Frekuensi Getar Alami Balok Kantilever Timoshenko

. Exact solution for dynamic system with distributed mass in elastic state is commonly analyzed by Euler-Bernoulli theory, that is ‘plane cross sections perpendicular to the axis of the beam remains plane and perpendicular to the axis after deformation [Wang, 1995]. Due to effect of transverse shear deformation, the plane cross sections remain plane but not necessarily normal to the longitudinal axis after deformation. This effect may have significant influence on the natural frequency of the large and deep beam. Also, the inertial resistance to rotational acceleration of the beam could not be ignored for the large and deep beam. Investigation is made for these two conditions by the use of Timoshenko's beam theory. This paper presents exact solution of natural frequency, of which shear deformation and rotary inertia effects are included in the analysis. Numbers of mode-shapes become definite if which shear deformation and rotary inertia effects are included in the analysi

Karakteristik Endapan Cairan Rumen Sapi Asal Rumah Potong Hewan Sebagai Feed Supplement

The aims of this experiment were to identify and characterize of sediment product from cattle rumen liquor as a source of amino acids, minerals and vitamins. The sediment were obtained as pellets upon centrifugation of rumen liquor at 10,000 g for 10 minutes for collection of supernatant. The sediment were evaluated for amino acids, minerals and vitamins composition and chararacterized for the pH, solubility of dry matter, specific density, bulk and compacted bulk densities and angle of response. Result of the experiment showed that sediment contained higher minerals: Na, K and Fe compared with the commercial premix, but lower in B-vitamins and amino acids. The composition of mineral Na, K, and Fe from rumen liquor of local cattle was 13.47%, 7.73 % and 14.52 %, while Na, K, and Fe from rumen liquor of imported cattle was 18.40%, 10.25%, and 14.52% respectively. The sediment had pH range from 10.01-10.03, the dry matter solubility was 35.5% up to 39.1%. The sediment from imported cattle had higher specific density, bulk and compacted bulk densities and angle of response than that of local cattle. It is concluded that sediment from cattle rumen liquor contained high Na, K and Fe, low amino acids and B-vitamin, high pH and low solubility

GRB 030329: 3 years of radio afterglow monitoring

Radio observations of gamma-ray burst (GRB) afterglows are essential for our understanding of the physics of relativistic blast waves, as they enable us to follow the evolution of GRB explosions much longer than the afterglows in any other wave band. We have performed a three-year monitoring campaign of GRB 030329 with the Westerbork Synthesis Radio Telescopes (WSRT) and the Giant Metrewave Radio Telescope (GMRT). Our observations, combined with observations at other wavelengths, have allowed us to determine the GRB blast wave physical parameters, such as the total burst energy and the ambient medium density, as well as investigate the jet nature of the relativistic outflow. Further, by modeling the late-time radio light curve of GRB 030329, we predict that the Low-Frequency Array (LOFAR, 30-240 MHz) will be able to observe afterglows of similar GRBs, and constrain the physics of the blast wave during its non-relativistic phase.Comment: 5 pages, 2 figures, Phil. Trans. R. Soc. A, vol.365, p.1241, proceedings of the Royal Society Scientific Discussion Meeting, London, September 200

Detailed study of the GRB 030329 radio afterglow deep into the non-relativistic phase

We explore the physics behind one of the brightest radio afterglows ever, GRB 030329, at late times when the jet is non-relativistic. We determine the physical parameters of the blast wave and its surroundings, in particular the index of the electron energy distribution, the energy of the blast wave, and the density (structure) of the circumburst medium. We then compare our results with those from image size measurements. We observed the GRB 030329 radio afterglow with the Westerbork Synthesis Radio Telescope and the Giant Metrewave Radio Telescope at frequencies from 325 MHz to 8.4 GHz, spanning a time range of 268-1128 days after the burst. We modeled all the available radio data and derived the physical parameters. The index of the electron energy distribution is p=2.1, the circumburst medium is homogeneous, and the transition to the non-relativistic phase happens at t_NR ~ 80 days. The energy of the blast wave and density of the surrounding medium are comparable to previous findings. Our findings indicate that the blast wave is roughly spherical at t_NR, and they agree with the implications from the VLBI studies of image size evolution. It is not clear from the presented dataset whether we have seen emission from the counter jet or not. We predict that the Low Frequency Array will be able to observe the afterglow of GRB 030329 and many other radio afterglows, constraining the physics of the blast wave during its non-relativistic phase even further.Comment: 9 pages, 2 figures; accepted for publication in Astronomy & Astrophysics after minor revisions; small changes in GMRT fluxes at 1280 MH

Psychological Injuries at Work - What Every Manager Should Know

A psychological injury is a diagnosable illness that affects a person’s thinking, emotional state and behavior. It can disrupt their ability to work and carry out other daily activities, and to engage in satisfying personal relationships. Unlike a physical injury, a psychological injury cannot be easily recognized and understood. This research document is a conceptual work, which tries to define and isolate stress and stress related injuries, as well as psychological injuries at work. Such an understanding would help the top management to cater and prevent injuries of such extent. Based on literature, a model has been developed for the study and the research document has defined “Psychological injury as an employee’s explicit manifestation of distress in the form of affective behavioral and cognitive dysfunction in work context”. This research document can be considered a seminal work done in Indian context. This works gains importance in the light of increasing number of lawsuits in Indian courts on work- related stress and agony. India still does not have any laws that deal with emotional health and stress related injuries at work or psychological injuries as compared to other countries like Canada, U.K and the U.

Inventarisasi Tumbuhan Kawasan Sempadan di situ Agathis, Universitas Indonesia, Depok, Jawa Barat

Situ Agathis adalah salah satu dari enam situ di Universitas Indonesia, Depok. Situ Agathis merupakan situ pertama yang menerima aliran air dari pemukiman warga. Ekosistemnya meliputi badan air dan sempadan yang telah rusak akibat pembuangan sampah dan limbah rumah tangga di sekitar Kawasan Beji, Depok. Namun terdapat beberapa spesies tumbuhan yang dapat bertahan hidup di sekitarnya. Oleh karena itu, dilakukan inventarisasi untuk mengetahui jenis-jenis tumbuhan yang dapat bertahan dalam wilayah tercemar situ. Studi dilakukan menggunakan metode line transect dengan tiga kali pengulangan pada tiap stasiun inlet, midlet, dan outlet. Hasil studi menunjukkan adanya 59 spesies yang berasal dari 51 genus dan 30 famili. Famili dengan jumlah spesies terbanyak adalah Asteraceae, Fabaceae, dan Malvaceae. Habitus yang banyak ditemukan adalah herba (47,46%), semak (6,78%), liana (3,39%), perdu (5,08%), dan pohon (37,29%). Jenis yang banyak ditemui merupakan spesies invasif, gulma, tanaman perintis, dan tanaman bioremediator yang toleran terhadap lingkungan tercemar

Optical observations of the bright long duration peculiar GRB 021004 afterglow

The CCD magnitudes in Johnson $B,V$ and Cousins $R$ and $I$ photometric passbands are determined for the bright long duration GRB 021004 afterglow from 2002 October 4 to 16 starting $\sim$ 3 hours after the $\gamma-$ray burst. Light curves of the afterglow emission in $B$,$V$,$R$ and $I$ passbands are obtained by combining these measurements with other published data. The earliest optical emission appears to originate in a revese shock. Flux decay of the afterglow shows a very uncommon variation relative to other well-observed GRBs. Rapid light variations, especially during early times ($\Delta t < 2$ days) is superposed on an underlying broken power law decay typical of a jetted afterglow. The flux decay constants at early and late times derived from least square fits to the light curve are $0.99\pm0.05$ and $2.0\pm0.2$ respectively, with a jet break at around 7 day. Comparison with a standard fireball model indicates a total extinction of $E(B-V)=0.20$ mag in the direction of the burst. Our low-resolution spectra corrected for this extinction provide a spectral slope $\beta = 0.6\pm0.02$. This value and the flux decay constants agree well with the electron energy index $p\sim 2.27$ used in the model. The derived jet opening angle of about $7^{\circ}$ implies a total emitted gamma-ray energy $E_{\gamma} = 3.5\times10^{50}$ erg at a cosmological distance of about 20 Gpc. Multiwavelength observations indicate association of this GRB with a star forming region, supporting the case for collapsar origin of long duration GRBs.Comment: 19 pages, 3 figures, BASI, 31, 1

Pandan Leaves Extract (Pandanus Amaryllifolius Roxb) as a Food Preservative

Background : Food poisoning or foodborne disease is still a serious concern in Indonesia. The use of harmful synthetic chemical preservatives are still widely found in society. Therefore, it would require efforts to develop safe natural preservatives― for instance, from Pandan leaves (Pandanus amayllifolius Roxb) which are often used as a natural food coloring and flavor concentrates, and has also widely known to have anti-bacterial activities. Objective : This study aims to determine the potential of pandan leaves extract (Pandanus amaryllifolius Roxb) in lowering the total plate count and the number of mold on traditional food. Methods : After making the water of pandan leaves extract, a phytochemical test was done to determine bioactive compounds, such as tannin, alkaloids, flavonoids, and polyphenols which has anti-microbial properties. In order to determine its food preservatives capabilities, Total Plate Count and Number of Mold was used on a traditional food called Putu Ayu. Results : Pandan leaves extract contain bioactive compound like tannin, alkaloids, flavonoids, and polyphenols. There were no colonization found in Putu Ayu that was added 15% pandan leaves extract concentration in 101 dilution. The result of Number of Mold Count of Putu Ayu that contain 15% pandan leaves extract concentration showed no mold growth in 104 dilution but failed to provide good fragarance and flavor in food products. Conclusion : Pandan leaves extract in the concentration of 15% were able to decrease Total Plate Count and Number of Mold in traditional food