Search Results (29)

The experimental and computational characterization of a cold model prototype designed to test the electromagnetic properties of a new RFQ (Radio-Frequency Quadrupole) cavity is reported. This cavity is intended to be an essential part of a compact, high-gradient proton accelerator for medical purposes. The RFQ’s design employs a novel RF power-coupler injection solution. One common way to couple the RF power in proton RFQs has been the use of loop-couplers inserted into the mid-section of the RFQ’s lobe sections. This technique has been demonstrated to be reliable and effective but introduces a significant perturbation into the lobe that can be more noticeable when dealing with compact structures. We propose a RF injection scheme that uses direct transition from a coaxial cable to the RFQ by connecting the inner coaxial conductor to the RFQ vane body. As a consequence, the lobe geometry is not perturbed, and the transversal electrical fields are directly excited through the vanes. Moreover, by using a pair of such couplers connected to opposite vanes at a given transversal plane of the RFQ, it is also possible to excite the desired quadrupolar TE210 modes while avoiding the excitation of dipolar TE110 modes. The resonances corresponding to different RFQ modes have been characterized, and the dependence of the amplitude of the modes on the relative phase of the field injected through the RF power ports has been demonstrated both by measurements and simulations. Full article

The production of artificial planted forage is important for the development of animal husbandry in the Qinghai–-Tibet Plateau, and oat forage is one of the main artificial planted forages in the area. However, the suitable oat varieties for harvesting and preparing silage feed in this region are still unclear. To investigate suitable oat forage varieties for silage production and the potential feeding value of different oat forage varieties, 16 oat forage varieties planted in Qinghai Province were selected in this experiment. These oat forages were subjected to two treatments: a group with no inoculants (CK) and a group with self-selected lactic acid bacteria (LAB) inoculants (IN). After 90 days of ensiling, silage quality and in vitro digestibility of the 16 oat forage varieties were determined. The results showed that all oat forage varieties ferment well after ensiling (pH < 4), the CK group had a silage pH range of 3.62–3.95, and the IN group had a silage pH range of 3.68–3.83. Tianyan No.1, Qingtian No.2, and Tianyan No.3 were in the top three in RFV and RFQ rankings in the CK group, while Qinghai 444, Tianyan No.1, and Tianyan No.3 were in the lead in GI rankings. Tianyan No.1, Qingtian No.2, and Everleaf 126 were in the lead in RFV and RFQ rankings in the IN group, while Qinghai 444, Titan, and Tianyan No.1 were in the top three in GI rankings. The dry matter digestibility and 72 h cumulative gas production of the IN group were higher than that of the CK group (p < 0.05). Based on principal component analysis and membership function comprehensive evaluation, Tianyan No.1, Qinghai 444, and Tianyan No.3 ranked the top three, demonstrating that these three oat forage varieties are suitable for silage processing in the Qinghai–Tibet Plateau region. Full article

Crowdshipping establishes a short-term connection between shippers and individual carriers, bridging the service requirements in last-mile logistics. From the perspective of a carrier operating multiple vehicles, this study considers the challenge of maximizing profits by optimizing bid strategies for delivery prices and transportation conditions in the context of bid-based crowdshipping services. We considered two types of bid strategies: a price bid that adjusts the RFQ freight charge and a multi-attribute bid that scores both price and service quality. We formulated the problem as a Markov decision process (MDP) to represent uncertain and sequential decision-making procedures. Furthermore, given the complexity of the newly proposed problem, which involves multiple vehicles, route optimizations, and multiple attributes of bids, we employed a reinforcement learning (RL) approach that learns an optimal bid strategy. Finally, numerical experiments are conducted to illustrate the superiority of the bid strategy learned by RL and to analyze the behavior of the bid strategy. A numerical analysis shows that the bid strategies learned by RL provide more rewards and lower costs than other benchmark strategies. In addition, a comparison of price-based and multi-attribute strategies reveals that the choice of appropriate strategies is situation-dependent. Full article

Particle radiotherapy based on the medical accelerator is emerging as a major treatment for cancer. To enhance the clinical flexibility of particle radiotherapy and further promote the use of medical accelerators, the Shanghai Institute of Applied Physics (SINAP) has presented a new linear accelerator plan for medical application. The new plan utilizes a 200 MHz Radio Frequency Quadrupole (RFQ) as the injector. The RFQ is designed to accelerate ions with charge-to-mass ratios of 1/3 to 1/2 from 8 keV/u to 750 keV/u. For the beam dynamics design, a new design strategy is presented to enhance the suppression of space charge effects and improve beam capture efficiency by optimizing the modulation, synchronous phase, and focusing strength. The simulation results demonstrate that the multi-ion RFQ can operate at a maximum beam current of 3.2 mA while maintaining a transmission efficiency above 95% with a compact length of 2.5 m. Multi-particle simulations confirm the high reliability of the design. Additionally, input and mechanical error analyses evaluate the RFQ’s tolerance and stability. The research results demonstrate the feasibility of a compact, high-efficiency RFQ for multi-ion acceleration in medical applications, contributing to the advancement of particle therapy. Full article

In light of current global challenges of climate change, the over-exploitation of natural resources, and increasing demand for livestock products, the exploration of excellent forage crop resources holds great potential for development. Therefore, selecting forage crops that are high-yield, high-quality, and have excellent resistance to pests and diseases can greatly promote the development of the livestock industry. Oat (Avena sativa L.), a dual-purpose crop for grain and forage, plays a vital role in the development of animal husbandry. Autumn-sown oats have a significantly longer growth cycle than spring-sown oats, ensuring a year-round forage supply and achieving higher yields. The agropastoral transitional zone in southwest China is a key region for autumn-sown oats, but the systematic evaluation of oat germplasm there is still limited. Therefore, we conducted a two-growing-season (2022–2024) field experiment across four locations to evaluate nine oat genotypes for growth phenotypes, forage productivity, and nutritional quality through 11 agronomic traits and nutritional parameters during the filling stage (Zadok’s 75). The results revealed the following: (1) agronomic performance: dry matter yield (DMY) ranged from 10.72 to 14.58 t/ha, with line ‘WC109’ achieving the highest DMY (14.58 t/ha) and crude protein (CP, 9.66%); (2) nutritional quality: CP exhibited a significant negative correlation with fiber content (NDF: r = −0.72, p < 0.01; ADF: r = −0.68, p < 0.01), highlighting a yield–quality trade-off; ‘WC109’ demonstrated superior forage value, with the highest relative forage quality (RFQ: 115.45) and grading index (GI: 19.30); (3) environmental adaptation: location-specific climatic conditions significantly influenced productivity, with Wenjiang (WJ) showing optimal performance due to favorable temperature and precipitation. These results position ‘WC109’ as a promising candidate for autumn-sown cultivation in southwest China, addressing winter forage shortages while enhancing livestock nutrition. Our findings further elucidate the mechanisms linking yield and feeding value to growth performance indicators, providing references for trait-based measures to enhance forage oat productivity and quality. Full article

The aim of this research carried out in the period 2021–2023 was to analyse the influence of competitiveness between Festuca arundinacea Schreb. and Trifolium pratense L., cultivated in simple mixtures, on the quality of the fodder obtained, under the conditions of the northern Romanian forest steppe. In the experiment organized at the Ezăreni Student Research and Practice Station of Iasi University for Life Sciences, at an altitude of 117 m, with coordinates 47°07′27″ N latitude and 27°30′25″ E longitude, on a cambic chernozem soil, with 2.40% humus, 0.178% Nt, 26 ppm P_AL and 242 ppm K in the 0–30 cm layer, two factors were studied, namely the cultivation system used, with five graduations: a₁—Festuca arundinacea Schreb. (100%—control); a₂—Festuca arundinacea Schreb. (75%) and Trifolium pratense L. (25%); a₃—Festuca arundinacea Schreb. (50%) and Trifolium pratense L. (50%); a₄—Festuca arundinacea Schreb. (25%) and Trifolium pratense L. (75%); and a₅—Trifolium pratense L. (100%), and mineral fertilization, with five graduations, respectively: b₁—unfertilized (control), b₂—N₅₀P₅₀; b₃—N₇₅P₇₅; b₄—N₁₀₀P₁₀₀; and b₅—N₁₅₀P₁₅₀. The obtained results showed that the process of interspecific competitiveness was greatly influenced by the percentage of participation in the sowing norm of the species in the mixture and the biological peculiarities of the species under study, as well as the climatic conditions specific to each agricultural year, with consequences for the quality of the feed. The crude protein quantity (Q_CP) obtained in the mixture of Festuca arundinacea Schreb. (25%) and Trifolium pratense L. (75%), fertilized with N₁₅₀P₁₅₀, was higher by 788.7 kg·ha⁻¹ than that in the control variant, represented by the Festuca arundinacea Schreb. species (100%), unfertilized. The lowest values of NDF (neutral detergent fiber) and ADF (acid detergent fiber) were recorded in the variants where the Trifolium pratense L. species was present and low doses of mineral fertilizers were used, determining a better quality of the forage. In the third year of vegetation, relative forage quality (RFQ) had values of 113.7 in the variant represented by the mixture of Festuca arundinacea Schreb. (25%) + Trifolium pratense L. (75%), unfertilized, and only 91.2 in the variant represented by the Festuca arundinacea Schreb. species (100%), fertilized with N₁₅₀P₁₅₀. Full article

Sorghum cultivars, particularly those used for forage and biomass, present significant potential as drought-resistant crops suitable for animal feed and biofuel production. This study evaluated 59 sorghum hybrids over five years (2019–2023) across three University of California research farm locations in the Central Valley: Kearney REC (KARE), West Side REC (WSREC), and Davis. The primary aim was to identify genotypes that exhibit high yield and stability across diverse environments in California, which is crucial for meeting the state’s significant feed needs associated with dairy operations and animal production. The evaluation focused on biomass yields, forage quality traits such as Relative Feed Quality (RFQ) and milk yield per ton (milk/ton), and biofuel-relevant chemical compositions like Neutral Detergent Fiber (NDF) and starch. A multi-trait stability index was employed to pinpoint superior genotypes that combine high yield with desirable quality traits. Results indicated significant genotypic, environmental, and genotype-by-environment (GxE) interaction effects for all traits except fat and water-soluble sugars. Eight hybrids were notable for maintaining high and stable biomass yields across different locations. Additionally, high fat and starch content were found to correlate with improved milk/ton potential, while lower fiber content (ADF, NDF) was associated with enhanced RFQ. Specifically, nine hybrids were identified as optimal for dairy forage due to their combination of high yield, RFQ, and milk/ton. Furthermore, distinct hybrids were identified for first-generation (starch-based) and second-generation (NDF-based) biofuel strategies. Three hybrids stood out as having desirable traits for both feed and biofuel applications, underscoring their versatility. This study highlights the utility of a multi-trait stability index in selecting superior sorghum genotypes for specific trait combinations. The identified candidates for forage and biofuel use, especially the multipurpose varieties, offer valuable insights that can aid growers and industry stakeholders in developing more sustainable and versatile sorghum production systems in California. Findings from this study contribute significantly to the development of more resilient sorghum production systems. By identifying hybrids that excel in both yield and quality across various environments, this research supports future cropping decisions aimed at enhancing water use efficiency and drought resilience in sorghum cultivation. These advancements are crucial for maintaining competitive dairy operations and advancing biofuel production in the face of climate change-induced challenges. Full article

We use a laboratory experiment to explore the effect of a change in pre-trade anonymity in a quote-driven dealer-to-customer market, organised as a request for quote (RFQ). We consider two treatments in which dealers interact with two types of customers (informed or uninformed). In the first treatment, there is no anonymity: dealers know whether the customer that sent them the request for quote is informed or uninformed. In the second treatment, there is complete anonymity: dealers do not know the type of customers they are interacting with. We find that anonymity improves price efficiency, whereas it does not adversely impact dealers’ trading profits. Our results contribute to the debate on transparency versus the adoption of anonymity in financial markets. Full article

This experiment was conducted to determine the nutrient composition of three agricultural by-products, namely garlic peel, sweet potato vine, and cotton straw, calculate their relative feeding value, effective energy value, and other indexes, and comprehensively evaluate their nutrient value by combining with rumen in vitro fermentation technology, with the aim of providing data references for the development and utilization of non-conventional feed resources for ruminants. The results showed that: 1) the dry matter (DM), ash, ether extract (EE), and crude protein (CP) contents of cotton straw were significantly higher than the other two feeds (p < 0.05), while the acid detergent fiber (ADF) and neutral detergent fiber (NDF) contents of garlic peel were highly significantly higher than the others (p < 0.05); 2) the relative feed value (DMI, DDM, TDN, RFV, and RFQ) and effective energy value (GE, DE, ME, NE_m, NE_g, and NE_L) indexes of cotton straw were significantly higher than garlic peel and sweet potato vine (p < 0.01); 3) after 48 h of in vitro fermentation, the dry matter degradation rate (IVDMD) of sweet potato vine was significantly higher than the other two feeds (p < 0.01), and the cumulative gas productions (mL) and estimated gas parameters (a, b, a + b, and c) of sweet potato vine were significantly (p < 0.01) higher than those of garlic peel and cotton straw; 4) the sweet potato vine had lower pH but higher NH₃-N compared to garlic peel and cotton straw (p < 0.05). The sweet potato vine had higher propionate, iso-butyrate, butyrate, iso-valerate, and total VFA than the other two roughages, which also had the lowest acetate-to-propionate ratio. Garlic peel produced the lowest acetate, while it produced the highest valerate (p < 0.05). These findings demonstrate that all three by-products have high potential as livestock feed based on their nutritive value parameters. Comparatively, sweet potato vines exhibit higher feeding value due to their relatively moderate NDF content and superior rumen fermentation performance. Full article

The ANTHEM (Advanced Technologies for Human-centered Medicine) Radio-Frequency Quadrupole (RFQ) will employ eight coaxial power couplers, which will be magnetically coupled to the device through a loop antenna. The coupler design can support up to 140 kW in continuous wave operation. This paper presents the design of the cavity used for high-power testing, with the primary objectives of both optimizing the coupling between the couplers and ensuring operations at the designated operating frequency. Furthermore, the paper encompasses thermal and structural assessments conducted through numerical simulations. Full article

The high nutritional value of alfalfa hay makes it a widely utilized component in animal feed. However, the current prevalent drying methods for forage have a significantly detrimental impact on the quality of alfalfa during the drying process. This study investigates the effects of high-voltage corona discharge (HVCD) treatment on post-cut alfalfa. Gradient experiments are conducted by adjusting the air-gap spacing at a voltage of 25 kV. The results demonstrate that as the distance decreases, there is an observed increase in the drying rate, rehydration rate, and color intensity of the HVCD-treated material. HVCD treatment significantly enhances crude protein content, which increases with decreasing air-gap spacing. Meanwhile, it negatively affects lignin, neutral detergent fiber (NDF), and acid detergent fiber (ADF) levels. The relative forage quality (RFQ) of alfalfa reaches its peak at an air-gap spacing of 7 cm. The application of HVCD disrupts the fiber structure and induces significant electroporation effects in cells. Minimal changes in functional groups preserve nutrient integrity. Furthermore, HVCD exhibits lower energy consumption compared to hot air dryers. The HVCD treatment is a highly efficient and effective method, with a gradual improvement in alfalfa hay quality as the air-gap distance decreases. Full article

Superconducting (SC) radio-frequency quadrupoles (RFQs) have exhibited outstanding performance in transmitting and accelerating high-current continuous-wave (CW) ion beams. They can complete beam acceleration at a much higher gradient and with much lower power consumption compared with normal conducting (NC) RFQs. In this study, we introduce a novel SC RFQ scheme operating at 162.5 MHz to accelerate 10 mA proton beams from 30 keV to 2.5 MeV. It will be used as a crucial component for a neutron source dedicated to Boron Neutron Capture Therapy (BNCT) and neutron imaging projects. For efficient transmission of proton beams, we selected a relatively high inter-vane voltage of 240 kV, and the beam dynamics design yielded satisfactory results. Subsequently, RF design and multi-physics analysis were carried out to validate the reliability of the design. A 30-centimeter-long cavity was specifically designed for the vertical test and allowed for a thorough evaluation of the performance of the SC RFQ after post-treatments. Additionally, the tuning design of the 30 cm cavity was also carried out. Full article

This paper reviews the development and present status of a novel gas dynamic RF-only funnel technique for low-energy ion beam extraction into vacuum. This simple and original technique allows for the production of high-quality continuous and pulsed ion beams in a wide range of masses, which have a very small transverse and longitudinal emittance. Full article

This paper presents the design of a high-intensity 10 mA deuteron RFQ accelerator that generates a 2.1 MeV beam in a continuous wave (CW) mode. The operation frequency is 162.5 MHz. The results of beam dynamics simulations demonstrate excellent output beam quality, achieving a transmission efficiency of 98.63%. The beam tracking results indicate that the RFQ is capable of managing errors within reasonable tolerances. In addition, the RF electromagnetic design and optimization are based on an RFQ model. Multiphysics simulations are then performed for the CW mode. Vacuum calculations suggest that the RFQ requires four 1200 L/s vacuum pumps and one 440 L/s ion pump to attain a vacuum pressure of 10⁻⁶ Pa. Full article

The European Spallation Source (ESS), currently under construction in Lund, Sweden, will be the brightest spallation neutron source in the world, when its driving superconducting proton linac achieves the design power of 5 MW at 2 GeV. Such a high-power linac requires production, efficient acceleration, and almost no-loss transport of a high-current beam (62.5 mA), thus making its design and beam commissioning challenging. Beam commissioning for the normal-conducting part of the linac is ongoing in stages. In 2022, the beam was accelerated up to the first tank of the five-tank drift-tube linac. This presentation provides a summary of the ESS linac project and presents highlights from ongoing beam commissioning. Full article