Multiwave Interactions in Turbulent Jets

Nonlinear wave-wave interactions in turbulent jets were investigated based on the integrated energy of each scale of motion in a cross section of the jet. The analysis indicates that two frequency components in the axisymmetric mode can interact with other background frequencies in the axisymmetric mode, thereby amplifying an enormous number of other frequencies. Two frequency components in a single helical mode cannot, by themselves, amplify other frequency components. But combinations of frequency components of helical and axisymmetric modes can amplify other frequencies in other helical modes. The present computations produce several features consistent with experimental observations such as: (1) dependency of the interactions on the initial phase differences, (2) enhancement of the momentum thickness under multifrequency forcing, and (3) the increase in background turbulence under forcing. In a multifrequency-excited jet, mixing enhancement was found to be a result of the turbulence enhancement rather than simply the amplification of forced wave components. The excitation waves pump energy from the mean flow to the turbulence, thus enhancing the latter. The high frequency waves enhance the turbulence close to the jet exit, but, the low frequency waves are most effective further downstream

Numerical simulation of nonlinear development of instability waves

The nonlinear interactions of high amplitude instability waves in turbulent jets are described. In plane shear layers Riley and Metcalf (1980) and Monkewitz (1987) have shown that these interactions are dependent, among other parameters, on the phase-difference between the two instability waves. Therefore, here researchers consider the nonlinear development of both the amplitudes and the phase of the instability waves. The development of these waves are also coupled with the development of the mean flow and the background turbulence. In formulating this model it is assumed that each of the flow components can be characterized by conservation equations supplemented by closure models. Results for the interactions between the two instability waves under high-amplitude forcing at fundamental and subharmonic frequencies are presented here. Qualitative agreements are found between the present predictions and available experimental data

Penuntutan Korporasi sebagai Pelaku Tindak Pidana dalam Kejahatan di Sektor Kehutanan: Optimalisasi Penggunaan Undang-undang Pencucian Uang dalam Pembuktian Tindak Pidana di Sektor Kehutanan di Indonesia yang Dilakukan oleh Korporasi.

Perkembangan industri saat ini menjadikan meningkatnya kebutuhan bahan baku salah satunya kebutuhan kayu. Akan tetapi kondisi tersebut didiiringi dengan pengawsan dan pengaturan sehingga terjadi pembalakan liar. Penegakan hukum yag dilakukan saat ini masih enggunakan cara konvensional. Berlakunya Undang-Undang No.8 Tahun 2010 tentang pemberantasan Tindak Pidana Pencucian Uang memberikan kesempatan bagi Penegak Hukum untuk tidak hanya menuntut pelaku pembalakan liar dengan tindak pidana asal tetapi juga menggunakan in trumen anti pencucian uang untuk dapat menyita dan merampas asset hasil pembalakan liar. Dalam tulisan ini akan dipaparkan tentang pembalakan liar yang dilakukan oleh korporasi, pola pencucian uang oleh pelaku pebalakan liar dan pendekatan baru tentang mekanisme penanganan perkara pembalakan liar melalui pendekatan multi door

Runtime Configurable Deep Neural Networks for Energy-Accuracy Trade-off

We present a novel dynamic configuration technique for deep neural networks that permits step-wise energy-accuracy trade-offs during runtime. Our configuration technique adjusts the number of channels in the network dynamically depending on response time, power, and accuracy targets. To enable this dynamic configuration technique, we co-design a new training algorithm, where the network is incrementally trained such that the weights in channels trained in earlier steps are fixed. Our technique provides the flexibility of multiple networks while storing and utilizing one set of weights. We evaluate our techniques using both an ASIC-based hardware accelerator as well as a low-power embedded GPGPU and show that our approach leads to only a small or negligible loss in the final network accuracy. We analyze the performance of our proposed methodology using three well-known networks for MNIST, CIFAR-10, and SVHN datasets, and we show that we are able to achieve up to 95% energy reduction with less than 1% accuracy loss across the three benchmarks. In addition, compared to prior work on dynamic network reconfiguration, we show that our approach leads to approximately 50% savings in storage requirements, while achieving similar accuracy

Effects of core turbulence on jet excitability

The effects of varying freestream core turbulence on the evolution of a circular jet with and without tonal excitation are examined. Measurements are made on an 8.8 cm diameter jet at a Mach number of 0.3. The jet is excitated by plane waves at Strouhal number 0.5. For the excited and unexcited cases the turbulence level is varied by screens and grids placed upstream of the nozzle exit. The experiment results are compared with a theoretical model which incorporates a variable core turbulence and considers the energy interactions between the mean flow, the turbulence and the forced component. Both data and theory indicate that increasing the freestream turbulence diminishes the excitability of the jet and reduces the effect of excitation on the spreading rate of the jet

Numerical Simulation of a High Mach Number Jet Flow

The recent efforts to develop accurate numerical schemes for transition and turbulent flows are motivated, among other factors, by the need for accurate prediction of flow noise. The success of developing high speed civil transport plane (HSCT) is contingent upon our understanding and suppression of the jet exhaust noise. The radiated sound can be directly obtained by solving the full (time-dependent) compressible Navier-Stokes equations. However, this requires computational storage that is beyond currently available machines. This difficulty can be overcome by limiting the solution domain to the near field where the jet is nonlinear and then use acoustic analogy (e.g., Lighthill) to relate the far-field noise to the near-field sources. The later requires obtaining the time-dependent flow field. The other difficulty in aeroacoustics computations is that at high Reynolds numbers the turbulent flow has a large range of scales. Direct numerical simulations (DNS) cannot obtain all the scales of motion at high Reynolds number of technological interest. However, it is believed that the large scale structure is more efficient than the small-scale structure in radiating noise. Thus, one can model the small scales and calculate the acoustically active scales. The large scale structure in the noise-producing initial region of the jet can be viewed as a wavelike nature, the net radiated sound is the net cancellation after integration over space. As such, aeroacoustics computations are highly sensitive to errors in computing the sound sources. It is therefore essential to use a high-order numerical scheme to predict the flow field. The present paper presents the first step in a ongoing effort to predict jet noise. The emphasis here is in accurate prediction of the unsteady flow field. We solve the full time-dependent Navier-Stokes equations by a high order finite difference method. Time accurate spatial simulations of both plane and axisymmetric jet are presented. Jet Mach numbers of 1.5 and 2.1 are considered. Reynolds number in the simulations was about a million. Our numerical model is based on the 2-4 scheme by Gottlieb & Turkel. Bayliss et al. applied the 2-4 scheme in boundary layer computations. This scheme was also used by Ragab and Sheen to study the nonlinear development of supersonic instability waves in a mixing layer. In this study, we present two dimensional direct simulation results for both plane and axisymmetric jets. These results are compared with linear theory predictions. These computations were made for near nozzle exit region and velocity in spanwise/azimuthal direction was assumed to be zero

Diabetes Mellitus Prevalence and Burden Among Community Acquired Pneumonia Patients

This work aimed at measuring the prevalence of Diabetes Mellitus among community acquired pneumonia (CAP) patients and declaring its effect on CAP patient\u27s outcome. Both community acquired pneumonia and diabetes mellitus are common in Egypt, and patients with associated CAP and DM need special care and supervision. This prospective study was carried out on 108 CAP patients admitted to Abassia Chest Hospital during the period from January 2016 to December 2016. Clinical and radiological diagnosis of pneumonia and DM diagnosis were performed. DM recorded a prevalence of 39.8% among community acquired pneumonia patients. Disturbed level of consciousness is more frequent among diabetic patients than non diabetics. Diabetic patients recorded higher rate of hospital admission, longer duration of hospital stay, higher rate of ICU admission and more sever pneumonia than among non diabetic patients. CURB-65 score showed significant positive correlation with HbA1c of the patients. Associated community-acquired pneumonia and diabetes mellitus is frequent in our locality and labor a double burden on the affected patients leading to poorer prognosis, higher rate of hospitalization with longer duration of hospital stay and ICU admission. So CAP patients with DM need intimate care

Pengaruh Kombinasi Media Pembelajaran terhadap Minat Belajar Mahasiswa pada Mata Kuliah Teknologi Pembelajaran Akuntansi

Tujuan penelitian ini adalah untuk mengetahui pengaruh kombinasi media pembelajaran (Microsoft PowerPoint dan Ulead Video Studio) terhadap minat belajar mahasiswa pada perkuliahan Teknologi Pembelajaran Akuntansi. Populasi yang digunakan dalam penelitian ini adalah mahasiswa semester IV Pendidikan Ekonomi BKK Pendidikan Akuntansi yang sedang mengikuti mata kuliah Teknologi Pembelajaran Akuntansi. Dalam penelitian ini, teknik pengambilan sampel yang dipilih adalah Nonprobability Sampling dengan Teknik Sampling Jenuh. Data yang digunakan adalah data primer yang berasal dari angket yang disebarkan oleh peneliti kepada mahasiswa sebagai responden pada akhir perkuliahan. Penelitian ini merupakan penelitian kuantitatif dengan menggunakan metode eksperimen, metode uji statistik yang digunakan adalah Uji-T dengan melakukan uji persyaratan analisis terlebih dahulu.Hasil penelitian menunjukkan bahwa terdapat pengaruh penggunaan kombinasi media pembelajaran terhadap minat belajar mahasiswa. Hal tersebut ditunjukkan melalui perhitungan Uji-T yang menghasilkan nilai t hitung sebesar 2,040 yang melebihi nilai t tabel sebesar 1,998 dan P-Value sebesar 0,045 lebih kecil dari taraf signifikansi yang telah ditentukan yaitu sebesar 0,05.Kata Kunci: Kombinasi Media Pembelajaran, Minat Belajar ABSTRACTThe purpose of this research is to know the effect of learning media combination (Microsoft PowerPoint and Ulead Video Studio) toward students interest in learning on Teknologi Pembelajaran Akuntansi course. The population that is used in this research is the 4th semester students of Economic Accounting Education who are joining Teknologi Pembelajaran Akuntansi course. In this research, sampling technique which choosen was Nonprobability Sampling withJenuh Sampling Technique. The determination of the group will be treated experimental and control is conducted randomly. The data that used is primary data which come from distributed questionnaries by researcher to students as respondents when the course ends. This research is quantitative research using experimental methods, statistical methods which used is T-Test with the test requirements prior analysis.The research result shows that learning media combination has effect to students interest in learning. It is shown by t0 = 2,040 which exceed the value of its critical value for 1,998 and P-Value for 0,045 smaller than a predetermined significance level for 0,05. Keyword: Learning Media Combination, Students Interest in LearningABSTRAKTujuan penelitian ini adalah untuk mengetahui pengaruh kombinasi media pembelajaran (Microsoft PowerPoint dan Ulead Video Studio) terhadap minat belajar mahasiswa pada perkuliahan Teknologi Pembelajaran Akuntansi. Populasi yang digunakan dalam penelitian ini adalah mahasiswa semester IV Pendidikan Ekonomi BKK Pendidikan Akuntansi yang sedang mengikuti mata kuliah Teknologi Pembelajaran Akuntansi. Dalam penelitian ini, teknik pengambilan sampel yang dipilih adalah Nonprobability Sampling dengan Teknik Sampling Jenuh. Data yang digunakan adalah data primer yang berasal dari angket yang disebarkan oleh peneliti kepada mahasiswa sebagai responden pada akhir perkuliahan. Penelitian ini merupakan penelitian kuantitatif dengan menggunakan metode eksperimen, metode uji statistik yang digunakan adalah Uji-T dengan melakukan uji persyaratan analisis terlebih dahulu.Hasil penelitian menunjukkan bahwa terdapat pengaruh penggunaan kombinasi media pembelajaran terhadap minat belajar mahasiswa. Hal tersebut ditunjukkan melalui perhitungan Uji-T yang menghasilkan nilai t hitung sebesar 2,040 yang melebihi nilai t tabel sebesar 1,998 dan P-Value sebesar 0,045 lebih kecil dari taraf signifikansi yang telah ditentukan yaitu sebesar 0,05.Kata Kunci: Kombinasi Media Pembelajaran, Minat Belajar ABSTRACTThe purpose of this research is to know the effect of learning media combination (Microsoft PowerPoint and Ulead Video Studio) toward students interest in learning on Teknologi Pembelajaran Akuntansi course. The population that is used in this research is the 4th semester students of Economic Accounting Education who are joining Teknologi Pembelajaran Akuntansi course. In this research, sampling technique which choosen was Nonprobability Sampling withJenuh Sampling Technique. The determination of the group will be treated experimental and control is conducted randomly. The data that used is primary data which come from distributed questionnaries by researcher to students as respondents when the course ends. This research is quantitative research using experimental methods, statistical methods which used is T-Test with the test requirements prior analysis.The research result shows that learning media combination has effect to students interest in learning. It is shown by t0 = 2,040 which exceed the value of its critical value for 1,998 and P-Value for 0,045 smaller than a predetermined significance level for 0,05