Assessing the wind energy potential of China in considering its variability/intermittency

While wind energy experienced massive deployment in the last decades, the intermittency of wind energy hindered its usage and hence leads to curtailment. It is imperative to quantify and mitigate the intermittency/variability of wind energy for research community as well as industry, but there are no consensus methods yet. The present study took the first attempt to quantify the cost of the variability/intermittency of wind energy with battery energy storage system, aiming at comprehensively assessing the spatial distribution of the exploitability of wind energy in China. The research found that the most abundant wind resources are located in Tibet Plateau, Hexi Corridor, Inner Mongolia in considering the abundance of wind resources, land use type, and landforms, as well as the variability of wind energy. In the near future, wind farms with the advanced energy storage technology in 2030 or 2050 could provide stable wind energy with marketing comparable prices, which is lower than the price of current coal-fired electricity (about 0.5 CNY/kWh). It is worth to note that the variability of wind energy in Qinghai Tibet Plateau could lead to high demanding of storage capacity and therefore unaffordable cost. The proposed methodology can be applied in different regions worldwide. The results of this study could also be a scientific foundation for policy makers for wind power development in China mainland

Comprehensive assessment of soil erosion risk for better land use planning in river basins: Case study of the Upper Blue Nile River

In the drought-prone Upper Blue Nile River (UBNR) basin of Ethiopia, soil erosion by water results in significant consequences that also affect downstream countries. However, there have been limited comprehensive studies of this and other basins with diverse agroecologies. We analyzed the variability of gross soil loss and sediment yield rates under present and expected future conditions using a newly devised methodological framework. The results showed that the basin generates an average soil loss rate of 27.5 t ha− 1 yr− 1 and a gross soil loss of ca. 473 Mt yr− 1, of which, at least 10% comes from gully erosion and 26.7% leaves Ethiopia. In a factor analysis, variation in agroecology (average factor score = 1.32) and slope (1.28) were the two factors most responsible for this high spatial variability. About 39% of the basin area is experiencing severe to very severe (> 30 t ha− 1 yr− 1) soil erosion risk, which is strongly linked to population density. Severe or very severe soil erosion affects the largest proportion of land in three subbasins of the UBNR basin: Blue Nile 4 (53.9%), Blue Nile 3 (45.1%), and Jema Shet (42.5%). If appropriate soil and water conservation practices targeted ca. 77.3% of the area with moderate to severe erosion (> 15 t ha− 1 yr− 1), the total soil loss from the basin could be reduced by ca. 52%. Our methodological framework identified the potential risk for soil erosion in large-scale zones, and with a more sophisticated model and input data of higher spatial and temporal resolution, results could be specified locally within these risk zones. Accurate assessment of soil erosion in the UBNR basin would support sustainable use of the basin's land resources and possibly open up prospects for cooperation in the Eastern Nile region

Shizuku2.0: Cooperative reading support system / Mao Tsunekawa, Haruki Ono, Kyoji Konishi... [et.al].

The paper aims to propose cooperative reading, which is a reading support technique that allows library users to help each other. To achieve cooperative reading, it is necessary for a user to discover others with similar interests. Therefore, this paper also aims to develop and evaluate a recommendation function that recommends similar users using Nippon Decimal Classification (NDC) Tree Profiling. Is the user recommendation using NDC Tree Profiling effective in finding similar users? Which parameter of NDC Tree Profiling method is the most effective expression of users‘ interests? We developed the Shizuku2.0 system to support the creation of a library user community in which users help each other efficiently and mutually. We also designed and developed NDC Tree Profiling, which enables the creation of library user profiles, for the purposes of the user recommendation mechanism. To verify the effect of the user recommendation mechanism, we performed an experiment with 37 student users to calculate recall and precision. We found that the recommendation using NDC Tree Profiling is more effective than a random recommendation. However, we also recognized that there is room for improvement relative to a past information recommendation technique. Moreover, we found the second level of the NDC code could be the most effective expression of users‘ interests. In the discussion of the optimization of parameters, we propose a new way of implementing the NDC Tree, based on the second division of NDC, which is expected to improve creation of user profiles

Appropriate level of alfalfa hay in diets for rearing Simmental crossbred calves in dryland China

Objective: In dryland areas of China, alfalfa hay (AH) is a possible substitute for concentrate feed for beef cattle. To evaluate the potential benefits of this substitution, we studied the effect of the ratio of AH intake to total dry matter (DM) intake on average daily body-weight gain (ADG), dietary energy utilization status, and economic benefit in Gansu province. Methods: In each of two feeding trials in 2016 (trial 1 [T1], July 3 to 17; trial 2 [T2], August 15 to September 23), crossbred male Simmental calves were allocated to low AH (LA), medium AH (MA), and high AH (HA) feeding groups (n = 4 per group). The target ADG was set as 1 kg for both trials. In a one-way-layout design based on conventional feeding practices in the province, calves received diets containing the different AH amounts, with a constant ratio of corn stover:total DM and decreasing rations of concentrate feed proportional to the increase in AH. Calves in T1 received AH at 15% (T1-LA), 23% (T1-MA), or 31% (T1-HA) of their dietary DM allowances; those in T2 received 9% (T2-LA), 24% (T2-MA), or 34% (T2-HA) AH. Results: Among the T1 groups, both ADG and economic benefit were highest in T1-LA; whereas in T2, they were higher in the T2-LA and T2-MA groups than in T2-HA. Energy digestibility did not significantly differ among the groups in either trial. The dietary AH inclusion ratios of 14% in the warm season and 8% to 21% in the cool season appeared to yield optimal ADG, metabolizable energy intake, and economic benefit. Conclusion: Low-level inclusion of AH, ranging from 8% to 21%, is a practical approach for beef cattle feeding. This modified feeding regimen likely will promote increased growth performance during the fattening stage of beef steers in dryland areas of Gansu province, China

Effect of feeding improved grass hays and Eragrostis tef straw silage on milk yield, nitrogen utilization, and methane emission of lactating Fogera dairy cows in Ethiopia

Simple Summary In tropical regions, it is common practice to feed dairy cows poor-quality roughage, but this diet has been shown to decrease animal productivity and increase methane emissions. For these reasons, introducing alternative roughage feeds, such as nutritionally improved forages or bio-chemically treated straw, is essential for improving milk yield, dietary nitrogen utilization, and reducing enteric methane emission from dairy cows. Thus, we evaluated the effects of natural pasture hay, two improved grass hays (Napier andBrachiariahybrid grasses), and treated teff straw silage feeding as basal diets on nutrient digestibility, milk yield, nitrogen utilization efficiency, and enteric methane emissions using lactating Fogera dairy cows. Our results showed that improved grass hays and treated teff straw silage diet feeding increased milk yield, nutrient digestibility, and nitrogen utilization efficiency as compared to natural pasture hay. Moreover, the cows fed with improved grass hays and treated teff straw resulted in changing the nitrogen excretion pathway from urine to feces, as well as reduction of the methane production per daily milk yield. Hence, these results provide a novel feeding regimen through feeding nutritionally upgraded forages as a basal diet, which improves milk yield, nutrient utilization efficiency, and reduction of methane emission for sustainable dairy production in tropical regions. The nutritionally imbalanced poor-quality diet feeding is the major constraint of dairy production in tropical regions. Hence, alternative high-quality roughage-based diets are required to improve milk yield and reduce methane emission (CH4). Thus, we tested the effects of feeding natural pasture hay, improved forage grass hays (Napier andBrachiariaHybrid), and treated crop residues (Eragrostis tefstraw) on nutrient digestibility, milk yield, nitrogen balance, and methane emission. The eight lactating Fogera cows selected for the experiment were assigned randomly to a 4 x 4 Latin square design. Cows were housed in well-ventilated individual pens and fed a total mixed ration (TMR) comprising 70% roughage and 30% concentrate. The four roughage-based basal dietary treatments supplemented with formulated concentrate were: Control (natural pasture hay (NPH)); treated teff straw silage (TTS); Napier grass hay (NGH); andBrachiariahybrid grass hay (BhH). Compared with the control diet, the daily milk yield increased (p< 0.01) by 31.9%, 52.9%, and 71.6% with TTS, NGH, and BhH diets, respectively. Cows fed BhH had the highest dry matter intake (8.84 kg/d), followed by NGH (8.10 kg/d) and TTS (7.71 kg/d); all of these intakes were greater (p= 0.01) than that of NPH (6.21 kg/d). Nitrogen digestibility increased (p < 0.01) from the NPH diet to TTS (by 27.7%), NGH (21.7%), and BhH (39.5%). The concentration of ruminal ammonia nitrogen was higher for cows fed NGH than other diets (p= 0.01) and positively correlated with plasma urea nitrogen concentration (R-2 = 0.45). Feeding TTS, NGH, and BhH hay as a basal diet changed the nitrogen excretion pathway from urine to feces, which can help protect against environmental pollution. Estimated methane yields per dry matter intake and milk yield were decreased in dairy cows fed BhH, NGH, and TTS diets when compared to cows fed an NPH diet (p< 0.05). In conclusion, feeding of TTS, NGH, and BhH roughages as a basal diet to lactating dairy cows in tropical regions improved nutrient intake and digestibility, milk yield, nitrogen utilization efficiency, and reduced enteric methane emission