Rates of solar angles for two-axis concentrators

The Sun's position by the azimuth and elevation angles and its rate of change at any time of day are determined to design 2 axis tracking mechanisms of solar concentrators. The Sun's angles and their rates for selected months of the year (March, June, September and December) and for seven selected atitudes (0, + or - 30, + or - 60, + or - 90) covering both the northern and southern hemispheres were studied. The development of the angle and angle rate analytical expressions for any month, hour of day, and latitude provides the solar concentrator designer with a quantitative determination of the limiting Sun's position and angle rates for an accurate automatic tracking mechanism

Neutron Energy Effects on Asteroid Deflection

In the future, a hazardous asteroid will find itself on a collision course with Earth. It is an inevitability; the question is not if, but when. For asteroids of moderate size or larger, a nuclear device is one of humanity\u27s only technologies capable of mitigating this threat via deflection on a timescale of less than a decade. This work examined how changing the output neutron energy from a nuclear device detonation affects asteroid deflection. The notional asteroid target was 300 meters in diameter and composed of silicon dioxide at a bulk density of 1.855 g/cm3. To calculate the energy deposition in the asteroid that results from a neutron source, the Monte Carlo radiation-transport code, MCNP6.2, was applied. MCNP6.2 simulations were performed for neutrons of various energies radiating towards the asteroid surface. The neutron energy was found to have an impact in terms of 1) the energy deposition spatial profile, and 2) the energy coupling efficiency. To model the mechanical response of the asteroid due to a spatially-varying energy deposition, the hydrodynamics code, ALE3D, was employed. The energy deposition outputs from MCNP6.2 served as inputs into the model representation of the asteroid in ALE3D. The momentum impulse imparted onto the asteroid body due to rapidly- evolving melted and/or vaporized blow-off ejecta was quantified. From this, the asteroid velocity change, or δV , was determined for two different neutron yields (50 kt and 1 Mt) and for two different source neutron energies (14.1 MeV from fusion and 1 MeV from fission). Underexplored in literature, the distribution of deposited energy and the energy coupling were both found to affect the asteroid deflection. The magnitude of energy deposition, as determined by the neutron energy and the coupling, generally appears to be the more significant factor

Endoscopic Shearography and Thermography Methods for Nondestructive Evaluation of Lined Pressure Vessels

The goal of this research effort was the development of methods for shearographic and thermographic inspection of coatings, bonds, or laminates inside rocket fuel or oxidizer tanks, fuel lines, and other closed structures. The endoscopic methods allow imaging and inspection inside cavities that are traditionally inaccessible with shearography or thermography cameras. The techniques are demonstrated and suggestions for practical application are made in this report. Drawings of the experimental setups, detailed procedures, and experimental data are included

A 32-GHz phased array transmit feed for spacecraft telecommunications

A 21-element phased array transmit feed was demonstrated as part of an effort to develop and evaluate state-of-the-art transmitter and receiver components at 32 and 34 GHz for future deep-space missions. Antenna pattern measurements demonstrating electronic beam steering of the two-dimensional array are reported and compared with predictions based on measured performance of MMIC-based phase shifter and amplifier modules and Vivaldi slotline radiating elements

The Value of a River

The Skokomish river was once the most productive salmon river in Puget Sound, but since 1926 the North Fork Skokomish has been diverted for hydropower. The Skokomish tribe has fought unsuccessfully to restore natural flows. At issue is the “non-market value” of the river’s biological productivity. The value of the river as “natural capital” for the tribe is analyzed from an historical, ethnographic, and ecological perspective. Keywords: non-market values, natural capital, salmon, Pacific Northwest, Skokomish, riverine ecology, ecosystem management

Structural design options for the new 34 meter beam waveguide antenna

In addition to the successful network of 34 m High Efficiency antennas recently built by JPL, the Deep Space Network (DSN) is embarking on the construction of a 34 m high performance, research and development antenna with beam waveguide optics at the Venus site. The construction of this antenna presents many engineering challenges in the area of structural, mechanical, RF, and pointing system design. A set of functional and structural design requirements is outlined to guide analysts in the final configuration selection. Five design concepts are presented covering both the conventional center-fed beam optics as well as the nonconventional, by-pass beam configuration. The merits of each concept are discussed with an emphasis on obtaining a homologous design. The preliminary results of structural optimization efforts, currently in progress, are promising, indicating the feasibility of meeting, as a minimum, all X-band (8.4 GHz) requirements, with a goal towards meeting Ka-band (32 GHz) quality performance, at the present budget constraints

The Contribution of Rice Farming on Nitrogen Enrichment in Yeh Sungi Watershed, Tabanan Bali

Pelaksanaan program intensifikasi pertanian melalui konsep revolusi hijau membuat meningkatnyaproduksi padi secara dramatis sehingga pada tahun 1984 Indonesia mencapai swa-sembada beras. Uniknya, sebelumtahun 1984 Indonesia dikenal sebagai negara pengimpor beras yang terbesar di dunia. Akan tetapi, disampingprestasi yang spektakular dalam produksi padi, dalam beberapa hal revolusi hijau juga memberi kontribusi dampakyang tidak menguntungkan terhadap ekosistem.Perkembangan pertanian di Bali, khususnya sawah sangat terkaitdengan sistem subak. Subak adalah pengaturan air irigasi tradisional di Bali yang telah dilaksanakan sejak berabadabadyang lalu. Sehubungan dengan masalah di atas, penelitian ini telah dilaksanakan di Daerah Aliran Sungai(DAS) Yeh Sungi di Kabupaten Tabanan, daerah di bagian barat Bali. Daerah penelitian meliputi delapan subakyaitu: Subak Apit Yeh and Subak Uma Poh di daerah hulu tempat tangkapan air; Subak Padangakitan, Jaka, Sungi I,Bena, dan Subak Tangkub di daerah tengah; dan Subak Gde Gadon I di daerah hilir. Penelitian ini dilakukan selama12 bulan, mulai dari bulan April 2001 hingga Maret 2002. Tujuan penelitian adalah: (1) meneliti tingkat pengayaanhara nitrogen di air irigasi yang berkaitan dengan aplikasi intensif pupuk anorganik di berbagai sistem pertaniandalam sistem subak di Bali; (2) meneliti kualitas lingkungan air, berkaitan dengan tingkat pengayaan hara nitrogendi dalam air irigasi. Hasil penelitian menunjukkan bahwa pengayaan hara pada air irigasi berkaitan dengan sistempertanian pada sistem subak. Tingkat pengayaan hara di daerah hulu lebih tinggi daripada di daerah tengah dan hiliruntuk N-NO3-; untuk memelihara kelangsungan ekosistem Subak, maka aplikasi pupuk N harus mempertimbangkankandungan hara tersebut dalam air irigasinya. Pelaksanaan pertanian telah menyebabkan pengayaan hara nitrogenyang berlebihan di daerah irigasi, khususnya di daerah tengah maupun hilir yang masing-masing didominasi olehpola pertanian padi-padi-padi dan padi-padi-palawija. Untuk memelihara kelangsungan ekosistem subak, makaaplikasi pupuk nitrogen harus mempertimbangkan kandungan hara di air irigasi.Kata kunci: sistem pertanian padi, pengayaan air irigasi, ekosistem subak. The implementation of agricultural intensification program through the green revolution concept has madethe increasing rice production dramatically and in 1984 Indonesia achieved ice self-sufficiency. Uniquely, before1984 Indonesia was known as the biggest rice importing country in the world. However, beside of spectacularachievement in rice production, green revolution to some cases also contributes less favorable impact to theecosystem. The agricultural development in Bali, particularly rice field is closely related to the subak system. Subakis a traditional model of irrigation water treatment in Bali practiced since centuries ago. The related to abovementionedissues, this research has been conducted at Yeh Sungi watershed in Tabanan District, western part ofBali. The research site includes eight subaks: Subak Apit Yeh and Subak Uma Poh at upstream area of catchmentsarea; Subak Padangakitan, Jaka, Sungi I, Bena, and Subak Tangkub at the middle area; and Subak Gde Gadon I atdownstream area. This research was carried out for 12 months between April 2001 and March 2002. The objectionof this research were: (1) to investigate the water enrichment level of N nutrients in the irrigation water related to theintensive application of inorganic fertilizers at various farming systems in subak system in Bali; (2) to investigatethe water environment quality, related to the water enrichment level of N nutrient in the irrigation water. Research96Jurnal Pengkajian dan Pengembangan Teknologi Pertanian Vol. 6, No. 2, Juli 2003 : 95-106results showed that nutrient enrichment on irrigation water related to farming system on subak ecosystem. The levelof nutrient enrichment at upstream (hulu) area is higher than the middle (tengah) and downstream (hilir) areas for N-NO3-.To maintain the sustainability of subak ecosystem, therefore the application of N fertilizer should considerthose nutrients content in irrigation water. The agricultural practice has caused excessive enrichment of N nutrientsin irrigated area, especially at the middle as well as downstream areas dominated by rice-rice-rice and rice-ricepalawija(second crop) cropping patterns

Pilot Study of a Web-Delivered Multicomponent Intervention for Rural Teens with Poorly Controlled Type 1 Diabetes

Objective. The purpose of this study was to examine the feasibility and effectiveness of a web-delivered multicomponent behavioral and family-based intervention targeting self-regulation and self-monitoring of blood glucose levels (SMBG) and glycemic control (HbA1c) in teens with type 1 diabetes (T1DM) living in rural US. Methods. 15 teens with poorly controlled T1DM participated in a 25-week web-delivered intervention with two phases, active treatment (weekly treatment sessions and working memory training program) and maintenance treatment (fading of treatment sessions). Results. Almost all (13 of 15) participants completed at least 14 of 15 treatment sessions and at least 20 of 25 working memory training sessions. SMBG was increased significantly at end of active and maintenance treatment, and HbA1c was decreased at end of active treatment (’s ≤ 0.05). Executive functioning improved at end of maintenance treatment: performance on working memory and inhibitory control tasks significantly improved (’s ≤ 0.02) and parents reported fewer problems with executive functioning (). Improvement in inhibitory control was correlated with increases in SMBG and decreases in HbA1c. Conclusions. An innovative web-delivered and multicomponent intervention was feasible for teens with poorly controlled T1DM and their families living in rural US and associated with significant improvements in SMBG and HbA1c

Probability of detection of defects in coatings with electronic shearography

The goal of this research was to utilize statistical methods to evaluate the probability of detection (POD) of defects in coatings using electronic shearography. The coating system utilized in the POD studies was to be the paint system currently utilized on the external casings of the NASA space transportation system reusable solid rocket motor boosters. The population of samples was to be large enough to determine the minimum defect size for 90-percent POD of 95-percent confidence POD on these coatings. Also, the best methods to excite coatings on aerospace components to induce deformations for measurement by electronic shearography were to be determined

A 32-GHz solid-state power amplifier for deep space communications

A 1.5-W solid-state power amplifier (SSPA) has been demonstrated as part of an effort to develop and evaluate state-of-the-art transmitter and receiver components at 32 and 35 GHz for future deep space missions. Output power and efficiency measurements for a monolithic millimeter-wave integrated circuit (MMIC)-based SSPA are reported. Technical design details for the various modules and a thermal analysis are discussed, as well as future plans