The Impact of Early Order Commitment on the Performance of a Simple Supply Chain

An example of supply chain coordination is early order commitment, wherein a retailer commits to purchase a fixed-order quantity and delivery time from a manufacturer before the real need takes place. In this paper, an analytical model is developed that quantifies the impact of early order commitment on the performance of a simple two-level supply chain consisting of a single manufacturer and a single retailer. The model reveals that the effect of early order commitment depends on a lot of factors such as the cost structure of the supply chain, the lengths of manufacturing and delivery lead times, and the correlation of the demand over time. This model can be used to evaluate the benefit of early order commitment, to determine the optimal early commitment periods of the supply chain, and to estimate the maximum incentives the manufacturer can provide to encourage the retailer to commit its orders in advance

Relative Status Determination for Spacecraft Relative Motion Based on Dual Quaternion

For the two-satellite formation, the relative motion and attitude determination algorithm is a key component that affects the flight quality and mission efficiency. The relative status determination algorithm is proposed based on the Extended Kalman Filter (EKF) and the system state optimal estimate linearization. Aiming at the relative motion of the spacecraft formation navigation problem, the spacecraft relative kinematics and dynamics model are derived from the dual quaternion in the algorithm. Then taking advantage of EKF technique, combining with the dual quaternion integrated dynamic models, considering the navigation algorithm using the fusion measurement by the gyroscope and star sensors, the relative status determination algorithm is designed. At last the simulation is done to verify the feasibility of the algorithm. The simulation results show that the EKF algorithm has faster convergence speed and higher accuracy

Cooling and Crack Suppression of Bone Material Drilling Based on Microtextured Bit Modeled on Dung Beetle

In recent years, the number of patients with orthopedic diseases such as cervical spondylosis has increased, resulting in an increase in the demand for orthopedic surgery. However, thermal necrosis and bone cracks caused by surgery severely restrict the development and progression of orthopedic surgery. For the material of cutting tool processing bone in bone surgery of drilling high temperature lead to cell death, easy to produce the problem such as crack cause secondary damage effects to restore, in this paper, a bionic drill was designed based on the micro-structure of the dung beetle’s head and back. The microstructure configuration parameters were optimized by numerical analysis, and making use of the optical fiber laser marking machine preparation of bionic bit; through drilling test, the mathematical model of drilling temperature and crack generation based on micro-structure characteristic parameters was established by infrared thermal imaging technology and acoustic emission signal technology, and the cooling mechanism and crack suppression strategy were studied. The experimental results show that when the speed is 60 m/min, the cooling effects of the bionic bit T1 and T2 are 15.31% and 19.78%, respectively, and both kinds of bits show obvious crack suppression effect. The research in this paper provides a new idea for precision and efficient machining of bone materials, and the research results will help to improve the design and manufacturing technology and theoretical research level in the field of bone drilling tools

A vacancy‐rich, partially inverted spinelloid silicate, (Mg,Fe,Si)_2(Si,□)O_4, as a major matrix phase in shock melt veins of the Tenham and Suizhou L6 chondrites

A new high‐pressure silicate, (Mg,Fe,Si)_2(Si,□)O_4 with a tetragonal spinelloid structure, was discovered within shock melt veins in the Tenham and Suizhou meteorites, two highly shocked L6 ordinary chondrites. Relative to ringwoodite, this phase exhibits an inversion of Si coupled with intrinsic vacancies and a consequent reduction of symmetry. Most notably, the spinelloid makes up about 30–40 vol% of the matrix of shock veins with the remainder composed of a vitrified (Mg,Fe)SiO_3 phase (in Tenham) or (Mg,Fe)SiO_3‐rich clinopyroxene (in Suizhou); these phase assemblages constitute the bulk of the matrix in the shock veins. Previous assessments of the melt matrices concluded that majorite and akimotoite were the major phases. Our contrasting result requires revision of inferred conditions during shock melt cooling of the Tenham and Suizhou meteorites, revealing in particular a much higher quench rate (at least 5 × 10^3 K s^(−1)) for veins of 100–500 μm diameter, thus overriding formation of the stable phase assemblage majoritic garnet plus periclase

Poirierite, a dense metastable polymorph of magnesium iron silicate in shocked meteorites

宇宙から飛来した隕石から新鉱物ポワリエライトを発見 --小天体の衝突過程、地球内部の変化等を探る重要な鍵に--. 京都大学プレスリリース. 2021-01-25.A dense magnesium iron silicate polymorph with a structure intermediate between olivine, ringwoodite, and wadsleyite was theoretically predicted about four decades ago. As this group of minerals constitute the major component of shocked meteorites, constraining their transitional forms and behaviour is of potential importance for understanding impact events on their parent bodies. Here we use high-resolution transmission electron microscopy techniques and single-crystal X-ray diffraction analyses to identify naturally occurring examples of this mineral – recently named poirierite – in shocked chondritic meteorites. We observe nanoscale lamellar poirierite topotactically intergrown within wadsleyite, and additionally within ringwoodite as recently reported. Our results confirm the intermediate structure of poirierite and suggest it might be a relay point in the shear transformations between its polymorphs. We propose that poirierite formed during rapid decompression at relatively low temperature in retrograde shock metamorphism of the meteorites

A novel mutation in the UBAP1 gene causing hereditary spastic paraplegia: A case report and overview of the genotype-phenotype correlation

Hereditary Spastic Paraplegia (HSP) is considered to be one of the common neurodegenerative diseases with marked genetic heterogeneity. Recently, the mutations in ubiquitin-associated protein 1 (UBAP1) have been described in patients with HSP, known as spastic paraplegias 80 (SPG80). Here, we reported a Chinese HSP family presenting a frameshift mutation in the UBAP1 gene leading to complex HSP. Their clinical features encompassed spastic paraparetic gait, exaggerated patellar tendon reflexes, bilateral Babinski signs, and hyperactive Achilles tendon reflex. The proband also had severe urinary incontinence and a dermoid cyst at the lumbar 4–5 spinal cord, which rarely occurs in HSP patients. Following whole-exome sequencing, a novel heterozygous mutation (c.437dupG, NM_016,525) was identified in the UBAP1 that segregated with the family’s phenotype and resulted in truncating UBAP1 protein (p.Ser146ArgfsTer13). Moreover, we reviewed the genotypes of UBAP1 and the phenotypic variability in 90 HSP patients reported in the literature. We found that the age of onset in UBAP1-related patients was juvenile, and there were population differences in the age of onset. The main complications were lower extremity spasticity, hyperreflexia, and the Babinski sign. Exon 4 of UBAP1 was identified as a mutation hotspot region. Our study expands the knowledge of UBAP1 mutations, which will aid in HSP patient counseling. Further molecular biological research is needed to explore the genotype-phenotype correlations of UBAP1-related HSP

Arrangement models of alkylammonium cations in the interlayer of HDTMA+ pillared montmorillonites

The orientation of HDTMA+ in the interlayer of organic pillared montmorillonites prepared at different concentrations of HDTMA+ have been studied using X-ray powder diffraction (XRD) and theoretical calculation. A series of arrangement models of HDTMA+ in the interlayer of montmorillonite have been proposed as lateral-monolayer (LM), lateral-bilayer (LB), pseudotrilayer (PT), paraffin-type-monolayer (PM), paraffin-type-bilayer (PB). With the increase of the concentration of HDTMA+, the arrangement model of HDTMA+ in the interlayer of montmorillonites changes as lateral-monolayer→lateral-bilayer→paraffin-type monolayer→pseudotrilayer→paraffin-type-bilayer and the packing density of HDTMA+ in the interlayer increases gradually. In the intermediate stages, different models may coexist

Design support for state-based distributed object software.

Design support for state-based distributed object software

Shenzhuangite, NiFeS2, the Ni-analogue of chalcopyrite from the Suizhou L6 chondrite

henzhuangite (IMA 2017-018), NiFeS2, is a new mineral species found in the shocked Suizhou L6 chondrite. The mineral is closely associated with forsteritic olivine, pyroxene, plagioclase glass (maskelynite), taenite and troilite. It is opaque, and in reflected light shenzhuangite is weakly anisotropic with light brown to greenish rotation tints. Internal reflections are absent. The reflectance COM values (air, R-1 and R-2 in %) are: 24.8, 26.0 (471.1 nm); 34.9, 36.2 (548.3 nm); 37.7, 39.1 (586.6 nm); 40.4, 41.1 (652.3 nm). The average result of 4 electron-microprobe analyses is Ni 22.37(55), Fe 30.87(67), Cu 10.88(22), Co 0.07(4), S 35.42(58), total 99.61 wt%. The empirical formula (based on 4 atoms pfu and assuming the crystal-chemical exchange: Cu+ + Fe3+ <-> Ni2+ + Fe2+) is (Ni0.692+Cu0.31+)((Fe0.69Fe0.313+)-Fe-2)S-2.00. The simplified formula is NiFeS2, which requires Ni 32.85, Fe 31.26, S 35.89, total 100.00 wt%. Shenzhuangite is tetragonal, space group I42d, with unit-cell parameters: a = 5.3121(4), c = 10.4772(7) angstrom V = 295.65(4) angstrom(3), c:a = 1.9723, Z = 4. The five strongest observed X-ray powder-diffraction lines [d in angstrom (I/I-0) (h k l)] are: 3.05 (100) (1 1 2), 1.875 (20) (2 2 0), 1.591 (25) (3 1 2, 1 1 6), 1.215 (10) (3 3 2, 3 1 6), 1.080 (10) (4 2 4). The crystal structure showed that shenzhuangite is the Ni-analogue of chalcopyrite. It likely formed as alteration of pre-existing taenite when pS(2)/pO(2) ratios allowed sulfurization of the FeNi metal. Shenzhuangite is named in honour of Prof. Shangyue Shen and Prof. Xiaoli Zhuang who first discovered the Ni-rich variety of chalcopyrite in the Suizhou meteorite