Endpoint resolvent estimates for compact Riemannian manifolds

We prove $L^p\to L^{p'}$ bounds for the resolvent of the Laplace-Beltrami operator on a compact Riemannian manifold of dimension $n$ in the endpoint case $p=2(n+1)/(n+3)$. It has the same behavior with respect to the spectral parameter $z$ as its Euclidean analogue, due to Kenig-Ruiz-Sogge, provided a parabolic neighborhood of the positive half-line is removed. This is region is optimal, for instance, in the case of a sphere.Comment: 14 page

Pergerakan Jalan Stabil Robot Hexapod di Atas Medan yang Tidak Rata

Beberapa tahun terakhir, bencana alam seperti gunung meletus, tanah longsor, dan banjir sering terjadi dan menimbulkan korban jiwa. Upaya penyelamatan korban jiwa dalam bencana tersebut menjadi sulit dilakukan, karena daerah bencana sangat sulit dicapai oleh tim penyelamat. Permukaan tanah daerah bencana yang tidak rata dan potensi bencana susulan menjadi salah satu kendala dalam penyelamatan korban oleh tim penyelamat. Proses penyelamatan korban biasa dilakukan oleh tim penyelamat dengan membawa mobil ambulans ke lokasi bencana dan tim penyelamat menyusuri daerah bencana untuk menemukan korban. Masalah yang akan muncul adalah tim penyelamat saat mencari korban membahayakan diri saat berada di daerah bencana yang masih berpotensi mengalami bencana susulan, mobil ambulans untuk mengangkut korban tidak bisa menuju lokasi korban karena permukaan tanah daerah bencana yang tidak rata. bila korban berada jauh dari lokasi mobil ambulans, tim penyelamat akan membutuhkan waktu untuk membawa korban menuju mobil ambulans. Sehubungan dengan ini diusulkan suatu rancangan pemecahan masalah dengan menggunakan teknologi robot. Robot digunakan untuk melewati daerah yang memiliki permukaan yang tidak rata berupa sebuah prototype robot hexapod yang menerapkan inverse kinematic dan algoritma gait, sehingga robot dapat melewati daerah yang memiliki permukaan tidak rata serta menjaga kestabilan badan robot saat berjalan. Robot hexapod dipilih karena memiliki tingkat kestabilan yang baik saat berjalan. Robot hexapod berhasil diuji dalam enam kondisi bidang berbeda dan sepenuhnya mampu menjaga kestabilan di setiap pengujian seperti ketika berdiri diam di permukaan yang bergerak, berjalan di permukaan miring, pemukaan rumput maupun berpasir dengan dengan persen kesalahan kurang dari 10

Electrical excitation of surface plasmons

We exploit a plasmon mediated two-step momentum downconversion scheme to convert low-energy tunneling electrons into propagating photons. Surface plasmon polaritons (SPPs) propagating along an extended gold nanowire are excited on one end by low-energy electron tunneling and are then converted to free-propagating photons at the other end. The separation of excitation and outcoupling proofs that tunneling electrons excite gap plasmons that subsequently couple to propagating plasmons. Our work shows that electron tunneling provides a non-optical, voltage-controlled and low-energy pathway for launching SPPs in nanostructures, such as plasmonic waveguide

Cosmological Solutions of Horava-Witten Theory

We discuss simple cosmological solutions of Horava-Witten theory describing the strongly coupled heterotic string. At energies below the grand-unified scale, the effective theory is five- not four-dimensional, where the additional coordinate parameterizes a S^1/Z_2 orbifold. Furthermore, it admits no homogeneous solutions. Rather, the vacuum state, appropriate for a reduction to four-dimensional supersymmetric models, is a BPS domain wall. Relevant cosmological solutions are those associated with this BPS state. In particular, such solutions must be inhomogeneous, depending on the orbifold coordinate as well as on time. We present two examples of this new type of cosmological solution, obtained by separation of variables rather that by exchange of time and radius coordinate applied to a brane solution, as in previous work. The first example represents the analog of a rolling radii solution with the radii specifying the geometry of the domain wall. This is generalized in the second example to include a nontrivial ``Ramond-Ramond'' scalar.Comment: 21 pages, Latex 2e with amsmath, minor addition

Incommensurate interactions and non-conventional spin-Peierls transition in TiOBr

Temperature-dependent x-ray diffraction of the low-dimensional spin 1/2 quantum magnet TiOBr shows that the phase transition at T_{c2} = 47.1 (4) K corresponds to the development of an incommensurate superstructure. Below T_{c1} = 26.8 \pm 0.3 K the incommensurate modulation locks in into a two-fold superstructure similar to the low-temperature spin-Peierls state of TiOCl. Frustration between intra- and interchain interations within the spin-Peierls scenario, and competition between two-dimensional magnetic order and one-dimensional spin-Peierls order are discussed as possible sources of the incommensurability.Comment: 5 pages including 3 figures and 1 tabl

Moving Five-Branes in Low-Energy Heterotic M-Theory

We construct cosmological solutions of four-dimensional effective heterotic M-theory with a moving five-brane and evolving dilaton and T modulus. It is shown that the five-brane generates a transition between two asymptotic rolling-radii solutions. Moreover, the five-brane motion always drives the solutions towards strong coupling asymptotically. We present an explicit example of a negative-time branch solution which ends in a brane collision accompanied by a small-instanton transition. The five-dimensional origin of some of our solutions is also discussed.Comment: 16 pages, Latex, 3 eps figure

Keragaan Eksisting Tanaman Aren (Arenga Pinnata Merr) Di Sumatera Utara (Peluang Dan Potensi Pengembangannya)

Sugar palm (Arenga pinnata, Merr) is the most important after the coconut because it is a versatile crop that has the potential to be developed. Sugar palm main products are produced from extracting male flower it can be made as sugar, drinks, acetic and alcohol. Other parts of the plant can be use for ingredient. Data from 2004 shows sugar palm plantation covers 5288.91 acres that are spread in 20 districts in North Sumatra. Utilization sugar palm excellent for especially extracting products can be used as feedstock for ethanol as the needs of the bioenergy development will need to be followed up. Opportunities and potential development in North Sumatra palm is huge in because ecosystems, climate and suitability of land in this area is very suitable for the sugar plant . Opportunities and potential development sugar palm in North Sumatra is very large in because ecosystems, climate and suitability of land in this area is very suitable for the sugar palm plant. Besides adaptable to various types of soils including degraded lands , reeds and for reforestation and forest conservation . Data in 2014 , there is the land area is temporarily not cultivated in North Sumatra tend to rise until 2013, covering an area of 296 032 ha . Another challenge than land development , are super - impose intesifikasi input technology is still minimal , improvement of production management , improved processing , marketi ng is still traditional , dissemination is still limited to a small proportion of farmers , and the difficulty of seeds . So, we need a shared commitment between the central government and local governments to create policies how the potential development of the sugar plant can be followed in the future. This paper reviews the prospects of development potential, especially palm acreage potential, opportunities and challenges as well as the availability of the technology in North Sumatra

Design and Testing of an Autonomous Ground Robot for Agricultural Applications

This senior project discusses the design and testing of an autonomous ground robot for agricultural applications such as strawberries. The vehicle will feature a robotic arm that will be programmed to perform various tasks, such as collecting soil and leaf samples of the crop or measuring soil moisture and salinity. Various components were chosen to be implemented on the vehicle due its power requirements and operating environment. Finite Element Analysis testing was done on the frame of the vehicle to ensure the adequacy of the design