A review of instability and noise propagation in supersonic flows

Originally analytical and numerical models were to be developed for noise production in supersonic jets, wakes and free shear layers. While the effort was concentrated initially on these aspects, other topics were also pursued, most were of interest to the Jet Noise Group of the Aeroacoustics Branch. An overview is given of subjects reviewed and the investigations that were carried out. A significant effort was devoted to numerically predicting the flow field of a turbulent supersonic wall jet. This information is necessary for computing the pressure in the far field. The wall jet was selected because it represents a generic flow that can be associated with plug nozzle in supersonic engines. It combines the characteristic of a boundary layer with that of a free shear flow. The spatially evolving flow obtained using Dash's code would form the input for the stability analysis program. This analysis would determine the large scale instability wave within the flow. The far field pressure can be computed from the shape of the evolving large scale structure by asymptotic methods. Flow characteristics obtained from a program that analyses the turbulent downstream supersonic flow in a nozzle are described and compared with experimental results

The Effect of Radial and Ulnar Length Change on Distal Forearm Loading

The effect of distal radial and ulnar length change on forearm bone loading is not well understood during simulated dynamic wrist loading. This thesis presents two studies which investigate the effect of these length changes on distal forearm loading under simulated dynamic wrist motion. The first study investigates the effect of radial length change on axial loading at the distal radius and ulna and relationship between ulnar variance and distal forearm loading. The complex variation in axial loads in the distal radius and during length change and dynamic wrist motion were studied and discussed. There was no correlation between native variance and distal loads. The second study investigates the effect of ulnar change on axial loading at the distal radius and ulna and the effect of triangular fibrocartilage ligament complex (TFCC) on this relationship. Variation in axial loads during ulnar lengthening followed similar trends to radial shortening and vice versa

Tuning Interparticle Hydrogen Bonding in Shear-Jamming Suspensions: Kinetic Effects and Consequences for Tribology and Rheology

The shear-jamming of dense suspensions can be strongly affected by molecular-scale interactions between particles, e.g. by chemically controlling their propensity for hydrogen bonding. However, hydrogen bonding not only enhances interparticle friction, a critical parameter for shear jamming, but also introduces (reversible) adhesion, whose interplay with friction in shear-jamming systems has so far remained unclear. Here, we present atomic force microscopy studies to assess interparticle adhesion, its relationship to friction, and how these attributes are influenced by urea, a molecule that interferes with hydrogen bonding. We characterize the kinetics of this process with nuclear magnetic resonance, relating it to the time dependence of the macroscopic flow behavior with rheological measurements. We find that time-dependent urea sorption reduces friction and adhesion, causing a shift in the shear-jamming onset. These results extend our mechanistic understanding of chemical effects on the nature of shear jamming, promising new avenues for fundamental studies and applications alike

Keterkaitan Karakteristik Kawasan Transit Berdasarkan Prinsip Transit Oriented Development (TOD) terhadap Tingkat Penggunaan Kereta Komuter Koridor Surabaya-Sidoarjo

Koridor Surabaya-Sidoarjo telah dilayani dengan kereta komuter dalam mendukung tulang punggung transportasi perkotaan Surabaya. Namun penggunaan moda ini belum optimal. Hal ini dilihat dari besarnya pergerakan penduduk yang masih didominasi oleh penggunaan kendaraan pribadi menyebabkan kemacetan. Untuk mengatasi permasalahan tersebut diperlukan strategi inovatif yang mengedepankan integrasi antara penggunaan lahan dengan transportasi, salah satunya melalui konsep Transit Oriented Development (TOD) di kawasan stasiun kereta di sepanjang koridor Surabaya-Sidoarjo. Sebagai upaya pengimplementasiannya, perlu dilakukan studi mengenai keterkaitan karakteristik kawasan transit berbasis TOD terhadap jumlah penggunaan kereta komuter koridor Surabaya-Sidoarjo. Melalui analisis korelasi diperoleh hasil penelitian bahwa kepadatan penggunaan lahan (KLB), index keberagaman guna lahan (mixed use entrophy index) perdagangan dan jasa dan fasilitas umum, rata-rata lebar jalur pejalan kaki, dan luas jalur pejalan kaki signifikan memiliki hubungan korelasi yang kuat dengan tingkat penggunaan kereta komuter. Hal ini menunjukkan bahwa adanya potensi pengembangan kawasan transit berbasis TOD pada koridor Surabaya-Sidoarjo dalam mendorong penggunaan kereta komuter

The genetic characteristics of cephalic abnormality and its aquaculture implication in Clarias gariepinus (Burchell 1822)

Cephalic abnormality in nine mating groups involving Clarias gariepinus with cephalic abnormality, non Cephalic and Maiduguri origin were investigated to determine the level and the genetic basis of the occurrences and its aquaculture implication. The highest mean percentage survival in a Cephalic crossed with non cephalic group was 68.6% whereas the last mean percentage survival was 25.7% in the group of Maiduguri cross with Maiduguri parent. Cephalic abnormality was observed in the crosses with both female and male cephalic with a total frequency ranging from 0 % to 70.8. %. The least number of cephalic abnormality was 18.5% which involved a cross of non cephalic with cephalic, and the highest was 70.8%. This level of cephalic abnormality shows that the defect was hereditary. This result implies that, the genetic factor is a major contributor in the feature of cephalic abnormality in Clarias gariepinus

Estimasi Nilai Lingkungan Perkebunan Kelapa Sawit Ditinjau dari Neraca Air Tanaman Kelapa Sawit (Studi Kasus: Perkebunan Kelapa Sawit di Kecamatan Dayun, Kabupaten Siak, Propinsi Riau)the Estimation Of Oil Palm Plantation ...

Dayun area is one of the centers of oil palm plantation in Siak Regency. State-owned company that develops oil palm plantation in Dayun is PT Perkebunan Nusantara V (PTPN V) which is the first company developing oil palm plantation in Siak Regency. The oil palm plantations cause various effects to the environment; one of them is the decreasing water availability for the water stakeholders. The decreasing water availability causes additional cost to the community. The objectives of this study were to determine the decreasing of water availability which was caused by oil palm plantation, and its cost to meet the needs of water. The study used water balance model by Thornwhite 1957 and Willingness to Pays (WTP) analysis using questionaire of Contingent Valuation Method (CVM) in Sawit Permai, Dayun Subdistrict, Siak Regency. The land cover, before and after, affects the water balance which impacts the water availability in Dayun. The decreasing water availability was comparable with the increasing water demand in oil palm plantation, equal to 67 mm/year. Oil palm plantation had greater runoff than that of forest. The need of water in oil palm plantation in Dayun was 42.728 liters/ha/day, with the daily need of a single palm tree equal to 0,012 m3/s. Based on the analysis of debt estimation, there is debt decreasing which indicates the decreasing water availability in Dayun, around 349 m3/s yearly. The estimated value of the environment for oil palm plantation by water resources consumption based on the difference of forest and oil palm plantation during the dry season (JJA) is equal to Rp 7.500.000. Average WTP for the water conservation program is Rp 26.400, with WTP maximum and minimum up to Rp 45.000 and Rp 5.000, respectively. The economic value of water conservation program is Rp 18.850.000/month.Dayun area is one of the centers of oil palm plantation in Siak Regency. State-owned company that develops oil palm plantation in Dayun is PT Perkebunan Nusantara V (PTPN V) which is the first company developing oil palm plantation in Siak Regency. The oil palm plantations cause various effects to the environment; one of them is the decreasing water availability for the water stakeholders. The decreasing water availability causes additional cost to the community. The objectives of this study were to determine the decreasing of water availability which was caused by oil palm plantation, and its cost to meet the needs of water. The study used water balance model by Thornwhite 1957 and Willingness to Pays (WTP) analysis using questionaire of Contingent Valuation Method (CVM) in Sawit Permai, Dayun Subdistrict, Siak Regency. The land cover, before and after, affects the water balance which impacts the water availability in Dayun. The decreasing water availability was comparable with the increasing water demand in oil palm plantation, equal to 67 mm/year. Oil palm plantation had greater runoff than that of forest. The need of water in oil palm plantation in Dayun was 42.728 liters/ha/day, with the daily need of a single palm tree equal to 0,012 m3/s. Based on the analysis of debt estimation, there is debt decreasing which indicates the decreasing water availability in Dayun, around 349 m3/s yearly. The estimated value of the environment for oil palm plantation by water resources consumption based on the difference of forest and oil palm plantation during the dry season (JJA) is equal to Rp 7.500.000. Average WTP for the water conservation program is Rp 26.400, with WTP maximum and minimum up to Rp 45.000 and Rp 5.000, respectively. The economic value of water conservation program is Rp 18.850.000/month

A multiscale approach to the adsorption of core-shell nanoparticles at fluid interfaces

Self-assembly of colloidal particles at liquid–liquid interfaces is a process with great potential for the creation of controlled structures, due to the trapping of the particles in the plane of the interface combined with their lateral mobility. Here we present a multiscale characterisation of the adsorption and interfacial behaviour of core–shell iron oxide–poly(ethylene glycol) nanoparticles at a water–n-decane interface using three complementary, in situ, methods, which span many different length scales. First, dynamic interfacial measurements are taken to follow the adsorption of particles from the bulk aqueous phase to the interface. The mechanical properties of the interface are then probed using micron-sized tracers in probe-particle tracking and nano-tracers in fluorescence correlation spectroscopy. The results show that the rate of particle adsorption to the interface scales with the square of bulk concentration, as predicted by a recent model. In addition, we show that despite full monolayers of nanoparticles forming, the interface remains unexpectedly fluid, with only a slowing of tracer particle mobility but no evidence of interface jamming as seen for hard nanoparticles. Our results illustrate that nanoparticles stabilised by soft, extended polymeric shells, display distinct features at fluid interfaces that can be harnessed for the fabrication of functional materials.ISSN:1744-683XISSN:1744-684

Limbaga (Peribahasa) bahasa Simalungun

Buku Limbaga (Peribahasa) Bahasa Simalungun ini merupakan salah satu hasil Bagian Proyek Pembinaan Bahasa dan Sastra Indonesia dan Daerah Sumatera Utara tahun 1993/1994. Penelitian ini adalah membuat deskripsi salah satu aspek bahasa dan sastra Simalungun, yaitu peribahasa berdasarkan data yang terkumpul. Dengan tujuan untuk menginventarisasi bahasa dan sastra daerah dalam rangka ikut serta membantu pemerintah dari usaha membina dan memelihara bahasa dan sastra daerah. Penelitian peribahasa Simalungun ini dilakukan sejalan dengan tugas yang diberikan kepada kami oleh Pimpinan Proyek Peneiitian Bahasa Dan Sastra Daerah Sumatera Utara, Kantor Wilayah Departemen Pendidikan dan Kebudayaan Sumatera Utara