Resonance testing of space shuttle thermoacoustic structural specimen

The resonance testing of a structural specimen related to the space shuttle vehicle is described. The specimen consisted of a thin aluminum skin reinforced by hat-section stringers and supported by two ribs or bulkheads of corrugated web. A representative section of the space shuttle thermal protection system was bonded to the outer surface of the skin. The tests were completed by using miniature accelerometers to collect vibration data from locations forming a predetermined mesh over the tiles and base structure. The signals were recorded on FM magnetic tape and subsequently analyzed on a modal analysis system

Ball Lightning–Aerosol Electrochemical Power Source or A Cloud of Batteries

Despite numerous attempts, an adequate theoretical and experimental simulation of ball lightning still remains incomplete. According to the model proposed here, the processes of electrochemical oxidation within separate aerosol particles are the basis for this phenomenon, and ball lightning is a cloud of composite nano or submicron particles, where each particle is a spontaneously formed nanobattery which is short-circuited by the surface discharge because it is of such a small size. As free discharge-shorted current loops, aerosol nanobatteries are exposed to a powerful mutual magnetic dipole–dipole attraction. The gaseous products and thermal energy produced by each nanobattery as a result of the intra-particle self-sustaining electrochemical reactions, cause a mutual repulsion of these particles over short distances and prevent their aggregation, while a collectivization of the current loops of separate particles, due to the electric arc overlapping between adjacent particles, weakens their mutual magnetic attraction over short distances. Discharge currents in the range of several amperes to several thousand amperes as well as the pre-explosive mega ampere currents, generated in the reduction–oxidation reactions and distributed between all the aerosol particles, explain both the magnetic attraction between the elements of the ball lightning substance and the impressive electromagnetic effects of ball lightning

RCA-E/Delta post launch report

The RCA-E spacecraft launch is summarized. Performance of the three stage Delta launch vehicle was nominal and placed the payload in a transfer orbit as planned. The ABM firing is also summarized

The LATDYN user's manual

The LATDYN User's Manual presents the capabilities and instructions for the LATDYN (Large Angle Transient DYNamics) computer program. The LATDYN program is a tool for analyzing the controlled or uncontrolled dynamic transient behavior of interconnected deformable multi-body systems which can undergo large angular motions of each body relative other bodies. The program accommodates large structural deformation as well as large rigid body rotations and is applicable, but not limited to, the following areas: (1) development of large flexible space structures; (2) slewing of large space structure components; (3) mechanisms with rigid or elastic components; and (4) robotic manipulations of beam members. Presently the program is limited to two dimensional problems, but in many cases, three dimensional problems can be exactly or approximately reduced to two dimensions. The program uses convected finite elements to affect the large angular motions involved in the analysis. General geometry is permitted. Detailed user input and output specifications are provided and discussed with example runstreams. To date, LATDYN has been configured for CDC/NOS and DEC VAX/VMS machines. All coding is in ANSII-77 FORTRAN. Detailed instructions regarding interfaces with particular computer operating systems and file structures are provided

Editorial

Somatostatin analogues and their clinical applicationLaparoscopic cholecystectom

The Computational Complexity of the Game of Set and its Theoretical Applications

The game of SET is a popular card game in which the objective is to form Sets using cards from a special deck. In this paper we study single- and multi-round variations of this game from the computational complexity point of view and establish interesting connections with other classical computational problems. Specifically, we first show that a natural generalization of the problem of finding a single Set, parameterized by the size of the sought Set is W-hard; our reduction applies also to a natural parameterization of Perfect Multi-Dimensional Matching, a result which may be of independent interest. Second, we observe that a version of the game where one seeks to find the largest possible number of disjoint Sets from a given set of cards is a special case of 3-Set Packing; we establish that this restriction remains NP-complete. Similarly, the version where one seeks to find the smallest number of disjoint Sets that overlap all possible Sets is shown to be NP-complete, through a close connection to the Independent Edge Dominating Set problem. Finally, we study a 2-player version of the game, for which we show a close connection to Arc Kayles, as well as fixed-parameter tractability when parameterized by the number of rounds played

Telesat-G/Delta post launch report

The Canadiari Telesat-G (ANIK-D1) commercial communications satellite was launched successfully from the Eastern space and Missile Center (ESMC) at 7:10 p.m., EDT, on August 25, 1982, by a Delta 3920 Vehicle, Mission Number 164. Performance of the two stage Delta launch vehicle was nominal and placed the payload in a low circular orbit as planned. The Payload Assist Module (PAM-D), which is part of the payload, also performed nominally. The synchronous transfer orbital elements achieved by Delta/PAM, compared with the nominal expected, are provided. The satellite performed satisfactorily during the transfer orbit, and the ABM was fired successfully at 5:29 p.m., EDT, on August 29, 1982. The satellite was maneuvered to a position 104 degrees West Longitude above the equator. Satellite status is satisfactory and it has entered service

Comorbid Chronic Pain and Depression: Patient Perspectives on Empathy

Clinician empathy is a well-documented component of effective patient/provider communication. Evidence surrounding the association between patient perspectives on clinician empathy and perception of pain management is currently limited, particularly among patients with chronic pain and depression. The aim of this study was to analyze patients’ perspectives on the emergent theme of empathy and describe how patients construct their experiences and expectations surrounding empathic interactions. A secondary analysis of focus group data was designed using grounded theory methodology. Veterans Affairs (VA) and University Primary Care Clinics. Respondents with chronic pain and comorbid depression (N = 18) were 27 to 84 years old (mean 54.8 years), 61% women, 22% black, and 74% white. Study participants highly valued empathy and two types of empathic interactions: empathic listening and empathic action. Patients who provided examples of empathic interactions claimed that others understood, valued, and cared for them. In contrast, patients who perceived a lack of empathy and empathic interactions felt frustrated and uncared for by others (including their physicians) physically and emotionally. Patients with chronic pain and depression claimed that empathy helped them feel understood, believed, taken seriously, and that their needs were met. In demonstrating empathy and engaging in empathic interactions with patients, providers relate better to patients, better understand their life experience, and provide patient-centered care that is meaningful for patients, providers, and the health care systems within which they interact. Future research is needed to purposefully study the effects of empathic interactions on outcomes for patients with chronic pain and comorbid depression

For whom is the feedback intended? A student-focused critical analysis of turnitin software as a tool for learning

Online systems like Turnitin have been identified as way to improve the quality of work that students submit. Related to this, recent studies concerned with Turnitin have foregrounded its capacity as an educative tool that improves students’ understanding of academic misconduct. Academic writing, and the ability of students to appreciate feedback as a significant component of learning is often hidden behind the technological platform of Turnitin. In many cases Turnitin is conceived as software used to detect dishonesty and frame students for inappropriate citation, or misuse of referencing. We seek to address this, by examining more the pedagogical value of online feedback systems in the context of widening participation and TEF. Significantly expanding the discussion beyond plagiarism, taking a genre-based approach, and positioning both academic writing and Turnitin/feedback within the context of academic literacies, this paper intervenes with current debates. The case study draws on qualitative data recorded from students, tutors, and the Turnitin software system. By doing so, insights are generated into best software practice that have profound implications for HEIs, most especially those with widening participation agendas. Based on these data, the study provides a series of practical software development recommendations to help raise standards amongst student writing