A comparison of the finite difference and finite element methods for heat transfer calculations

The finite difference method and finite element method for heat transfer calculations are compared by describing their bases and their application to some common heat transfer problems. In general it is noted that neither method is clearly superior, and in many instances, the choice is quite arbitrary and depends more upon the codes available and upon the personal preference of the analyst than upon any well defined advantages of one method. Classes of problems for which one method or the other is better suited are defined

Interactive computation of radiation view factors

The development of a pair of computer programs to calculate the radiation exchange view factors is described. The surface generation program is based upon current graphics capabilities and includes special provisions which are unique to the radiation problem. The calculational program uses a combination of contour and double area integration to permit consideration of radiation with obstruction surfaces. Examples of the surface generation and the calculation are given

The application of Multi Attribute Decision Methods (MADM) on prioritizing Iranian fisheries research projects

The ultimate goal of an agriculture research system is on-time, correct and clear response to the problems and expectations of agriculture household and stakeholders. In this respect, though, due to variation and frequency of the problems and expectations and as well as many limitations such as financial deficit, short time and shortage in work force and equipments etc, the system cannot be thoroughly responsive. Therefore, the necessity for optimizing the system to response through prioritizing the research projects has been a major challenge before the responsible managers and authorities. In this paper, the Analytical Hierarchical Process (AHP) has been introduced as a well known Multi Attribute Decision Methods (MADM) that combines qualitative and quantitative criteria for prioritizing the research projects of the Iranian Fisheries Research Organization. For implementation of the mentioned principles and methods of prioritizing the research projects have been studied and then by determining the final decision making criteria, the priority of the projects in the Institute have been determined by drawing decision hierarchy tree. Required data was gathered through pair wise comparison questionnaires filled by the experts and researchers. In the next step, Expert Choice software used to analyze and determine the priorities. Based on results criteria of research possibility, scientific development, economic development, and stability development with respective weight .377, .263, .187, and .173 are the most important criteria for the institute in the south area of Caspian Sea. Finally, according to the produced results, the priorities of the six studied research programs determined

Biomedical and biophysical limits to mathematical modeling of pulmonary system mechanics: a scoping review on aerosol and drug delivery.

Undoubtedly, the construction of the biomechanical geometry systems with the help of computer tomography (CT) and magnetic resonance imaging (MRI) has made a significant advancement in studying in vitro numerical models as accurately as possible. However, some simplifying assumptions in the computational studies of the respiratory system have caused errors and deviations from the in vivo actual state. The most important of these hypotheses is how to generate volume from the point cloud exported from CT or MRI images, not paying attention to the wall thickness and its effect in computational fluid dynamic method, statistical logic of aerosol trap in software; and most importantly, the viscoelastic effect of respiratory tract wall in living tissue pointed in the fluid-structure interaction method. So that applying the viscoelastic dynamic mesh effect in the form of the moving deforming mesh can be very effective in achieving more appropriate response quality. Also, changing the volume fraction of the pulmonary extracellular matrix constituents leads to changes in elastic modulus (storage modulus) and the viscous modulus (loss modulus) of lung tissue. Therefore, in the biomedical computational methods where the model wall is considered flexible, the viscoelastic properties of the texture must be considered correctly

Efectos de los coadyuvantes tecnológicos y técnicas sobre la extractabilidad e índices de calidad del aceite de oliva

This study was conducted to investigate the effects of processing aids and techniques such as talcum powder (2% w/w), calcium carbonate (2% w/w), warm water dipping (45 °C), combined treatment (warm water dipping+2% calcium carbonate) and control (without adding processing aid) on extractability and quality of ‘Tarom 7’ olive oil as randomized complete block design with three replicates. The results showed that there were no significant differences in the carotenoid content, K232, fatty acid profile or the Cox’s value in the oil obtained from untreated and treated fruits with processing aids. The highest chlorophyll content (0.84 mg/kg), total phenolic content (236.94 mg/kg), paste extractability (8.5%) and the lowest peroxide values (0.32 meqO2/kg), K270 (0.38) were obtained from the oil extracted with 2% talc powder. According to the results, it can be suggested that the 2% talc powder treatment could have a positive effect on olive oil quality and paste extractability.Este estudio se llevó a cabo para investigar los efectos de los coadyuvantes del procesamiento y técnicas, como talco (2 % p/p), carbonato de calcio (2 % p/p), inmersión en agua tibia (45 °C), tratamiento combinado (inmersión en agua tibia + carbonato de calcio al 2%) y control (sin adición de coadyuvante) sobre la extractabilidad y calidad del aceite de oliva ‘Tarom 7’ en un diseño de bloques completos al azar con tres repeticiones. Los resultados mostraron que no hubo diferencias significativas en el contenido de carotenoides, K232, perfil de ácidos grasos y el valor de Cox del aceite obtenido de frutos no tratados y tratados con coadyuvantes de procesamiento. El mayor contenido de clorofila (0,84 mg/kg), contenido de fenoles totales (236,94 mg/kg), extractabilidad de la pasta (8,5%) y los valores más bajos de peróxidos (0,32 meqO2/kg) y K270 (0,38) se obtuvieron para el aceite extraído con 2 % de talco. De acuerdo con los resultados, se puede sugerir que el tratamiento con talco al 2% podría tener un efecto positivo sobre la calidad del aceite de oliva y la extractabilidad de la pasta. &nbsp

Human bocavirus in hospitalized iranian adults with respiratory tract infections during January-June 2014

The epidemiology of respiratory human bocavirus (HBoV) infection has not been described in Tehran's adult and to determine the epidemiological and clinical characteristics associated with HBoV infection, a population of adults hospitalized with respiratory tract infections were chosen. Throat swab samples were collected from 91 hospitalized adults aged between 29 to 91 year and Real-time PCR TaqMan was used to screen specimens by amplifying a part of the NP1 gene. HBoV was detected in 6 adults (6.6). Mean age was 76 years and 67 of patients were female. The most common symptoms were wheezing (100), tachypnea (100), cough (100), rhinorrhea/pharyngitis (83.33) and fever (83.33) which clinically diagnosed by a physician. Gastrointestinal symptoms was present only in 1 patient (16.6). In our study the distribution of HBoV was influenced by temperature, relative humidity and precipitation. HBoV is circulating in Tehran and is associated with both upper and lower respiratory tract disease in adults

Smokeless tobacco - a substantial risk for oral potentially malignant disorders in South Asia

Data sources: Medline, the Science Citation Index (SCI) via Web of Science, Scopus, CINAHL, Global Index Medicus, Google Scholar and SLT-related reports of the International Agency for Research on Cancer and the National Cancer Institute of the United States. Study selection: Observational studies on the use of SLT and the risk of developing OPMDs in South Asian Populations. Data extraction and synthesis: Duplicate selection of studies was undertaken with two reviewers undertaking data abstraction and quality assessment independently. Risk and odds ratios were extracted or calculated for studies where possible. Meta odds ratios (mOR) were calculated using a random effects analysis. Results: Fifteen papers reporting 18 studies were included. The majority (12) were from India. All the studies were case-control designs. MOR for any OPMD with the use of any SLT product was 15.5 (95% CI; 9.9–24.2). Risk was higher in women; mOR = 22.2 (95% CI, 9.1–54.1) than men; mOR = 8.7 (95% CI, 2.1–34.8). Betel quid with tobacco carried the highest risk for OPMD, mOR = 16.1 (95% CI, 7.8–33.5). Conclusions: The findings of our study point towards a strong association between some forms of OPMDs and SLT use in South Asia. The risk estimates are high, irrespective of controlling for confounders such as smoking and alcohol or stratification by sex, country or source of controls. There is also an exposure-response relationship between OPMDs and SLT use

Comparative survey on anesthetizing effects of medicinal herbs Valerian officinalis, Melissa officinalis, Papaver somniferum, and Papaver bracteatum on gold fish (Carassius auratus)

Anesthetic drugs are widely used aquaculture farms and can create consumption problems for humans, so there is a great need to safer drugs. With regard to long record of herbal drugs consumption in Iran and their benefits, we survey the possibility of using Valerian officinalis, Melissa officinalis, Papaver somniferum, and P. bracteatum as fish anesthetic. We provided, processed, and made consistent extractions of V. officinalis (2, 3 4g/lit), M. officinalis (5, 10, 15g/lit), P. somniferum (0.85, 1.6, 3.2g/lit) and P. bracteatum (0.3, 0.6, 0.9g/lit). We selected 60 goldfish Carassius auratus in the weight range of 7.41 plus or minus 0/2g, and the length range of 8.4 plus or minus 0/11cm and kept them in laboratory conditions under the same oxygen and temperature. The fish were divided into four groups each containing 15 fish and further into three subgroups of five fish each. During the experiments, two herbs P. somniferum and P. bracteaturn were eliminated from statistical analysis because of biased results