Tree-inspired dendriforms and fractal-like branching structures in architecture: A brief historical overview

The shapes of trees are complex and fractal-like, and they have a set of physical, mechanical and biological functions. The relation between them always draws attention of human beings throughout history and, focusing on the relation between shape and structural strength, architects have designed a number of treelike structures, referred as dendriforms. The replication and adoption of the treelike patterns for constructing architectural structures have been varied in different time periods based on the existing and advanced knowledge and available technologies. This paper, by briefly discussing the biological functions and the mechanical properties of trees with regard to their shapes, overviews and investigates the chronological evolution and advancements of dendriform and arboreal structures in architecture referring to some important historical as well as contemporary examples.     

Partially saturated flow from sand into a discrete smooth open vertical fracture at the soil–rock interface: experimental studies

The two proposed conceptual models explaining partially saturated flow from soil into fractured rock in the intermediate fractured vadose zone have not been confirmed due to the difficulty involved in observing the soil–rock interface in situ. To address that challenge, this paper presents a series of newly developed physical experiments using a geotechnical centrifuge model of sand overlying a single dry clean smooth vertical fracture. The model shows the development of a perched water system and a saturated wetting front that progresses transversely along the interface, while breaching through the interface occurs via multiple point sources. The dominant flow mechanisms within the fracture comprise droplets, discontinuous rivulets with droplet formation, and continuous rivulets. A maximum drainage area of 30% of the width of the fracture contributes to the flow in the model, and this drainage area decreases with depth due to the merging of oscillating rivulets in the upper regions of the fracture. The presence of evidence supporting both conceptual models shows that a combined conceptual model is required to accurately explain partially saturated flow at the soil–rock interface.

     

Fractal-based algorithmic design of Chinese ice-ray lattices

Chinese ice-ray lattices are perhaps one of the earliest and controlled designs of asymmetric and complex patterns applied as a traditional motif in windows. Such intricate and complex designs developed centuries back have created an evident curiosity to explore its underlying geometric rules. Some scholars used the Shape Grammar as a tool to explain and recreate similar patterns. The previous studies conceive the ice-ray lattice design as the iterative subdivisions of a polygon. However, they missed explaining this geometric quality through the discussion of fractal geometry, which can explain the shapes consuming self-similar or self-affine repetitions of itself at different scales. As a novel approach, this paper analytically focuses on the fractal characters of ice-ray lattice designs and uses fractal geometry as a unique tool for generating different types of ice-ray lattices. The significance of this study is the demonstration of the efficacy of fractal geometry and the simple geometric rule of IFS for analyzing and algorithmically modeling complex lattices and cracked-like patterns.     

L250Z系列柴油机的研制

在原6L250GZC－Ⅱ型柴油机的基础上，通过加长行程、改进增压系统、匹配先进的增压器、选择合适的平均有效压力和最高燃烧压力、改进燃油系统、提高燃油喷射压力、优化供油规律和喷油规律并选择合适的燃烧室，使燃油、空气在燃烧室中达到较理想的混合和燃烧，从而达到增加功率、降低油耗、改善排放、提而各项性能指标的要求。改进后的L2502系列柴油机在国内处于领先水平。     

强力甜味剂纽甜的合成研究

以异丁烯、乙烯和阿斯巴甜为原料,经加成、氧化和催化氢化等步骤合成了纽甜,总产率14.5%(以异丁烯计),产品的物理性质与波谱数据与文献一致。     

The Behavior of Precipitates during Hot-Deformation of Low-Manganese,Titanium-Added Pipeline Steels

The behavior of manganese and titanium sulfides during the hot deformation of a low-carbon, low-manganese, titanium-added steel has been studied using transmission electron microscopy (TEM), scanning electron microscopy (SEM), and energy-dispersive spectrometry (EDS) analysis. In addition, the effects of deformation temperature and strain rate on the size and distribution of precipitates have been studied using an automatic inclusion analysis system. Also, the effect of precipitate distribution on mechanical properties was studied at different deformation conditions of temperature and strain rate. The TEM and SEM analyses revealed the presence of a wide variety of simple and/or complex precipitates in the as-cast structure. These precipitates behaved differently during the hot deformation of steel. Precipitates deformed less at higher deformation temperatures, whereas an increase in strain rate increased the elongation of precipitates.     

Kinetics of the peritectic phase transformation: In-situ measurements and phase field modeling

An experimental study has been conducted into the role of cooling rate on the kinetics of the peritectic phase transformation in a Fe-C alloy. The interfacial growth velocities of the peritectic phase transformation were measured in situ for cooling rates of 100, 50, and 10 K/min. In-situ observations were obtained using high-temperature laser scanning confocal microscopy (HTLSCM) in a concentric solidification configuration. The experimentally measured interface velocities of the liquid/austenite (L/γ) and austenite/delta-ferrite (γ/δ) interphase boundaries were observed to increase with higher cooling rates. A unique finding of this study was that as the cooling rate increased, there was a transition point where the L/γ interface propagated at a higher velocity than the γ/δ interface, contrary to the findings of previous researchers. Phase field modeling was conducted using a commercial multicomponent, multiphase package. Good correlation was obtained between model predictions and experimental observations in absolute values of interface velocities and the effect of cooling rate. Analysis of the simulated microsegregation in front of the L/γ and γ/δ interfaces as a function of cooling rate revealed the importance of solute pileup. This microsegregation plays a pivotal role in the propagation of interfaces; thus, earlier modeling work in which complete diffusion in the liquid phase was assumed cannot fully describe the rate of propagation of the L/γ and δ/γ interfaces during the course of the peritectic transformation.     

Transient hyperammonaemia in an adult German shepherd dog

Investigations on two batches of 25 pigs each were carried out to characterize two different access systems for electrical stunning by physiological responses such as heart frequency (HF) and the blood constituents lactate and cortisol. All animals were of the same hybrid breeding program. The access race in system A, where the animals are separated was 11 m long. The personnel used different equipments including electrical rods to move the pigs forward. The lairage time after transport was between 1 to 2 h. In system B the animals arrived the evening before slaughter and spent the night in groups in straw-littered lairage boxes. The access race was 3.5 m long. The heart frequencies of the pigs in system A were between 80 and 240 beats/min, in system B the average HF were between 60 and 170 beats/min. In the lairage the HF were at about 113 beats/min (system A) and 66 beats/min (system B). Blood samples were taken immediately after stunning. The lactate concentrations differed by 6 mmol/l (8.6 mmol/l in system A, 2.6 mmol/l in system B). Cortisol was distinctly higher in the blood of the animals from system A (166 ng/ml) compared to system B (126 ng/ml). The results show that the used techniques are suitable to examine stress indicators of pigs under practical conditions. Access systems with long races seem to pose a higher stress than short access ways. The influence of handling (human factor) and management (size of groups, origin of pigs) is equally important. The role of longer resting times in the lairage should be investigated in more detail. This should also include the keeping conditions on the farm where the animals are raised.