Actual Outdoor Research Articles

Dilution of Precision Analysis for GNSS Collaborative Positioning

Performance analysis of Global Navigation Satellite Systems (GNSS) collaborative positioning accuracy is a challenging task since there are too many impact factors. To simplify the analysis, the collaborative dilution of precision (CDOP) model is proposed to specify the multiplicative effect of various factors on the accuracy of collaborative positioning. Based on this CDOP model, the theoretical analysis and simulation tests are performed, and the results are compared with GNSS standalone positioning. The impacts of the number of users and their distribution and of relative distance measurement accuracy are also analyzed and verified under this CDOP model. Experiments are carried out with several real-time GNSS receivers in actual outdoor and partially blockage scenarios, respectively, and the results are consistent with theoretical analysis.

Annoyance from Road Traffic, Trains, Airplanes and from Total Environmental Noise Levels.

There is a lack of studies assessing the exposure-response relationship between transportation noise and annoyance in North America. Our aims were to investigate the prevalence of noise annoyance induced by road traffic, trains and airplanes in relation to distance to transportation noise sources, and to total environmental noise levels in Montreal, Canada; annoyance was assessed as noise-induced disturbance. A telephone-based survey among 4336 persons aged >18 years was conducted. Exposure to total environmental noise (A-weighted outdoor noise levels—LAeq24h and day-evening-night equivalent noise levels—Lden) for each study participant was determined using a statistical noise model (land use regression—LUR) that is based on actual outdoor noise measurements. The proportion of the population annoyed by road traffic, airplane and train noise was 20.1%, 13.0% and 6.1%, respectively. As the distance to major roads, railways and the Montreal International Airport increased, the percentage of people disturbed and highly disturbed due to the corresponding traffic noise significantly decreased. When applying the statistical noise model we found a relationship between noise levels and disturbance from road traffic and total environmental noise, with Prevalence Proportion Ratios (PPR) for highly disturbed people of 1.10 (95% CI: 1.07–1.13) and 1.04 (1.02–1.06) per 1 dB(A) Lden, respectively. Our study provides the first comprehensive information on the relationship between transportation noise levels and disturbance in a Canadian city. LUR models are still in development and further studies on transportation noise induced annoyance are consequently needed, especially for sources other than road traffic.

Comparative study between dynamic transient and degree-hours methods to estimate heating and cooling loads of building's wall

In this paper, dynamic transient method and conventional degree-hours method (static) have been compared to estimate heating and cooling loads of building’s wall. All main wall surfaces of various orientations, i.e.South, West, East, North, and horizontal are considered in the climate of Tehran, Iran. In this study, a conventional wall structure, which is comprisedconcrete as main wall material, and EPS (expanded polystyrene), as insulation material, areused. The actual outdoor air temperature (used in dynamic method) was obtained by mean hourly measurementsrecorded in meteorological data over the period of 2006–12. Annual heating and cooling degree-hoursare calculated based on this recent weather data, and results are compared with the values reported in the national building regulations (topic 14). One dimensional transient heat transfer problem for multilayer walls has been solved to obtain temperature distribution within the wall. Annual heating and cooling load resulting from dynamic method have been compared with degree-hoursmethod; the results showed that there is a significant difference between these two estimations.

Development of a Robust Path-Planning Algorithm Using Virtual Obstacles for an Autonomous Mobile Robot

<div class=""abs_img""> <img src=""[disp_template_path]/JRM/abst-image/00270003/08.jpg"" width=""340"" /> Proposed path-planning result</div> In this paper, we describe the development of a robust path planning algorithm for an autonomous mobile robot. In order to achieve safe navigation in areas with moving obstacles, the mobile robot has to be controlled by a dynamic path-planning algorithm to avoid collisions. However, depending on changes in obstacle positions, the dynamic path planning algorithm frequently faces path-switching problems. In order to avoid the path-switching problems in the dynamic path planning algorithm, we introduce a virtual obstacle assignment method to suppress events caused by the path-switching problems. The effectiveness of proposed method is proved by an actual mobile robot. The validity of proposed method is confirmed by both simulations and actual outdoor experiments.

Feasibility of smartphone diaries and personal dosimeters to quantitatively study exposure to ultraviolet radiation in a small national sample

In 2007, a national skin cancer prevention campaign was launched to reduce the UV exposure of the Danish population. To improve campaign evaluation a questionnaire validation using UV-dosimeters was initiated. To show the feasibility of dosimeters for national representative studies and of smartphones as a data collection tool. Participants were sent a dosimeter which they wore for 7days, received a short diary questionnaire by text message each day and subsequently a longer questionnaire. Correlation between responses from questionnaire, smartphone diaries and dosimeters were examined. This study shows a 99.5% return rate (n=205) of the dosimeters by ordinary mail and high response-rates for a smartphone questionnaire dairy. Correlation coefficients for outdoor-time reported through smartphones and dosimeters as average by week 0.62 (0.39-0.77), P<0.001 (n=40). Correlation coefficient for outdoor time estimated by questionnaire and dosimeters were 0.42 (0.11-0.64), P=0.008. The subjective perception of the weather was the only covariate significantly influencing questionnaire estimates of actual outdoor exposure. We showed that dosimeter studies are feasible in national settings and that smartphones are a useful tool for monitoring and collecting UV behavior data. We found diary data reported on a daily basis through smartphones more strongly associated with actual outdoor time than questionnaire data. Our results demonstrate tools and possible considerations for executing a UV behavior questionnaire validation.

Impact of solar irradiance intensity and temperature on the performance of compensated crystalline silicon solar cells

Low-cost upgraded metallurgical grade silicon (UMG-Si) with inherent boron (B) and phosphorus (P) compensation is a novel material for photovoltaic application. This paper presents the impact of solar irradiance intensity and temperature on the performance of compensated crystalline silicon solar cells. For the same rated output power, compensated crystalline silicon solar cells generate less electricity than the reference silicon solar cells at low irradiance intensity, owing to the strong injection dependence of the carrier lifetime due to high concentration of B–O complexes in compensated silicon. However, at high temperature, compensated crystalline silicon solar cells generate more electricity than the reference silicon solar cells, which mainly originates from the lower temperature-variation of the minority electron mobility in compensated silicon. It suggests that compensated silicon solar cells will be more appropriate for high irradiation application, which often contains high irradiance intensity and high temperature. These results are of great significance for understanding the actual outdoor performance of the solar cells based on the UMG-Si and their application in the photovoltaic (PV) industry.

ENHANCEMENT OF THERMAL EFFICIENCY BY USING HEMISPHERICAL PROTRUSIONS ON SOLAR AIR HEATERS

Artificial roughness elements in the form of hemispherical protruded impressions were designed and developed on a 14-gauge commercially available aluminum sheet with the help of appropriate dies and punches. This aluminum sheet was used as an absorber for a solar air heater. Artificial roughness augments turbulence and heat transfer to the air flowing over. This aluminum solar energy absorber with protrusions had been tested for flow Reylonds number of 3500−15,000 under actual outdoor conditions in OPJU campus. The thermal efficiency of a roughened solar air heater was found to be a strong function of air mass flow rate. Maximum thermal efficiencies were observed as 80%, 70%, and 60% at mass flow rates of 1 = 0.0417, 2 = 0.0313, and 3 = 0.0208 kg/s, respectively. The collector heat removal factor (FR) varied from 0.42 to 0.50, the collector efficiency factor (F') varied from 0.45 to 0.75, and the heat removal factor based on outlet air (F0) varied from 0.55 to 0.80 at corresponding air mass flow rate. For a given value of p/e (12), the Reynolds number and increased value of e/D (0.045−0.055), there was an augmentation in the Nusselt number 2.67 and 3.62 with respect to a smooth collector. The Nusselt number was maximum for a p/e value of 12 and it decreased in either sides of 12. The values of F0Ul for roughened and smooth collectors were computed to be 10 W/m2·K and 3 W/m2·K and F0(τα) to be 0.837 and 0.377, respectively. For e/D equal to 0.055, 0.045, and 0.035 and constant p/e = 12, the values of F0, Ul, and F0(ατ) are 10, 09, and 08 W/m2·K and 0.884, 0.746, and 0.664, respectively for this solar absorber. There was a ±5% variation of experimental and predicted Nusselt number based on the modified correlation developed from experimental data analysis.

Detection of Vehicle’s Number Plate at Nighttime using Iterative Threshold Segmentation (ITS) Algorithm

An Iterative method of ind ividual nameplate detection using color images acquired fro m a high position is proposed for guidance of nighttime vehicles and other similar purposes. Segmentation is a very critical and d ifficult stage to accomplish in co mputer aided detection systems. Fundamentally the method contains iterative automatic thresholding and selecting the best threshold value which is applied to the original or enhanced dark night images. The main focus of the iteration based threshold to distinguish the image of the background and foreground. This method was tested on an actual outdoor vehicle images and results obtained fro m automat ic thresholding of the experimental images are showing the validity of the method.

Thermal performance of artificially roughened solar air heaters

Artificially roughened solar air heaters have been analysed (Prasad and Saini, 1988) for fully developed turbulent flow and found to perform better both quantitatively and qualitatively compared to the smooth ones under the same operating conditions. Optimal thermo-hydraulic performance of such solar air heaters has been analysed (Prasad and Saini, 1991) and investigated (Prasad and Verma, 2000) for the maximum heat transfer and minimum pressure drop.This paper represents the experimental results on heat transfer and thereby thermal performance of artificially roughened solar air heaters for fully developed turbulent flow data collected under actual outdoor conditions. Such solar air heaters have been found to give considerably high value of collector heat removal factor (FR), collector efficiency factor (F′) and thermal efficiency (ηth) as compared to the corresponding values of those of smooth collectors. In the range of the operating parameters investigated, the ratio of the respective values of the parameters FR, F′ and ηth for the roughened collectors to the smooth collectors have been found to be 1.786, 1.806 and 1.842 respectively.

表面被覆工法の付着性能評価における促進劣化試験の適用に関する研究

In these days, many repair examples of the concrete structure have been reported and the durability of concrete structure is taken up as an important issue. Outdoor exposure test is the most practical way to evaluate the durability of surface coating material on the concrete structure but it requires long time to complete. Therefore it is also a big issue to propose an accelerated weathering test to shorten the time for evaluation.The Subcommittee on Polymers for Repairing and Strengthening Concrete Structures under the Committee on Polymers in Concrete (Chair: Toyoaki Miyagawa) within the Society of Materials Science Japan (JSMS), has conducted common tests on the surface coating materials since 2006. The purposes of common tests are to propose common test procedures which enable comprehensively to evaluate the durability of the surface coating material on concrete. Furthermore the Subcommittee carried out another two weathering tests (accelerated) in the secondary part of the common test to obtain the durability of surface coating material in short time.As a result of investigation on adhesion performance focusing on the relationship between the actual outdoor exposure test and the accelerated weathering tests, it was concluded that an accelerated weathering test was effective for some of the coating systems.

Dual layer structural thermoplastic polyester powder coating film and its weathering resistance

AbstractMicro FTIR analysis was performed to the point with a 50–80 μm spatial resolution to verify the exact structure of a new blend thermoplastic powder coating film. Resistance to certain artificially accelerated conditions and actual outdoor exposure were examined to confirm the performance of the film as a protective coating for use in the telecommunication field. The new blend powder coating film consists of primary polyethylene terephthalate (PET) and secondary polyvinyl butyral (PVB) resins, and has a distinct dual phase structure. Specifically, it forms a continuous PVB phase in a surface layer with a thickness of approximately 100–150 μm. Good corrosion resistance was confirmed in artificially accelerated testing using salt water spray, heat cycle, and accelerated UV tests. Actual outdoor exposure in a metropolitan area (Shinkiba in Tokyo) and a coastal area (Miyake Island) revealed good weathering performance throughout the study period. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

Effect of Temperature on Performance Parameters of Metallurgical Grade Polysilicon Solar Cells

By the stable operation of the experiments in actual outdoor conditions nearly a year, we find that the property of metallurgical silicon solar cells proves to be stable. The results show that the relationship between S-P could be expressed as a quartic equation. As the higher surface temperature of solar cells at noon on sunny day, both the open circuit voltage and the operating voltage are lower, the output power is reduced. It is concluded that the water cooling on the surface of the solar cells when the temperature T&gt;50°C could improve power generation efficiency.

Initial Operation and Performance Evaluation of the Developed Solar Thermal and Electric Desiccant Cooling System

The system in this article was operated for electric heating and thermal storage, thermal storage and desiccant cooling, three days of controlled system operation, and a one-day actual outdoor air conditions operation. Results show that almost 9 h of electric heating is needed to store sufficient thermal energy and that same thermal stored energy is barely enough to support the desiccant cooling operation for only 7 h. It is also shown that excess thermal energy in the tank from the previous day's operation cannot support the early-hour desiccant cooling the following day.

Corrosion of inhibitor treated carbon steel during wet/dry cycling tests

PurposeThe purpose of this paper is to study the inhibition of carbon steel corrosion under wet/dry conditions using electrochemical techniques.Design/methodology/approachSodium dihydrogen orthophosphate, dicyclohexylamine nitrite and sodium benzoate were used as inhibitors in the investigation. Plain carbon steel specimens were treated with three different inhibitors for a set period of time. One group of the specimens was subjected to 60 wet/dry cycles whilst a second group was kept continuously immersed in distilled water during the same period. The corrosion rates of the specimens were determined by electrochemical methods at several intervals during corrosion.FindingsThe three inhibitors showed good performance during the whole 60 days of wet/dry cycling. Sodium dihydrogen orthophosphate was the best of the three, giving the lowest corrosion rates. However, during full immersion tests in distilled water, specimens that had been treated with dicyclohexylamine nitrite and sodium benzoate performed better than did those treated with sodium dihydrogen orthophosphate. Moreover, the corrosion rates were significantly higher in the case of wet/dry cycling due to differential aeration created through partial immersion, which was a consequence of the wet and dry cycling process.Originality/valueThis study showed the beneficial effect of inhibitors in slowing down the corrosion of steel. Furthermore, wet/dry cycling of steel samples in the laboratory produced corrosion rates that were comparable to those measured under actual outdoor conditions.

Impact of spectral irradiance distribution and temperature on the outdoor performance of amorphous Si photovoltaic modules

Performance of photovoltaic (PV) modules is evaluated under the standard test condition, which rarely meets actual outdoor conditions. Environmental conditions greatly affect the output energy of PV modules. The impact of environmental factors, especially solar spectrum distribution and module temperature, on the outdoor performance of amorphous Si (a-Si) and multicrystalline Si (mc-Si) PV modules is characterized. The results show that the output energy of a-Si modules mainly depends on spectrum distribution and is higher under blue-rich spectrum. In contrast, the output energy of mc-Si module is sensitive to module temperature but not to spectrum distribution.

Older persons afraid of falling reduce physical activity to prevent outdoor falls

Objective. The aim of this study was to test the assumption that the level of outdoor physical activity mediates the relationship between fear of falling and actual outdoor falls according to the Task Difficulty Homeostasis Theory. Method. A prospective follow-up study of 10 months conducted in the year 2000 in three municipalities in the province of Friesland, The Netherlands. The participants were 1752 people aged 65 and older, living independently, in the community. Main baseline data were age, sex, outdoor physical activities (walking, bicycling), and fear of outdoor falls. The number of people who fell outdoors was recorded. Results. People with a high fear of falling were more often low to moderately active or active compared with people who had no such fears and were more often very active. Fear of falling was not associated with outdoor falls, but it was after taking the level of physical activity into account. Conclusions. Outdoor physical activity mediates the relationship between fear of falling and actual outdoor falls. This implies that the incidence of falls as an outcome in studies does not adequately represent the impact of risk factors for falls and that level of physical activity should be taken into account.

USING A FIELD TRIP TO A WETLAND AS A GUIDE FOR CONCEPTUAL UNDERSTANDING IN ENVIRONMENTAL EDUCATION – A CASE STUDY OF A PRE-SERVICE TEACHER’S RESEARCH

This paper describes a pre-service chemistry teacher in her senior year at the university, who attended an environmental education (EE) course, in which within a project assignment, she studied her peers’ and other college students' conceptions of the swamps in Israel. In her study she discovered that the students held naive conceptions about the swamps as filthyhazardous places that must be drained for improving the public health. A visit to the swamp, which included observations and investigation of its water quality, caused a conceptual change that allowed the students to understand the ecosystem better and to re-assess their pre-conceptions. The pre-service teacher, who was at the focus of this study challenged her own and her colleagues conceptions and used the conceptual change as a lever for her own professional growth as an environmental educator. Her project provides a better insight on pre-service environmental education experiences. The changes that the prospective teacher identified are discussed in the context of constructivist learning and teaching in EE, suggesting that pre-service training in EE must include actual outdoors learning experiences, which allow students to challenge previous knowledge and practice effective teaching methods. [Chem. Educ. Res. Pract.: 2004, 5, 127-142]

A vehicle parking detection method using image segmentation

AbstractA method of individual vehicle detection using grayscale images acquired from a high position is proposed for guidance of incoming vehicles to vacant cells in a parking lot and other similar purposes. With the proposed method, each image region corresponding to a cell is fragmented according to density (gray level), and the distribution of segment area is analyzed to decide if a vehicle is present. Reference images taken in vacant state are not needed, hence the method can be easily applied to parking lots in continuous service. Shape features are not employed, hence detection is performed independent of car shape. The proposed method was tested on an actual outdoor parking lot during 4 days with different weather conditions from sunrise through sunset. The results confirmed the efficiency of the proposed method, with the detection rate being over 98.7%. © 2001 Scripta Technica, Electron Comm Jpn Pt 3, 84(10): 25–34, 2001

Evaluation of Property Retention in E-Glass/Vinylester Composites after Exposure to Salt Solution and Natural Weathering

E-glass fiber reinforced vinylester composites are attractive for use in civil infrastructure applications ranging from repair and rehabilitation to new structural systems due to their potential durability and low cost. However, these materials, generally cured under ambient conditions, must withstand changing and severe environmental conditions over extended periods of time. Data related to their degradation kinetics and property retention are largely anecdotal and lack the existence of both fundamental and mechanistic information and a data-base on the basis of which service life could be reasonably established. This study investigates the degradation of two E-glass architectures after exposure to salt solution, accelerated heat cycles based on a summer in Sydney, and actual outdoor weathering over an 18 month period in Sydney, Australia. It is seen that both tensile strength and modulus are reduced due to the various exposures with attendant degradation at the matrix, fiber, and interphase levels. Based on results of the study it is concluded that natural weathering can lead to rather severe degradation at the surface level, which if not corrected leads to rapid degradation through the thickness, emphasizing the criticality in use of surface coatings and/or veils/layers of mat. It is also shown that changes in Tg are due to both physical and chemical aging with overall effects to an extent being irreversible due to matrix hydrolysis and cracking, and fiber degradation.

Fire Detection in Tunnels by means of Image Processing

The fire detection is very important to prevent a secondary disaster and to save the assistance for safe driving in the master plan of ITS. At present, the fire detectors, which have a high sensitivity, are used in order to detect the fire in tunnels. It has problems such that the detection area is very narrow and sensor head is fouled by exhaust fumes. Compared with the fire detectors, image sensor is suitable to detect the fire, because it can cover two-dimensional wide space. We had attempted elsewhere the fire detection, which compares two histograms with various shades of gray level, by means of image processing. However, there remained problems about the influence of passing vehicle in the actual outdoors environment. The flame has characteristic such that its state is unstable and repeats growth and decay. A new approach toward the fire detection based on fluctuation of the flame has been described in this paper. Conventional fire detectors could detect only a phenomenon of the fire. However, proposal method could detect not only the flame but also its position. We conducted simulation and field tests to verify the accuracy of this method, and confirmed the effectiveness.