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Architectured hierarchical porous materials exist widely in nature. Inspired by their unique mechanical and functional responses, extensive efforts have been made to develop architectured hierarchi...

Additive manufacture (AM) enables the fabrication of highly efficient lattice structures. However, the mathematical efficiency of characterising AM lattice geometry can be poor, potentially restricting the commercial application of AM lattice structures. This research quantifies the effect of the polygon order used to characterise the geometric resolution of lattice strut elements on the associated manufacturability and geometric qualities of the manufactured lattice. The effect of these design parameters on manufactured quality is experimentally determined for aluminium and titanium specimens fabricated by selective laser melting (SLM), although the method can be generally applied to any AM technology. This research finds that geometric thresholds exist, below which additional geometric resolution does not result in increased part quality. These thresholds are a function of material, lattice inclination angle, cross-sectional area and the polynomial order used to represent the cross section. These findings enable significantly reduced computational cost in managing AM lattice structures, and can be directly integrated with algorithmic methods for the optimisation of AM lattice structures.

Based on the leakage of the coalbed methane (CBM) drilling engineering practice of Luan mining area in China, the author determines the safe drilling fluid density range for the stable borehole wall based on borehole wall collapse and fracture pressure. Such parameters as the drilling fluid hydraulic parameters (including pump pressure, pump power and displacement, nozzle diameter, bit pressure drop, bit hydraulic horsepower, circulation pressure drop, impact force and jet velocity) and drilling parameters (including weight-on-bit, drilling rotary speed, bit tooth wear) in each borehole section are optimized. Taking the lowest drilling cost as the controlling target, the drilling parameter optimization model is designed and solved by the genetic algorithm. Furthermore, a software named “CBM borehole wall stability parameter design and optimization” characterized by visualization and applicable for drilling formation condition, which can be used to design and optimize the borehole drilling technological parameters, is developed. This program includes such modules as drilling fluid density prediction, drilling technology design, database management, user management and help. The developed software is proven to solve the drilling leakage effectively in the No.67 borehole practice, which can help drilling engineers to optimize CBM drilling technological parameters safely and quickly.

Additive manufacturing (AM), particularly Selective Laser Melting (SLM) has enabled development of lattice structures with unique properties. Through control of various parameters lattice structures can produce unique mechanical, electrical, thermal and acoustic properties, and have received much research attention. Despite the increasing volume of published data on the mechanical response of specific SLM lattice structures, there exists no overarching analysis. This work addresses this identified deficiency by providing a comprehensive summary of the experimental data reported on the mechanical response of SLM lattice structures. The design, fabrication and performance of SLM lattice structures are reviewed and the quality of data reported is analysed to inform best-practice for future studies. This comprehensive data summary enables meta-analysis of the reported mechanical performance of SLM lattice structures, providing insight into the bounds of their technical capabilities. Correlations were identified between the relative density and mechanical properties of many unit cell topologies consistent with the predictions of the Gibson-Ashby model, indicating its usefulness in describing and predicting the behaviour of SLM lattice structures. This review provides designers with a compiled resource of experimental data and design for AM tools to inform future design applications of SLM lattice structures and facilitates their further commercial adoption. Keywords: Additive manufacturing, SLM, Selective laser melting, Lattice structures, DFAM, Mechanical properties

Additive Manufacture (AM) enables the fabrication of highly complex lattice structures with exceptional engineering properties. Inconel is a technically useful material in that it provides high resistance to oxidisation, creep and loss of mechanical properties at elevated temperatures. The combination of Inconel material properties and the geometric freedom of AM provides a unique opportunity for the fabrication of engineered structures with exceptional strength and stiffness at elevated temperatures, as for example is required for high temperature turbomachinery. Despite the associated technical opportunities, there exists no design data on the mechanical response, deformation characteristics and failure modes of AM Inconel 625 lattice structures. This research provides a comprehensive reference for the mechanical response of Inconel 625 lattice structures fabricated by Selective Laser Melting (SLM). Furthermore, the high ductility of Inconel 625 lattice enables novel insight into the structural mechanics of AM lattice, and the associated deformation photography provides a reference for the validation and verification of numerical models of AM lattice behaviour. Keywords: Additive manufacture, Lattice structures, Selective laser melting (SLM), Inconel 625, Design for additive manufacture (DFAM)

To describe the MRI features of Iliotibial band friction syndrome (ITBFS), in order to improve the understanding and diagnosis of ITBFS.The MR findings of 16 patients (18 knees )of clinically diagnosis ITBFS were reviewed retrospectively.The MRI features of ITBFS:(1)Ill- defined abnormal signal intensity extended to the lateral femoral epicondyle.(2) Poorly defined abnormal signal intensity presented deep to the ITB adjacent to the lateral femoral epicondyle. (3) Fluid collections medial to the ITB adjacent to the lateral femoral epicondyle. (4) The part of ITB over the lateral femoral epicondyle was thicker. (5) Joint effusion. (6)Other abnormal signs.MRI is a relatively good method for detection of ITBFS.

To explore the program for calculating the necrotic articular surface area (NASA) and the ratio of NASA to whole articular surface area (WASA) of osteonecrosis of the femoral head (ONFH), to verify the accuracy of this calculation and to predict the collapse of the femoral head clinically using this program.From June 2001 to June 2003, The specimens of the necrotic femoral head from eight patients (13 hips) were obtained by total hip arthroplasty. The magnetic resonance imaging (MRI) was taken in all patients before operation. According to a series of T1-weight pictures, the NASA and the ratio of NASA to WASA were calculated by designing program. The specimens of the necrotic femoral head were sawed into lays similar to MRI pictures using the coordinate paper stick on the auricular surface, the data processing were done by analytic instrument for pictures. The data of both were analyzed statistically by software SPSS 10.0 edition. The NASA and the ratio of NASA to WASA were calculated on MRI in ARCO Stage I, II 16 patients (25 hips) with non-operation. Follow-up was done to the patients with collapse of the femoral head and to the patients with no collapse for at least 24 months. The data were compared in collapse group and non-collapse group.There were no significant differences between MRI pictures calculation and specimens measurement (NASA: 0. 412, ratio of NASA to WASA: 0.812, P0.05). Of the 25 hips followed up, collapse occurred in 17 hips. NASA was 31.06+/-8.10 cm2, (95% CI. 26.58 to 35.55), the ratio of NASA to WASA was 58.91%+/-15.11%, (95% CI: 51.14 to 66. 68). No collapse appeared in 8 hips. NASA was 14.16+/-9.32 cm2 (95% CI: 6.04 to 21. 95), the ratio of NASA to WASA was 29.48%+/-19.76% (95% CI: 12.97 to 45.99). The ratio in the patients with collapse was beyond 33%.The NASA and the ratio of NASA to WASA in patients with ONFH can be accurately calculated with the MRI pictures. The possibility of collapse can be predicted by this method. As it is complicated in operation, improvement should be made in order to put it into clinical use.

To investigate the factors influencing the diagnostic accuracy of CT-guided percutaneous transthoracic aspiration biopsy of chest lesions.Data of pathology and clinical follow-up of 224 patients who had undergone CT-guided percutaneous transthoracic biopsy were collected. Univariate analysis and multivariate stepwise Logistic regression analysis were made to study the influence of the patient-related factors (sex, age, and presence of emphysema), lesion-related factors (histology, size, location, depth, and presence of cavity discovered by CT), and procedure factor (posture of patient during operation) on the diagnostic accuracy of CT-guided biopsy.(1) One hundred and sixty-five lesions were diagnosed as malignant and 79 lesions as benign. The accuracy rate of CT-guided biopsy was 82.4% (201/244). Univariate analysis showed that the diagnostic accuracy rates of CT-guided biopsy for malignant and benign lesions were 88.5% and 69.6% respectively (chi(2) = 13.096, P0.01). The mean diameters of the lesions with correct diagnosis and of those misdiagnosed were 4.0 cm +/- 1.8 cm and 3.1 cm +/- 1.4 cm respectively (F = 8.805, P0.01). (2) Multivariate stepwise Logistic regression analysis showed that among the various factors only histology (regression coefficient = 0.320, Wald chi(2) = 7.126, P0.01) and size (regression coefficient = 1.114, Wald chi(2) = 4.951, P0.05) were significantly associated with diagnostic accuracy.Histology and size of lesion are the determining factors for diagnostic accuracy of CT-guided transcutaneous thoracic needle aspiration biopsy.