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IDENTITAS KELUARGA KRISTIANI DI HADAPAN BUDAYA KONSUMERISME
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| Pengarang | : | - |
| Nama Majalah/Jurnal | : | Orientasi Baru: Jurnal Filsafat dan Teologi |
| Volume / Edisi | : | 25 (No. 1) |
| Halaman | : | 75-92 |
| Abstrak | : | In this article I explore the notion of "domestic church" as identity for the christian families. One important character of christian family is found here, i. e. counter-culture as way of being in the society. In our present society which is marked by consumerism, how could christian families unfold and develop their identity as "domestic church"? This article tries to answer this question by proposing some practices that can be considered as alternative culture. |
INTERNET DAN PEWARTAAN DALAM PESAN PAUS UNTUK HARI KOMUNIKASI SEDUNIA 2002-2016
| Pengarang | : | Purwatma, Matheus |
| Nama Majalah/Jurnal | : | Orientasi Baru: Jurnal Filsafat dan Teologi |
| Volume / Edisi | : | 25 (No. 1) |
| Halaman | : | 57-74 |
| Abstrak | : | The Message of the Holy Father John Paul II for 36th the World Communication Day 2002, reflects on the means of the Internet for evangelization, "Internet: A New Forum for Proclaiming the Gospel". The Internet is a new “forum” into which the Holy Father encourages the Christians to follow the Lord's command to "put out into the deep”: Duc in altum! (Lk 5:4). The subsequent Messages for the World Communication Day give some directions to the Christians on the internet as a new social communication media. Internet is modern Aeropagus, which is unifying humanity and connecting each other in the same time, and has its own languages and cultures. It is a challenge for evangelization. The Holy Fathers not only invites to use internet as means of proclaiming the Gospel, but integrates the message of the Gospel in it. |
High-speed escape from a circular orbit
| Pengarang | : | - |
| Nama Majalah/Jurnal | : | American Journal of Physics |
| Volume / Edisi | : | 89 (No. 1) |
| Halaman | : | 72-79 |
| Abstrak | : | You have a rocket in a high circular orbit around a massive central body (a planet or the Sun) and wish to escape with the fastest possible speed at infinity for a given amount of fuel. In 1929, Hermann Oberth showed that firing two separate impulses (one retrograde and one prograde) can be more effective than a direct transfer that expends all the fuel at once. This is due to the Oberth effect, whereby a small impulse applied at periapsis can produce a large change in the rocket's orbital mechanical energy, without violating energy conservation. In 1959, Theodore Edelbaum showed that this effect could be exploited further by using up to three separate impulses: prograde, retrograde, and then prograde. The use of more than one impulse to escape can produce a final speed even faster than that of a fictional spacecraft that is unaffected by gravity. We compare the three escape strategies in terms of their final speeds attainable, and the time required to reach a given distance from the central body. To do so, in the Appendix we use conservation laws to derive a “radial Kepler equation” for hyperbolic trajectories, which provides a direct relationship between travel time and distance from the central body. The 3-impulse Edelbaum maneuver can be applied to interplanetary transfers, exploration of the outer solar system and beyond, and (in time reverse) efficient arrival and orbital capture. The physics principles employed are appropriate for an undergraduate mechanics course. |
A vertical race up and back down with and without drag
| Pengarang | : | - |
| Nama Majalah/Jurnal | : | American Journal of Physics |
| Volume / Edisi | : | 89 (No. 1) |
| Halaman | : | 67-71 |
| Abstrak | : | Two identical objects are simultaneously projected vertically upward with the same initial speed in a uniform gravitational field and then return to their starting point. One object is subject to a resistive force proportional to the nth power of its speed where ?≥0?, such as linear (Stokes) drag for n = 1 or quadratic (Newtonian) drag for n = 2. The other object moves through vacuum with no resistance. Which object returns to its starting point first? It is shown analytically that the object subject to drag always wins the race if ?≥1?, but that either object can win otherwise, depending on the ratio of the launch speed to the terminal speed of the object subject to drag if 0<?<1 or depending on the ratio of the frictional acceleration to the gravitational acceleration if n = 0. These analytical results are confirmed by Euler–Cromer numerical integration of the equations of motion. |
Teaching college writing from a physicist's perspective
| Pengarang | : | Kristen L. Thompson |
| Nama Majalah/Jurnal | : | American Journal of Physics |
| Volume / Edisi | : | 89 (No. 1) |
| Halaman | : | 61-66 |
| Abstrak | : | College writing has conventionally been taught by faculty in the humanities, but many schools have begun to encourage writing instruction by faculty from a variety of disciplines. Our institution, Davidson College, has a college-wide writing requirement of all first-year students, and encourages a broad spectrum of faculty to contribute to the writing curriculum. We describe our recent experiences teaching three different writing courses that focus on topics in 20th century physics and astronomy. The goal of this teaching is to prepare students to be intellectual writers on scientific and technical topics, while focusing on concepts in physics and related areas. The writing and rhetorical skills emphasized in our classes have wide applicability for students seeking various professions. Our writing courses have required us to develop teaching methods unfamiliar to some physicists but have proven to be popular with many students and warmly received by our colleagues. Teaching these courses has helped to increase student interest in physics and has also helped the authors to grow intellectually and professionally. Here, we share our experiences teaching courses within our college's first-year writing program. We find the endeavor to be beneficial to our college, faculty, and students and hope to encourage other non-writing faculty to consider contributing to the writing programs at their institutions. |
Six textbook mistakes in computational physics
| Pengarang | : | - |
| Nama Majalah/Jurnal | : | American Journal of Physics |
| Volume / Edisi | : | 89 (No. 1) |
| Halaman | : | 51-60 |
| Abstrak | : | This article discusses several erroneous claims which appear in textbooks on numerical methods and computational physics. These are not typos or mistakes an individual author has made, but widespread misconceptions. In an attempt to stop these issues from further propagating, we discuss them here, along with some background comments. In each case, we also provide a correction, which is aimed at summarizing material that is known to experts but is frequently mishandled in the introductory literature. To make the mistakes and corrections easy to understand, we bring up specific examples drawn from elementary physics and math. We also take this opportunity to provide pointers to the specialist literature for readers who wish to delve into a given topic in more detail. |
Equilibrium probability distribution for number of bound receptor-ligand complexes Available to Purchase
| Pengarang | : | - |
| Nama Majalah/Jurnal | : | American Journal of Physics |
| Volume / Edisi | : | 89 (No. 1) |
| Halaman | : | 41-50 |
| Abstrak | : | The phenomenon of molecular binding, where two molecules, referred to as a receptor and a ligand, bind together to form a ligand-receptor complex, is ubiquitous in biology and essential for the accurate functioning of all life-sustaining processes. The probability of a single receptor forming a complex with any one of ? surrounding ligand molecules at thermal equilibrium can be derived from a partition function obtained from the Gibbs-Boltzmann distribution. We extend this approach to a system consisting of ? receptors and ? ligands to derive the probability density function ??;?,? to find ? bound receptor-ligand complexes at thermal equilibrium. This extension allows us to illustrate two aspects of this problem which are not apparent in the single receptor problem, namely, (a) a symmetry to be expected in the equilibrium distribution of the number of bound complexes under exchange of ? and ? and (b) the number of bound complexes obtained from chemical kinetic equations has an exact correspondence to the maximum probable value of ? from the expression for ??;?,??. We derive the number fluctuations of ? and present a practically relevant molecular sensing application which benefits from the knowledge of ?(?;?,?)?. |
Calculating spin correlations with a quantum computer
| Pengarang | : | Gavin Guzman |
| Nama Majalah/Jurnal | : | American Journal of Physics |
| Volume / Edisi | : | 89 (No. 1) |
| Halaman | : | 35-40 |
| Abstrak | : | We calculate spin correlation functions using IBM quantum processors, accessed online. We demonstrate the rotational invariance of the singlet state, interesting properties of the triplet states, and surprising features of a state of three entangled qubits. This exercise is ideal for remote learning and generates data with real quantum mechanical systems that are impractical to investigate in the local laboratory. Students learn a wide variety of skills, including calculation of multipartite spin correlation functions, design and analysis of quantum circuits, and remote measurement with real quantum processors. |
Index matching computerized tomography
| Pengarang | : | Vincent Daley |
| Nama Majalah/Jurnal | : | American Journal of Physics |
| Volume / Edisi | : | 89 (No. 2) |
| Halaman | : | 220-226 |
| Abstrak | : | Computerized tomography (CT) has been used for decades by medical professionals to detect and diagnose injuries and ailments. CT scanners are based on interesting physics, but due to their bulk, cost, and safety, hands on experience with a medical CT scanner are unrealistic for undergraduate students. Therefore, operationally similar, yet small, safe, and inexpensive CT scanners are desirable teaching tools. This project details the development of a novel model CT scanning apparatus. The experimental setup presented utilizes visible light, has short data acquisition time, and operates on the same physics as its X-ray counterpart. The apparatus employs a laser and photodiode to image a transparent material, while avoiding loss of transmitted intensity through index of refraction matching. A simple back-projection algorithm results in a 2D cross section of the scan object. We found we could collect data and reliably image samples in 15 min. |
Spatial structuring of light for undergraduate laboratories
| Pengarang | : | - |
| Nama Majalah/Jurnal | : | American Journal of Physics |
| Volume / Edisi | : | 89 (No. 2) |
| Halaman | : | 210-219 |
| Abstrak | : | In recent times, spatial light modulators have become a common tool in optics laboratories as well as industrial environments for shaping the spatial structure of a light beam. Although these devices are often easy to use, their high cost has limited their use in many undergraduate laboratories. However, in recent years the progress in developing more cost-effective projectors has led to affordable spatial light modulators in the form of so-called Digital Micromirror Devices (DMD). This reduction in price, as well as their simple employment, make such devices increasingly suitable for use in undergraduate instructional laboratories to demonstrate optical effects and the shaping of light fields. Here, we show one of the most cost-effective ways to make a DMD available, namely, turning a projector evaluation module into a computer-controlled spatial light modulator. We explain the underlying functioning and how this low-cost spatial light modulator can be used in undergraduate laboratories. We further characterize the efficiency of the device for the most commonly used laser wavelengths and demonstrate various exemplary optics experiments suitable for undergraduate laboratories ranging from single and multi-slit diffraction to optical Fourier transformations. Finally, we show that by using amplitude holography, the device can generate transverse spatial modes, e.g., Laguerre-Gaussian beam, which are one of the most commonly used spatially structured beams. |