生态多样性米兰垂直森林双塔

文章介绍了由意大利著名设计师斯坦法诺·博埃里设计的米兰垂直森林双塔.“垂直森林”是一个高层建筑的新概念,它使树木和人类得以在城市中共生.“垂直森林”是对创新建筑的鼓励和宣言,它邀请人们憧憬建筑与人类的和谐未来.“垂直森林”不仅可以节约能源,还能够提升周边环境质量,是一个适宜植入全世界各个城市中心的,竖向种植不同尺寸和种类树木的高密度塔楼.它将超越传统的地标身份,成为城市中调节环境的重要装置,并启发人类去解决高密度城市发展和生物多样性的矛盾.     

Categories of indoor environmental quality and building energy demand for heating and cooling

Maintaining suitable indoor climate conditions is a need for the occupants’ well being, while requiring very strictly thermal comfort conditions and very high levels of indoor air quality in buildings represents also a high expense of energy, with its consequence in terms of environmental impact and cost. In fact, it is well known that the indoor environmental quality (IEQ), considering both thermal and indoor air quality aspects, has a primary impact not only on the perceived human comfort, but also on the building energy consumption. This issue is clearly expressed by the European Energy Performance of Buildings Directive 2002/92/EC, together with the most recent 2010/31/EU, which underlines that the expression of a judgment about the energy consumption of a building should be always joint with the corresponding indoor environmental quality level required by occupants. To this aim, the concept of indoor environment categories has been introduced in the EN 15251 standard. These categories range from I to III, where category I refers to the highest level of indoor climate requirement. In the challenge of reducing the environmental impact for air conditioning in buildings, it is essential that IEQ requirements are relaxed in order to widen the variations of the temperature ranges and ventilation air flow rates. In this paper, by means of building energy simulation, the heating and cooling energy demand are calculated for a mechanically controlled office building where different indoor environmental quality levels are required, ranging from category I to category III of EN 15251. The building is located in different European cities (Moscow, Torino and Athens), characterized by significantly different wheatear conditions. The mutual relation between heating and cooling energy demand and the required levels of IEQ is highlighted. The simulations are performed on a typical office room which is adopted as a reference in validation tests of the European Standard EN 15265 to validate calculation procedures of energy use for space heating and cooling.     

Danieli Universal Endless (DUE)

Over the last 25 years, the thin slab casting and rolling process has been gaining a major market share in the production of hot rolled strip, progressively eroding the areas previously of exclusive domain of conventional mills.     

Effects of low frequency electromagnetic fields on expression of lymphocyte subsets and production of cytokines of men and women employed in a museum

The objective of this study was to analyse the immune response to electromagnetic fields (ELMFs) in seven men and eight women employed in a museum. The workers were exposed in a room to an ELMFs (range 0.2-3.6 microT and 40-120 V/m) induced by 50 Hz electricity for 20 h a week. Control groups consisted of 47 women and 39 men with a similar percentage of atopic subjects, age (range 30-51 years) and smoking habits of the workers included in the study. Levels of blood lead (Pb) and urinary trans-trans muconic acid, a metabolite of benzene (markers of exposure to traffic and smoking) of the control and exposed groups were similar. Lymphocyte subsets were determined in men and women using conjugated antibodies. Serum interleukin (IL) 4 and interferon gamma and their 'in vitro' production by peripheral mononuclear blood cells (PMBCs) stimulated by phytohemoglutinin (PHA), as well as blastogenesis of PMBCs induced by PHA, were determined in women only. ELMF-exposed women showed a significant reduction in the percentage of B and NK CD3(-)-CD25+ lymphocytes and a slight reduction of CD16(+)-56+ NK lymphocytes. They also showed significantly lower levels of interferon gamma in serum, or produced in the supernatants by PMBCs both spontaneously and stimulated by PHA, while they did not show significant changes in serum and 'in vitro' produced IL-4, or in blastogenesis of PMBCs. Men working in the museum showed, in relation to the controls, a statistically significant reduction in both number and percentage of CD16(+)- CD56+ and CD3(-)-CD25+ lymphocyte subsets. On the whole, this investigation demonstrates a reduction of blood NK lymphocytes and of the production of interferon gamma in workers exposed to low frequency ELMFs. Recent studies have shown that stress and poor lifestyle induce the reduction of blood cytotoxic activities possibly acting on nervous functions. This may suggest that ELMFs reduces blood NK lymphocytes by combined effects on the immune and nervous systems.     

Discriminatory prices and the prisoner dilemma problem

We ask whether the tendency of Hotelling duopolists to choose uniform pricing (discriminatory pricing) when the pricing policy is chosen before (after) the location is robust to the case of imperfect or third-degree price discrimination. By using a general framework encompassing both perfect and imperfect price discrimination for any degree of imperfectness, we show that both firms choose uniform pricing when the pricing policy is chosen before the location for any degree of imperfectness of price discrimination. When the pricing policy is chosen after the location and price discrimination is precise enough both firms choose price discrimination; if price discrimination is highly imprecise, an equilibrium exists where both firms commit not to price discriminate.     

Effects of the orientational distribution of cracks in isotropic solids

The paper deals with the elastic characterisation of microcracked solids: we analyse dispersions of cracks with arbitrary non-random orientational distributions. Particular cases of angular distributions are given by cracks all oriented in a given direction or cracks uniformly random oriented in the space. A unified theory covers all the orientational distributions between the random and the parallel ones. The micromechanical averaging inside the composite material is carried out by means of explicit results which allows us to obtain closed-form expressions for the macroscopic or equivalent elastic moduli of the overall material. The analysis has been performed in two-dimensional (2D) elasticity (plane stress and plane strain) with slit like cracks and in three-dimensional (3D) elasticity with planar circular cracks. The elastic behaviour of the microcracked solid depends upon the density of cracks and upon their orientational distribution. In particular, this study allows us to state that in two-dimensions the elastic behaviour of such a microcracked material is completely defined by one order parameter, which depends on the given angular distribution while the elastic characterisation in three-dimensions depends on two order parameters. The particular cases of isotropic orientations of cracks (both in 2D and in 3D) have been generalised to higher values of the cracks density by means of the method of the iterated homogenisation, which leads to some differential equations. Their solutions show that the equivalent elastic moduli depend exponentially on the cracks density.     

Dual-band,dual-polarized patch antennas

Two new configurations of patch antennas are introduced, which provide dual-band and dual-polarization operations. The two patches have a square and cross shape, and are printed on a single layer; the dual-frequency and the dual-polarization behavior is obtained by means of four narrow slots close to the edges. Excellent decoupling between the two orthogonal modes at each frequency is obtained in both configurations. Furthermore, a satisfactory performance of simultaneous matching when using a single feed point is demonstrated. Simple and accurate design formulas to predict the two resonant frequencies are derived on the basis of a physical model and tested by using a full-wave analysis. Some prototypes have been carried out and measured.