A RANS modelling approach for predicting powering performance of ships in waves

In this paper, a modelling technique for simulating self-propelled ships in waves is presented. The flow is modelled using a RANS solver coupled with an actuator disk model for the propeller. The motion of the ship is taken into consideration in the definition of the actuator disk region as well as the advance ratio of the propeller. The RPM of the propeller is controlled using a PID-controller with constraints added on the maximum permissible RPM increase rate. Results are presented for a freely surging model in regular waves with different constraints put on the PID-controller. The described method shows promising results and allows for the studying of several factors relating to selfpropulsion. However, more validation data is needed to judge the accuracy of the mode

Land Grant Application- Hudson, Stephen (Marlborough)

Land grant application submitted to the Maine Land Office on behalf of Stephen Hudson for service in the Revolutionary War, by their widow Louisa.https://digitalmaine.com/revolutionary_war_mass/1194/thumbnail.jp

SYNTHESIS, CHARACTERIZATION, AND APPLICATION OF Ag NANOSTRUCTURES

Noble metal nanoparticles (NPs) have been used for many centuries; however their properties were not truly scrutinized until Michael Farady\u27s investigations in the 1850\u27s. Advances in the field of nanotechnology over the last three decades have enabled insights into the properties of materials as their dimensions are reduced to the nanoscale. The repercussions of these insights are seen in many modern applications. In this dissertation, properties of novel nanostructures based on Ag NPs are presented and discussed. The exceptional optical properties of Ag NPs stem from the collective oscillations of the conduction electrons known as plasmon resonances. The excitation of plasmon resonances leads to the strongest known interaction of light with matter as compared to any known organic or inorganic chromophore. A novel type of nanostructure, composed of Ag NPs capped with various materials and termed asymmetric hybrid nanoparticles (AHNs) was proposed and implemented. The concept of AHNs allows the addition of new properties to nanoparticles. Metals and dielectric materials were used as caps, imparting strong effects on the plasmon resonances of the AHNs. Multilayer AHNs were fabricated to render magnetic properties to Ag NPs. The AHN concept led to the development of a novel type of optical labels. The labels are based on the surface enhanced Raman scattering (SERS) phenomenon from organic molecules sandwiched between Ag core and Ag cap. The observed strong SERS is well suited for multiplexed assays with optical detection. The structures were also used for fundamental SERS investigations. An alternative enhancement mechanism termed plasmon-induced electronic coupling was proposed from the results. Capitalizing on their large cross-section for the interaction with light, Ag NPs were also investigated as optical labels based on light scattering. Ag NPs were encapsulated in silica shells, modified with amine functionalities, followed by conjugation with neutravidin molecules. Neutravidin offers a scaffold for attaching biotinylated biomolecules including antibodies. Silica shells provided nearly complete protection of Ag core in saline solutions often used in bioanalytical applications. The ongoing work focused on the application of these labels to flow cytometry

Structure and Strength: Anisotropic Polyvinyl Alcohol Hydrogels and Spider Mite Silk Fibres

Polyvinyl alcohol (PVA) is a hydrophilic, biocompatible polymer which can be made into physically cross-linked hydrogels by freezing and thawing PVA solution. These hydrogels can be made with anisotropic mechanical properties closely matching those of porcine aorta, making them a promising material for producing artificial heart valves and heart valve stents. Small- and ultra small-angle neutron scattering has been used to study the structure of isotropic and anisotropic PVA hydrogels at length-scales of 2 nm to 10 μm. By supplementing the neutron data with data from atomic force microscopy, a large range of length-scales have been probed, within which structural changes responsible for bulk anisotropy occur. The gel is modelled as interconnected PVA blobs of size 20 to 50 nm arranged in fractal aggregates extending to micrometers or tens of micrometers. Bulk mechanical anisotropy appears to be due to the alignment of blobs and connections between blobs. To further understand the connection between structure and bulk mechanical properties, the uniaxial extension behaviour of isotropic PVA hydrogels was modelled using the 3-chain and 8-chain models, and anisotropic versions of the models were developed for modelling the behaviour of anisotropic PVA hydrogels. The mechanical models are compatible with the structural model described above. The models show that the most highly extended strands dominate the entropy and that there are more dominant strands aligned in the direction for which the gel is strongest than in the other directions. Nanostructures can be used to reinforce materials, such as PVA hydrogels, providing a new method to alter the properties of materials. The spider mite genome was recently sequenced, possibly allowing for spider mite silks with bioengineered properties and new polymer-silk nanocomposite materials. Despite this progress, little is known about the properties of natural spider mite silks. The fibres have diameters of tens of nanometres in comparison to typical spider silk fibres with diameters of several microns. 3-point bending tests were performed with an atomic force microscope to determine the mechanical properties of single spider mite fibres and a new model which accounts for bending, stretching, and an initial tensile stress was developed. Adult and larval fibres have Young’s moduli of 24 ± 3 GPa and 15 ± 3 GPa, respectively. Both adult and larval fibres have an estimated ultimate strength of 200–300 MPa and a toughness of order 9 MJ/m3

The Evolution of American Foreign Policy in Southeast Asia

American interests in Southeast Asia have received ample scholarly attention in the wake of the Vietnam War. Much of this material seeks to understand how policies in the first post-war years led to American military involvement in Vietnam. A sizable body of work is also devoted to U.S. policy in Indonesia in its first years of independence. But very few of these studies trace American interests in the region before 1940. Previous concerns for Southeast Asia are usually summed up in a few sentences that dismiss them as minor commercial interests of private companies. However, the development of American policy in Southeast Asia was not as sudden as these studies suggest. Since the late nineteenth century, the United States had become increasingly concerned with Southeast Asia. The process was a gradual one, but in no way did America\u27s interest in the region start fresh in 1945. Several large scale continuities in American policy in Southeast Asia during the first half of the twentieth century can be observed. First among these was a gradual and ongoing expansion of United States interests in the region. American involvement through the mid-nineteenth century was limited principally to trade in spices and a few other non-essential commodities. American exports to Southeast Asia were relatively unimportant. Then, in the late nineteenth century, American trade with Southeast Asia began to expand. Southeast Asia took on a new significance as a market for American manufactures. By the 1920\u27s, however, interest in Southeast Asia as a buyer of American goods was preempted by concern for the region as a supplier of vital raw materials. The oil and rubber resources of the Netherlands East Indies were of special concern to the United States. Within ten years, however, military and security concerns gradually supplanted these economic interests. For the first time, events in Southeast Asia became an important strategic issue for the United States. After World War II, American policy entered a new era. While economic and security concerns continued no factor into American policy decisions in Southeast Asia after 1945, they were subordinated to larger ideological questions like the future of the European colonial empires and the spread of communism

Cosmological parameters from the comparison of peculiar velocities with predictions from the 2M++ density field

Peculiar velocity measurements are the only tool available in the low-redshift Universe for mapping the large-scale distribution of matter and can thus be used to constrain cosmology. Using redshifts from the 2M++ redshift compilation, we reconstruct the density of galaxies within 200 Mpc/h, allowing for the first time good sampling of important superclusters such as the Shapley Concentration. We compare the predicted peculiar velocities from 2M++ to Tully-Fisher and SNe peculiar velocities. We find a value of $\beta^* \equiv \Omega_{\rm{m}}^{0.55}/b^* = 0.431 \pm 0.021$, suggesting $\Omega_{\rm{m}}^{0.55}\sigma_{\rm{8,lin}} = 0.401 \pm 0.024$, in good agreement with other probes. The predicted peculiar velocity of the Local Group arising from the 2M++ volume alone is $540 \pm 40$ km/s, towards $l = 268 \pm 4, b= 38 \pm 6$, only $10^\circ$ out of alignment with the Cosmic Microwave Background dipole. To account for velocity contributions arising from sources outside the 2M++ volume, we fit simultaneously for $\beta^*$ and an external bulk flow in our analysis. We find that an external bulk flow is preferred at the 5.1$\sigma$ level, and the best fit has a velocity of $159\pm23$ km/s towards $l=304 \pm 11, b = 6 \pm 13$. Finally, the predicted bulk flow of a 50 Mpc/h Gaussian-weighted volume centred on the Local Group is $230 \pm 30$ km/s, in the direction $l=293\pm 8, b = 14 \pm 10$, in agreement with predictions from $\Lambda$CDM.Comment: 17 pages. MNRAS, in press. Density and peculiar velocity grids available at http://cosmicflows.uwaterloo.ca or http://cosmicflows.iap.f

Efforts Towards the Total Synthesis of Labelled CCL2 Proteins and Dipeptide Chemotaxis Inhibitors

Chemokines such as CCL2 are small proteins with molecular weights between 8-10 kDa. They promote chemotaxis and play a vital role in the recruitment of leukocytes to the site of inflammation. Given their key biological functions, understanding their mechanism of action and inhibiting their action has therapeutic potential in a range of diseases. Selective inhibitors of CCL2 induced chemotaxis based on the diketopiperazine (DKP) natural product, cyclo(13,15-dichloro-L-Pro-L-Tyr) were recently reported by the Cobb group. In order to develop this work further and to produce an expanded library, we optimised an on-resin DKP synthesis. In collaboration with researchers at Newcastle Medical School, chemotaxis assays were performed in an attempted to define the structural features (required for inhibition) of the DKPs. To faciliate the aforementioned work, facile synthetic routes to a number of novel heteraromatic and proline derivatives were developed. The posttranslational nitration of CCL2 is used as a mechanism to a modulate CCL2. However, in all previous studies nitrated CCL2 was utilised as a heterogeneous mix of protein. Having access to single site nitrated CCL2 will enable the mechanism of abrogration to be pinpointed to a specific residue. Therefore, the total chemical synthesis of both native CCL2 and site-specifically nitrated CCL2 via solid phase peptide synthesis (SPPS) was undertaken. The work focused on the potential application of microwave assisted SPPS as a means to rapidly access the target proteins

The Evolution of American Foreign Policy in Southeast Asia

American interests in Southeast Asia have received ample scholarly attention in the wake of the Vietnam War. Much of this material seeks to understand how policies in the first post-war years led to American military involvement in Vietnam. A sizable body of work is also devoted to U.S. policy in Indonesia in its first years of independence. But very few of these studies trace American interests in the region before 1940. Previous concerns for Southeast Asia are usually summed up in a few sentences that dismiss them as minor commercial interests of private companies. However, the development of American policy in Southeast Asia was not as sudden as these studies suggest. Since the late nineteenth century, the United States had become increasingly concerned with Southeast Asia. The process was a gradual one, but in no way did America\u27s interest in the region start fresh in 1945. Several large scale continuities in American policy in Southeast Asia during the first half of the twentieth century can be observed. First among these was a gradual and ongoing expansion of United States interests in the region. American involvement through the mid-nineteenth century was limited principally to trade in spices and a few other non-essential commodities. American exports to Southeast Asia were relatively unimportant. Then, in the late nineteenth century, American trade with Southeast Asia began to expand. Southeast Asia took on a new significance as a market for American manufactures. By the 1920\u27s, however, interest in Southeast Asia as a buyer of American goods was preempted by concern for the region as a supplier of vital raw materials. The oil and rubber resources of the Netherlands East Indies were of special concern to the United States. Within ten years, however, military and security concerns gradually supplanted these economic interests. For the first time, events in Southeast Asia became an important strategic issue for the United States. After World War II, American policy entered a new era. While economic and security concerns continued no factor into American policy decisions in Southeast Asia after 1945, they were subordinated to larger ideological questions like the future of the European colonial empires and the spread of communism