Dialogic weaving: a favorable tension between design and craft

Focusing on a process where a designer embeds herself in craftspeople’s workshops with the intention of ‘learning from inside’ and ‘making together’; this paper proposes pathways for considering collaboration between designers and craftspeople via digital fabrication and weaving. The tension of forces that make weaving possible, act as an analogy for this collaboration as well as providing the title of the project as ‘One Over, One Under’. The project proposes a mode of working and a spectrum of outcomes where the designer has a first-hand experience of production techniques, engages in a serious and continuous dialogue through making, and develops an intervention that also brings forth her own skill set (introducing digital fabrication and structural variations), thus transforming the conventions and boundaries between established roles and manufacturing techniques. An experiment that resulted in a series of objects considering both the technologies of production and the input of the designer, this process not only increases the potentials that crafts hold for the field of design, but it also offers possibilities of collaboration and a further articulation of the design act.     

Moulded pulp products manufacturing with thermoforming

For an effective optimization of pulp thermoforming and of the moulded pulp products manufactured by this process, a full understanding of the process physics combined with full knowledge of the pressing equipment is necessary. For this reason, in this Addendum, we clarify how the process parameters “Holding time,” “Vacuum time,” “Cycle time,” and “Temperature” were interpreted and subsequently defined for the analysis of the process and product‐related outputs of the thermoforming experiments.     

Evaluation of particle recovery from microalgae

Coccoliths are micro-structured biomineral particles found in cell protective covering layers of coccolithophore species. They are mainly composed of CaCO₃ and their individual crystal entities are arranged in such a way that they construct complex and unique structures. This complexity is found down to the individual particle level and appears to have promising properties to offer. This study focuses on the essential step prior to any kind of implementation, which is the recovery of the material. It summarizes cleaning protocols found in literature, compares them for the first time for the same freshly cultivated material and addresses challenges that still need to be overcome. Further, it highlight the advantages and disadvantages of the best cleaning protocols, suggests optimizations with promising results and uses size distribution measurements to analyse the recovery efficiency. To that end, further characterization techniques, new for coccoliths, are introduced and used to improve our current knowledge of the particles behaviour.     

Novel high-energy ionic molecules deriving from new monovalent and divalent 4-oxyl-3,5-dinitropyrazolate moieties

ABSTRACT

In recent years, the exploration of a practical strategy for novel energetic molecules with high energy and low sensitivity is very desirable but highly challenging. Novel ionic energetic molecules have attracted much attention in this area due to their prominent advantages including low sensitivities, high thermal stability, and excellent energy performances. Herein, five different ionic energetic molecules based on new monovalent and divalent 4-oxyl-3,5-dinitropyrazolate moieties with enhanced oxygen balance have been synthesized, characterized and evaluated as potential high-energy materials. Thermal stability, sensitivities and energy output test were measured and studied in detail. The heats of formation and energetic parameters were calculated by using Gaussian 09 suite of programs and EXPLO 5 code. The results suggest that all as-prepared new molecules exhibit good thermal stability with high decomposition temperature (3, 231°C; 5, 160°C; 6, 185°C; 7, 180°C; 8, 213°C), and relative low sensitivity (IS > 20 J, FS = 324 N). Inheriting the significant oxygen content of monovalent and divalent 4-oxyl-3,5-dinitropyrazolate moieties, they also possess good energy properties (v _D = 8238 ~ 9208 m s^?1, P = 26.8 ~ 36.7 GPa, V _o = 481.8 ~ 959.4 L kg^?1), which make them competitive high-energy materials.     

γ-radiation effects on metal oxide particles and their wetted surfaces

ABSTRACT

Typical metal oxide corrosion products of structural materials have been irradiated with γ-rays in ultra-pure water to investigate the effect of radiation on the surface oxide and the nature of adsorbed water. Analysis techniques including thermal gravimetric analysis, differential thermal analysis, diffuse reflectance infrared Fourier transform spectroscopy, and X-ray photoelectron spectroscopy before and after γ-irradiation were employed to investigate surface structural effects and adsorbed water behaviour. The production of H₂ in the oxide nanoparticle mixtures was investigated by gas chromatography to probe the mechanism of radiolysis in the water/oxide mixtures and the relationship with surface water. The nature of water at the surface of the oxides was affected by γ-radiation and the relationship was dependent on the particle composition. The rate of H₂ production was shown to be oxide dependent, and higher rates of H₂ formation were attributed to the decomposition of surface adsorbed water. Changes to the surface chemistry and H₂ production rates were found to be highly dependent on the surface chemistry of the metal oxide nanoparticle and no bulk structural changes were observed.     

Aluminium/tin (IV) oxide thermite composite: sensitivities and reaction propagation

ABSTRACT

Thermites are energetic composites made of metal and oxidizer particles that react according to an exothermic reaction and release large amounts of energy. Many possible metal and oxidizer couples exist in the literature. Here, the performance of the aluminum reducing metal and tin (IV) oxide (SnO₂) combination was reported as a function of the fuel/oxidizer mass ratio. The Al/SnO₂ energetic composite, in stoichiometric conditions, was insensitive to impact, sensitive to friction and extremely sensitive to electrostatic discharge. The combustion velocity was determined to be close to 600 m/s. Changing the stoichiometry affected both the sensitivity thresholds to the friction test (160 N to > 360 N) and flame propagation velocity (480–588 m/s) of the Al/SnO₂ composite. These results are reported for the first time.     

三级连续碳化法生产纳米碳酸钙新工艺研究

采用有效容积依次递增的预塔、中塔、后塔三个碳化塔串联,塔内气液连续逆流操作、塔间气液连续并流或错流操作,严格控制氢氧化钙浆液的浓度、流量、温度和碳化气的浓度、流量,并通过pH计或电导仪进行跟踪检测碳化度,可实现纳米碳酸钙生产工艺连续化、产品质量稳定化、产量规模化.     

纳米粉体粒度特性表征方法讨论

实验中采用不同的方法对四种ZrO2纳米粉体的颗粒特性进行了表征。对颗粒呈现球形、不发生硬团聚的微小粒子，例如YSZ—KD试样，一次颗粒粒度为10～15nm，比表面为64．2m^2／g，采用XRD获得的微晶粒子尺寸与TEM和BET方法获得的颗粒尺寸相一致。由于比表面高，颗粒之间容易发生静电力、范德华力和液桥力的作用而软团聚在一起，其团聚系数较大为62．5，粒度分布宽度为14．58。TEM和BET与XRD方法获得的颗粒尺寸出现偏差，说明YSZ—HW1、YSZ—TH试样中出现了基元为2～3的多晶颗粒，多晶颗粒存在使得颗粒体偏离球形。团聚系数为25．71，粒度分布宽度为18．94的YSZ—HW1试样中仍存在较多的软团聚体，团聚系数为6．89，粒度分布宽度为8．91的YSZ—TH试样中软团聚状况明显较少。YSZ—HW2试样中TEM和BET与XRD方法获得的颗粒尺寸出现很大偏差，说明其中存在较多的硬团聚体，硬团聚体使得颗粒呈现不规则外形，其比表面小，活性低，表现为团聚系数小，粒度分布窄。     

高钨高硅电炉锡渣烟化条件下的特性

针对高钨高硅电炉锡渣，考察炉渣发泡性能，测定其熔点、粘度，分析ＷＯ３等组分对各性质的影响。通过化学分析、化学物相分析、Ｘ射线衍射、电子探针、光学显微镜鉴定等手段，查明高钨高硅电炉锡渣的相组成及化学元素在各相中的分配以及渣中各相相对百分含量、结构构造、各矿物相的嵌布关系等。对在烟化条件下的炉渣成分、发泡性能、粘度、炉渣中的锡相等特性进行研究和分析。指出电炉锡渣可通过适当措施顺利实现烟化作业。它为烟化法处理该复杂物料提供了理论依据，也是完善冶炼工艺和条件的前提和基础。     

20CrNi2MoA钢锻件去氢退火工艺的研究

分析了氢在钢中的存在状态,阐明了氢的溶解度与扩散系数之间的关系,据此,科学地设计了20CrNi2MoA钢锻件的去氢退火工艺,该钢退火前的氢质量分数为(1.50～1.90)×10-6,退火后的氢质量分数为(0.37～0.57)×10-6,回火索氏体组织,硬度212～229HB,满足标准要求,并获得显著经济效益.