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1
Manjunath, Pramod, D. Devaprakasam, and Dipen Paul. "Estimation of Global Solar Radiation and Optimal Tilt Angles of Solar Panels for Pune, India." International Journal of Design & Nature and Ecodynamics 16, no. 1 (February 28, 2021): 85–90. http://dx.doi.org/10.18280/ijdne.160111.
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Solar panels can achieve the highest yield when they are oriented in the right way as the influence of the tilt angles can lead to a high impact on the performance. This paper demonstrates the effect of the tilt angle on the final yield and maximum utilization of solar energy. The annual optimal tilt angle of the solar panels for Pune was found out using the Liu and Jordan model. The optimal tilts yielding an increase of 7% was found out to be 0° on the months starting from April and lasting till September and 40° starting from October and holding at 40° till March. By changing the tilt angle every month, there was an increase in the yield by more than 8%. For better yield and maximum utilization of solar energy, optimizing the tilt angles of solar panels monthly or even twice a year is effective based on the study. Most of the panels are fixed at an angle equal to the latitude of the place and oriented towards the Southern sky in the northern hemisphere. Measurements of the monthly average global solar radiation, monthly average temperatures, and monthly average relative humidity were compared. Further ahead regression correlation for a linear model was carried and the regression coefficients a and b were found out to be 0.2804 and 0.3618 respectively.
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Aljanabi, Mohanad, Muhammed Salah Sadiq Al-Kafaji, and Ahmed Hussein Duhis. "Optimum yearly and seasonal tilt angle of solar system in the center of Babylon/Iraq using PVsyst software." Indonesian Journal of Electrical Engineering and Computer Science 31, no. 2 (August 1, 2023): 626. http://dx.doi.org/10.11591/ijeecs.v31.i2.pp626-635.
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The photovoltaic system tilt angle is one of the more significant factors for obtaining the maximum solar energy that will fall on the PV panel. Consequently, then obtain maximum power output, the solar array needs to be angled properly. The analysis for a stand-alone system is simulated and modelled using PVsyst software version-7.2 for system power 3,120 Wp to obtain the optimum value of the tilt angles of maximum solar irradiation in the center of Babylon Governorate, Iraq. The ideal tilt angle for the south has been found for both yearly and the seasons. Different tilt angles were taken which were (29°, 30°, and 31°) annually, azimuth angle for all is (0°). The incident global irradiation in the collector plane, Incident beam irradiation in the collector plane is maximum at tilt angle (29°) that produces maximum available energy 5,132 kWh/kWp/year. same processing for annual different tilt angle was taken for seasonally; the results show that the angle (49°) for summer and (13°) for winter are the optimum tilt angle which obtains the maximum incident global irradiation in the collector plane, maximum incident beam irradiation in the collector plane at this angle then product maximum available energy 5,343 kWh/kWp/year.
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Soulayman, S., and W. Sabbagh. "Optimum Tilt Angle at Tropical Region." International Journal of Renewable Energy Development 4, no. 1 (February 15, 2015): 48–54. http://dx.doi.org/10.14710/ijred.4.1.48-54.
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: One of the important parameters that affect the performance of a solar collector is its tilt angle with the horizon. This is because of the variation of tilt angle changes the amount of solar radiation reaching the collector surface. Meanwhile, is the rule of thumb, which says that solar collector Equator facing position is the best, is valid for tropical region? Thus, it is required to determine the optimum tilt as for Equator facing and for Pole oriented collectors. In addition, the question that may arise: how many times is reasonable for adjusting collector tilt angle for a definite value of surface azimuth angle? A mathematical model was used for estimating the solar radiation on a tilted surface, and to determine the optimum tilt angle and orientation (surface azimuth angle) for the solar collector at any latitude. This model was applied for determining optimum tilt angle and orientation in the tropical zones, on a daily basis, as well as for a specific period. The optimum angle was computed by searching for the values for which the radiation on the collector surface is a maximum for a particular day or a specific period. The results reveal that changing the tilt angle 12 times in a year (i.e. using the monthly optimum tilt angle) maintains approximately the total amount of solar radiation near the maximum value that is found by changing the tilt angle daily to its optimum value. This achieves a yearly gain in solar radiation of 11% to 18% more than the case of a solar collector fixed on a horizontal surface.
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Jiao, Qirong, Jie Jiang, and Zi-Fan Wang. "Sunspot tilt angles revisited: Dependence on the solar cycle strength." Astronomy & Astrophysics 653 (September 2021): A27. http://dx.doi.org/10.1051/0004-6361/202141215.
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Context. The tilt angle of sunspot groups is crucial in the Babcock-Leighton (BL) type dynamo for the generation of the poloidal magnetic field. Some studies have shown that the tilt coefficient, which excludes the latitudinal dependence of the tilt angles, is anti-correlated with the cycle strength. If the anti-correlation exists, it will be shown to act as an effective nonlinearity of the BL-type dynamo to modulate the solar cycle. However, some studies have shown that the anti-correlation has no statistical significance. Aims. We aim to investigate the causes behind the controversial results of tilt angle studies and to establish whether the tilt coefficient is indeed anti-correlated with the cycle strength. Methods. We first analyzed the tilt angles from Debrecen Photoheliographic Database (DPD). Based on the methods applied in previous studies, we took two criteria (with or without angular separation constraint Δs > 2.°5) to select the data, along with the linear and square-root functions to describe Joy’s law, and three methods (normalization, binned fitting, and unbinned fitting) to derive the tilt coefficients for cycles 21–24. This allowed us to evaluate different methods based on comparisons of the differences among the tilt coefficients and the tilt coefficient uncertainties. Then we utilized Monte Carlo experiments to verify the results. Finally, we extended these methods to analyze the separate hemispheric DPD data and the tilt angle data from Kodaikanal and Mount Wilson. Results. The tilt angles exhibit an extremely wide scatter due to both the intrinsic mechanism for its generation and measurement errors, for instance, the unipolar regions included in data sets. Different methods to deal with the uncertainties are mainly responsible for the controversial character of the previous results. The linear fit to the tilt-latitude relation of sunspot groups with Δs > 2.°5 of a cycle carried out without binning the data can minimize the effect of the tilt scatter on the uncertainty of the tilt coefficient. Based on this method the tilt angle coefficient is anti-correlated with the cycle strength with strong statistical significance (r = −0.85 at 99% confidence level). Furthermore, we find that tilts tend to be more saturated at high latitudes for stronger cycles. The tilts tend to show a linear dependence on the latitudes for weak cycles and a square-root dependence for strong cycles. Conclusions. This study disentangles the cycle dependence of sunspot group tilt angles from the previous results that were shown to be controversial, spurring confusion in the field.
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Howard, Robert F. "The Development of Sunspot Groups." International Astronomical Union Colloquium 141 (1993): 492–94. http://dx.doi.org/10.1017/s0252921100029699.
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AbstractIt is shown that the growth and decay rates of sunspot groups are both a function of the axial tilt angles of the groups. Both of these rates reach a maximum near the average tilt angle, which is around +5°, not 0°. (A positive tilt angle represents the situation where the leading spots are equatorward of the following spots). The fact that this peak angle is close to the average tilt and not 0° suggests that this may be the orientation of the subsurface toroidal flux tube(s) from which the sunspot groups form. In general, spot groups with positive tilt angles show faster average percentage growth rates for greater positive tilt angles. For negative tilt angles (following spots equatorward of leading spots) the situation is quite different. Within certain well-defined ranges of tilt angles the average group percentage area growth rates are quite high and the dispersion in this quantity is large. In other well-defined tilt angle ranges the percentage growth rates are uniformly (relatively) small. The difference between these average growth rates is more than a factor two. The reality of this result can be demonstrated by selecting for analysis various subsets of the data. It may be hypothesized that in general the dispersion measured in group tilt angles results from the random action of large-scale convection on the rising magnetic flux loops. Both growth and decay are facilitated in the case of flux loops that have a minimum twist. The percentage growth and decay rates are affected by the fact that groups with tilt angles near the average value tend to be larger than groups with different tilt angles. The ‘quantized’ behavior of the percentage growth rates for negative tilt angles is difficult to fit into any rough model of flux emergence. The more or less ‘quantized’ nature of the growth-tilt angle relationship for negative tilt angles is quite puzzling and may reflect some characteristic of the subsurface flux orientation or development which is at present unknown.
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Hassanian, Reza, Morris Riedel, Nashmin Yeganeh, and Runar Unnthorsson. "A Practical Approach for Estimating the Optimum Tilt Angle of a Photovoltaic Panel for a Long Period—Experimental Recorded Data." Solar 1, no. 1 (November 24, 2021): 41–51. http://dx.doi.org/10.3390/solar1010005.
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In this study, recorded empirical data were applied with a practical approach to investigate the optimal tilt angle of the flat plate collectors facing south for a long period in Tehran, Iran. The data included 20 years of recorded average total radiation on the horizontal plane in Tehran’s meteorological station. Based on the previous studies, the annual optimum tilt angle for Tehran was estimated at 33 degrees annually; however, this estimation does not focus on the energy absorption and effectiveness of changing the tilt angle monthly, seasonally, and bi-annually via measured data. This paper aims to explain this distinction between various radiation receptions with different tilt angle adjustments. This study shows that annual solar cumulative radiation energy gained via a monthly tilt angle can be approximately 7% higher than that achieved with an annual tilt angle setup. Additionally, the seasonal and bi-annual tilt angles have about 6% more annual cumulative radiation absorption than the annual tilt angle setup. Moreover, with consideration of similar monthly received radiation, the results illustrate that the radiation gained with a monthly tilt angle set up was 20% greater in the summer months than an annual tilt angle adjustment.
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Chauhan, Ranchan, N. S. Thakur, and Sunil Chamoli. "Tilt Angle Optimization for Grid Interactive Solar Photovoltaic Array." Applied Mechanics and Materials 110-116 (October 2011): 4554–58. http://dx.doi.org/10.4028/www.scientific.net/amm.110-116.4554.
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The overall performance of any solar energy project largely depends upon the available solar radiations, inclination and orientation of solar collectors. Presented in this paper is the analytical study on optimum tilt angles and lifetime differential savings for a distributed 200 kW grid connected mono-crystalline solar PV system operating at Khatkar Kalan, Punjab, India. The optimum tilt angles for monthly, seasonally and yearly basis is carried out by searching the values of tilt angle for which electric power output is maximum for a particular day or a specific period using energy conversion model. The results reveal that the yearly optimum tilt angle for the SPV plant at Khatkar Kalan is 36° which is 4.58° higher than the latitude angle. The power output from the array increases with increase in angle of tilt for winter months whereas the trend is reverse for the summer months. In winter months the maximum power output is achieved for the array surface with a tilt of angle 13° - 23° higher than the local latitude while for summer months the maximum power output is achieved at 16° lower than the latitude angle. The optimum tilt angles maximizing monthly power output for south facing surface shows that the monthly optimum tilt angle varies from 15° to 55°. Also the parametric analysis for some influential factors such as latitude of location and reflectivity of ground surface is explored.
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Memon, Qasir Ali, Abdul Qadir Rahimoon, Khurshed Ali, Muhammad Fawad Shaikh, and Shoaib Ahmed Shaikh. "Determining Optimum Tilt Angle for 1 MW Photovoltaic System at Sukkur, Pakistan." International Journal of Photoenergy 2021 (May 21, 2021): 1–8. http://dx.doi.org/10.1155/2021/5552637.
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Solar energy is directly converted into electrical energy by using photovoltaic (PV) panels. The efficiency of PV panel varies with its orientation and tilt angle with the horizontal plane. In this paper, we investigate the optimum tilt angle of solar panels installed at Sukkur IBA University. The optimum angle for tilted surfaces varying from 0° to 90° in steps of 1° was calculated for the values of which the daily total solar radiation was maximum for a specific period. It was found that the optimum tilt angle changed between 0° and 61.1° throughout the year in Sukkur IBA University, Sindh Pakistan ( latitude = 27.7268 ° N, longitude = 68.8191 ° E). For calculating irradiance, optimal fixed (15 and 29.5 degrees) and variable tilt angles are used for every month of year 2019. The irradiance calculated at 15 degrees tilt angle is compared with the fixed angle of 29.5 and variable angles. It was found that optimal tilt angle for the region of Sukkur located in northern Pakistan is to be 29.5 degrees.
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Salam T. Hussain, Abadal. "Measuring PV Module Performance at Different Tilt Angles in Southern Iraq Based Simulation." International Journal of Engineering & Technology 7, no. 2.34 (June 8, 2018): 84. http://dx.doi.org/10.14419/ijet.v7i2.34.13918.
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This paper presented that how to calculate the tilt angles and solar irradiance on photovoltaic (PV) module in southern Iraq (latitude 30° N). The latitude and day number of the city is taken into account to calculate the tilt angle and solar irradiance by using a mathematical equation. The optimum tilt angles of PV module in southern Iraq are range from 38° to 84°. The yearly maximum total and average solar irradiance is needed to determine the optimum tilt angle of PV module. The result shows that 50° of tilt angle is the best performance of PV module in southern Iraq.
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Lin, Jing, Yuli Wang, Todd Ochs, Chaoshu Tang, Junbao Du, and Hongfang Jin. "Tilt angles and positive response of head-up tilt test in children with orthostatic intolerance." Cardiology in the Young 25, no. 1 (October 15, 2013): 76–80. http://dx.doi.org/10.1017/s1047951113001601.
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AbstractThis study aimed at examining three tilt angle-based positive responses and the time to positive response in a head-up tilt test for children with orthostatic intolerance, and the psychological fear experienced at the three angles during head-up tilt test. A total of 174 children, including 76 boys and 98 girls, aged from 4 to 18 years old (mean 11.3±2.8 years old), with unexplained syncope, were randomly divided into three groups, to undergo head-up tilt test at the angles of 60°, 70° and 80°, respectively. The diagnostic rates and times were analysed, and Wong–Baker face pain rating scale was used to access the children’s psychological fear. There were no significant differences in diagnostic rates of postural orthostatic tachycardia syndrome and vasovagal syncope at different tilt angles during the head-up tilt test (p>0.05). There was a significant difference, however, in the psychological fear at different tilt angles utilising the Kruskal–Wallis test (χ2=36.398, p<0.01). It was mildest at tilt angle 60° utilising the Kolmogorov–Smirnov test (p<0.01). A positive rank correlation was found between the psychological fear and the degree of tilt angle (rs=0.445, p<0.01). Positive response appearance time was 15.1±14.0 minutes at 60° for vasovagal syncope children. There was no significant difference in the time to positive response, at different tilt angles during the head-up tilt test for vasovagal syncope or for postural orthostatic tachycardia syndrome. Hence, it is suggested that a tilt angle of 60° and head-up tilt test time of 45 minutes should be suitable for children with vasovagal syncope.
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Sado, Kerry A., Lokman H. Hassan, and Shivan Sado. "Photovoltaic panels tilt angle optimization." E3S Web of Conferences 239 (2021): 00019. http://dx.doi.org/10.1051/e3sconf/202123900019.
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The tilt angle of solar panels is significant for capturing solar radiation that reaches the surface of the panel. Photovoltaic (PV) performance and efficiency are highly affected by its angle of tilt with respect to the horizontal plane. The amount of radiation reaching the surface of a PV panel changes with the changes in its tilt angle, hence adding a solar tracking system will maximize the amount of solar radiation reaching the surface of a PV panel at any time during the day, however, integrating solar tracking system will increase the total cost and maintenance of any PV system. Thus, using an optimized fixed tilt angle is the solution to element the initial, maintenance, and operation costs of a solar tracking system. Yet, the fixed angle is location-specific because it depends on the daily, monthly, and yearly location of the sun. In this study; daily, monthly and seasonally angles are calculated mathematically and the amount of incident radiation on the surface of the PV panel is measured along with its voltage. By comparing the practical measurements of the output voltage of PV panels, an optimized tilt angle is decided.
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Martin, William J., and Alan Shapiro. "Impact of Radar Tilt and Ground Clutter on Wind Measurements in Clear Air." Journal of Atmospheric and Oceanic Technology 22, no. 6 (June 1, 2005): 649–63. http://dx.doi.org/10.1175/jtech1737.1.
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Abstract From geometrical considerations, the optimum tilt angle for a meteorological radar at which the best possible vertical resolution results is derived. This optimum angle is a compromise between the effects of beam divergence and range gate spacing. For typical S-band radar parameters, this optimum tilt angle is found to be about 7°. However, wind analyses at this tilt angle were found not to be accurate in practice because of ground clutter contamination, and suboptimal angles need to be used. Most of the ground clutter was found to be sensed in the radar beam sidelobes. The data presented here imply that ground clutter is a serious contaminant at tilt angles as high as 45°. For clear-air wind profiling in the boundary layer, the impact of ground clutter contamination increased as the tilt angle was increased. Data presented from four radars [the Goodland, Kansas, Weather Surveillance Radar-1988 Doppler (WSR-88D); the University of Oklahoma’s Doppler on Wheels; NCAR’s S-band dual-polarization Doppler radar (S-Pol); and NSSL’s Cimarron] suggest that a fairly narrow range of tilt angles from 1° to 2° is generally acceptable for wind profiling of the boundary layer in clear-air conditions. Tilt angles outside this range lead to significant systematic errors, primarily from ground clutter contamination.
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Salih, Aqeel R. "Seasonal Optimum Tilt Angle of Solar Panels for 100 Cities in the World." Al-Mustansiriyah Journal of Science 34, no. 1 (March 30, 2023): 104–10. http://dx.doi.org/10.23851/mjs.v34i1.1250.
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Solar energy is the most abundant renewable energy source. This energy can be converted directly into electricity using solar panels. The fixed tilt solar panels are the most practical and the most widely installed throughout the world. Optimum tilt angle calculation has the advantage that it does not use expensive solar trackers. This research calculates the seasonal optimum tilt angle of solar panels for 17 cities in Iraq and 83 cities in 83 countries distributed around the world. Solar Panel Angle Calculator program was used in calculating the optimum tilt angles from vertical. The optimum tilt angle varies between 6° and 112° throughout the year. This angle for winter, spring/ autumn and summer seasons are found to be between 6° to 66°, 30° to 89° and 54° to 112°, respectively. All angles calculated from the calculator program are validated by comparing it with those obtained from equations. An excellent agreement was established. Cities which have approximately the same absolute values of the latitudes are have the same optimum tilt angles. Based on the results, adjusting angles four times a year is recommended. This work can serve as a guidance for installing solar panels.
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Sharma, Gori Shankar, Om Prakash Mahela, Mohamed G. Hussien, Baseem Khan, Sanjeevikumar Padmanaban, Muhammed B. Shafik, and Zakaria M. Salem Elbarbary. "Performance Evaluation of a MW-Size Grid-Connected Solar Photovoltaic Plant Considering the Impact of Tilt Angle." Sustainability 14, no. 3 (January 27, 2022): 1444. http://dx.doi.org/10.3390/su14031444.
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This paper presents a study for the estimation of generation from a large-scale, grid-interfaced solar PV plant using the PVsyst software. This study aims to investigate the effect of tilt angle on the performance of the grid-integrated solar PV plant. Two types of tilt angle test plants, i.e., a fixed tilt angle of 30° (1 MW) and two seasonal tilt angles, in summer 13° and in winter 30° (2.5 MW), have been selected at the same location in Bikaner, India. The performance of the proposed test solar power plants, rated at 1 MW (fixed tilt angle) and 2.5 MW (two seasonal tilt angles), is established by comparing the results obtained using the PVsyst software with the practical data of annual solar insolation. It is established that the radiation incident on PV modules will increase by 2.41% if two seasonal tilt angles are considered. Hence, the annual capacity utilization factor (CUF) has increased by 0.26%. Furthermore, it is established that the proposed method’s performance is superior compared to the statistical methods reported in the literature.
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Sun, Yong, and Xing Sheng Li. "Determination of Attack Angle and Tilt Angle of a Cutting Pick." Advanced Materials Research 705 (June 2013): 415–18. http://dx.doi.org/10.4028/www.scientific.net/amr.705.415.
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Mechanical excavators play an important role in mining and construction. An excavation machine cuts rocks using its cutterhead which is normally composed of a large number of cutting picks. These picks are installed on a drum with certain attack angles, tilt angles and skew angles. These angles, especially attack and tilt angles, will affect the forces acting on individual picks and the cutterhead. To ensure the reliability and productivity of the excavation machine, these angles have to be kept in their optimal values. However, in manufacturing, these three types of angles cannot be set simultaneously. They have to be respectively set one after another. As a result, the angle which is set previously will be changed by the angles which are determined after it. Understanding the relationship between the values of the final angle and the designed angle is important for optimizing drum and pick design. This paper develops a formula for quantitatively analyzing this relationship, with the research scope limited to attack angle and tilt angle only as the first stage of the study.
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Kamanga, B., J. S. P. Mlatho, C. Mikeka, and C. Kamunda. "Optimum Tilt Angle for Photovoltaic Solar Panels in Zomba District, Malawi." Journal of Solar Energy 2014 (January 9, 2014): 1–9. http://dx.doi.org/10.1155/2014/132950.
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A study to determine the optimum tilt angle for installing photovoltaic solar panels in Zomba district, Malawi, has been conducted. The study determined the optimum monthly tilt angles of PV solar panels and the seasonal adjustments needed for the panels in order to collect maximum solar radiation throughout the year. In this study, global solar radiation (GSR) on four tilted surfaces was measured. The north-facing surfaces were titled at angles of 0°, 15°, 20°, and 25°. The GSR data was used to determine the daily and monthly optimum tilt angles for the PV panels. The optimum tilt angles were found to be 0° or 25° depending on the time of the year. From October to February, the optimum tilt angle has been determined to be 0° and, from March to September, the optimum tilt angle is observed to be 25°. There are only two seasonal adjustments that are needed for PV solar panels in Zomba district and these should be carried out at the end of February and at the end of September. For fixed solar panels with no seasonal adjustments, the optimum tilt angle for the PV solar panels that are northfacing has been determined to be 25°.
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Xia, Senbin, Ziqiang Yin, Cheng Huang, Yawen Guo, and Chao Zhang. "Characteristics of Elliptical Vibration-Assisted Cutting with Variations in Tilt Angle of Elliptical Locus." Micromachines 14, no. 7 (July 15, 2023): 1426. http://dx.doi.org/10.3390/mi14071426.
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Elliptical vibration-assisted cutting (EVAC), one of the advanced micromachining methods, enables results not possible with traditional ultra-precision machining. It is considered to be one of the most viable options for manufacturing micro/nanostructured surfaces. However, it is difficult to control the elliptical locus with different tilt angles; therefore, previous studies have primarily focused on fixed locus and investigated the effects of the amplitude and frequency on machining performance. In addition, tilt angle is an important factor affecting the characteristics of EVAC. To maximize the cutting performance of EVAC, the cutting characteristics of EVAC with variations in tilt angle of elliptical locus are investigated. The mathematical model of elliptical trajectory based on different tilt angles is established via geometric analysis. The effects of the different tilt angle (0–180°) on cutting forces, chip formation, defect generation and surface roughness are observed and theoretically analyzed in microgroove experiments. The experimental results show that the tilt angle has a significant effect on the cutting force, chip formation, defects and surface roughness. The best cutting performance can be obtained at the tilt angle of 30°, while the worst is recorded at 90°. The results can provide a valuable reference for further comprehensive studies to maximize the cutting performance of EVAC.
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Melhem, Raghed, and Yomna Shaker. "Optimum Tilt Angle and Solar Radiation of Photovoltaic Modules for Gulf Collaboration Council Countries." International Journal of Energy Research 2023 (May 9, 2023): 1–17. http://dx.doi.org/10.1155/2023/8381696.
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This article focuses on the optimization of tilt angle for solar panels in the Gulf Cooperation Council (GCC) countries. The tilt angle is a crucial factor that affects the amount of solar radiation received by the solar panel. The study uses a mathematical model to calculate the optimal tilt angle based on the latitude and longitude of the location and compares the results with the PVWatts calculator. The importance of selecting the optimal tilt angle for maximizing solar energy production is emphasized. The study finds that the mathematical model and PVWatts calculator are in good agreement, except for the negative tilt angles calculated by the model. The article also provides monthly, seasonally, and yearly irradiance values for the GCC countries calculated using the PVWatts calculator. It suggests that changing the tilt angle 12 times during the year can enhance the power output by 10.9%. The results show that the monthly automated angle has a maximum in December and a minimum in June, with Oman having the highest maximum angle of 50.5 and the lowest minimum angle of -10.58. Kuwait has the highest maximum angle of 58.33 and the lowest minimum angle of -2.75. The results are verified by the PVWatts calculator, showing a good similarity with a percentage of error around 3%. The study highlights the importance of selecting the optimal tilt angle to achieve maximum solar energy production in the GCC countries. The mathematical model and PVWatts calculator can serve as tools to calculate the optimum tilt angle for solar panels.
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Wang, Qiang, Kangping Liao, and Qingwei Ma. "The Influence of Tilt Angle on the Aerodynamic Performance of a Wind Turbine." Applied Sciences 10, no. 15 (August 4, 2020): 5380. http://dx.doi.org/10.3390/app10155380.
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Aerodynamic performance of a wind turbine at different tilt angles was studied based on the commercial CFD software STAR-CCM+. Tilt angles of 0, 4, 8 and 12° were investigated based on uniform wind speed and wind shear. In CFD simulation, the rotating motion of blade was based on a sliding mesh. The thrust, power, lift and drag of the blade section airfoil at different tilt angles have been widely investigated herein. Meanwhile, the tip vortices and velocity profiles at different tilt angles were physically observed. In addition, the influence of the wind shear exponents and the expected value of turbulence intensity on the aerodynamic performance of the wind turbine is also further discussed. The results indicate that the change in tilt angle changes the angle of attack of the airfoil section of the wind turbine blade, which affects the thrust and power of the wind turbine. The aerodynamic performance of the wind turbine is better when the tilt angle is about 4°. Wind shear will cause the thrust and power of the wind turbine to decrease, and the effect of the wind shear exponents on the aerodynamic performance of the wind turbine is significantly greater than the expected effect of the turbulence intensity. The main purpose of the paper was to study the effect of tilt angle on the aerodynamic performance of a fixed wind turbine.
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Flores, M., S. Chávez, H. Terres, A. Lizardi, and A. Lara. "Thermal analysis of a solar still through CFD." Journal of Physics: Conference Series 2307, no. 1 (September 1, 2022): 012008. http://dx.doi.org/10.1088/1742-6596/2307/1/012008.
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Abstract Present work shows the results of the thermal performance of a single-slope solar still under different tilt angles of the glass cover, using numerical simulation through CFD. Simulations were carried out using Computational Fluid Dynamics for glass-cover tilt angles of 10°, 20°, 30°, and 40°. For each angle, distributions of temperature, density and velocity of the fluid were obtained. Besides, the convective heat transfer coefficient between the basin and the fluid was calculated. As a result, it was found that the water temperature and density differences between the basin and the glass cover increase as the tilt angle also increases. Furthermore, the fluid flow follows a laminar regime for the 10° and 20° angles, while for the tilt angles of 30° and 40°, flow obeys a turbulent behavior. Finally, simulation results show that heat transfer coefficient increases as a function of the tilt angle, ranging from 2.45 W/m2-K to 3.29 W/m2-K.
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Doole, Ron. "On Measuring Section Thickness." Microscopy Today 9, no. 4 (May 2001): 17. http://dx.doi.org/10.1017/s1551929500057291.
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Section thickness can be measured by placing beads of some kind on the top and bottom surfaces of the section. This is then a simple parallax problem.Imagine the specimen in cross section. If there are two particles, one vertically above the other they are separated by the film thickness T. Tilt the film through an angle A and in plan view the particles will separate by a distance D. This can also be extended to account for two particles not vertically above each other but I'll stick to the easy case for the explanation.Take two negatives one at zero tilt and one at tilt of A and measure the separation D. The thickness can be calculated by T=D/sinA.The direction of the tilt axis must be known for the measurements and it is easy to see that the larger the tiit angle and the more accurately the separation is measured, the more accurate the measurement will be. Tilt at both positive and negative angles to get a more accurate result.
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Eshaghzadeh, Ata. "Depth Estimation Using the Tilt Angle of Gravity Field due to the Semi-Infinite Vertical Cylindrical Source." Journal of Geological Research 2017 (January 9, 2017): 1–7. http://dx.doi.org/10.1155/2017/3513272.
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Tilt angle filter is an interpretation method that is used to determine the source borders locations from potential fields data. Moreover, the tilt angle is applied for estimation of the anomaly source depth, such as contact-depth method and tilt-depth method. In this paper an application of the tilt angle technique obtained from the first vertical and horizontal gradients of the gravity anomaly from semi-infinite vertical cylindrical source is described. The technique is based on the tilt angle and derivatives ratio. In this approach the depth estimates are proportional to the computed tilt angles and their distances from the cross section center of the anomaly cause on the surface. This new method is termed the tilt-distance-depth (TDD). The method is demonstrated using synthetic gravity data, with and without random noise, and real gravity data from Iran. The results are also compared with the solutions from Euler deconvolution technique and inverse modelling using Modelvision software.
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Tyler, Timothy F., Elliott B. Hershman, Stephen J. Nicholas, Jeffery H. Berg, and Malachy P. McHugh. "Evidence of Abnormal Anteroposterior Patellar Tilt in Patients with Patellar Tendinitis with Use of a New Radiographic Measurement." American Journal of Sports Medicine 30, no. 3 (May 2002): 396–401. http://dx.doi.org/10.1177/03635465020300031501.
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Background A number of clinical conditions of the patellofemoral joint have been correlated with abnormal patellofemoral radiographic measurements. Hypothesis An abnormal anteroposterior patellar-tilt angle may be a contributing factor to pathologic conditions of the knee. Study Design Prospective nonrandomized clinical trial. Methods The anteroposterior patellar-tilt angle was measured in cadaveric knees to determine the best knee position. The radiographs of normal subjects and patients with patellar tendinitis or patellofemoral pain syndrome were examined for differences in patellar-tilt angle. Results Cadaveric measurements demonstrated highest intertester and intratester reliability at 30° of knee flexion and neutral femoral rotation. Intratester measurements on normal subjects exhibited high reliability, with a mean anteroposterior tilt angle of 30.8° ± 6.7°. In the patellofemoral pain group the mean anteroposterior tilt angle was 29.1° ± 8.5°; however, for patients with patellar tendinitis, it was 25.6° ± 7.0°, significantly lower than in the normal population. Furthermore, there was no difference between the angles of involved and uninvolved knees of patients with unilateral patellar tendinitis. Conclusion The anteroposterior patellar-tilt angle is a clinically reliable measurement of patellar tilt in the sagittal plane that can be used to study patellofemoral tilt in a variety of clinical situations. The results of this study demonstrate that patients with patellar tendinitis have abnormal patellar tilt in the sagittal plane.
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Matsumoto, Hirofumi, Makoto Shiraishi, Ariaki Higashi, Sakae Hino, Mayumi Kaburagi, Heisuke Mizukami, Futaba Maki, et al. "The Forward and Lateral Tilt Angle of the Neck and Trunk Measured by Three-Dimensional Gait and Motion Analysis as a Candidate for a Severity Index in Patients with Parkinson’s Disease." Neurology International 14, no. 3 (September 13, 2022): 727–37. http://dx.doi.org/10.3390/neurolint14030061.
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(1) Objective: To evaluate the usefulness of a three-dimensional motion-analysis system (AKIRA®) as a quantitative measure of motor symptoms in patients with Parkinson’s disease (PD). (2) Method: This study included 48 patients with PD. We measured their motion during 2 m of walking using AKIRA®, we calculated the tilt angles of the neck and trunk, ankle height, and gait speed, then we compared these parameters with the MDS-UPDRS and the Hoehn and Yahr scale. Furthermore, we measured these AKIRA indicators before and after 1 year of observation. (3) Results: The forward tilt angle of the neck showed a strong correlation with the scores on parts II, III, and the total MDS-UPDRS, and the tilt angle of the trunk showed a moderate correlation with those measures. The lateral tilt angle of the trunk showed a moderate correlation with a freezing of the gait and a postural instability. Regarding changes over the course of 1 year (n = 34), the total scores on part III of the MDS-UPDRS and the forward tilt angle of the neck improved, while the lateral tilt angle of the trunk worsened. (4) Conclusion: Taken together, the forward and lateral tilt angles of the neck and trunk as measured by AKIRA® can be a candidate for quantitative severity index in patients with PD.
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Song, Huixu, Qingwei Li, and Zhaoyao Shi. "Maximum Acceptable Tilt Angle for Point Autofocus Microscopy." Sensors 23, no. 24 (December 6, 2023): 9655. http://dx.doi.org/10.3390/s23249655.
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The complete and accurate acquisition of geometric information forms the bedrock of maintaining high-end instrument performance and monitoring product quality. It is also a prerequisite for achieving the ‘precision’ and ‘intelligence’ that the manufacturing industry aspires to achieve. Industrial microscopes, known for their high accuracy and resolution, have become invaluable tools in the precision measurement of small components. However, these industrial microscopes often struggle to demonstrate their advantages when dealing with complex shapes or large tilt angles. This paper introduces a ray-tracing model for point autofocus microscopy, and it provides the quantified relationship formula between the maximum acceptable tilt angle and the beam offset accepted in point autofocus microscopy, then analyzing the maximum acceptable tilt angle of the objects being measured. This novel approach uses the geometric features of a high-precision reference sphere to simulate the tilt angle and displacement of the surface under investigation. The research findings show that the maximum acceptable tilt angles of a point autofocus microscope vary across different measured directions. Additionally, the extent to which the maximum acceptable tilt angles are affected by the distances of the beam offset also varies. Finally, the difference between the experiment results and the theoretical results is less than 0.5°.
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Chang, Ying Pin. "Optimal Tilt Angle for PV Modules Using the Neural-Genetic Algorithm Considering Mathematical Model of the Solar Orbit and Position." Advanced Materials Research 512-515 (May 2012): 250–53. http://dx.doi.org/10.4028/www.scientific.net/amr.512-515.250.
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This paper presents a method which combines an artificial neural network and a genetic algorithm (ANNGA) in determining the tilt angle for photovoltaic (PV) modules. First, a Taguchi experiment was used to perform an efficient experimental design and analyze the robustness of the tilt angles for fixed south-facing PV modules. Following, the results from the Taguchi experiment were used as the learning data for an artificial neural network (ANN) model that could predict the tilt angles at discrete levels. Finally, a genetic algorithm method was applied to obtain a robust tilt angle setting of the tilt angle of PV modules with continuous variables. The objective is to maximize the electrical energy of the modules. In this study, three Taiwanese areas were selected for analysis. The position of the sun at any time and location was predicted by the mathematical procedure of Julian dating; then, the solar irradiation was obtained at each site under a clear sky. To confirm the computer simulation results, experimental system are conducted for determining the optimum tilt angle of the modules. The results show that the seasonal optimum angle is 26.4 (deg.) for February-March-April; -9.47(deg.) for May-June-July, 21.32(deg.) for August-September-October and 53.13(deg.) from November-December-January in the Taiwan area.
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VAHEY, DAVID W., JOHN M. CONSIDINE, and MICHAEL A. MACGREGOR. "Influence of forming conditions on fiber tilt." TAPPI Journal 12, no. 4 (May 1, 2013): 33–40. http://dx.doi.org/10.32964/tj12.4.33.
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Fiber tilt describes the projection of fiber length in the thickness direction of paper. The projection is described by the tilt angle of fibers with respect to the plane of the sheet. A simple model for fiber tilt is based on jet-to-wire velocity differential in combination with cross-flows on the wire. The tilt angle of a fiber is found to vary as the sine of its in-plane orientation angle. The phase of variation is a large multiple of the fiber-misalignment angle associated with the cross flow. The multiple can decrease from 40 to 8 as the cross-flow angle increases from 1° to 10°, showing a high degree of nonlinearity. Application of the model was demonstrated by characterizing previously published tape-peels conducted at 45° intervals on both sides of a lightweight-coated base sheet. Degree of fiber pullout, a surrogate for fiber tilt, was indicated by measuring the mean gray value of images of the tape surface against a dark background. On tape peels from each side of the sheet, gray value versus angle was well described by a sine wave, but the phase of the wave was different on each side. By comparing the phases of the sine waves with those of the model, top and bottom fiber misalignment angles were calculated. The model is most sensitive to variations in misalignment angles less than 2.5°.
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Wang, Fei, and Xue Zeng Zhao. "Tilt of Atomic Force Microscope Cantilevers: Effect on Friction Measurements." Key Engineering Materials 353-358 (September 2007): 742–45. http://dx.doi.org/10.4028/www.scientific.net/kem.353-358.742.
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The cantilevers of atomic force microscope (AFM) are mounted under a certain tilt angle, which is commonly assumed to have negligible effect on friction measurements in AFM. We present a theoretical study of the effect of the tilt angle on AFM based friction measurements. A method for correcting the friction coefficient between sample surfaces and AFM tips is also presented to minimize the effects of the tilt. The frictional forces between a silicon tip and a silicon surface at tilt angles ranging from 5 degrees to 25 degrees were measured. The results show that the measured friction coefficient increases with the tilt angle effectively, whereas the variation range of the corrected friction coefficient is within 10%.
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Wren, Tishya A. L., and Paul C. Mitiguy. "A Simple Method to Obtain Consistent and Clinically Meaningful Pelvic Angles from Euler Angles during Gait Analysis." Journal of Applied Biomechanics 23, no. 3 (August 2007): 218–23. http://dx.doi.org/10.1123/jab.23.3.218.
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Clinical gait analysis usually describes joint kinematics using Euler angles, which depend on the sequence of rotation. Studies have shown that pelvic obliquity angles from the traditional tilt-obliquity-rotation (TOR) Euler angle sequence can deviate considerably from clinical expectations and have suggested that a rotation-obliquity-tilt (ROT) Euler angle sequence be used instead. We propose a simple alternate approach in which clinical joint angles are defined and exactly calculated in terms of Euler angles from any rotation sequence. Equations were derived to calculate clinical pelvic elevation, progression, and lean angles from TOR and ROT Euler angles. For the ROT Euler angles, obliquity was exactly the same as the clinical elevation angle, rotation was similar to the clinical progression angle, and tilt was similar to the clinical lean angle. Greater differences were observed for TOR. These results support previous findings that ROT is preferable to TOR for calculating pelvic Euler angles for clinical interpretation. However, we suggest that exact clinical angles can and should be obtained through a few extra calculations as demonstrated in this technical note.
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Hua, Lyu-Guang, Qasir Ali Memon, Muhammad Fawad Shaikh, Shoaib Ahmed Shaikh, Rehan Ali Rahimoon, Syed Hadi Hussain Shah, and Abdul Qadir. "Comparative Analysis of Power Output, Fill Factor, and Efficiency at Fixed and Variable Tilt Angles for Polycrystalline and Monocrystalline Photovoltaic Panels—The Case of Sukkur IBA University." Energies 15, no. 11 (May 26, 2022): 3917. http://dx.doi.org/10.3390/en15113917.
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Photovoltaic technology mainly uses beam, diffused, and reflected solar radiation to produce power. To increase the photovoltaic power output, the surface of the solar panel must be at the optimal tilt angle. In this paper, a numerical study is carried out to investigate the optimal tilt angle for a 1 MW PV system installed at Sukkur IBA University (latitude = 27.7268° N, longitude = 68.8191° E). Moreover, power output, efficiency, and fill factor are calculated for polycrystalline and monocrystalline solar panels. Results obtained at different tilt angles are used to compare the solar gain from photovoltaic modules installed at the university. In conclusion, an optimal tilt angle is decided for both polycrystalline and monocrystalline solar panels used at Sukkur IBA University. It was found that the optimal tilt angle for the installed 1 MW systems is 29.5 degrees.
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Du, Yuzhou, Mingyi Zheng, Yanfeng Ge, and Bailing Jiang. "Anisotropy in tensile behavior of an extruded Mg-4.50Zn-1.13Ca (wt.%) alloy." International Journal of Materials Research 112, no. 10 (October 1, 2021): 787–93. http://dx.doi.org/10.1515/ijmr-2020-8182.
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Abstract The present study investigated anisotropy in tensile behavior of an extruded Mg-4.50Zn-1.13Ca (wt.%) alloy through tensile testing along different tilt angles relative to the extrusion direction. Results showed that the as-extruded Mg-4.50Zn-1.13Ca (wt.%) alloy exhibited anisotropy in tensile behavior due to the formation of basal texture. Basal slip, prismatic slip and tensile twinning were the dominant deformation modes depending on the tensile direction. Prismatic slip was the dominant deformation mode for samples with small tilt angle (θ = 0° and 22.5°). Basal slip was activated when the tilt angle was increased, which also resulted in the decrease of yield strength. Tensile twinning was responsible for the yielding of the samples with high tilt angles (θ = 67.5° and 90°). The ductility was significantly reduced at high tilt angle, which was mainly attributed to the appearance of tensile twinning during tensile deformation.
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Işık, Emre, Seda Işık, and Bahar B. Kabasakal. "Sunspot group tilt angles from drawings for cycles 19-24." Proceedings of the International Astronomical Union 13, S340 (February 2018): 133–36. http://dx.doi.org/10.1017/s1743921318001461.
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AbstractThe tilt angle of a sunspot group is a critical quantity in the surface transport of magnetic flux and the solar dynamo. To contribute long-term databases of the tilt angle, we developed an IDL routine, which allows the user to interactively select and measure sunspot positions and areas on the solar disc. We measured the tilt angles of sunspot groups for solar cycles 19-24 (1954.6-2017.8), using the sunspot drawing database of Kandilli Observatory. The method is similar to that used in the discontinued Mt. Wilson and Kodaikanal databases, with the exception that sunspot groups were identified manually, which has improved the accuracy of the resulting tilt angles. We obtained cycle averages of the tilt angle and compared them with the values from other datasets, keeping the same group selection criteria. We conclude that the previously reported anti-correlation with the cycle strength needs further investigation.
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كاظم, عماد جواد. "مقارنة بين زوايا الميل للألواح الشمسية الثابتة لمدينة بغداد باستخدام جهاز محلل الظل للإشعاع الشمسي على مدار سنة كاملة." University of Thi-Qar Journal of Science 4, no. 4 (July 9, 2014): 18–23. http://dx.doi.org/10.32792/utq/utjsci/v4i4.654.
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Generated energy by fixed solar panels depended on the optimum tilt angle with the horizon, so it must be defined correctly to improve the performance of the solar panel system. In this research the values of optimum tilt angle with the horizon of solar panels for Baghdad city was calculated monthly and quarterly and annually by using shadow analyzer of solar radiation. The optimum tilt angles is (60.51, 37, 19.5, 0, 0.13, 30, 45.55 , 60) degrees monthly, respectively and quarterly is 58 ° for months (12, 1, 2) and 19 degrees for months (3, 4, 5) and 2 degrees for months (6, 7, 8) and 45 degrees for months (9, 10, 11 ) When dividing the year into two seasons the optimal angle is 13 degrees for months (4, 5, 6, 7, 8, 9) and 51 degrees for months (10,11, 12, 1, 2, 3). The annual optimum tilt angle is 30 degrees it is noticed an increase in optimum tilt angle in winter than in summer and that is because of the increasing in the sun declination and the decreasing in the number of noon hours in winter. The increasing in the amount of energy falling on the solar panels was 8.34% when the tilt angle changed monthly and 6.85% when it changed quarterly and 6.61% when it changed for two seasons with respect to yearly fix tilt angle.
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Almuzaiqer, Redhwan, Mohamed Elsayed Ali, and Khaled Al-Salem. "Tilt Angle’s Effects on Free Convection Heat Transfer Coefficient inside a Water-Filled Rectangular Parallelepiped Enclosure." Processes 10, no. 2 (February 18, 2022): 396. http://dx.doi.org/10.3390/pr10020396.
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The effect of tilt angle on free convection heat transfer is investigated experimentally inside a rectangular parallelepiped cavity filled with water. The cavity had the dimensions S × S × H (m3), where S was the inside length, and H was the inside height of the cavity. The lower surface was subject to constant heat flux, and the upper surface was cooled by a stream of ambient air. The free convection heat transfer data were generated using different uniform heat fluxes. Four tilt angles were considered: 0°, 30°, 60°, and 90°. The surface temperature measurements were collected 10 h after the experimental run to ensure that a steady-state was reached. It was noticeable that the free convection heat transfer strongly depended on the tilt angle and the modified Rayleigh numbers. The 3D results showed that the Nusselt number reached a maximum at 60° at a fixed modified Rayleigh number. An enhancement in the Nusselt number at any tilt angle was observed over that of a zero tilt angle, and the percent of enhancement was 7.92–62.38%, depending on the modified Rayleigh numbers and the tilt angle. It was also observed that as the modified Rayleigh number increased, the temperature uniformity on both the hot and cold surfaces was disturbed. Furthermore, an empirical correlation between the modified Rayleigh numbers and Nusselt numbers was obtained for each angle. Moreover, two overall general correlations are obtained to cover the four tilt angles (i.e., 0°, 30°, 60°, and 90°) and the modified Rayleigh numbers, which should be helpful for engineering applications.
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Ockajova, Alena, Adrian Banski, and Tomasz Rogoziński. "Tilt Angle of Wood Dust." Annals of WULS, Forestry and Wood Technology 121 (March 29, 2023): 37–42. http://dx.doi.org/10.5604/01.3001.0053.8589.
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Tilt Angle of Wood Dust. The aim of this article is to point out a risk factor – wood dust, which settles on various structures, inclined surfaces in operation and, if not regularly cleaned, it is a source of secondary dust, because it is swirled up again with any movement. By measuring the tilt angle of bulk wood material obtained from sawing on a table circular saw, using different saw blades and wood dust from longitudinal and transverse sanding on a hand belt sander, we determined which characteristics affect it. We found that the size of the particles is an important characteristic, the larger they are, the smaller the tilt angle and also the surface of the pad on which the dust particles settle, wood did not play a significant role in this case. The smallest tilt angle was measured for sawdust from longitudinal sawing of 27, and the largest tilt angle for wood dust from transverse sanding of oak and was 57 on beech pad
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Makenzi, Macben, Joseph Muguthu, and Evan Murimi. "Maximization of Site-Specific Solar Photovoltaic Energy Generation through Tilt Angle and Sun-Hours Optimization." Journal of Renewable Energy 2020 (November 11, 2020): 1–11. http://dx.doi.org/10.1155/2020/8893891.
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Many photovoltaic solar projects do not achieve optimum energy and power outputs due to poor technical sizing and system design approaches. Concerns on low-conversion rates, high intermittencies, and high-capital costs still haunt PV projects. The establishment of design methodologies that would result in increased outputs from solar arrays is crucial in addressing the aforementioned issues. The tilt angles of installed PV modules are critical factors that influence the power output of solar modules. Several resources are available that provide generic linear fits and estimation of tilt angles for various global regions. However, very few are capable of determining precise, location-specific tilt angles that would allow for optimal power output and energy generation. This paper presents a methodology developed to establish the optimum tilt angles for solar panels installed at specific locations, thus ensuring maximum energy generation. The modeling is based on the maximization of the solar irradiation incident on the surface of a PV panel by considering multiple site-specific variables. Different sets of transcendent equations have been derived which were used to calculate optimum tilt angles and the subsequent energy generation from specific configurations of photovoltaic arrays. The resulting algorithms were used to determine optimum tilt angles and energy generation for solar PV installations in Athi River, Kenya. Dynamic and static optimal tilt angles were compared with the region’s baseline industry practice of using a fixed tilt angle of 15◦. It was observed that the dynamic tilt angles improved the daily solar energy output by up to 6.15%, while the computed optimal static tilt angle provided a 2.87% output increment. This improvement presents a significant impact on the technical specification of the PV system with a consequent reduction in the investment and operational cost of such installations. It further demonstrated that the use of the optimum static tilt angle results in cost and space savings of up to 2.8% as compared to the standard industry practice. Additionally, 5.8% cost and space savings were attained by the utilization of dynamic tilt angles.
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Hailu and Fung. "Optimum Tilt Angle and Orientation of Photovoltaic Thermal System for Application in Greater Toronto Area, Canada." Sustainability 11, no. 22 (November 15, 2019): 6443. http://dx.doi.org/10.3390/su11226443.
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We present a study conducted to obtain optimum tilt angle and orientation of a solar panel for the collection of maximum solar irradiation. The optimum tilt angle and orientation were determined using isotropic and anisotropic diffuse sky radiation models (isotropic and anisotropic models). The four isotropic models giving varying optimum tilt angles in the range of 37 to 44°. On the other hand, results of the four anisotropic models were more consistent, with optimum tilt angles ranging between 46–47°. Both types of models indicated that the collector tilt should be changed four times a year to receive more solar radiation. The results also indicate that the solar panel should be installed with orientation west or east of due south with a flatter tilt angle. A 15° change in orientation west or east of due south results in less than 1% reduction of the total solar radiation received. For a given optimum tilt angle, the effect of photovoltaic/thermal (PV/T) orientation west or east of due south on the outlet temperature was determined using a one-dimensional steady state heat transfer model. It was found that there is less than 1.5% decrease in outlet temperature for a PV/T panel oriented up to 15° east or west of due south from March to December. This result indicates that existing roofs with orientations angles up to 15° east or west of due south can be retrofitted with a PV/T system without changing the roof shape.
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Chisholm, M. F., and S. J. Pennycook. "High-resolution z-contrast imaging of YBa2Cu3O7-δ grain boundaries." Proceedings, annual meeting, Electron Microscopy Society of America 47 (August 6, 1989): 198–99. http://dx.doi.org/10.1017/s0424820100152963.
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A rapid reduction of the critical current density across grain boundaries with increasing tilt angle up to ∽10° has been observed in YBa2Cu3O7−δ superconductors. These results fit nicely with an investigation of the structure of low-angle tilt boundaries in these materials. The boundaries are observed to be composed of an asymmetric array of dislocations with a Burgers vector of 1.17 nm for [100] tilt boundaries (Fig. 1) and 0.389 nm for [001] tilt boundaries. It is observed that at 7.5° tilts, the dislocation cores begin to overlap (Fig. 2). Increasing the tilt angle beyond this value is not expected to significantly change the boundary structure which corresponds closely to the point where tilt angle had little further effect on critical current. A complication which was not completely addressed in the study of the structure of these low-angle boundaries is that ceramic materials have a strong tendency to form thin intergranular glass phases and to exhibit enhanced segregation of impurities to the grain boundaries. Conventional transmission electron microscopy and x-ray microanalysis with emitted photons using an energy dispersive spectrometer is of questionable use for this application. A new method for forming high resolution images with strong chemical sensitivity using large-angle elastically scattered electrons in a scanning transmission electron microscope has been used in this study to directly address the grain boundary segregation question.
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Olatona, Gbadebo I., and Tolulope J. Fadairo. "Measurement of Solar Irradiance for Determining the Optimal Tilt Angle for Photovoltaic Panels." Tanzania Journal of Science 49, no. 1 (March 31, 2023): 263–73. http://dx.doi.org/10.4314/tjs.v49i1.23.
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The challenge of solar panel installers in determining the tilt angle needed to obtain optimal performance from the photovoltaic panels was the focus of this paper. The performances of two 150 W panels under varied conditions of temperature and solar irradiance on a plane at two different heights (1 m and 11.5 m) from the ground surface were determined to find the effects of tilt angle and altitude on their performances. Measurements of solar irradiance, temperature, open-circuit voltage, and short circuit current were made at various tilt angles and compared to one another based on the measured irradiance. The optimal tilt angle at the experimental site was found to be 15°SW (165°). At this angle, the irradiance was 818.05 Wm–2 compared to 792.26 Wm–2 at 15°NE (15°), 780.44 Wm–2 45°NE (45°) and 767.63 Wm–2 at 45°SW(135°) at 1 m from ground surface, while at 11.5 m the irradiance at 15°SW was 861.99 Wm–2 compared to 685.98 Wm–2 at 15°NE, 624.33 Wm–2 at 45°NE and 676.49 Wm–2 at 45°SW. Hence the performance of a photovoltaic panel solely depends on the tilt angles relative to the height at which the panel is mounted.
Keywords: Solar, Irradiance, Photovoltaic, Panels, Tilt angle
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Hou, Fuchen, Yubo Zhang, Daiyue Li, Liangyu Che, and Junhao Lin. "Deciphering the structure-photoluminescence correlation at small-tilt-angle grain boundaries in monolayer WS2." Applied Physics Letters 121, no. 5 (August 1, 2022): 051104. http://dx.doi.org/10.1063/5.0097638.
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Grain boundaries (GBs) frequently emerge in a CVD-grown large-scale transition metal dichalcogenides monolayer thin film, which affect the electronic and optical properties of the material. Photoluminescence (PL) can be easily quenched/enhanced at GBs, which are, however, merely investigated in relatively large tilt angles ([Formula: see text]) in previous research. Here, we experimentally examine the PL properties of monolayer WS2 GBs with tilt angles as small as a few degrees. Contrary to conventional wisdom, we find that PL intensity remains intact by the GBs when their tilt angles [Formula: see text]. The abnormal PL behavior is elucidated by a detailed structure analysis on the dislocation cores. For a small tilt angle, the strain fields introduced by the defective cores are sparsely distributed without mutual coupling, and the chemical stoichiometry along the GBs preserves very well. These two key structural features of the small-tilt-angle GBs allow excitons to diffuse transparently across the GB, leading to a neglectable influence on the optical and electronic properties, as verified by our first-principle simulations. The PL invariant of the small-tilt-angle GBs sheds light on the future development of CVD-grown wafer-scale techniques and their optical applications.
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Machidon, Dragos, and Marcel Istrate. "Tilt Angle Adjustment for Incident Solar Energy Increase: A Case Study for Europe." Sustainability 15, no. 8 (April 21, 2023): 7015. http://dx.doi.org/10.3390/su15087015.
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The work presented in this paper aims to analyze the efficiency of using optimum tilt angles defined for several time intervals to maximize the incident solar irradiation on a certain surface deployed in Europe. Such a technique would improve the solar energy harvesting process, both for photovoltaic panels and solar thermal collectors, while not investing in the more expensive sun-tracking devices. The optimum tilt angles have been determined for the yearly, bi-annual, seasonal, and monthly time intervals, which were delimited on a calendar and astronomical base, respectively, considering multiple locations from Europe, and using various mathematical models based on empirical equations and solar irradiation estimation. The total incident solar irradiation provided by adjusting the tilt angle multiple times per year was calculated and compared to that obtained when using the yearly optimum tilt angle. The gains for each type of adjustment were investigated, and the monthly optimization of the tilt angle is obviously the most effective one, ensuring gains of up to 7%, depending on the considered latitude. Otherwise, an optimization twice per year, using the bi-annual optimum tilt angles determined for the astronomical-defined warm and cold seasons, would be the next best solution.
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Rajabi, Benjamin, Oyvind Roed, Kristian Roed, Paal Sandoe Alm-Paulsen, Harald Russwurm, and Vilhjalmur Finsen. "ACCURATE RADIOGRAPHIC MEASUREMENT OF THE DISTAL RADIAL TILT." Hand Surgery 16, no. 03 (January 2011): 259–62. http://dx.doi.org/10.1142/s0218810411005515.
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Both wrists in 189 patients who had been treated for dorsally displaced distal radius fracture were X-rayed with both right angle and 15° tilted lateral views. Two investigators measured the radial tilt. The mean difference in the angles recorded by the two investigators was 2.5° for the tilted and 3.7° for the right angle projections (p = 4.7 × 10-8). The precision of the method was 2.6° for the tilted and 3.5° for right angle projection. The mean angle measured on the tilted views was 3° more dorsal than on the right angle views for wrists with a volar tilt between 10° and 15°, and 0° to 2° for wrists with less volar tilt or dorsal displacement. Lateral projections tilted 15° allow more precise measurements than right angle views. Correction is not necessary when comparing to right angle views, as long as there is displacement in a dorsal direction of the distal fragment.
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Ashetehe, Ahunim Abebe, Belachew Bantyirga Gessesse, and Fekadu Shewarega. "Development of Optimal Tilt Angle Models of a Photovoltaic Module for Maximum Power Production: Ethiopia." International Journal of Photoenergy 2022 (August 8, 2022): 1–18. http://dx.doi.org/10.1155/2022/8729570.
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The power generated from the photovoltaic module is directly related to the magnitude of total incident solar radiation on the surface of the solar module. The total incident solar radiation depends on the location, tilt angle, and orientation of the solar module. In this paper, generic models were developed that determine the seasonal and annual optimal tilt angle of the Photovoltaic module at any location in Ethiopia without using meteorological data. Both isotropic and anisotropic diffuse solar radiation models were used to estimate monthly, seasonal, and annual optimal tilt angles. The monthly average daily global horizontal solar radiation for a total of 44 cities -32 for training and 12 for testing were obtained from the National Aeronautical and Space Administration database, and algorithms were developed and implemented using MATLAB and R programming software to obtain optimum tilt angle and regression models. The study showed that the developed model accurately estimates the optimal tilt angle with the minimum statistical validation errors. It is also found that 5.11% to 6.275% (isotropic) and 5.72% to 6.346% (anisotropic models) solar radiation energy is lost when using the yearly average fixed optimal tilt angle as compared with the monthly optimal tilt angle. The result of this study was also validated by comparing it with the previously published works, PVGIS and PVWatt online software. The graphical abstract is included in the supplementary file.
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Schunker, H., C. Baumgartner, A. C. Birch, R. H. Cameron, D. C. Braun, and L. Gizon. "Average motion of emerging solar active region polarities." Astronomy & Astrophysics 640 (August 2020): A116. http://dx.doi.org/10.1051/0004-6361/201937322.
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Context. The tilt of solar active regions described by Joy’s law is essential for converting a toroidal field to a poloidal field in Babcock-Leighton dynamo models. In thin flux tube models the Coriolis force causes what we observe as Joy’s law, acting on east-west flows as they rise towards the surface. Aims. Our goal is to measure the evolution of the average tilt angle of hundreds of active regions as they emerge, so that we can constrain the origins of Joy’s law. Methods. We measured the tilt angle of the primary bipoles in 153 emerging active regions (EARs) in the Solar Dynamics Observatory Helioseismic Emerging Active Region survey. We used line-of-sight magnetic field measurements averaged over 6 h to define the polarities and measure the tilt angle up to four days after emergence. Results. We find that at the time of emergence the polarities are on average aligned east-west, and that neither the separation nor the tilt depends on latitude. We do find, however, that EARs at higher latitudes have a faster north-south separation speed than those closer to the equator at the emergence time. After emergence, the tilt angle increases and Joy’s law is evident about two days later. The scatter in the tilt angle is independent of flux until about one day after emergence, when we find that higher-flux regions have a smaller scatter in tilt angle than lower-flux regions. Conclusions. Our finding that active regions emerge with an east-west alignment is consistent with earlier observations, but is still surprising since thin flux tube models predict that tilt angles of rising flux tubes are generated below the surface. Previously reported tilt angle relaxation of deeply anchored flux tubes can be largely explained by the change in east-west separation. We conclude that Joy’s law is caused by an inherent north-south separation speed present when the flux first reaches the surface, and that the scatter in the tilt angle is consistent with buffeting of the polarities by supergranulation.
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Jeong, Kicheol, and Seibum Choi. "Road Bank Angle Estimation for Three Wheel Tilting Vehicle Using Multi Model Estimator." MATEC Web of Conferences 166 (2018): 02008. http://dx.doi.org/10.1051/matecconf/201816602008.
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In recent years, the need for micro-mobility, especially three-wheel vehicles, is increasing to address pollution and traffic congestion problems. With regard to the development of tilting vehicles, the precise tilt angle is important information in the tilting mechanism. Since the road environment affects the vehicle tilt angle, the road bank and hill angle have to be estimated to optimize the tilt control system. Furthermore, a new tilt mechanism is required due to the energy consumption of the previous active tilting mechanism. This paper introduces the road state observer. In this paper, the observer that combines a kinematic model with a dynamic model of a three wheel vehicle is proposed. The dynamic model has four states, including lateral velocity, yaw rate, tilt angle, and tilt angle ratio. Similarly, kinematic model has two states, including roll and pitch angles. It is assumed that the data set received from the six-dimensional inertial measurement unit including the vehicle acceleration and angular velocity of all axes is available. To verify the proposed algorithm, simulation verification using Carsim ADAMS and Matlab&Simulink is performed and a discussion of the result is provided. In addition, this paper proposes a semi-active tilt system.
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Fitri Dwi Kartikasari, Elieser Tarigan, Fenny Irawati, Maya Hilda Lestari Louk, Susana Limanto, and Endah Asmawati. "Optimal solar panel tilt angle calculation and simulation in Indonesia: A Liu and Jordan sky isotropic model-based approach." International Journal of Science and Research Archive 9, no. 2 (July 30, 2023): 116–21. http://dx.doi.org/10.30574/ijsra.2023.9.2.0517.
Full textAbstract:
The efficient utilization of solar energy is crucial for meeting the growing energy demands while reducing greenhouse gas emissions and dependence on fossil fuels. Solar panel tilt angle optimization plays a vital role in maximizing the energy output of photovoltaic (PV) systems. Determining the optimal tilt angle is essential as it directly affects the amount of sunlight captured by the solar panels. In the context of Indonesia, a country rich in solar resources and a rapidly expanding renewable energy sector, understanding the optimal tilt angle for solar panels is of paramount importance. This paper studies the optimal solar panel tilt angle calculation using Liu and Jordan Sky isotropic model-based approach. The numerical simulations were carried out for several main city locations of Indonesia. The objectives of the work are to address the suitable and optimal tilt angle of solar panels by proposing an approach based on the Liu and Jordan Sky Isotropic Model. The calculation result shows that the boundary for the tilted angle empirically satisfies all the mathematical domain of the inverse trigonometric functions. While, the optimal tilted angles will be differed for any location.
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Griffiths, A. Fuzz, and Qasim Zaidi. "Perceptual Assumptions and Projective Distortions in a Three-Dimensional Shape Illusion." Perception 29, no. 2 (February 2000): 171–200. http://dx.doi.org/10.1068/p3013.
Full textAbstract:
We examine a shape illusion, in which the balconies of a building appear to tilt up or down, depending on the viewpoint. The balconies are actually level parallelogram shapes, but appear as tilted rectangles. We measured the illusory tilts observed when parallelogram shapes are viewed above the line of sight, using three-dimensional stimuli consisting of parallelograms of various tilts viewed at different orientations. Under perspective projection, parallelism and orthogonality are not preserved. However, perspective distortions alone cannot account for the perceived tilts measured in these experiments, since observers perceived illusory tilts even for stimuli in the frontoparallel plane. We introduce a model, based on the theory that observers assume ambiguously projected three-dimensional angles to be equal to 90°, but revise their predictions on the basis of observation. In the model, perceived tilt is predicted as a weighted sum of the tilts predicted by the assumptions that the shape is rectangular, and that the shape is level (ie that the angle between the shape and the vertical backboard is equal to 90°). We prove that it is mathematically impossible for a planar rectangle to share a projection with a nonrectangular parallelogram. A less restrictive assumption that just the two leading internal angles are equal to 90° is suggested as an alternative, and it is further proven that this new configuration of angles leads to a unique perceived tilt. The relative weights in the model reflect the amount that each prediction is revised, and are shown to vary systematically with stimulus orientation. For some observers a better fit was found by replacing the level-tilt assumptions with an assumption that physical tilt was equal to the projected tilt.
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CHEN, Zhen, Pan ZHAO, Yaoyao SHI, Feng LI, Ying DING, and Danni LU. "Forward polishing process planning of aero-engine blisk blade." Xibei Gongye Daxue Xuebao/Journal of Northwestern Polytechnical University 41, no. 6 (December 2023): 1107–13. http://dx.doi.org/10.1051/jnwpu/20234161107.
Full textAbstract:
The surface roughness can be reduced by increasing the forward-tilt angle of polishing process. It is of great significance to explore the influence law of the forward-tilt angle on the quality of the polished surface to improve the polishing efficiency of the blisk blade. In this paper, the surface roughness of the polished TC4 blisk blades polished by the belt flapwheel with a grain size of P400-P1200 under different polishing times and different forward-tilt angles was obtained through the forward-tilting polishing experiment. The experimental results show that the roughness of the polished surface decreases with the increase of the forward-tilt angle. Then the mechanism of the influence of the change of the forward-tilt angle on the quality of the polished surface was analyzed from multiple aspects. By quantifying the polishing efficiency, the variation law of the polishing efficiency of the belt flapwheel with various grain sizes with the forward-tilt angle was studied, and the optimal forward-tilt angle was obtained. On this basis, the polishing process planning with the optimal polishing efficiency was carried out, and verified by polishing experiments. The experimental results show that the optimized polishing process planning can obtain qualified surface roughness in fewer processes, which verifies the reliability of the polishing process planning results. This study provides a theoretical basis and practical guidance for the optimization of the belt flapwheel polishing process for TC4 blisk blades.
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Liu, Tong, Li Liu, Yufang He, Mengfei Sun, Jian Liu, and Guochang Xu. "A Theoretical Optimum Tilt Angle Model for Solar Collectors from Keplerian Orbit." Energies 14, no. 15 (July 23, 2021): 4454. http://dx.doi.org/10.3390/en14154454.
Full textAbstract:
Solar energy has been extensively used in industry and everyday life. A more suitable solar collector orientation can increase its utilization. Many studies have explored the best orientation of the solar collector installation from the perspective of data analysis and local-area cases. Investigating the optimal tilt angle of a collector from the perspective of data analysis, or guiding the angle of solar collector installation, requires an a priori theoretical tilt angle as a support. However, none of the current theoretical studies have taken the real motion of the Sun into account. Furthermore, a complete set of theoretical optimal tilt angles for solar energy is necessary for worldwide locations. Therefore, from the view of astronomical mechanics, considering the true orbit of the Sun, a mathematical model that is universal across the globe is proposed: the Kepler motion model is constructed from the solar orbit and transformed into the local Earth coordinate system. After that, the calculation of the optimal tilt angle solution is given. Finally, several examples are shown to demonstrate the variation of the optimal solar angle with month and latitude. The results show that for daily fixed solar collectors, the altitude angle of the collector should be about 6° above the noon solar altitude angle in summer and 6° lower in winter. For annual fixed collectors, the tilt angle should be slightly higher than the latitude. In summary, this study demonstrates that when a location is specified, this model can be used to calculate the theoretical optimum tilt angle of solar collectors for that position.
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Cui, Zhaoliang, Rui He, Wanyu Wu, Fengtao Wang, and Liu Heng. "Effect of structural parameters and service conditions on the tilt angle of double row angular contact ball bearing." Proceedings of the Institution of Mechanical Engineers, Part K: Journal of Multi-body Dynamics 236, no. 1 (December 17, 2021): 168–81. http://dx.doi.org/10.1177/14644193211061002.
Full textAbstract:
In this paper, for double row angular contact ball bearing, a five-degrees-of-freedom bearing analysis model based on quasi-statics is proposed. This model is used to study the influence of structural parameters and service conditions on the tilt angle and limit tilt angle of the bearing. The results show that the radial clearance will increase the ultimate tilt angle. The coincidence degree between the roller and the inner raceway will reduce the ultimate tilt angle, but the coincidence degree between the roller and the outer raceway has the opposite effect. The increase in the external load of the bearing will increase the tilt angle. The moment load has the greatest effect on the tilt angle. The rotation speed of the bearing has no effect on the tilt angle. The coincidence degree between the roller and the raceway will reduce the tilt angle; furthermore, the influence of the coincidence degree between roller and different ring on the tilt angle is also different when different rings are fixed. The tilt angle will decrease with the increase of the initial contact angle, and this effect is more and more obvious. The fixation of different ring has no effect on this influence.