Linking Light Scalar Modes with A Small Positive Cosmological Constant in String Theory

Based on the studies in Type IIB string theory phenomenology, we conjecture that a good fraction of the meta-stable de Sitter vacua in the cosmic stringy landscape tend to have a very small cosmological constant $\Lambda$ when compared to either the string scale $M_S$ or the Planck scale $M_P$, i.e., $\Lambda \ll M_S^4 \ll M_P^4$. These low lying de Sitter vacua tend to be accompanied by very light scalar bosons/axions. Here we illustrate this phenomenon with the bosonic mass spectra in a set of Type IIB string theory flux compactification models. We conjecture that small $\Lambda$ with light bosons is generic among de Sitter solutions in string theory; that is, the smallness of $\Lambda$ and the existence of very light bosons (may be even the Higgs boson) are results of the statistical preference for such vacua in the landscape. We also discuss a scalar field $\phi^3/\phi^4$ model to illustrate how this statistical preference for a small $\Lambda$ remains when quantum loop corrections are included, thus bypassing the radiative instability problem.Comment: 35 pages, 7 figures; added subsection: Finite Temperature and Phase Transitio

An investigation of combustion instability in aircraft-engine reheat systems

The principal objective of this study was to examine experimentally the effects of upstream temperature, velocity, gutter blockage, tailpipe length, and main and pilot fuel flows, on the form of combustion instability encountered in aircraft reheat systems which is sometimes referred to as 'buzz'. Tests were carried out at atmospheric pressure for upstream temperatures of between 200 and 500°C, and upstream velocities ranging from 140 to 200 ft/sec. Three values of stabilizer blockage were employed, namely 25, 30 and 35%. The tailpipe length was varied between 9 and 45 inches. Auto-correlation techniques were used in the frequency analysis of the buzz waveforms. It was found that a certain minimum tailpipe length is necessary in order to produce buzz which is then strengthened as the tailpipe length is increased. Buzz also becomes more pronounced with an increase in gas velocity but stabilizer blockage appears to have no discernible effect … [cont.]

Effects of harvesting methods on sustainability of a bay scallop fishery: dredging uproots seagrass and displaces recruits

Fishing is widely recognized to have profound effects on estuarine and marine ecosystems (Hammer and Jansson, 1993; Dayton et al., 1995). Intense commercial and recreational harvest of valuable species can result in population collapses of target and nontarget species (Botsford et al., 1997; Pauly et al., 1998; Collie et al. 2000; Jackson et al., 2001). Fishing gear, such as trawls and dredges, that are dragged over the seafloor inflict damage to the benthic habitat (Dayton et al., 1995; Engel and Kvitek, 1995; Jennings and Kaiser, 1998; Watling and Norse, 1998). As the growing human population, over-capitalization, and increasing government subsidies of fishing place increasing pressures on marine resources (Myers, 1997), a clear understanding of the mechanisms by which fishing affects coastal systems is required to craft sustainable fisheries management

Analisis Yuridis Penegakan Pasal 351 Kuhp pada Perkelahian Antar Pemain dalam Pertandingan Sepak Bola

Skripsi ini membahas tentang analisa yuridis normatif terhadap perkelahian antar pemain dalam sepak bola. Sepak bola merupakan olahraga masyarakat sedunia yang menggunakan full body contact yang terkadang menjurus ke arah kasar dan keras. Peraturan Manual Liga dibuat sebagai upaya menjaga sportifitas dalam bertanding dan menjaga pemain dari unsur permainan yang keras menjurus kasar. Terkait dengan hal tersebut, permasalahan yang diangkat dalam skripsi ini adalah pakah perkelahian antar pemain dalam suatu pertandingan sepak bola dapat dipidana berdasarkan Pasal 351 KUHP tentang tindak pidana penganiayaan. Tujuan dari pembuatan skripsi ini adalah Untuk mengetahui dan menganalisis apakah perkelahian antar pemain dalam suatu pertandingan sepak bola dapat dipidana berdasarkan Pasal 351 KUHP tentang tindak pidana penganiayaan. Metode pendekatan yang digunakan adalah yuridis normatif kemidian dilakukan analsis secara preskriptif kualitatif.Berdasarkan hasil analsis sumber hukum dapat ditarik kesimpulan bahwa perkelahian antar pemain sepak bola tidak dapat dipidana berdasarkan pasal 351 KUHP karena berdasarkan The Laws of The Game FIFA sepanjang jalannya pertandingan sepak bola 2 x 45 menit itu merupakan kewenangan PSSI. Dan yang berhak memberi sanksi jika ada perkelahian antar pemain dalam pertandingan sepak bola tesebut adalah wasit, berupa kartu kuning dan merah. Selain wasit yang berhak memberi hukuman adalah komisi disiplin PSSI.Menyikapi fakta-fakta tersebut diatas diharap pihak kepolisian tidak mencampuri wilayah hukum PSSI pada saat pertandaingan dalam kurun waktu 2x45 menit karena sesuai dengan peraturan FIFA yang menyebutkan bahwa 2x45 menit di lapangan merupakan wewenang daripada wasit sebagai pengadil di dalam pertandingan tersebut.Kata kunci : Sepakbola, Persatuan Sepakbola Seluruh Indonesia (PSSI), Penganiayaa

Orientation filtering by growth-velocity competition in zone-melting recrystallization of silicon on SiO_2

We describe a method of controlling the in-plane directions of grains in (100)-textured silicon films produced by zone-melting recrystallization over amorphous SiO2. Grains having in-plane orientation within a narrow range are able to grow through an orientation filter consisting of a pattern of crystallization barriers, while grains having other orientations are occluded. The results of experiments using an orientation filter, and the parameters which optimize filter performance, are reported