Typological Classification and the Chronology of Iron Age pottery in central-southern Britain

Pottery has been one of the most popular artefacts in the study of the Iron Age in central-southern Britain because of its advantages of commonality, durability and volume. Pottery studies have provided important clues for understanding the society and culture in the region. These studies also have contributed to constructing the chronologies of the regions. However, pottery studies have tended to be unpopular in recent decades. Despite their crucial importance to the field of Iron Age archaeology, ceramic studies of classification and chronology have not been adequately developed. The lack of these places all related studies at a disadvantage, which can be clearly identified in recent works of the region. This thesis re-examines the existing fundamental studies of Iron Age pottery. The method of classification and chronology of pottery uses statistical analyses, considering the importance of objectivity and actual data, which appears to be lacking in the existing studies. According to this approach, a new framework of the Iron Age pottery is created. The analysis also addresses other important issues for ceramic studies including classification, stratigraphy and absolute dating. These issues are discussed in order to produce reliable studies in the future by providing useful approaches to ceramic chronology. Most importantly, this thesis aims to emphasise the importance of the classification and chronology of pottery and to encourage the continuous re-examination of these studies

Improvement of durability and sliding properties of food packaging equipment by combined treatment of Diamond-like carbon coating and Fine particle bombarding

Recently, there is a demand for the development of an eco-friendly surface treatment technology that can replace PTFE coating and hard chrome plating, which are a common process for food packaging equipment. We intended to improve the sliding properties and wear resistance of food packaging equipment by the fine particle bombarding (FPB) process to a metal substrate and depositing diamond like carbon thin film under atmospheric pressure (AP-DLC). These treatments are eco-friendly and low-cost. The Stainless steel substrates treated by FPB showed better sliding properties than the mirror substrate. By FPB treatment, AP-DLC coating was successfully applied to steel substrates without peeling. Also, by coating AP-DLC on the FPB-treated substrate, the width of wear track after the sliding test was reduced by 20% compared to the mirror substrate, and the wear resistance was improved. These results indicate that the metal using the combined treatment of FPB and AP-DLC coating is a promising material for food packaging equipment

Implications of statistics of near-range Doppler velocity observed with the Syowa East HF radar

A large data-set of line-of-sight Doppler velocity obtained with the Antarctic Syowa East HF radar from February to December 1997 is analyzed to discuss the statistical characteristics of Doppler velocity (V_D) at ranges of 180-1200 km and their implications. Syowa Station K-indices during the observation period were between 0 and 7 with a maximum occurrence at K = 1. On average V_D has a minimum of about 100 m/s at 180-225 km ranges. With increasing range it increases monotonically to attain a maximum of 300-350 m/s at 400-500 km, decreases gradually to reach 250-300 m/s at about 700km, and again increases slowly at farther ranges. These values of V_D and the range vary depending on both local time and radar beam direction. In the light of recent knowledge of plasma instabilities in the ionosphere we suggest that such range profile of V_D is mainly caused by the combined effects of altitude-dependent phase velocities of ionospheric plasma waves, HF wave refraction due to enhanced E region electron density, and latitude-dependent electric field. We infer that the low V_D (～ 100 m/s) at ranges of 180-225 km may originate in part from neutral winds and/or turbulence of the neutral atmosphere

E region echoes observed with the Syowa HF radar under disturbed geomagnetic conditions

E region radar echo parameters (echo power, Doppler velocity and spectral width) obtained with the Syowa Station HF radar under disturbed geomagnetic conditions are qualitatively analyzed to study how echoing region changes due to HF wave refraction caused by ionospheric disturbance. It is found that with increasing disturbance level, echo ranges become shorter because of wave refraction during propagation due to more enhanced D and E region electron density. When geomagnetic H component variation (ΔH) is less than about -900 nT, echoes are returned from the central E region where geomagnetic aspect angle is close to zero. When ΔH is very high (= - 1500nT), the echoes are backscattered from the D and lower E regions and their power, Doppler velocity and spectral width are largely suppressed. The results suggest that we must always consider, more or less, wave refraction effect in analyzing near-range E region HF radar echoes

Effects of in vivo cyclic compressive loading on the distribution of local Col2 and superficial lubricin in rat knee cartilage

This study aimed to examine the effects of an episode of in vivo cyclic loading on rat knee articular cartilage (AC) under medium-term observation, while also investigating relevant factors associated with the progression of post-traumatic osteoarthritis (PTOA). Twelve-week-old Wistar rats underwent one episode comprising 60 cycles of 20 N or 50 N dynamic compression on the right knee joint. Spatiotemporal changes in the AC after loading were evaluated using histology and immunohistochemistry at 3 days and 1, 2, 4, and 8 weeks after loading (n = 6 for each condition). Chondrocyte vitality was assessed at 1, 3, 6, and 12 hours after loading (n = 2 for each condition). A localized AC lesion on the lateral femoral condyle was confirmed in all subjects. The surface and intermediate cartilage in the affected area degenerated after loading, but the calcified cartilage remained intact. Expression of type II collagen in the lesion cartilage was upregulated after loading, whereas the superficial lubricin layer was eroded in response to cyclic compression. However, the distribution of superficial lubricin gradually recovered to the normal level 4 weeks after loading-induced injury. We confirmed that 60 repetitions of cyclic loading exceeding 20 N could result in cartilage damage in the rat knee. Endogenous repairs in well-structured joints work well to rebuild protective layers on the lesion cartilage surface, which may be the latent factor delaying the progression of PTOA

Statistical study of Doppler velocity and echo power around 75゜ magnetic latitude using data obtained with the Syowa East HF radar in 1997

We present the statistical relationship between the echo power and Doppler velocity of radar echoes observed with the Syowa East HF radar in Antarctica in 1997. The objective of this analysis was to clarify the mechanisms by which high-latitude (～75° magnetic latitude) F region irregularities are generated. Although data points are scattered over a large area, a positive correlation between Doppler velocity and echo power appears to be present. This relationship can be interpreted in terms of gradient-drift instability, which is the most probable cause of the decameter-scale irregularities in the F region. The positive correlation deteriorates in the afternoon and midnight sectors, probably as a result of other mechanisms related to particle precipitation (field-aligned current), such as the current-convective instability

Statistical analysis of echo power, Doppler velocity and spectral width obtained with the Syowa South HF radar

Statistical analyses are made of the physical parameters (echo power, Doppler velocity and spectral width) of Doppler spectra obtained in September 1995 with the Syowa South HF radar. We present time and range distributions and histograms of the parameters and cross-correlations among them. With K index at Syowa Station the distributions and histograms vary slightly but the correlations do not change so much. The most noticeable feature is that there is a positive correlation between the absolute values of Doppler velocity and echo power. This relationship can be interpreted in terms of the gradient-drift instability which is the most probable cause to generate decameter-scale irregularities in the F-region ionosphere

Characteristics of polar mesosphere summer echoes observed with oblique incidence HF radars at Syowa Station

Polar mesosphere summer echoes(PMSE) are strong VHF-UHF radar echoes from the high-latitude cold mesopause at around 80-90km altitudes in summer. Although a number of in situ and radar observations of PMSE have been made until now, generation mechanisms of PMSE and scattering processes of radar waves due to PMSE-associated irregularities are still controversial. In this paper, PMSE detected for the first time in December 1997 and January 1998 with the oblique incidence SuperDARN HF radars at Syowa Station, Antarctica(69.0°S , 39.6°E ), are summarized to reveal the characteristics of PMSE at HF band. They appear at slant ranges of 180-315km with elevation angles of 15°-30° between 1030 and 1230UT or between 2100 and 0140UT, and are characterized by durations of 65-110min with intermittent subsidence and quasi-periodic oscillations of echo power with periods of 5-20min, due to short-period atmospheric gravity waves. Detailed analysis of the December 15, 1997 event reveals the followings: 1) echo power is less than 30dB, Doppler velocity between -40 and +40m/s, and spectral width less than 50m/s, respectively, 2) there exists no particular correlation among power, velocity and width, and 3) PMSE occurrence can be related to eastward neutral wind due to semi-diurnal tide that may induce the decrease in the mesospheric temperature