adalah metode analisis SWOT. Hasil penelitian menunjukan bahwa kekuatan USAha dalam pemasaran dodol ubi kayu ini adalah produksi dodol ubi kayu secara terus menerus, bahan baku mudah diperoleh dan produk tanpa menggunkan bahan pengawet. Kelemahan USAha dalam pemasarannya yaitu pengolahan dodol uni kayu masih manual, kurangnya pemanfaatan teknologi dan produk tidak tahan lama. Peluang USAha dalam pemasarannya adalah permintaan dodol ubi kayu selalu meningkat, transportasi lancar dan luasnya potensi pasar, yang menjadi ancaman bagi USAha dalam pemasaranya yaitu banyaknya jenis makanan baru, selera konsumen yang selalu berubah ubah, kemasan cemilan siap saji yang lebih menarik. Dari hasil analisi SWOT yang dilakukan , diperoleh hasil penelitian bahwa strategi yang digunakan oleh kelompok USAha karya mandiri sepakat adalah strategi Growth /pertumbuhan. Kata kunci : Strategi Pemasran, Dodol Ubi Kayu, Analisis SWO

Solution of two-center time-dependent Dirac equation in spherical coordinates: Application of the multipole expansion of the electron-nuclei interaction

A non-perturbative approach to the solution of the time-dependent, two-center Dirac equation is presented with a special emphasis on the proper treatment of the potential of the nuclei. In order to account for the full multipole expansion of this potential, we express eigenfunctions of the two-center Hamiltonian in terms of well-known solutions of the "monopole" problem that employs solely the spherically-symmetric part of the interaction. When combined with the coupled-channel method, such a wavefunction-expansion technique allows for an accurate description of the electron dynamics in the field of moving ions for a wide range of internuclear distances. To illustrate the applicability of the proposed approach, the probabilities of the K- as well as L- shell ionization of hydrogen-like ions in the course of nuclear alpha-decay and slow ion-ion collisions have been calculated

Multi-dimensional laser spectroscopy of exciton-polaritons with spatial light modulators

We describe an experimental system that allows one to easily access the dispersion curve of exciton-polaritons in a microcavity. Our approach is based on two spatial light modulators (SLM), one for changing the excitation angles (momenta), and the other for tuning the excitation wavelength. We show that with this setup, an arbitrary number of states can be excited accurately and that re-configuration of the excitation scheme can be done at high speed.Comment: 4 pages, 5 figure

Implementasi O-score Model untuk Memprediksi Financial Distress Perusahaan (Studi pada Perusahaan Manufaktur Sub Sektor Tekstil dan Garmen yang Terdaftar di Bursa Efek Indonesia Periode 2011-2015)

This study aims to predict the level of financial distress of textile and garment manufacturing companies listed in Indonesia Stock Exchange period 2011-2015 using O-Score Model. This research is a descriptive research. Sources of data in the study are secondary data in the form of financial statements of sample companies and gnp data. Sample selection technique is using purposive sampling method and obtained 13 companies used as sample research. There are 9 independent variables used in the O-Score formula. The O-Score Model illustrates the possibility of financial distress using logistical transformations or P (O-Score). The company will be in a safe zone, if P (O-Score) <0.50. Conversely, the company will experience financial distress when P (O-Score)> 0.50. The results show that nine out of 13 companies are always in the safe zone for five consecutive years. One company is predicted to be in the financial distress zone for five consecutive years, while three companies are in an unstable condition for five years