Experimental comparison of combine performance with two harvesting methods: stripper header and conventional header

Residual straw status on the field after harvesting was one of the important obstacles in using stripper header in Iran. In this work, combine performance studied with two type headers, conventional and stripper in wheat farm. Residual stems after harvesting collected, baled, and two methods were compared. The results showed that fuel consumption in the stripper header was 5.68 L/ha less than the conventional header. Combines with stripper header harvested 1500 m2 more than the conventional header in each hour. Stripper header in comparison with the conventional had 21% harvesting efficiency and 840 kg/h field performance which harvested more wheat. Harvesting time and fuel consumption for straw harvesting operation in the harvested field with stripper header were 1.5 minutes and 23.53 L respectively, which were higher than conventional header. However, with stripper method, 2040 kg/ha more straw were collected compared to conventional method. Stripper field status after harvesting operations was far cleaner and more ready for next operation than the other

Temporal-spatial variation of wave energy and nearshore hotspots in the Gulf of Oman based on locally generated wind waves

This study aims to assess the wave energy at five coastal stations in the Gulf of Oman using the time series of locally generated wind waves obtained by numerical modeling for 11 years. For this purpose, the spatial, seasonal, monthly, directional, inter-annual of wave energy and power were investigated. The spatial distribution shows that the wave power increases towards the Indian Ocean and the highest mean wave power is located at the eastern station in all seasons. In addition, monthly mean wave power is highest during July and August while the monthly maximum wave power is highest during February at all stations. The ratio of monthly maximum to mean wave power is also the lowest during May to August. Moreover, Monthly Variability Index is the highest in west of the domain where there is no significant wave power potential. In addition, annual wave power as well as total and exploitable wave energies increases from west to east, where the dominant waves propagate from the south, and the exploitable wave energy is approximately 20 times greater than of the central stations

Sustainability of wave energy resources in southern Caspian Sea

This study aims to evaluate the wave energy potential and its spatial and temporal variations in the southern Caspian Sea. For this purpose, SWAN model was used to hindcast wave characteristics for 11 years. The wave energy assessment was conducted in four nearshore stations in order to assess the feasibility of wave energy harvesting and locate the most appropriate station. Assessment of seasonal and monthly variations of the mean and maximum wave powers showed that the central station contains the highest values, especially in November; while the north-eastern station has the lowest values with the highest variation of directional distribution of the wave power. Moreover, the seasonal and monthly variability indices indicate a relatively stable wave condition in all stations. The total and exploitable storages of wave energy were also higher in the central station. Therefore, it was concluded that the central station is the most appropriate location for wave energy harvesting. Furthermore, the inter-annual variations of the mean wave power illustrate no significant long-term change in wave power in the southern Caspian Sea. Therefore, considering the relatively stable condition and comparable exploitable storage of wave energy, this area can be a suitable location for developers

Climate change impact on wave energy in the Persian Gulf

Excessive usage of fossil fuels and high emission of greenhouse gases have increased the earth’s temperature, and consequently have changed the patterns of natural phenomena such as wind speed, wave height, etc. Renewable energy resources are ideal alternatives to reduce the negative effects of increasing greenhouse gases emission and climate change. However, these energy sources are also sensitive to changing climate. In this study, the effect of climate change on wave energy in the Persian Gulf is investigated. For this purpose, future wind data obtained from CGCM3.1 model were downscaled using a hybrid approach and modification factors were computed based on local wind data (ECMWF) and applied to control and future CGCM3.1 wind data. Downscaled wind data was used to generate the wave characteristics in the future based on A2, B1, and A1B scenarios, while ECMWF wind field was used to generate the wave characteristics in the control period. The results of these two 30-yearly wave modelings using SWAN model showed that the average wave power changes slightly in the future. Assessment of wave power spatial distribution showed that the reduction of the average wave power is more in the middle parts of the Persian Gulf. Investigation of wave power distribution in two coastal stations (Boushehr and Assalouyeh ports) indicated that the annual wave energy will decrease in both stations while the wave power distribution for different intervals of significant wave height and peak period will also change in Assalouyeh according to all scenarios

Internal Wave Generation in the Gulf of Oman (Outflow of Persian Gulf)

371-375<span style="font-size:9.0pt;font-family: " times="" new="" roman";mso-fareast-font-family:"times="" roman";mso-bidi-font-family:="" mangal;mso-ansi-language:en-gb;mso-fareast-language:en-us;mso-bidi-language:="" hi"="" lang="EN-GB">Internal waves are a much more complex phenomenon. They are guided by stratification varying with time. From a turbulence modellers point of view, internal wave dynamics must not be neglected, since dissipation of internal waves creates mixing, which is a priori not considered by classical turbulence closure models. In this work, we used GOTM model for calculating and simulating the time series of oceanic parameters related to mixing process and internal waves. The generation of internal waves in the Gulf of Oman (outflow of Persian Gulf) has been investigated by analysis of these parameters. Most important parameters which been analaysed for derivation of internal waves are sigma_t variations, bouyancy frequency squared and salinity profiles.</span

Spectral analysis of wind waves using field data in Strait of Hormuz

729-735Present study consists the analysis of extreme wind wave spectrum in Strait of Hormuz. Data was measured by Port and Maritime organization from 2009 to 2011 in “Monitoring and Modeling Study of Coastal Zone of Persian Gulf” project framework. Wave measurement instrument type was AWAC under sea equipment which has been implanted at 25m depth. Data records analyzed by computer program in STORM, MATLAB and SPSS environments for quality controlling and identifying wave spectrum characteristics like spectrum dispersal, directional spectrum, multi peak spectrum, spectrum shape, parameters of spectrum and spectral classification. Model parameters of JONSWAP and PM spectra were estimated for the observed spectra by using the least square error method

Experimental study of a permeable sloping wave absorber. November 1993.

Wave absorbers are used in wave basins to minimise the reflected wave height form the boundaries of the basin. This reports presents the results of a series of laboratory tests of permeable sloping absorber made of artificial horsehair material. They were carried out on the 0.9 m wide wave flume of the Water Research laboratory, UNSW. Results indicate that the employed absorber can be as effective as a beach absorber made of sand or gravel. The best performance was obtained for the minimum surface slope of the structure

Optimization of the modeled surface temperature by assimilation of SST data over the Persian Gulf

1803-1808Present study is the impact of sea surface temperature(SST) data assimilation on the results of FVCOM by using Nudging scheme. Results of statistical assessments showed the capabilities of the SST assimilation. The SST bias decreases from-0.57°C in control run to -0.49 °C in assimilation run. Mean RMS difference of modeled and observations SST is significantly reduced and approaching to 0.69°C. Surface temperatures of shallow parts were optimized specially near the Hormuz Strait