EXPERIMENTS OF MORPHOGENESIS IN SWARMS OF SIMPLE MOBILE ROBOTS

In this paper, we focus on the problem of having a multitude of very simple mobile robots self-organize their relative positions so as to obtain a variety of spatial configurations. The problem has a variety of applications in mobile robotics, modular robots, sensor networks, and computational self-assembly. The approach we investigate in this paper attempts at minimizing the local capability of robots and at verifying how and to what extent a variety of global shapes can be obtained by exploiting simple self-organizing algorithms and emergent behaviors. Several experiments are reported showing the effectiveness of the approach.     

一种新的康复与代步外骨骼机器人研究

针对老年人及下肢障碍者康复训练与代步问题,本文提出一种新的康复与代步外骨骼机器人.本文首先详细介绍了机器人各部分组成及机构设计方案,通过下肢外骨骼与轮椅的有机结合,有效保持或恢复老年人、脑卒中患者下肢运动能力的同时,为患者提供一种方便的代步工具;运用脚蹬车运动制订康复训练策略,可保持下肢康复训练轨迹固定,保证患者安全;提出主从式操作方法及多模态康复训练控制流程提高使用者参与感.最后通过仿真与实验验证了所提康复系统的可行性与设计的正确性.     

The Link between the Entry Decision and Post-entry Performance: Evidence from Italy

This paper aims to link together entry decision and post-entryperformance. It relies on a database of 100 new Italian firmsto link post-entry performance to the original factors thatshaped the decision to start a new firm. The evidence suggeststhat those motivations underlying the decision to start a newfirm a not have a neutral influence on post-entry performance.Rather, an innovative motivation and certain traditional economicfactors tend to be related to a superior post-entry performance.The same seems also to be true for background push-factors suchas the previous employment position.     

Retardation of Tricalcium Aluminate Hydration by Calcium Sulfate

The influence of calcium sulfate on the hydration of 3CaO· Al₂O₃ in the presence of Ca(OH)₂ was studied using conduction calorimetry, differential thermogravimetry, and X-ray diffraction. Sodium sulfate was also used instead of calcium sulfate. A substantial retardation of tricalcium aluminate hydration in the presence of sulfate occurs only when calcium sulfate is used and enough ettringite is formed. When ettringite disappears due to the consumption of gypsum, tricalcium aluminate hydration is renewed. Sodium sulfate does not significantly retard this hydration. The results confirm the hypothesis that ettringite formation is essential for coating 3CaO·Al₂O₃ grains and then retarding their hydration.     

BACTERIOCIN EXPOSURE AND FOOD INGREDIENTS INFLUENCE ON GROWTH AND VIRULENCE OF LISTERIA MONOCYTOGENES IN A MODEL MEAT GRAVY SYSTEM

The antilisterial activity of bacteriocin-producing Lactobacillus sakei 1 bac⁺ alone and combined with food ingredients (sodium chloride, D-glucose, oregano, black pepper) was studied in a model meat gravy (1.8% proteose peptone, 1.2% meat extract, 0.6% yeast extract, 2.0% corn starch) kept under refrigeration for 10 days. Two strains of L. monocytogenes (serotypes 4b and 1/2a) were employed in coinoculation experiments and Lactobacillus sakei ATCC 15521 was used as a negative control for bacteriocin production. The LAB bac⁺ strain was more effective in inhibiting both L. monocytogenes serotypes than the LAB bac⁻ strain. The serotype 4b was more sensitive to bacteriocin than serotype 1/2a. The effect of the ingredients on inhibition of L. monocytogenes was serotype dependent. Bacteriocin exposure did not affect sensitivity to ampicilin and rifampicin. However, L. monocytogenes partially lost their hemolytic activity after exposure to bacteriocin-producing Lb. sakei 1 and food ingredients.     

EFFECT OF STORAGE PERIOD AND EXPOSURE CONDITIONS ON THE QUALITY OF BOSANA EXTRA-VIRGIN OLIVE OIL

Changes in quality parameters, antioxidant compounds, oxidative stability and antioxidant activity during 18 months of storage of a monovarietal extra‐virgin olive oil from Bosana cultivar , and exposed to light and dark, were studied. Analysis of data showed that all the parameters underwent significant changes during storage: free acidity, peroxide and ultraviolet (UV) spectrophotometric indexes remained below the limits reported in the EEC Regulations 2568/91 and 1989/03 , and these are: ≤0.8% for acidity, ≤20 meq O₂/kg for peroxide and ≤2.50 and ≤0.22 for K232 and K270, respectively. Phenol andα‐tocopherol content decreased during storage (42.0 and 29.6%, respectively) while chlorophylls and carotenoids underwent a decrease until 8 months of storage (49% and 30%, respectively); after that, the values remained constant. Oxidative stability and antioxidant activity had not changed dramatically during 18 months. Phenols were significantly correlated to the antioxidant activity of the oil, while oxidative stability measured by Rancimat did not show any correlation with carotenoids, chlorophylls, phenols andα‐tocopherol. Regarding exposure conditions, storage in the dark was better in retaining the quality of the oil, as expected.     

UNIAXIAL COMPRESSION AND STRESS RELAXATION TESTS ON ALGINATE GELS

The rheological behavior of alginate gels was analyzed using uniaxial compression and stress relaxation tests. The engineering compressive stress (σ_E)-deformation (ɛ_E curves were found to be concave upward and independent of the crosshead speed (V_t for V_t≥ 120 mm/min. By considering all the stress (σ_E)-time (t) data for t greater than 10 times the average loading period, the viscoelastic response of these gels was described by means of a 3-element Maxwell body characterized by a relaxation time of 300 s. Such gels exhibited an apparent linear viscoelastic solid behavior for ɛ_E≤ 8% and a nonlinear one for larger deformations. However, for ɛ_E>32% their solid viscoelastic behavior tended to a liquid one. Empirical models allowed the viscoelastic properties, as well permanent deformation, of these gels to be quantitatively described as functions of the deformation applied and/or loading rate.     

Preparation of a Mesquite (Prosopis spp.) Pod Enhanced Protein Reduced Fiber Fraction

Raw, extruded (alone and a 50/50 blend with soybeans) or toasted mesquite (Prosopis spp.) pods were passed 1 and 4 times through an Alpine pin mill, and the resulting ground products separated into different sieve fractions. Protein concentration and recovery were maximum, and fiber content minimum, in the fines. Maximum protein concentration and recovery were obtained in both extrusion runs; of the remaining two runs, toasted pods gave higher protein recovery, but lower protein concentration in the fines, than raw pods.