Contribution of skin and stone to texture measurements of spherical model fruits

Fruits are composite materials often surrounded by a skin and sometimes containing rigid stones (pits). To understand the contribution of skin and stone to the overall texture of the fruit, model fruits were constructed from molded gelatin spheres, with rigid inclusions and a skin layer. Cross polarized light revealed the stress distribution during puncture testing and the mechanical measures of firmness, Poisson's ratio and breaking force were determined. Skin significantly raised the breaking force. Spherical stones raised the firmness—effectively reducing the deformable material in the sphere, resulting in inflated strains. Disc shaped stones compared with spherical ones, with the narrow edge normal to the force acted like an internal blade and significantly lowered the breaking force. Neither skin nor stone had any significant impact on Poisson's ratio. Three examples of real fruit (raspberries, grapes, and cherries) were tested to contextualize the findings.

Practical applications

Consumers gently squeeze fruit to gauge ripeness. Unwittingly, what we perceive while squeezing fruit is not wholly dependent on the texture of the internal flesh. In this work, we have attempted to model how the firmness and breaking force are influenced by the presence of a skin and stones of various size and shape. This has implications in both sensory and instrumental fruit testing.     

Synthesis and nano-mechanical characterization of calcium-silicate-hydrate (C-S-H) made with 1.5 CaO/SiO2 mixture

In this study, calcium silicate hydrate (C-S-H) is synthesized and characterized. C-S-H slurry was made with calcium oxide (CaO) to micro-silica (SiO₂) mixture ratio of 1.5 and enough deionized water. The slurry was continuously mixed for 7 days, then the excess water was removed. Two methods of drying were implemented: one method used the standard d-dry technique and the other was equilibrated to 11% relative humidity (RH). The dried powders were characterized using thermo gravimetric analysis (TGA), X-ray diffraction analysis (XRDA), and ²⁹Si magic angle spinning (MAS) nuclear magnetic resonance (NMR) spectroscopy. The stoichiometric formulas of synthetic C-S-H powders dried to d-dry and 11% RH in this study were approximated as C_1.2SH_0.7 and C_1.2SH_2.4 respectively. The powders were then compacted to create specimens with porosities similar to C-S-H in hydrated cement. The specimens underwent nanoindentation to mechanically characterize C-S-H. The experiments provide insight on the nanoscale mechanical characteristics of C-S-H.     

Subgrain growth in Al and Al-1% Mn during annealing

The subgrain growth during annealing of cold-worked Al-1% Mn and Al(4N) has been measured in the temperature intervals 300 to 400° C and 100 to 200° C respectively. For Al-1%Mn the subgrain diameter showed a parabolic growth, while for Al the diameter gradually reached a constant value. The microstructural investigations which included in situ annealing in a high voltage electron microscope demonstrated that the operating mechanism for growth in the higher temperature range was collective migration of sub-boundary dislocations. In the lower temperature range extraction of dislocations was found to be the dominating mechanism, i.e. dislocations partly lying in the boundaries are pulled out by the stress field in the subgrain interior. The observed growth rates were consistent with models for these mechanisms presented in two previous papers.     

Personality profiles of gifted women: Psychologists.

Compared the responses to the 16PF of 124 highly successful women psychologists with women in general, college women, and successful academic men to identify personality factors enabling these women to succeed in spite of powerful sex-role expectations to the contrary. In terms of test scores, women psychologists were significantly more intelligent, socially aloof, dominant, serious, adventuresome, sensitive, flexible, imaginative, insightful, unconventional, secure, self-sufficient, and less anxiety-prone than women in general and college girls. Despite similar test profiles of successful academic men and women, the women scored higher on intelligence, radicalism, and super-ego strength, and lower on self-sentiment. Women who published extensively were more exacting and socially aloof than less productive women psychologists. (28 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Electrically Programmed Doping Gradients Optimize the Thermoelectric Power Factor of a Conjugated Polymer

Functionally graded materials (FGMs) are widely explored in the context of inorganic thermoelectrics, but not yet in organic thermoelectrics. Here, the impact of doping gradients on the thermoelectric properties of a chemically doped conjugated polymer is studied. The in-plane drift of counterions in moderate electric fields is used to create lateral doping gradients in films composed of a polythiophene with oligoether side chains, doped with 2,3,5,6-tetrafluoro-tetracyanoquinodimethane (F₄TCNQ). Raman microscopy reveals that a bias voltage of as little as 5 V across a 50 µm wide channel is sufficient to trigger counterion drift, resulting in doping gradients. The effective electrical conductivity of the graded channel decreases with bias voltage, while an overall increase in Seebeck coefficient is observed, yielding an up to eight-fold enhancement in power factor. Kinetic Monte Carlo simulations of graded films explain the increase in power factor in terms of a roll-off of the Seebeck coefficient at high electrical conductivities in combination with a mobility decay due to increased Coulomb scattering at high dopant concentrations. Therefore, the FGM concept is found to be a way to improve the thermoelectric performance of not yet optimally doped organic semiconductors, which may ease the screening of new materials as well as the fabrication of devices.     

Frontal polymerization accelerated by continuous conductive elements

Frontal polymerization (FP), a propagating reaction wave driven by exothermic polymerization, is increasingly considered for the rapid fabrication of fiber-reinforced composites. However, the effect of the fibers on the FP reaction has not yet been explored. In this contribution, we demonstrate that thermally conductive continuous elements accelerate FP using an experimental model system and finite-element-based numerical simulations. Furthermore, the degree of acceleration is shown to be affected by the amount of available monomer in the system. These results suggest that thermally conductive carbon fiber reinforcement may facilitate FP for composite manufacturing. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47418.     

支持感测功能的SensorPath单线接口

目前有很多系统需要处理混合信号,而SensorPath便是专为这类系统而设计的单线接口,而且不需付特许使用费.这类系统需要检测基本的电压或温度,以便对系统进行诊断及控制风扇转速.为了减低系统噪音,以及确保系统外型可以更为纤薄小巧,大部分系统都必须控制风扇转速.此外,部分系统还要能灵活地提供不同的性价比.将感测电压及温度的传感器集成到复杂的混合信号芯片之内是一个明显可行的解决办法,但这样做只会令电路板的设计更为复杂,系统成本也更高,而系统性能也会受到影响.而SensorPath是一个成本较低的分立解决方案.     

Nutritional and amino acid contents of differently treated Roselle (Hibiscus sabdariffa L.) seeds

The effects of sun-drying and boiling sun-drying on the nutritional composition of Roselle (Hibiscus sabdariffa L.) seeds, grown from Malaysia, were investigated. The treatments were raw freeze-dried Roselle seeds (RRS), sun dried Roselle seeds (DRS) and boiled sun-dried Roselle seeds (BRS). Protein, lipids and dietary fibre were found to be high in all the treatments. The seeds, regarded as by-product of Roselle processing had 57.3% moisture. Raw freeze-dried, sun dried and boiled sun-dried seeds contained 6.81%, 9.9% and 9.8% moisture; 35.4%, 33.5% and 30.6% protein; 27.2%, 22.1% and 29.6% lipids; 2.3%, 13.0% and 4.0% available carbohydrate; 25.5%, 18.3%, and 19.2% total dietary fibre; and 7.4%, 7.5% and 6.6% ash, respectively. The carbohydrate, protein, lipids and moisture of RRS were significantly different (p < 0.05) from DRS and BRS. The predominant minerals in Roselle seeds were potassium (99–109 mg/100 g), magnesium (26–28 mg/100 g) and calcium (24–31 mg/100 g). The total dietary fibre of the seeds was within the acceptable range, with soluble and insoluble fibre ratios ranging from 1.2 to 3.3. The study detected 17 essential and non-essential amino acids. The seeds were rich in lysine (14–15 g/100 g), arginine (30–35 g/100 g), leucine (15.4–18.6 g/100 g), phenylalanine (11–12 g/100 g) and glutamic acid (21–24 g/100 g). The study indicated that Roselle seeds may serve as a potential source of functional ingredients.