ERGO - EVALUATION OF URBAN BUS DRIVER’S WORKSTATIONS IN SOUTH WEST NIGERIA

This study evaluated the ergonomic performance of drivers’ workstations in southwest Nigeria. Fifty urban buses selected from ten brands were investigated by direct measurement. The buses were mini-A and midi-B. Vertical and horizontal distances of the seat reference point to the pedal and steering wheel, with the seat dimensions were considered. The anthropometric dimensions of 150 male bus drivers were taken from South-west Nigeria. The results revealed that the values for driver’s seat height from the cabin floor, seat backrest height, seat shoulder level width and low back width were 44.00- 50.00cm, 53.00-58.15cm, 40.00-50.00cm and - 40.15cm respectively as against 39.15- 43.00cm, 38.75-49.49cm, 34.60-43.59cm and 45.73-53.25cm respectively in the urban bus workstations. It is concluded that the drivers’ workstations in the urban buses were not ergonomically fit for the bus drivers since the anthropometric dimension of the Nigerian male bus drivers were not considered in the designing of the buses.

Электронные и теплофизические свойства газовых гидратов: результаты моделирования из первых принципов

The results of an ab-initio molecular dynamics study of the electronic and thermophysical properties of methane hydrate with a cubic sI structure are presented. Good agreement of the simulation results for heat capacity at constant volume and density with experimental data is found. Based on the analysis of the density of electronic states, the temperature dependences of the electronic properties of methane hydrate, including the Fermi energy level, width and boundaries of the band gap are determined. For the empty framework of the hydrate (water clathrate framework), the electron energy spectra E(k) were calculated along the directions M-X, X-G, G-M, and G-R. It was found that the presence of CH4 molecules in an aqueous clathrate leads to an increase in the Fermi energy of the hydrate from 2.4 to 3.0 eV.

Hybrid driven three-terminal thermoelectric refrigerators based on resonant tunneling quantum dots

In this paper, we propose a pair of symmetric three-terminal refrigerator models with a hot cavity connected to two colder reservoirs via ideal tunneling quantum dots. The cooling of the refrigerators is achieved by investing thermal power from a hot reservoir and electric power from an applied voltage. Based on the model proposed, we numerically analyze the performance of the refrigerators with different half width of energy levels, and particularly discuss the coefficient of performance for zero applied voltage in the limit of a small half level width. Finally, we optimize with half width of energy levels and get the optimal region of the refrigerators.

Non-Pedicled Buccal Fat Pad Grafts to Treatment for Class I and II Gingival Recessions: A Clinical Trial

The aim of this study was to analyze the transplant efficiency of non-pedicled buccal fat pad graft (BFPG) for the treatment of Miller Class I or II gingival recessions (GRs) and to compare these results with those of subepithelial connective tissue graft (SCTG), which is considered the gold standard. Twelve patients with Miller Class I or II (≥2 mm) bilateral recessions in maxillary premolars or canines were selected. Recessions were randomly assigned to receive SCTG or BFPG. The clinical parameters evaluated at baseline and at 1, 3, and 6 months postoperatively included gingival index, plaque index, probing depth, GR, clinical attachment level, width of keratinized tissue, thickness of keratinized tissue and gingival margin to the acrylic guide. None of the evaluated clinical parameters differed significantly between the groups. At all evaluated postoperative time-points, both groups exhibited statistically significant differences in GR and gingival margin to the acrylic guide compared to baseline. Six months after surgery, the mean percentages of root coverage were 67.5% and 87.5% in the BFPG and SCTG groups respectively. In both groups, complete root coverage was observed in 50% of cases 6 months after surgery. The results presented herein indicate that the use of BFPG transplant has clinical similarities with SCTG and both may be considered as clinically successful methods for treating Miller Class I and II GRs.

Application of hydrological models for agri-environmental management based on international and national experiences

The ecological restoration of surface water flows requires the use of complex GIS and hydrological models. The HEC -RAS and MIKE11 programs calculate the hydraulic characteristics of runoff using the geometry and bed resistance the of flows. The presentation of some possible applications made through an example of the Berettyó, which is an extremely regulated river. The river belongs to the meandering category by Parker's classification system, which uses the relationship of the slope-Froude number and the depth- width ratio. Three coefficient of the four determining factor (entrenchment ratio, slope of water level, width-depth ratio) also indicates a mediocre to high sinuosity, while the river regulations established nearly straight bed-line. The standard water flow rates and characteristics have been determined based on the modeled Froude and Reynolds numbers. The flow conditions shifted to the laminar type by the changed line drawing which is ecologically lower status. Based on the results the morphological and ecohydrological river rehabilitation is appropriate.

Energy Level Width of 2DEG in Different Well in Mesoscopic System

Applying theories on quasi-classical particles and the uncertainty relation of quantum mechanics, we get the formula of uncertainty and energy level width in triangular well and parabolic well of two dimension electron gas (2DEG).Based on these ,we find energy width will increase along with the increasing of electronic field intensity and quantum number at the same electronic field, the energy width of parabolic well is more narrow than width of triangular well. At the same time, the result of this paper is agreement with the experiment.

Study on Energy Materials with Energy Level Width of 2DEG in Triangular Well

Applying theories on quasi-classical particles and the uncertainty relation of quantum mechanics, we deduce the formula of energy uncertainty in energy materials with electric field .We use it to two dimension electron gas (2DEG) in triangular well and get its energy width. Based on these, we find energy width will increase along with the increasing of electronic field intensity. At the same time, the energy width of the first excitated state is wider than the ground state, At the same time, the result of this paper is agreement with the experiment.

Exchange Enhancement of g-Factor in Narrow-Gap InAs/AlSb Quantum Well Heterostructures

We report on the study of exchange enhancement of g-factor in 2D electron gas in n-type narrow-gap semiconductor heterostructures that feature a strong nonparabolicity of electric subbands. We demonstrate that exchange g-factor enhancement not only shows maxima at odd values of Landau level filling factors but, due to subband nonparabolicity, persists at even filling factor values as well. The magnitude of the exchange enhancement, the amplitude and shape of the g-factor oscillations are governed by both the screening of electron-electron interaction and the Landau level width. The enhanced g-factor values calculated for 2D electron gas in InAs/AlSb quantum well heterostructures are compared with previous experimental magnetotransport data.