The Battle for China: The U.S. Navy, Marine Corps, and the Cold War in Asia, 1944-1949

The U.S. Navy and Marine Corps’ long history in China before World War II was a prelude to a little known struggle. In the aftermath of Japan’s surrender in August 1945, the U.S. Navy and Marine Corps embarked on a complex series of operations to rescue Allied prisoners of war, stabilize North China, and repatriate millions of Japanese soldiers and civilians. The more than 50,000 Marines and over a hundred vessels of the U.S. Seventh Fleet committed to China repatriated over three million Japanese and transported 200,000 Chinese Nationalist soldiers to North China. While doing so, they became enmeshed in the complex military and political landscape that was the Chinese Civil War. Over the next four years, U.S. Navy leaders, intent on reestablishing the longstanding presence and strategic role of the Navy in China, opposed efforts by the U.S. Army and State Department to withdraw all U.S. forces from the vast country. From 1944 to 1949, a core group of civilian and naval leaders worked steadily to shore up Nationalist China in the face of a growing and intractable Chinese Communist Party. Unwavering in their view that China was a strategic priority and that Asia stood at the forefront of the nascent Cold War, these leaders repeatedly clashed with General George C. Marshall and President Harry Truman. Exacerbated by an atmosphere of distrust and intra-service rivalry, this conflict over China revealed stark divisions between the U.S. Navy and its sister services, and illuminated inherent differences as the United States struggled to come to terms with both the new Cold War and the reality of nuclear warfare

Upriver to Hue and Dong Ha: The U.S. Navy's War in I Corps, Vietnam 1967-1970

The United States Navy's involvement in the Vietnam War, especially its role in the region's inland waterways, has long been an overshadowed aspect of the conflict. Most histories ignore or minimize the Navy's contribution, especially its river patrol or 'brown water' role. Through archival and library research as well as interviews with U.S Navy Vietnam War veterans this thesis demonstrates the vital role played by the brown water navy in the northern provinces of South Vietnam. A key but understudied component of this effort was Task Force Clearwater, an improvised brown water fleet that-along with the maritime logistics campaign that it supported-would prove essential for the successful defense of South Vietnam's northernmost provinces and demonstrate the vital importance of inland naval power. Task Force Clearwater and its supported maritime logistics effort form a little explored component of the U.S. Navy's role in South Vietnam. A brown water task force that proved essential for the successful defense of the northern provinces of I Corps, Clearwater repeatedly demonstrated the vital importance of inland naval power and the critical need for reliable and protected routes of supply. The task force revealed many lessons that had been long understood, forgotten, and then relearned by the U.S. Navy, among them that control of inland waterways was perhaps the most advantageous form of logistical supply in war. Created in part to satisfy the ancient maxim of "keeping the supply lines open", the task force's role broadened with time. In the course of its existence the men and boats of Clearwater would provide not only the tools of war in I Corps but also provide key lessons for the future

A novel soft cardiac assist device based on a dielectric elastomer augmented aorta: an in vivo study

Although heart transplant is the preferred solution for patients suffering from heart failures, cardiac assist devices remain key substitute therapies. Among them, aortic augmentation using dielectric elastomer actuators (DEAs) might be an alternative technological application for the future. The electrically driven actuator does not require bulky pneumatic elements (such as conventional intra-aortic balloon pumps) and conforms tightly to the aorta thanks to the manufacturing method presented here. In this study, the proposed DEA-based device replaces a section of the aorta and acts as a counterpulsation device. The feasibility and validation of in vivo implantation of the device into the descending aorta in a porcine model, and the level of support provided to the heart are investigated. Additionally, the influence of the activation profile and delay compared to the start of systole is studied. We demonstrate that an activation of the DEA just before the start of systole (30 ms at 100 bpm) and deactivation just after the start of diastole (0-30 ms) leads to an optimal assistance of the heart with a maximum energy provided by the DEA. The end-diastolic and left ventricular pressures were lowered by up to 5% and 1%, respectively, compared to baseline. The early diastolic pressure was augmented in average by up to 2%

The unpredictable nature of internal tides on continental shelves

Author Posting. © American Meteorological Society, 2012. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Physical Oceanography 42 (2012): 1981–2000, doi:10.1175/JPO-D-12-028.1.Packets of nonlinear internal waves (NLIWs) in a small area of the Mid-Atlantic Bight were 10 times more energetic during a local neap tide than during the preceding spring tide. This counterintuitive result cannot be explained if the waves are generated near the shelf break by the local barotropic tide since changes in shelfbreak stratification explain only a small fraction of the variability in barotropic to baroclinic conversion. Instead, this study suggests that the occurrence of strong NLIWs was caused by the shoaling of distantly generated internal tides with amplitudes that are uncorrelated with the local spring-neap cycle. An extensive set of moored observations show that NLIWs are correlated with the internal tide but uncorrelated with barotropic tide. Using harmonic analysis of a 40-day record, this study associates steady-phase motions at the shelf break with waves generated by the local barotropic tide and variable-phase motions with the shoaling of distantly generated internal tides. The dual sources of internal tide energy (local or remote) mean that shelf internal tides and NLIWs will be predictable with a local model only if the locally generated internal tides are significantly stronger than shoaling internal tides. Since the depth-integrated internal tide energy in the open ocean can greatly exceed that on the shelf, it is likely that shoaling internal tides control the energetics on shelves that are directly exposed to the open ocean.This research was supported by ONR Grants N00014-05-1-0271, N00014-08-1-0991, N00014-04- 1-0146, and N00014-11-1-0194.2013-05-0

Dielectric elastomer actuator

A dielectric elastomer actuator (1) comprising: a plurality of polymer layer (2);a plurality of stretchable electrode layers (3), each polymer layer (2) being sandwiched between two electrode layers (3) so as to control the electric field within the polymer layer;; at least one stretchable charge distribution layer (4), each charge distribution layer being adjacent to one stretchable electrode layer (3) and/or to one polymer layer (2)

Towards the material limit and field concentration smoothing in multilayer dielectric elastomer actuators

Performance of dielectric elastomer actuators is closely related to its breakdown field. On the other hand, to enhance the available energy, multilayer configuration is needed to increase the amount of active material. However, multilayer configuration suffers from a drastic reduction of the affordable electric field related to field concentration at edges. After showing how the conductivity of the air helps to smooth the field in a single layer configuration, this effect has been mimicked in the multilayer by adding carbon particles in a thin silicone layer around the electrode. A change in the electric properties around the edges reduces the local concentration of the electric field and allows a significant improvement of the voltage breakdown in the multilayer structure. Therefore, the performance of multilayer has been considerably enhanced

Feasibility of a Dielectric Elastomer Augmented Aorta

Although heart transplantation is a gold standard for severe heart failure, there is a need for alternative effective therapies. A dielectric‐elastomer aorta is used to augment the physiological role of the aorta in the human circulatory system. To this end, the authors developed a tubular dielectric elastomer actuator (DEA) able to assist the heart by easing the deformation of the aorta in the systole and by increasing its recoil force in the diastole. In vitro experiments using a pulsatile flow‐loop, replicating human physiological flow and pressure conditions, show a reduction of 5.5% (47 mJ per cycle) of the heart energy with this device. Here, the controlled stiffness of the DEA graft, which is usually difficult to exploit for actuators, is perfectly matching the assistance principle. At the same time, the physiological aortic pressure is exploited to offer a prestretch to the DEA which otherwise would require an additional bulky pre‐stretching system to reach high performances

Energy Analysis of a Cardiac Assist Device based on Dielectric Elastomer Actuator through an Equivalent Electrical Circuit

Lumped parameter model and mock circulation loop are two tools commonly used in biomedical research to simulate cardiac system in order to study different assist devices. In this paper, a lumped parameter model is proposed to simulate a circulation loop. This model is further validated with measurement directly into a custom made mock-up. The objective of the model is to be able to study the influence of the geometrical parameters of a dielectric elastomer actuator based left ventricle assist device and its electrical activation in order to optimise the energy provided. Once the optimum actuator is designed with the equivalent model, the actuator is finally tested on the mock-up. It has been demonstrated thanks to the model, that the proposed actuator with the adequate activation, allows to release the energy of the heart of 4 to 5%

A novel soft cardiac assist device based on a dielectric elastomer augmented aorta: An in vivo study

Abstract Although heart transplant is the preferred solution for patients suffering from heart failures, cardiac assist devices remain key substitute therapies. Among them, aortic augmentation using dielectric elastomer actuators (DEAs) might be an alternative technological application for the future. The electrically driven actuator does not require bulky pneumatic elements (such as conventional intra‐aortic balloon pumps) and conforms tightly to the aorta thanks to the manufacturing method presented here. In this study, the proposed DEA‐based device replaces a section of the aorta and acts as a counterpulsation device. The feasibility and validation of in vivo implantation of the device into the descending aorta in a porcine model, and the level of support provided to the heart are investigated. Additionally, the influence of the activation profile and delay compared to the start of systole is studied. We demonstrate that an activation of the DEA just before the start of systole (30 ms at 100 bpm) and deactivation just after the start of diastole (0–30 ms) leads to an optimal assistance of the heart with a maximum energy provided by the DEA. The end‐diastolic and left ventricular pressures were lowered by up to 5% and 1%, respectively, compared to baseline. The early diastolic pressure was augmented in average by up to 2%