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På Världskulturmuseet i Göteborg har man sedan museet öppnade i december 2004 haft en utställningsinriktning där man i den mån det ansetts möjligt exponerat föremål fritt. Syftet är främst att öka upplevelsen för besökaren. Efter två års verksamhet kan man ur bevarandehänseende konstatera att denna modell i en del fall har haft negativ påverkan på föremålen. Förutom en ökad utsatthet för damm har
Även om Egypten på 1600- och 1700-talet var ett otillgängligt land för européerna så var det inte okänt eller främmande. I stället ingick Egypten som en viktig referenspunkt i den europeiska religiösa kulturen och historiesynen. Via kyrkomålningar och i predikan återgavs Bibelns berättelser om Moses i vassen, Josefs drömtydning och flykten från Egypten. Den forntida egyptiska civilisationen hyll
This paper examines the role of student facial attractiveness on academic outcomes under various forms of instruction, using data from engineering students in Sweden. When education is in-person, attractive students receive higher grades in non-quantitative subjects, in which teachers tend to interact more with students compared to quantitative courses. This finding holds both for males and female
Rapporten undersöker hur de olika utbildningstraditionerna i Sverige och USApåverkar undervisning och lärande. Rapporten lyfter fram svenska akademikers erfarenheter av att undervisa vid amerikanska universitet inom ramen för STINT Teaching Sabbatical-programmet och syftar till att ge en utgångspunkt för framtida diskussioner.
The spectral functions of the one-band half-filled one-dimensional Hubbard chain are calculated using the exchange-correlation potential formalism developed recently. The exchange-correlation potential is adopted from the exact potential derived from the Hubbard dimer. Within an approximation in which the full Green's function is replaced by a noninteracting one, the spectral functions can be calc
he case that constitutes the subject for this paper is a voluntourism project organized in the Faroe Islands that has gained worldwide attention. Unskilled volunteers were called to perform maintenance works while popular hiking trails remained closed for regular tourists. The idea turned into a successful marketing campaign for the Faroe Islands. Our study is anchored in theories on tourism desti
As the modern society becomes larger and increasingly diverse, its problems become more elusive and solutions far-fetched. This puts pressure on relevant education. Geographical knowledge, whose raison d’être has always been to deal with complexity, should therefore be in high demand, but isn’t. In this presentation we want to investigate why this is the case, by outlining three major problems geo
The case that constitutes the subject for this paper is a voluntourism project organized in the Faroe Islands that has gained worldwide attention. Unskilled volunteers were called to perform maintenance works while popular hiking trails remained closed for regular tourists. Thousands applied to build and mark trails in exchange for bed and board, while the idea was a successful marketing campaign
The article presents a theoretical framework for analyzing domestic innovative capability in relation to industrial espionage, drawing on material from the Soviet military aerospace sector, 1946–1990. It employs a structured comparative case study of six Soviet aircraft systems, which are compared to their closest Western equivalent. Three ideal types are used to categorize each case: copycat (mos
Functional lubrication has been shown to be a promising method for improving the performance ofultrasonic motors (USMs). However, the complex lubrication mechanisms have not been studied and the effect of lubricant properties on motor performance remains unknown. In this paper, both low-traction fluids and high-traction fluids with a wide viscosity range are applied, and the lubricating effects ar
The ultrasonic velocities in a colloidal solution and a thixotropic hydrogel containing imogolite are measured. Our original experimental setup can detect the change of ultrasonic velocity caused by the mixing of imogolite and maleic acid in pure water. Using this setup, the ultrasonic velocity is found to remain unchanged during the macroscopic solid/liquid transition and viscoelastic change of a
Small ultrasonic motors are driven by the oscillation of piezoelectric transducers. They are primarily applied to equipment components that require precise movements, such as drivers for auto-focus lenses in cameras, and actuators in robots and positioning devices. While lubrication has been proven effective in improving the performance of ultrasonic motors, the friction materials still play a sig
A bidirectional non-contact rotary motor using a piezoelectric torsional vibrator and the giant electrorheological (GER) fluid is described in this paper. By applying the dynamic electric signal with a square waveform to the GER fluid, which is in phase with the vibration velocity of the torsional vibrator, bidirectional rotation at an excitation frequency of 118 Hz is achieved. This motor generat
Lubrication has been proven to be an effective approach to drastically improve the efficiency of ultrasonic motors without losing the output torque. This phenomenon is attributed to the effective modulation of the friction force by lubricant, according to the theory described in the Stribeck curve. Previous findings even show a potential to increase the motor output torque with lubrication. Here,
Ultrasonic motors have hit a bottleneck caused by low efficiency and short life, which limits their applications to some niche areas. We believe that lubrication is a promising candidate to solve these problems. In this paper, we clarify, both analytically and experimentally, that the performance of the hybrid transducer-type ultrasonic motor (HTUSM), including the transduction efficiency, can be
Ultrasonic motors (USMs) have been extensively studied for three decades, due to their attractive features, such as high torque at low speed, simple structure, and precise positioning capability. However, since USMs are driven by the friction force between the rotor and the stator in most cases, they inherently possess the friction loss and the wear of contact materials, which cause their low effi
