Numerical Investigation of a Shielded Chevron Nozzle

Reynolds-Averaged Navier-Stokes simulations have been performed on a three-stream invertedvelocity profile nozzle with and without various configurations of chevrons attached.The nozzle was mounted on a planform to imitate an engine mounted above a wing, shieldingground observers from engine noise. Several chevron designs intended to aggressively mix thejet and move noise sources upstream for shielding were examined to investigate their effects onnoise and thrust. Numerical results for the baseline nozzle and one chevron configuration werecompared with far-field noise and particle image velocimetry data obtained in NASA GlennResearch Centers Aero-Acoustic Propulsion Laboratory. A configuration in which chevronsalternate penetration into the primary stream and tertiary fan stream was explored using theModern Design of Experiments approach. Short, high-penetration chevrons demonstrated asignificant noise reduction for a relatively small thrust penalty

Broadside Dual-channel Orthogonal-Polarization Radiation using a Double-Asymmetric Periodic Leaky-Wave Antenna

The paper demonstrates that double unit-cell asymmetry in periodic leaky-wave antennas (P-LWAs), i.e. asymmetry with respect to both the longitudinal and transversal axes of the structure -- or longitudinal asymmetry (LA) and transversal asymmetry (TA) -- allows for the simultaneous broadside radiation of two orthogonal modes excited at the two ports of the antenna. This means that the antenna may simultaneously support two orthogonal channels, which represents an interesting polarization diversity characteristics for wireless communications. The double asymmetric (DA) unit cell combines a circularly polarized LA unit cell and a coupled mode TA unit cell, where the former provides equal radiation in the series and shunt modes while the latter separates these two modes in terms of their excitation ports. It is also shown that the degree of TA in the DA unit cell controls the cross-polarization discrimination level. The DA P-LWA concept is illustrated by two examples, a series-fed line-connected patch (SF-LCP) P-LWA and a series-fed capacitively-coupled patch (SF-CCP) P-LWA, via full-wave simulation and also experiment for the SF-LCP P-LWA case

THE EFFECT OF THE NUMBER OF CHOICE SETS ON RESPONSES IN A STATED CHOICE SURVEY

An important issue for the stated choice method is the effect of the number of choice sets on responses. Based on a study of this issue in a mailed survey, results indicate that the number of choice sets does not affect survey response rates or item non-response rates.Research Methods/ Statistical Methods,

Improving Stability of Tumor Suppressor Protein, p53

Denman Research Competition, 3rd Place in Biological SciencesTumor suppressor protein p53 is a critical transcription factor involved in an intricate signaling network responsible for cell fate. In over half of all human cancers, p53 is found inactivated from missense mutations and is only marginally stable at physiological conditions. Therefore, immense research has become focused on stabilizing p53. This study intends to test two p53 mutants for relative stability based on prior computational predictions that involved a previously engineered ‘super-stable’ mutant and a simulated loop deletion mutant, which is predicted to be more stable. Based on protein purification observations for both mutants, significant differences in structural features seem apparent, even before detailed biophysical characterization. The significance of this study is twofold. First, this work may initiate similar studies to ultimately impact the reliability on computational predictions for molecular stability, possibly leading to a widespread use for high throughput analysis of biomolecules. Finally, we may be able to develop insight for additional stabilizing forces of p53 that may enhance therapeutic drug design for many cancer types.Arts and Sciences College Research ScholarshipSummer Undergraduate Research Program (SURP) Award, OSU Department of BiochemistryDean's Undergraduate Research Fund, OSU College of Biological SciencesLouis G. Bernstein Memorial Scholarshi

Polynomial Chaos Expansion method as a tool to evaluate and quantify field homogeneities of a novel waveguide RF Wien Filter

For the measurement of the electric dipole moment of protons and deuterons, a novel waveguide RF Wien filter has been designed and will soon be integrated at the COoler SYnchrotron at J\"ulich. The device operates at the harmonic frequencies of the spin motion. It is based on a waveguide structure that is capable of fulfilling the Wien filter condition ($\vec{E} \perp \vec{B}$) \textit{by design}. The full-wave calculations demonstrated that the waveguide RF Wien filter is able to generate high-quality RF electric and magnetic fields. In reality, mechanical tolerances and misalignments decrease the simulated field quality, and it is therefore important to consider them in the simulations. In particular, for the electric dipole moment measurement, it is important to quantify the field errors systematically. Since Monte-Carlo simulations are computationally very expensive, we discuss here an efficient surrogate modeling scheme based on the Polynomial Chaos Expansion method to compute the field quality in the presence of tolerances and misalignments and subsequently to perform the sensitivity analysis at zero additional computational cost.Comment: 12 pages, 19 figure

Широкополосный генератор синусоидального сигнала для спектроскопии электрохимического импеданса

Показана возможность реализации широкополосного генератора синусоидального сигнала посредством совмещения цифрового вычислительного синтезатора и цифро-аналогового преобразователя

Перспективность применения новых технических решений по усовершенствованию подготовки машинных классов на ЦОФ "Червоноградская"

Виконано аналіз існуючої технології і апаратурного оформлення вузла мокрого підготовчого грохотіння на ЦЗФ "Червоноградська". Запропоновані нові технічні рішення по удосконаленню технології підготовки машинних класів: прив’язка агрегатно установлених нерухомого гідрогрохота ГГН-4,2 і рухомого грохота ГІСТ-72, а також застосування комбінованого гідровібраційного метода розділення частинок на рухомій поверхні. Приведено опис і переваги нових технічних рішень по удосконаленню технології підготовки машинних класів на ЦЗФ "Червоноградська".Выполнен анализ существующей технологии и аппаратурного оформления узла мокрого подготовительного грохочения на ЦОФ "Червоноградская". Предложены новые технические решения по совершенствованию технологии подготовки машинных классов: привязка агрегатно установленных неподвижного гидрогрохота ГГН-4,2 и подвижного грохота ГИСТ-72, а также применение комбинированного гидровибрационного метода разделения частиц на подвижной поверхности. Приведено описание и преимущества новых технических решений по совершенствованию технологии подготовки машинных классов на ЦОФ "Червоноградская"

Numerical Investigation of a Shielded Chevron Nozzle

Reynolds-Averaged Navier-Stokes simulations have been performed on a three-stream inverted velocity profile nozzle with and without various configurations of chevrons attached. The nozzle was mounted on a planform to imitate an engine mounted above a wing, shielding ground observers from engine noise. Several chevron designs intended to aggressively mix the jet and move noise sources upstream for shielding were examined to investigate there effects on noise and thrust. Numerical results for the baseline nozzle and one chevron configuration were compared with far-field noise and particle image velocimetry data obtained in NASA Glenn Research Center's Aero-Acoustic Propulsion Laboratory. A configuration in which chevrons alternate penetration into the primary stream and tertiary fan stream was explored using the Modern Design of Experiments approach. Short, high-penetration chevrons demonstrated a significant noise reduction for a relatively small thrust penalty

Electromagnetic Simulation and Design of a Novel Waveguide RF Wien Filter for Electric Dipole Moment Measurements of Protons and Deuterons

The conventional Wien filter is a device with orthogonal static magnetic and electric fields, often used for velocity separation of charged particles. Here we describe the electromagnetic design calculations for a novel waveguide RF Wien filter that will be employed to solely manipulate the spins of protons or deuterons at frequencies of about 0.1 to 2 MHz at the COoler SYnchrotron COSY at J\"ulich. The device will be used in a future experiment that aims at measuring the proton and deuteron electric dipole moments, which are expected to be very small. Their determination, however, would have a huge impact on our understanding of the universe.Comment: 10 pages, 10 figures, 4 table