Model based evaluation of exterior daylight illuminance distribution

Energy conservation in buildings is greatly influenced by natural daylight in tropical region. A vital step towards development and promotion of daylighting technology in buildings is a prior study on estimation of exterior daylight availability for illuminating its interiors. In view of this, the present communication depicts the preliminary work progress carried out to arrive at a comprehensive idea on assessment of daylight availability and its characteristics. The study is reported taking the representative case of Bangalore (India) (latitude 12.97° N, longitude 77.56° E),which in future work facilitates to device suitable interior illuminance models and lighting controls for a daylight-artificial light integrated scheme. The objective of this paper is to document the estimation of spatial exterior daylight parameters like exterior horizontal as well as vertical global and diffuse daylight illuminance in addition to their respective luminous efficacies computed using an established analytical model. The paper also highlights user friendly computer simulation tool developed, for the detailed estimation of daylight availability at a particular region by the inclusion of corresponding solar radiation data.     

Effect of enzyme activity and frozen storage on jalapeño pepper volatiles by selected ion flow tube-mass spectrometry

Abstract: Samples of unblanched (fresh), stannous chloride-treated, or blanched jalapeño peppers were measured for real-time generation of lipoxygenase-derived volatiles during 10 min after tissue disruption. Volatiles were also measured before and after 1.5, 2.5, 3, 6, and 9 mo of frozen storage at −15 °C. The concentration of all lipoxygenase-derived compounds was significantly higher in unblanched jalapeño peppers compared to enzyme inhibited peppers. The maximum concentration of (Z)-3-hexenal, (E)-2-hexenal, and hexanal was detected at about 1.2, 1.5, and 1.5 min after tissue disruption, respectively. A decrease in (Z)-3-hexenal and an increase in dimethyl sulfide and methylbutanal occurred in blanched compared to stannous chloride-treated peppers due to heat. Frozen storage resulted in no major changes in the lipoxygenase-derived volatiles of whole and pureed blanched peppers after 9 mo. However, in whole unblanched peppers a gradual decrease of (Z)-3-hexenal, (E)-2-hexenal, hexanal, hexenol, and hexanol was observed over time; whereas in pureed unblanched peppers these compounds increased, reached maximum concentration, and then decreased. Similarly, the minor volatiles 2-pentenal, 1-penten-3-one, (E)-2-heptenal, (E)-2-octenal, and (E)-2-nonenal showed an initial increase followed by a decline in both whole and pureed unblanched peppers. Tissue disruption increased generation and degradation rates during frozen storage. The compounds (E,Z)-2,6-nonadienal, n-propyl aldehyde, 2-isobutyl-3-methoxypyrazine, and a mixture of terpenes decreased in unblanched and blanched frozen samples, while nonanal and methylbutanal increased only in unblanched samples. Practical Application: Data obtained in this study contribute to the understanding of the dynamics of lipoxygenase-derived volatile formation upon tissue disruption of jalapeño pepper. In addition, it contributes to generate knowledge on the effect of processing techniques, namely blanching and frozen storage, on the volatile profile of these peppers. This knowledge has applications in the manufacturing, product development, and quality control areas of the food industry as useful information to help in the designing and monitoring of processes aimed to obtain products with specific aroma characteristics. For instance, maximum levels of “fresh” and “green” aroma compounds are achieved rapidly during the first few minutes after pepper tissue is disrupted. The inhibition of enzyme activity shortly after this may help to maximize concentration of these aroma notes in the product. Frozen storage produces enzymatic and chemical changes in the volatile profile of unblanched peppers. The aroma profile of blanched peppers is more stable under frozen conditions, with a lower total volatile concentration.     

Comparison of Volatile Release in Tomatillo and Different Varieties of Tomato during Chewing

ABSTRACT: The release of volatiles from tomatillos (Physalis ixocarpa Brot.) and tomatoes in the mouthspace and nosespace was measured in real-time using selected ion flow tube mass spectrometry (SIFT-MS). (Z)-3-Hexenal, (E)-2-hexenal, hexanal, and 1-penten-3-one increased, while isobutyl alcohol, nonanal, and methylbutanal showed no significant change in the first 30 s of chewing. Cherry tomato released more (E)-2-hexenal, (Z)-3-hexenal, and 1-penten-3-one than tomatillo, Roma tomato, and vine-ripened tomato during chewing. The proportion of the average concentration of volatiles in the mouthspace after swallowing to before swallowing (MSas/MSbs) varied from 2.8% to 73.9% between different volatiles and varieties. Methylbutanal, hexanal, and nonanal were retained at a higher percentage in the mouth after swallowing than (Z)-3-hexenal, (E)-2-hexenal, 1-penten-3-one, and isobutyl alcohol. The proportion of the average volatile concentration in the mouthspace, to the headspace in a glass container (MS/HS) of 1-penten-3-one, hexanal, methylbutanal, and nonanal, and the proportion of nosespace to headspace (NS/HS) for 1-penten-3-one, hexanal, (Z)-3-hexenal, and nonanal was significantly higher in tomatillo than in tomatoes. There was no difference between tomatoes of different varieties in NS/HS ratio. Practical Application: The real-time volatile release from tomatillos and tomatoes was measured and compared. The information obtained on the dynamic generation of volatile compounds provides a better understanding of volatile release in the headspace of tomatillo and tomatoes. The compounds and their volatile release patterns were similar for the tomatillo and tomatoes. The green aldehydes released during chewing were not significantly higher than most tomato varieties, except for Roma tomatoes. Cherry tomato released relatively more volatiles during chewing, whereas Roma tomatoes were generally poor in mouthspace volatiles. The lingering of volatiles in the mouth after swallowing was different for different volatiles and varieties, which may appear as a sensory difference detected by consumers.     

Effects of buffer and temperature on formation of furan, acetic acid and formic acid from carbohydrate model systems

Effects of temperature, pH and phosphate buffer on volatiles formed by heating model solutions of fructose, glucose, sucrose, lactose or starch were investigated by selected ion flow tube-mass spectrometry (SIFT-MS). Among the carbohydrates studied, the monosaccharide reducing sugars fructose and glucose were more reactive than macro molecular starch, lactose and sucrose, which are not reducing sugars. Furan was formed from fructose heated at 120, 100 and 80 °C at pH 5-7 in phosphate buffer and at 100 °C in unbuffered solution. Glucose did not yield furan in unbuffered solution at 100 °C but glucose did yield furan in phosphate buffer solution at a similar pH. Furan formation increased as temperature and pH increased. As temperature, pH value, and buffer components changed, furan formation may occur by different reactive pathways. Both of the buffer components, NaH₂PO₄ and citric acid, enhanced the formation of thermal degradation products from fructose. The enhancing effect of NaH₂PO₄ was stronger than citric acid. Formic and acetic acids were concomitantly formed with furan. More formic acid was produced from fructose than glucose, and more acetic acid was produced from glucose than fructose.     

Developmental and Ripening-Related Effects on the Cell Wall of Pepino (Solanum muricatum) Fruit

Several cell wall components in ripening pepino fruit have been quantitatively and qualitatively characterised, with the aim of identifying their contributions to the loss of tissue firmness. Pepinos were graded into nine groups based on progressive, characteristic skin colour changes, previously shown to correspond with decreasing fruit firmness. While fruit softening began when the pepinos were still green but with newly acquired purple stripes, the first significant quantitative signs of cell wall modification (total pectin and hemicellulose content declining and CDTA-soluble pectin content increasing, on a fresh weight basis) were detectable later in ripening, when the fruit began to acquire yellow skin pigmentation. Gel fractionation studies demonstrated that there were increased levels of low-molecular-weight pectin and xyloglucan during pepino ripening. The change in molecular weight distribution of CDTA-soluble pectin occurred as fruit started to acquire yellow pigmentation, while xyloglucan polymers were modified at an earlier stage that coincided with the initial loss of firmness. © 1997 SCI.     

A simple method for improving local binary patterns by considering non-uniform patterns

The basic idea behind LBP is that an image is composed of micropatterns. A histogram of these micropatterns contains information about the local features in an image. These micropatterns can be divided into two types: uniform and non-uniform. In standard applications using LBP, only the uniform patterns are used. The non-uniform patterns are considered in only a single bin of the histogram that is used to extract features in the classification stage. Non-uniform patterns have undesirable characteristics: they are of a high dimension, partially correlated, and introduce unwanted noise. To offset these disadvantages, we explore using random subspace, well-known to work well with noise and correlated features, to train features based also on non-uniform patterns. We find that a stand-alone support vector machine performs best with the uniform patterns and random subspace with histograms of 50 bins performs best with the non-uniform patterns. Superior results are obtained when the two are combined. Based on extensive experiments conducted in several domains using several benchmark databases, it is our conclusion that non-uniform patterns improve classifier performance.     

Effects of traditional storage practices of small‐scale organic farmers on potato quality

A study was undertaken to investigate the effect of traditional storage practices of small‐scale organic farmers in rural KwaZulu–Natal on the quality of potatoes. Changes in sugar and starch content were monitored. A preference ranking test was used to investigate preference for organically produced potatoes left in situ, stored under ambient conditions in a farmer's house and under controlled conditions (7 °C and 90% relative humidity) for 2, 4 and 6 weeks. The lowest and highest sugar levels were observed in potatoes stored in situ and under controlled conditions, respectively. Potatoes stored in situ were significantly preferred by sensory panellists (P < 0.05) over those stored in both the farmer's house and in controlled storage. Preference rank scores were negatively correlated to total sugar content and positively correlated to starch content although not all correlations were statistically significant. This gives an indication that other factors not investigated in this study, like glycoalkaloid content, may have contributed to the acceptability of potatoes from different modes of storage and requires further investigation. However, the study clearly shows that leaving potatoes in situ as a method of storage maintains desirable sensory properties of potatoes by maintaining low sugar levels and higher starch content. Copyright © 2007 Society of Chemical Industry     

Parent–child attitude congruence on type and intensity of physical activity: Testing multiple mediators of sedentary behavior in older children.

Objective: This study examined parent–child attitudes on value of specific types and intensities of physical activity, which may explain gender differences in child activity, and evaluated physical activity as a mechanism to reduce time spent in sedentary behaviors. Design: A community sample of 681 parents and 433 children (mean age 9.9 years) reported attitudes on importance of vigorous and moderate intensity team and individually performed sports/activities, as well as household chores. Separate structural models (LISREL 8.7) for girls and boys tested whether parental attitudes were related to child TV and computer via child attitudes, sport team participation, and physical activity, controlling for demographic factors. Main Outcome Measures: Child 7-day physical activity, sport teams, weekly TV, computer. Results: Parent–child attitude congruence was more prevalent among boys, and attitudes varied by ethnicity, parent education, and number of children. Positive parent–child attitudes for vigorous team sports were related to increased team participation and physical activity, as well as reduced TV and computer in boys and girls. Value of moderate intensity household chores, such as cleaning house and doing laundry, was related to decreased team participation and increased TV in boys. Only organized team sports, not general physical activity, was related to reduced TV and computer. Conclusion: Results support parents’ role in socializing children’s achievement task values, affecting child activity by transferring specific attitudes. Value of vigorous intensity sports provided the most benefits to activity and reduction of sedentary behavior, while valuing household chores had unexpected negative effects. (PsycINFO Database Record (c) 2010 APA, all rights reserved)