Tooth Contact Shift in Loaded Spiral Bevel Gears

An analytical method is presented to predict the shifts of the contact ellipses of spiral bevel gear teeth under load. The contact ellipse shift is the motion of the tooth contact position from the ideal pitch point to its location under load. The shifts are due to the elastic motions of the gear and pinion supporting shafts and bearings. The calculations include the elastic deflections of the gear shafts and the deflections of the four shaft bearings. The method assumes that the surface curvature of each tooth is constant near the unloaded pitch point. Results from these calculations will help designers reduce transmission weight without seriously reducing transmission performance

Helicopter transmission research at NASA Lewis Research Center

A joint helicopter transmission research program between NASA Lewis Research Center and the U.S. Army Aviation Systems Command has existed since 1970. Program goals are to reduce weight and noise and to increase life and reliability. Reviewed are significant advances in technology for gears and transmissions and the experimental facilities at NASA Lewis for helicopter transmission testing are described. A description of each of the rigs is presented along with some significant results from the experiments

An investigation of the nature and reactivity of the carbonaceous species deposited on mordenite by reaction with methanol

An investigation of the nature of the carbonaceous species deposited upon mordenite by reaction with methanol has been undertaken. The nature of the species has been shown to be a strong function of both temperature and time on stream. Upon reaction at 300 degrees C a range of alkyl and aromatic species, consistent with the development of an active hydrocarbon pool, are evident and time on stream studies have shown that these are developed within 5 min. Upon reaction at 500 degrees C, a narrower range of hydrogen deficient aromatic species is evident. Thermal volatilisation analysis (TVA), not previously applied to the study of coked zeolites, is shown to be complementary to the more commonly applied C analysis, C-13 MAS NMR and TGA techniques

Transmission diagnostic research at NASA Lewis Research Center

The NASA Lewis Research Center and the U.S. Army Research Laboratory are involved in a joint research program to advance the technology of aerospace transmissions. Within the last six years, a transmission diagnostics research team was formed to address current and future technology barriers in transmission diagnostics. The diagnostics team conducted a survey to determine critical needs of the diagnostics community. Survey results indicated that experimental verification of gear and bearing fault detection methods and damage magnitude assessment were considered the two most critical research areas of a highly reliable health and usage monitoring system. A plan was implemented by the diagnostics team to address these key research areas, by in-house research and university grants. A variety of transmission fault detection methods were applied to experimentally obtained fatigue data. Failure modes of the fatigue tests include a variety of gear pitting failures, tooth wear, tooth fracture, and bearing spalling failures. Accomplishments to date include verification of several specific gear diagnostic methods, verification of a new pattern recognition method to determine failure, and development of a new method to model gear tooth damage. This paper presents the results of these accomplishments in transmission diagnostics research at NASA Lewis Research Center

PENGEMBANGAN BISKUIT MP-ASI DENGAN PENAMBAHAN PUREE LABU KUNING (Cucurbita moschata) DAN TEPUNG BERAS MERAH (Oryza nivara)

Makanan pendamping air susu ibu (MP-ASI) merupakan makanan pendamping dari air susu ibu yang disiapkan untuk membantu memenuhi kebutuhan gizi bayi. MP-ASI diberikan kepada bayi ketika air susu ibu sudah tidak cukup dalam memenuhi kebutuhan gizi anak. Pada bayi usia 12-24 bulan mulai diperkenalkan dengan jenis makanan padat seperti biskuit sebagai MP-ASI. Biskuit MP-ASI dapat dikembangkan melalui pemanfaatan bahan pangan lokal seperti labu kuning yang memiliki kandungan beta karoten dan tepung beras merah yang memiliki kandungan protein. Puree labu kuning merupakan bentuk produk olahan dari buah labu kuning dengan pemberian proses pengukusan. Tepung beras merah merupakan bentuk produk olahan dari beras merah. Penelitian ini bertujuan untuk mendapatkan biskuit MP-ASI yang mampu memberikan kandungan gizi terbaik seperti vitamin A dan protein, untuk mengetahui pengaruh penambahan puree labu kuning dan tepung beras merah pada biskuit MP-ASI, selain itu juga mengetahui tingkat kesukaan pada masing-masing formulasi biskuit. Pada penelitian ini menggunakan 4 formulasi biskuit MP-ASI, yaitu biskuit kontrol tanpa penambahan puree labu kuning dan tepung beras merah, biskuit formulasi 1 dengan penambahan 5% tepung beras merah dan 10% puree labu kuning, biskuit formulasi 2 dengan penambahan 7,5% tepung beras merah dan 7,5% puree labu kuning, serta biskuit formulasi 3 dengan penambahan 10% tepung beras merah dan 5% puree labu kuning. Analisa yang dilakukan dalam penelitian ini adalah analisa fisik, analisa kimiawi, dan analisa organoleptik. Pada analisa fisik warna yang terbaik dimiliki biskuit kontrol dan analisa tekstur terkeras dimiliki biskuit formulasi 3 dan formulasi terlunak dimiliki biskuit formulasi 1 dengan penambahan puree labu kuning terbanyak. Analisa kimiawi yang dilakukan menghasilkan biskuit formulasi 3 memiliki kadar abu tertinggi yaitu 1,63%, kadar protein tertinggi yaitu 6,16%. Kadar air tertinggi dimiliki biskuit formulasi 1 yaitu 4,80%, kadar lemak teringgi dimiliki biskuit kontrol sebesar 37,59%, dan kadar karbohidrat tertinggi dimiliki biskuit formulasi 2 yaitu sebesar 56,61%. Kadar beta karoten tertinggi dimiliki biskuit formulasi 1 yaitu sebesar 4,32 mg/100 gram produk. Hasil analisa organoleptik biskuit MP-ASI kontrol memiliki tingkat kesukaan overall tertinggi dengan rata-rata 2,88. Selain itu biskuit formulasi 1 merupakan formulasi yang agak disukai disukai panelis dengan rata-rata 2,65 dengan penambahan 10% puree labu kuning dan 5% tepung beras merah

Small-Size Resonant Photoacoustic Cell of Inclined Geometry for Gas Detection

A photoacoustic cell intended for laser detection of trace gases is represented. The cell is adapted so as to enhance the gas-detection performance and, simultaneously, to reduce the cell size. The cell design provides an efficient cancellation of the window background (a parasite response due to absorption of laser beam in the cell windows) and acoustic isolation from the environment for an acoustic resonance of the cell. The useful photoacoustic response from a detected gas, window background and noise are analyzed in demonstration experiments as functions of the modulation frequency for a prototype cell with the internal volume ~ 0.5 cm^3. The minimal detectable absorption for the prototype is estimated to be ~ 1.2 10^{-8} cm^{-1} W Hz^{-1/2}.Comment: 11 pages, 5 figure

Continuous wave optical parametric oscillator for quartz-enhanced photoacoustic trace gas sensing

A continuous wave optical parametric oscillator, generating up to 300 mW idler output in the 3–4 μm wavelength region, and pumped by a fiber-amplified DBR diode laser is used for trace gas detection by means of quartz-enhanced photoacoustic spectroscopy (QEPAS). Mode-hop-free tuning of the OPO output over 5.2 cm-1 and continuous spectral coverage exceeding 16.5 cm-1 were achieved via electronic pump source tuning alone. Online monitoring of the idler wavelength, with feedback to the DBR diode laser, provided an automated closed-loop control allowing arbitrary idler wavelength selection within the pump tuning range and locking of the idler wavelength with a stability of 1.7×10-3 cm-1 over at least 30 min.\ud \ud Using this approach, we locked the idler wavelength at an ethane absorption peak and obtained QEPAS data to verify the linear response of the QEPAS signal at different ethane concentrations (100 ppbv-20 ppmv) and different power levels. The detection limit for ethane was determined to be 13 ppbv (20 s averaging), corresponding to a normalized noise equivalent absorption coefficient of 4.4×10-7 cm-1  W/Hz1/2

Arguing with behavior influence: A model for web-based group decision support systems

In this work, we propose an argumentation-based dialogue model designed for Web-based Group Decision Support Systems, that considers the decision-makers' intentions. The intentions are modeled as behavior styles which allow agents to interact with each other as humans would in face-to-face meetings. In addition, we propose a set of arguments that can be used by the agents to perform and evaluate requests, while considering the agents' behavior style. The inclusion of decision-makers' intentions intends to create a more reliable and realistic process. Our model proved, in different contexts, that higher levels of consensus and satisfaction are achieved when using agents modeled with behavior styles compared to agents without any features to represent the decision-makers' intentions.- (undefined

Evaluations of Tactics for Automated Negotiations

[[abstract]]Automated negotiation under the infrastructure of e-commerce is becoming an important issue. However, although the communication protocols and frameworks of automated negotiation have been extensively investigated, the corresponding tactics and strategies are still underdeveloped and need to be evaluated further. Based on the negotiation model proposed by Faratin et al., this paper examines the performance of automated negotiation tactics and intends to provide concise suggestions for the users of automated negotiation. First, theoretical analysis is used to evaluate the behavior-dependent tactics. Constructive conclusions are obtained when single-issue negotiations are considered. Next, a new framework for applying single-issue tactics to multi-issue negotiation is proposed. Based on this framework, theoretical analysis is then extended to multi-issue cases. Finally, different from the previous work, exhaustive simulations based on two-issue negotiations are performed to evaluate the effectiveness of behavior-dependent and time-dependent tactics. The experimental results provide several important insights into negotiation tactics.[[booktype]]紙本[[booktype]]電子