Design of reinforced concrete beams with web openings

The provision of transverse openings in floor beams to facilitate the passage of utility pipes and service ducts results not only in a more systematic layout of pipes and ducts, it also translates into substantial economic savings in the construction of a multi-storey building. To investigate the problem of openings in beams, the author initiated a research program in the early 1980s. Since then extensive research has been carried out giving a comprehensive coverage on both circular and large rectangular openings under various combinations of bending, shear and torsion. In this paper, major findings relevant to the analysis and design of such beams under the most commonly encountered loading case of bending and shear are extracted and summarized. An attempt has been made to answer the frequently asked questions related to creating an opening in an already constructed beam and how to deal with multiple openings. It has been shown that the design method for beams with large openings can be further simplified without sacrificing rationality and having unreasonable additional cost

An Investigation of the Ability to Recover from Transients Following Failures for Single-Pilot Rotorcraft

A moving-base simulation was conducted to investigate a pilot's ability to recover from transients following single-axis hard-over failures of the flight-control system. The investigation was performed in conjunction with a host simulation that examined the influence of control modes on a single pilot's ability to perform various mission elements under high-workload conditions. The NASA Ames large-amplitude-motion Vertical Motion Simulator (VMS) was utilized, and the experimental variables were the failure axis, the severity of the failure, and the airspeed at which the failure occurred. Other factors, such as pilot workload and terrain and obstacle proximity at the time of failure, were kept as constant as possible within the framework of the host simulation task scenarios. No explicit failure warnings were presented to the pilot. Data from the experiment are shown, and pilot ratings are compared with the proposed handling-qualities requirements for military rotorcraft. Results indicate that the current proposed failure transient requirements may need revision

Pengaruh Rekrutmen, Seleksi, dan Penempatan Tenaga Kerja terhadap Produktivitas Kerja Karyawan pada PT. Bank Papua Jayapura

Penelitian ini bertujuan untuk mengetahui rekrutmen, seleksi, dan penempatan tenaga kerja berpengaruh terhadap produktivitas kerja karyawan pada PT Bank Papua Jayapura, untuk mengetahui variabel manakah yang lebih dominan pengaruh terhadap produktivitas kerja karyawan pada PT Bank Papua Jayapura.. Jumlah Popuasi di PT Bank Papua Jayapura adalah 457 karyawan. Jumlah populasi yakni sebanyak 91 responden. Model analisis yang digunakan yaitu analisis regresi linier berganda. Hasil penelitian membuktikan bahwa rekrutmen berpengaruh terhadap produktivitas kerja hal ini dibuktikan dengan membandingkan tingkat signifikan alpha 0,05 dengan nilai probabilitas rekrutmen 0,000. Dengan demikian 0,000< 0,05 maka Ha diterima dan H0 ditolak. Seleksi tidak berpengaruh terhadap produktivitas kerja. Hal ini dibuktikan dengan membandingkan tingkat signifikan alpha 0,05 dengan nilai probabilitas seleksi 0,158. Dengan demikian 0,158 > 0,05 maka Ha ditolak dan H0 diterma. Penempatan tenaga kerja berpengaruh terhadap produktivitas kerja. Hal ini dibuktikan dengan membandingkan tingkat signifikan alpha 0,05 dengan nilai probabilitas penempatan tenaga kerja 0,000. Dengan demikian 0,05 > 0,000 maka Ha diterma dan H0 ditolak. Penempatan tenaga kerja mempunyai pengaruh yang paling dominan terhadap produktivitas kerja. Hal ini dibuktikan pada tabel 4.12 bahwa variabel nilai korelasi parsial penempatan tenaga kerja sebesar 0,468 lebih besar dari nilai korelasi parsial rekrutmen 0,384 dan seleksi 0,151

Limbah Pemanenan dan Faktor Eksploitasi Iuphhk-ha PT. Rizki Kacida Reanakabupaten Paser Provinsi Kalimantan Timur

The purpose of this study was to determine and quantify waste harvesting and exploitation factors IUPHHKA-HA PT. Rizki Kacida Reana Tajur Village, District Long Ikis, Paser Regency, East Kalimantan Province for 1 month in June and July 2013.Experiments in coupe IUPHHK-HA PT. Rizki Kacida Reana RKT 2013 with a sample of 50 trees on the 3 coupe and the data collected is primary data in the form of observations and measurements of length and diameter of trees that have fallen felled to obtain results which are expected to be utilized tree volume up to the first branch and stem volume not utilized, while the secondary data obtained directly from IUPHHK-HA PT. Rizki Kacida Reana and from the literature that supports.The results obtained are 1). The percentage of waste timber harvesting of species bangkirai 18.09%, 21.69% kapur types, types keruing 15.39%, 16.25% meranti merah, meranti putih 10.98%, and 34.79% rimba campuran types. Percentage of waste timber harvesting on average is equal to 14.73%. 2). Exploitation of timber harvesting factor IUPHHK-HA PT. Rizki Kacida Reana from 0.83 bangkirai types, types of kapur 0.82, 0.84 keruing type, 0.86 meranti merah, meranti putih 0.90, 0.69 rimba campuran types, so that the average size is 0.86 this was in accordance with that stipulated by the Ministry of Forestry Republic of Indonesia using 0.8 exploits factor in determining the level of annual production, and twenty-five-year annual. 3). Optimizing the use of waste as a whole can be used, either in the form of wood and a small scale as household firewood

A first-principles study of helium storage in oxides and at oxide--iron interfaces

Density-functional theory calculations based on conventional as well as hybrid exchange-correlation functionals have been carried out to study the properties of helium in various oxides (Al2O3, TiO2, Y2O3, YAP, YAG, YAM, MgO, CaO, BaO, SrO) as well as at oxide-iron interfaces. Helium interstitials in bulk oxides are shown to be energetically more favorable than substitutional helium, yet helium binds to existing vacancies. The solubility of He in oxides is systematically higher than in iron and scales with the free volume at the interstitial site nearly independently of the chemical composition of the oxide. In most oxides He migration is significantly slower and He--He binding is much weaker than in iron. To quantify the solubility of helium at oxide-iron interfaces two prototypical systems are considered (Fe|MgO, Fe|FeO|MgO). In both cases the He solubility is markedly enhanced in the interface compared to either of the bulk phases. The results of the calculations allow to construct a schematic energy landscape for He interstitials in iron. The implications of these results are discussed in the context of helium sequestration in oxide dispersion strengthened steels, including the effects of interfaces and lattice strain.Comment: 13 pages, 10 figures, 4 table

Use of the local-global concept in detecting component vibration in reactors

The local-global concept, based on the detector adjoint function, was used to develop the response of a detector to an absorber vibrating in one dimension. A one-dimensional two-group diffusion code was developed to calculate the frequency dependent detector response as a function of detector and absorber positions for the coupled-core UTR-10 reactor. Results from this code indicated the best possible detector and absorber locations, where more detailed calculations were made using a two-group, three-dimensional diffusion code with finite detector and absorber volumes. An experiment was then designed, for the chosen positions, using a vibrating cadmium absorber with a detector on each side. The assembly was placed in the vertical central stringer of the reactor. Investigations were carried out for vibrations in two flux gradients and experimental data were analyzed in the frequency domain using a microcomputer based data acquisition system;The experimental investigation showed the validity of the local-global concept. A normalized outputs cross power spectral density was developed that correctly predicted the different flux tilts in the two flux gradients. It was also shown that the frequency response of the local component had a wide plateau region. Monitoring the behavior of the normalized cross power spectral density was thought to be a promising indicator for the detection and localization of malfunctioning vibrating components. It might also be used to detect flux irregularities in the vicinity of a vibrating component