Exponential, Gamma, and Power Law Distributions in Information Flow on a Construction Site

This paper examines the statistical distributions of interarrival and response times for construction-site correspondence. Data from a number of construction projects are analyzed and hypotheses are proposed and tested to link the probability distribution to the type of correspondence. Although the commonly assumed exponential distribution of interarrival times is found to be accurate for all types of correspondence, the response times for different types of correspondence follow different distributions depending on the type of correspondence. In particular, a power law relationship is observed between incidence frequency and response time for requests for information. Knowing the statistical distributions for a class of events helps managers forecast future work and manage risk. Simulation models used by practitioners and researchers for various project management goals are also improved by incorporating appropriate statistical distributions for generating various events.     

Performance of Evaporative Condensers

Experimental investigation is conducted to study the performance of evaporative condensers/coolers. The analysis includes development of correlations for the external heat transfer coefficient and the system efficiency. The evaporative condenser includes two finned-tube heat exchangers. The system is designed to allow for operation of a single condenser, two condensers in parallel, and two condensers in series. The analysis is performed as a function of the water-to-air mass flow rate ratio (L/G) and the steam temperature. Also, comparison is made between the performance of the evaporative condenser and same device as an air-cooled condenser. Analysis of the collected data shows that the system efficiency increases at lower L/G ratios and higher steam temperatures. The system efficiency for various configurations for the evaporative condenser varies between 97% and 99%. Lower efficiencies are obtained for the air-cooled condenser, with values between 88% and 92%. The highest efficiency is found for the two condensers in series, followed by two condensers in parallel and then the single condenser. The parallel condenser configuration can handle a larger amount of inlet steam and can provide the required system efficiency and degree of subcooling. The correlation for the system efficiency gives a simple tool for preliminary system design. The correlation developed for the external heat transfer coefficient is found to be consistent with the available literature data.     

Phenolic Contents and Antioxidant Activities of Date Palm (Phoenix dactylifera L.) Leaves

The antioxidant capacity and phenolic content of three varieties of Phoenix dactylifera leaves, namely Deglet Nour, Medjhoul, and Barhee, were studied. The antioxidant activities of extracts of different leaf varieties obtained with solvents of different polarity were investigated using assays of 2, 2-diphenyl-2-picrymhydrasyl hydrate radical-scavenging activity, total phenolics and flavonoids amount, condensed tannins, reducing power, and total antioxidant capacity. The results showed that all the extracts exhibited antioxidant and radical-scavenging activities at different magnitudes and potency. The decreasing order of antioxidant and radical-scavenging activities among the extracts assayed were found to be methanol (MeOH) fraction > ethyl acetate fraction > hexane fraction > water extract. Correlation analysis indicated that there is a linear relationship between antioxidant potency, free radical-scavenging ability, and the content of phenolic and flavonoids compounds of Phoenix dactylifera leaf extracts. These results showed that Phoenix dactylifera leaf extracts are a valuable natural antioxidant, which can be applied in both healthy medicine and food industry and biotechnology.     

Prevalence of salmonella on retail chicken meat in Russian Federation

The objective of this study was to estimate the prevalence of Salmonella on raw retail chicken meat in Russia. Broiler chicken carcasses (n = 698) were collected from three regions of Russia: central (i.e., Moscow area), northwest (i.e., St. Petersburg area), and southern (i.e., Krasnodar area). In each region, samples were collected to represent various cities and districts, as well as different types of retail stores and carcass storage temperatures (i.e., chilled and frozen). All chicken samples were analyzed for the presence of Salmonella using a whole-carcass rinse method. The overall Salmonella prevalence was 31.5%. There were significant differences (P < 0.05) in Salmonella prevalence by (i) region-29.3% (n = 464) in Moscow, 38.5% (n = 192) in St. Petersburg, and 23.8% (n = 42) in Krasnodar; (ii) retail store type-28.8% (n = 236) in hypermarkets, 31.9% (n = 260) in supermarkets (part of chain stores), 44.3% (n = 61) in independent supermarkets, 42.9% (n = 28) in independent minimarkets, and 26.6% (n = 113) in wet markets; and (iii) poultry company-34.3% (n = 545) on chickens produced by integrated companies compared with 22.9% (n = 118) on chickens produced by nonintegrated companies. Strategies such as good agriculture and management practices should be enhanced to reduce Salmonella prevalence on raw poultry in Russia and therefore increase the safety of chicken products.     

Occurrence and Antimicrobial Susceptibility of Listeria monocytogenes Isolated from Brined White Cheese in Jordan

Listeria monocytogenes is a serious foodborne pathogen that has been isolated from different dairy food products. Several foodborne outbreaks of listeriosis have been associated with consumption of cheese. The aims of this study were to determine the occurrence of L. monocytogenes and Listeria spp. in brined white cheese (BWC) sold in Jordan, and to determine the susceptibility of isolated L. monocytogenes to antimicrobials. Three hundred and fifty samples of 5 different types of BWC (akkawi, boiled, halloumi, pasteurized, and shellal) were collected from a local market in Jordan. The ISO (11290-1) procedure was followed for isolation and identification of Listeria spp. from cheese samples and a polymerase chain reaction (PCR) technique was used for confirmation of L. monocytogenes isolates. The VITEK2 automated system was used for testing antimicrobial susceptibility of L. monocytogenes isolates. The overall prevalence of Listeria spp. in cheese sample was 27.1%. L. monocytogenes was isolated from 39 (11.1%) samples. Other isolated species were L. grayi (6.9%), L. innocua (2%), L. ivanovii (4%), L. seeligeri (2%), and L. welshimeri (0.3%). The pH values and salt concentrations of L. monocytogenes positive cheese samples ranged from 5.10 to 6.32 and 5.64 to 13.16, respectively. L. monocytogenes isolates were sensitive or intermediate susceptible to imipenem, gentamicin, linezolid, teicoplanin, vancomycin, fusidic acid, trimethoprim/sulfamethoxazole, benzylpenicillin, ciprofloxacin, erythromycin, tetracycline, and rifampicin, but resistant to fosfomycin, oxacillin, and clindamycin.     

A novel hardware/software embedded system based on automatic censored target detection for radar systems

This paper presents a practical design exploration for a new application related to real-time, high-resolution target detection for radar systems. In this paper, an embedded architecture that combines the hardware and software components in a single platform is experienced using a field programmable gate array FPGA-based PC-board. The detection process utilises three techniques: namely, automatic censored ordered statistics detection (ACOSD), cell averaging (CA) and ordered statistics (OS) CFAR techniques, all of which operate in parallel to increase the accuracy of the detection and to reduce the false-alarm rate for both homogeneous and non-homogeneous environments. A prototype of the embedded system detector has been implemented for homogeneous and non-homogeneous environments on Stratix IV FPGA Board. The prototype operates at 200 MHz and performs real-time target detection with an execution delay of 0.27 μs, which is less than the critical time (0.5 μs) for high-resolution detection.     

On the appropriate monitoring period for voltage flicker measurement in the presence of distributed generation

Voltage flicker or voltage fluctuations are considered a major power quality problem causing temperature rise, generators and motors overloading and affecting humans through the irritating light flicker. It is expected that the level of voltage flicker will increase due to the increased penetration of distributed generation (DG) in the distribution system. Site monitoring is required to make sure that the level of voltage flicker is within the allowed limit. In order to determine the appropriate monitoring period for voltage flicker measurement while considering DGs, two case studies were considered in the paper; 1 week and 1 day monitoring periods. The results reveal that a monitoring period of 1 week may be very long especially in the presence of DG and it may hide valuable information. On the other hand a 1-day monitoring period is more appropriate in these situations. Therefore it is recommended to use 1-day monitoring period instead of 1 week especially in the presence of DG.     

On the usage of acoustic properties combined with an artificial neural network - A new approach of determining presence of dairy fouling

Fouling and cleaning in heat exchangers are severe and costly issues in food processing. In this study, a new pattern recognition method for detecting fouling on stainless steel is presented. It is based on a combination of ultrasonic parameters and a multilayer perceptron feed forward neural network. Chosen acoustic parameters change significantly with fouling compared with tap water as standard. When fouling is present echo energy of echo 2 increases up to 73.84%, characteristic acoustic impedance shows 1.802 ± 0.169 MRayl (17.54% higher than impedance for water), and logarithmic decrement seems to decrease. These acoustic parameters have been combined in an artificial neural network (ANN) with one hidden layer and back propagation algorithm to disentangle error proneness of single parameters and increase detection stability. After training with 400 and validation of 250 of 1000 samples, the ANN displayed an accuracy of 98.58% for fouling presence/absence.     

Study of Reaction Between Slag and Carbonaceous Materials

The chemical interaction of a typical slag of EAF with three different carbon sources, coke, rubber-derived carbon (RDC), coke-RDC blend, was studied in atmospheric pressure at 1823 K (1550 °C). Using an IR-gas analyzer, off-gases evolved from the sample were monitored. While the coke-RDC blend exhibited the best reducing performance in reaction with molten slag, the RDC sample showed poor interaction with the molten slag. The gasification of the coke, RDC, and coke-RDC blend was also carried out under oxidizing conditions using a gas mixture of CO₂ (4 wt pct) and Ar (96 wt pct) and it was shown that the RDC sample had the highest rate of gasification step \( C_{0} \mathop{\longrightarrow}\limits{{k_{3} }}{\text{CO}} + nC_{\text{f}} \) (11.6 site/g s (×6.023 × 10²³/2.24 × 10⁴)). This may be attributed to its disordered structure confirmed by Raman spectra and its nano-particle morphology observed by FE-SEM. The high reactivity of RDC with CO₂ provided evidence that the Boudouard reaction was fast during the interaction with molten slag. However, low reduction rate of iron oxide from slag with RDC can be attributed to the initial weak contact between RDC and molten slag implying that the contact between carbonaceous matter and slag plays significant roles in the reduction of iron oxide from slag.     

Similarity queries: their conceptual evaluation, transformations, and processing

Many application scenarios can significantly benefit from the identification and processing of similarities in the data. Even though some work has been done to extend the semantics of some operators, for example join and selection, to be aware of data similarities, there has not been much study on the role and implementation of similarity-aware operations as first-class database operators. Furthermore, very little work has addressed the problem of evaluating and optimizing queries that combine several similarity operations. The focus of this paper is the study of similarity queries that contain one or multiple first-class similarity database operators such as Similarity Selection, Similarity Join, and Similarity Group-by. Particularly, we analyze the implementation techniques of several similarity operators, introduce a consistent and comprehensive conceptual evaluation model for similarity queries, and present a rich set of transformation rules to extend cost-based query optimization to the case of similarity queries.