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The main belt asteroids 4747, 5255, 11411, 15433, and 17866 were studied at the Baldone Astrophysical Observatory in the time span range 2018–2022. The obtained light curve data together with published Minor Planet Center data are analyzed with Fourier series, Lomb-Scargle periodogram, and phase dispersion minimization methods. A plan of analysis is given. The results computed from different observatories’ data are compared, and mean-weighted periods are obtained.

This study’s aim was to calculate the weathering rates of Ca and Mg for five boreal forest soils in southern Finland on granitic and gabbro containing bedrock. The effect of mineralogy on the total concentrations of Ca and Mg in soil and weathering rates was evaluated. The aim was also to estimate the effect of mechanical soil disturbance related to ploughing on the weathering in the gabbro area. The total concentrations of SiO2, CaO, MgO, and Zr were determined by XRF, and weathering rates of Ca and Mg were determined based on the changes in the CaO, MgO, and Zr concentrations. The weathering rates of Ca+Mg varied 5–38 mmolc m–2 year–1 in the E+B/BC horizons among the plots. Soil disturbance related to ploughing increased the weathering of Ca and Mg largely in the disturbed part of the topmost mineral soil as indicated by the decreasing concentrations of Ca and Mg after mechanical soil disturbance. The weathering input of Ca in the undisturbed soil did not fully replace the Ca output in final whole-tree cutting. The weathering input of Mg in the undisturbed soil was sufficient to replace the lost Mg in stemwood harvesting but not on all the plots the lost Mg in whole-tree harvesting. Weathering rates were higher in the gabbro than the granitic areas.

The entry of forestry carbon sequestration products into the carbon trading mechanism is conducive to giving full play to the emission reduction function of the forestry ecosystem. Value accounting of forestry carbon sequestration products can endow forestry carbon sequestration with economic value. We review the evolution of emission reduction mechanisms of forestry carbon trading in China and abroad and take forest carbon sequestration products as the research object to analyze the correlation between forestry carbon sequestration products and forestry carbon sequestration projects. Based on the dual benefits of wood and carbon sequestration, this study uses the net present value method to summarize the applicability of three carbon accounting models for forestry carbon sequestration products. We further compare the models on the aspects of carbon price fluctuation response, tree species applicability, and management characteristics of forestry carbon sequestration projects. This study finds that: (1) Forestry carbon sequestration can realize the dual value of climate emission reduction and economic benefits through voluntary carbon emission reduction and mandatory carbon trading mechanisms. However, China's forestry carbon sequestration faces problems such as unclear product definition and mismatch in accounting methodology. (2) The value accounting of forestry carbon sequestration products should be based on the optimal rotation period and 'carbon amount' of forestry carbon sequestration projects. Three types of forestry carbon sequestration products, tCER, lCER, and CCER, are identified based on the time period. tCER and lCER can be used to solve the non-persistence of forestry projects. Through permanent credit and a stable pricing mechanism, CCER can improve the effectiveness of emission reduction of forestry carbon sequestration products. (3) The core value of forestry carbon sequestration products lies in their carbon storage capacity and carbon level. Its value accounting should take ' carbon amount' as the basic premise. Combined with the calculation standards of carbon storage, the carbon accounting models of forestry carbon sequestration products are classified into total carbon model, carbon increment model, and carbon average model. (4) In terms of carbon price fluctuation response, the carbon average model can mitigate the impact of carbon price fluctuation through the whole project. In terms of carbon sink tree species, the total carbon model is suitable for slow-growing tree species, the carbon increment model is suitable for fast-growing tree species, and the carbon average model is more suitable for adjusting tree species selection schemes according to ecological value. In terms of project management characteristics, the carbon increment model is suitable for a long-term management scheme, while the carbon average model can be combined with the historical baseline of the project, making it easier to formulate a reasonable carbon reserve level. [ABSTRACT FROM AUTHOR]

At present, majority of commercial poplar plantations aimed at producing quality timbers with larger dimension are established in wider planting spacings in Turkey. The experimental poplar plantations in closer spacings were established for this study purposes in order to investigate the prospects for producing mass quantity of small dimensioned chip wood relatively in shorter period of plantation rotation rather than producing quality timber of larger dimension in longer period of rotation. Along with five various planting spacings, five different poplar clones such as “I-214”, “I-45/51”, “Samsun (I-77/51)”, “İzmit (S.307-26)” and “89.M.060” were sampled in the experimental plantation blocks which were repeated on sites of three different growth conditions. The criteria of “Net Present Value (NPV) and “Internal Rate of Return” (IRR) were used for economic analyses. The results of the analyses showed that the most suitable spacing for producing mass quantity of chip wood is “3m x 1,5m” (4,5 m2 / plant) and most promising poplar clone is “89.M.060”. The plantation rotation periods were also determined in accordance with the criteria of NPV and IRR. The period of rotation varied by the variation of the discount rate involved when the NPV criterion is used for the evaluation. The periods of rotation determined in accordance with the IRR criterion are shorter than the period determined in accordance with the NPV criterion. Therefore, the IRR criterion should be preferred for the evaluation of industrial plantation investments. According to the results of the analyses, the recommended period of plantation rotation varies between 6 to 8 years on good sites, 7 to 9 years on medium sites and 8 to 10 years on poor sites.

This paper presents the results of the photometric CCD observations of the NEA (2100) Ra-Shalom carried out on August 24–29, 2019, at the 1-m telescope of the Sanglokh Observatory of the Institute of Astrophysics, National Academy of Sciences of the Republic of Tajikistan. The rotation period P = 19.8 ± 0.1 h was determined. Composite light curves were plotted in the photometric BVR bands; the brightness amplitude ΔV = 0.61m ± 0.05m and the average values of the color indices B–V = 0.75m ± 0.05m, V–R = 0.40m ± 0.02m were determined. Variations in the color indices with rotation period are within the measurement errors, which indicates that the reflectivity of Ra-Shalom's surface is uniform. The absolute stellar magnitude of the asteroid is 15.91m ± 0.10m. The ratio of the asteroid's axes a/b = 1.75. [ABSTRACT FROM AUTHOR]

The wear process of the wheel flange and the rolling circle diameter was described by the Gamma random process， and the method of calculating the reliability of the wheel flange degradation and the rolling circle diameter degradation was studied by using the Copula function and the fourth-order moment method， and the dynamic indexes of the train at different stages were obtained by dynamics software simulation. The reliability of the wheel degradation process with a rotation cycle of 200，000 km and the sensitivity of the wheel diameter degradation process were studied. The correctness of the method was verified by Monte Carlo simulation (MCS).The results showed that the reliability of wheels reaching the expected life is high when the rotation cycle is 200，000 km， and the reliability calculated based on the Copula function correlation failure degradation model is higher than that calculated by the independent failure model. The sensitivity study of the wheel diameter degradation reliability model indicates that the scheme with less reduction of wheel diameter should be selected during the rotation repair. [ABSTRACT FROM AUTHOR]

The asteroid (13553) Masaakikoyama was observed with the ZA-320M and MTM-500M telescopes of the Pulkovo observatory in August and September 2018. Its axial rotation period was estimated based on the observed sections of the light curve (and additional observational data provided by B.D. Warner) at 97.2 ± 0.3 h. This estimation was made difficult by the fact that the period is commensurable with a day. The light curve has certain features suggestive of tumbling rotation and a complex shape. The orbit of (13553) Masaakikoyama was improved using the obtained astrometric positions of the asteroid. [ABSTRACT FROM AUTHOR]

Inactive space objects are usually rotating and tumbling as a result of internal or external forces. KOREASAT 1 has been inactive since 2005, and its drift trajectory has been monitored with the optical wide-field patrol network (OWL-Net). However, a quantitative analysis of KOREASAT 1 in regard to the attitude evolution has never been performed. Here, two optical tracking systems were used to acquire raw measurements to analyze the rotation period of two inactive satellites. During the optical campaign in 2013, KOREASAT 1 was observed by a 0.6 m class optical telescope operated by the Korea Astronomy and Space Science Institute (KASI). The rotation period of KOREASAT 1 was analyzed with the light curves from the photometry results. The rotation periods of the low Earth orbit (LEO) satellite ASTRO-H after break-up were detected by OWL-Net on April 7, 2016. We analyzed the magnitude variation of each satellite by differential photometry and made comparisons with the star catalog. The illumination effect caused by the phase angle between the Sun and the target satellite was corrected with the system tool kit (STK) and two line element (TLE) technique. Finally, we determined the rotation period of two inactive satellites on LEO and geostationary Earth orbit (GEO) with light curves from the photometry. The main rotation periods were determined to be 5.2 sec for ASTRO-H and 74 sec for KOREASAT 1.

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Results of astrometric and BVRI photometric observations of the active asteroid (596) Scheila are presented. The observations were carried out at the Zeiss-1000 telescope of the Sanglokh International Astronomical Observatory of the Institute of Astrophysics of the Academy of Sciences of the Republic of Tajikistan on June 16−17 and from July 30 to August 1, 2017. The coordinates of the object and its orbit were determined; and the apparent brightness in four filters, the absolute brightness in the V and R filters, and the color indices were obtained. The light curves suggest that no substantial changes in the asteroid’s brightness occurred during the observations. The absolute brightness of the asteroid in the V and R filters was (9.1 ± 0.05)m and (8.8 ± 0.03)m, respectively. The mean value of the asteroid diameter was (119 ± 2) km. The mean values of the color indices (B−V = (0.72 ± 0.05)m, V−R = (0.29 ± 0.03)m, and R−I = (0.31 ± 0.03)m) agree well with the values for asteroids of the P- and D-types and its averages. The rotation period of the asteroid estimated from photometric observations was 16.1 ± 0.2 h. The analysis of the data has shown that the asteroid continues to exhibit the same values of absolute brightness and other characteristics as those before the collision with a small body in December 2010, though the latter resulted in the outburst event and cometary activity of the asteroid. Most likely, the collision of asteroid (596) Scheila with a small body did not lead to catastrophic changes in the surface of the asteroid or to its compete break-up. [ABSTRACT FROM AUTHOR]

We investigate the influence of the rotation period (Prot) on the mean climate of an aquaplanet, with a focus on the role of sea-ice albedo. We perform aquaplanet simulations with the atmospheric general circulation model ECHAM6 for various rotation periods from one Earth-day to 365 Earth-days in which case the planet is synchronously rotating. The global-mean surface temperature decreases with increasing Prot and sea ice expands equatorwards. The cooling of the mean climate with increasing Prot is caused partly by the high surface albedo of sea ice on the dayside and partly by the high albedo of the deep convective clouds over the substellar region. The cooling caused by these deep convective clouds is weak for non-synchronous rotations compared to synchronous rotation. Sensitivity simulations with the sea-ice model switched off show that the global-mean surface temperature is up to 27 K higher than in our main simulations with sea ice and thus highlight the large influence of sea ice on the climate. We present the first estimates of the influence of the rotation period on the transition of an Earth-like climate to global glaciation. Our results suggest that global glaciation of planets with synchronous rotation occurs at substantially lower incoming solar irradiation than for planets with slow but non-synchronous rotation. [ABSTRACT FROM AUTHOR]