Influence of polydispersity on micromechanics of granular materials

We study the effect of polydispersity on the macroscopic physical properties of granular packings in two and three dimensions. A mean-field approach is developed to approximate the macroscale quantities as functions of the microscopic ones. We show that the trace of the fabric and stress tensors are proportional to the mean packing properties (e.g. packing fraction, average coordination number, and average normal force) and dimensionless correction factors, which depend only on the moments of the particle-size distribution. Similar results are obtained for the elements of the stiffness tensor of isotropic packings in the linear affine response regime. Our theoretical predictions are in good agreement with the simulation results.Comment: 13 pages, 13 figures, 2 table

Adaptive PID Type Iterative Learning Control

In this paper, an adaptive PID-type iterative learning control scheme is proposed for tracking problem in repetitive systems with unknown parameters. In this scheme, we use a combination of an optimal PID-type iterative learning controller and progection like adgusting algorithm that is based on tracking error which decreases by iterations increment. Layapunov method is used for convergence analysis of the presented scheme, and convergence condition is obtained in term of algorithm step size range. the effectiveness of proposed technique is illustrated by simulation results.DOI:http://dx.doi.org/10.11591/ijece.v4i6.643

Diagnostic value of high sensitivity C-reactive protein levels in dedifferentiation of stable angina from unstable angina

BACKGROUND: Differentiation of stable angina from unstable angina is important because they need different approaches. Few studies have been conducted to assess the diagnostic value of high sensitive C-reactive protein (hs-CRP) in differentiating these two diseases. This study aimed to evaluate the diagnostic value of hs-CRP levels for differentiating stable angina from unstable angina. METHODS: After signing the consent form, patients with unstable angina who referred to Tohid Hospital emergency in Sanandaj, Iran, and patients with stable angina who referred to the special clinic of the hospital were evaluated. Disease was confirmed by a cardiologist. Morning serum hs-CRP was tested using MONOBIND laboratory kit (USA). Data were analyzed by SPSS using Student’s independent t-test, Mann-Whitney U, chi-square, Fisher exact test, and receiver operating characteristic curve. RESULTS: hs-CRP levels in patients with stable angina and unstable angina were 1.6 (± 1.18) and 2.35 (± 1.30) mg/l, respectively (P = 0.025). The hs-CRP level ≥ 2.31 mg/l was the best cut-off point for differentiating stable from unstable angina. At this cut-off point, the sensitivity and specificity were 56% and 73%, respectively. Area under the curve was calculated to be 0.679 (95% confidence interval: 0.54-0.81) (P = 0.017). CONCLUSION: hs-CRP level is helpful for differentiating patients with stable angina from those with unstable angina. It is recommended to consider the hs-CRP level of 2.31 mg/l as the best cut-off point

Diagnostic value of high sensitivity C-reactive protein in differentiating unstable angina from myocardial infarction

BACKGROUND: Differentiating between unstable angina and myocardial infarction (MI) is clinically important as they require different treatments. High sensitivity C-reactive protein (hs-CRP) has recently been recognized as prognostic factor in acute coronary syndrome. Since this biomarker may indicate the prognosis of heart disease, identifying its diagnostic value will be clinically important. This study investigated the diagnostic value of the level of hs-CRP in differentiating MI from unstable angina. METHODS: Blood samples were obtained from all patients with suspected MI or unstable angina at the time of referral. The patients were put in one of the two groups based on final diagnosis. The exclusion criteria were infectious diseases, immune system diseases, history of a recent surgery or trauma, kidney failure, liver failure, cancers, and use of anti-inflammatory drugs. Data was entered in SPSS and analyzed by independent t-test, Mann-Whitney U and chi-square or Fisher’s exact test. ROC curve was used to determine hs-CRP cut-off point. The sensitivity and specificity were calculated at the cut-off point. RESULTS: Overall, 60 patients (30 patients with MI and 30 patients with unstable angina) were studied. Hs-CRP level was 3.68 ± 0.86 mg/l in patients with MI and 2.35 ± 1.30 mg/l in patients with unstable angina (P < 0.001). The best cut-off point for differentiating unstable angina from MI was hs-CRP levels equal to or greater than 3.27 mg/l. At this cutoff point, the sensitivity and specificity were both 77%. CONCLUSION: Patients with MI had higher levels of hs-CRP than subjects with unstable angina. Hs-CRP levels equal to or higher than 3.27 mg/l are more likely to be associated with MI. It is recommended to test this biomarker in all patients with acute coronary syndrome

The effect of topical olive oil on prevention of bedsore in intensive care units patients

Background: Bedsores are injuries to skin and underlying tissues caused by prolonged pressure. Although, some methods like frequently changing position and using particular tools are used for preventing and caring of pressure ulcers, their prevention would still be as a vital urgency. Olive oil is an herbal product with potential preventive effects to prevent bedsores because of its numerous medical properties. The major aim of this study was to determine whether topical olive oil can prevent the risk of developing bedsores in I.C.U. patients.  Methods: This clinical trial was accomplished in 2014 with 60 patients who were selected by simple random sampling method into intervention and control groups. During three weeks, the control group had received routine skin care, while the intervention group had received topical Olive oil in addition to the routine care. Statistical analysis, including Chi-square, T-test and Fisher’s tests, were performed with SPSS version 20 software.  Results: The intervention group had contained 19 male and 11 female, with an average age of 60.46 ± 18.06 and the control group had contained 20 male, 10 female, with an average age of 50.96 ± 21.38. Five patients (16%) who received routine care plus topical olive oil had developed bedsore after an average of 18.73 ± 5.36 days and twelve patients (40%) who received routine care only had developed bedsore after an average of 15.46 ± 7.40 days. The risks of developing bedsores between two groups were statistically significant (P=0.03).  Conclusions: Our study has revealed potential effects of topical olive oil to prevent bedsores in I.C.U. patients.

Diagnostic value of high sensitivity C-reactive protein levels in dedifferentiation of stable angina from unstable angina

BACKGROUND: Differentiation of stable angina from unstable angina is important because they need different approaches. Few studies have been conducted to assess the diagnostic value of high sensitive C-reactive protein (hs-CRP) in differentiating these two diseases. This study aimed to evaluate the diagnostic value of hs-CRP levels for differentiating stable angina from unstable angina. METHODS: After signing the consent form, patients with unstable angina who referred to Tohid Hospital emergency in Sanandaj, Iran, and patients with stable angina who referred to the special clinic of the hospital were evaluated. Disease was confirmed by a cardiologist. Morning serum hs-CRP was tested using MONOBIND laboratory kit (USA). Data were analyzed by SPSS using Student’s independent t-test, Mann-Whitney U, chi-square, Fisher exact test, and receiver operating characteristic curve. RESULTS: hs-CRP levels in patients with stable angina and unstable angina were 1.6 (± 1.18) and 2.35 (± 1.30) mg/l, respectively (P = 0.025). The hs-CRP level ≥ 2.31 mg/l was the best cut-off point for differentiating stable from unstable angina. At this cut-off point, the sensitivity and specificity were 56% and 73%, respectively. Area under the curve was calculated to be 0.679 (95% confidence interval: 0.54-0.81) (P = 0.017). CONCLUSION: hs-CRP level is helpful for differentiating patients with stable angina from those with unstable angina. It is recommended to consider the hs-CRP level of 2.31 mg/l as the best cut-off point

Effect of process parameters on quality properties and drying time of hawthorn in a vibro-fluidized bed dryer

The drying kinetics of hawthorn in a pilot-scale experimental fluidized bed dryer with and without vibration was investigated. The effect of operating parameters, such as vibration intensity, drying air flow rate, and temperature, on the drying rate and shrinkage of hawthorn was studied. The hawthorn fruit was dried at various drying air temperatures ranging from 40-70oC and drying air volume flow rates ranging from 22-30 m3/h with the vibration intensity ranging from 6.8 to 8.2 Hz. The entire drying process occurred in the falling rate period and no constant rate period was observed in the drying of hawthorn. Four mathematical drying models investigating the drying behavior of hawthorn were evaluated and then the experimental moisture data were fitted in these models. The quality of the models fitting was assessed using the coefficient of determination, chi-square and root mean square error. The logarithmic and Page models for drying rate and the Ratti and Vazquez models for shrinkage were found to be the most suitable for describing the drying and shrinkage curves of hawthorn. The results showed that the vibration intensity, drying air temperature and flow rate has no significant effect on the shrinkage of hawthorn. All mentioned parameters had a significant effect on the drying rate of hawthorn, but the effect of drying air temperature was considerably more compared to the other parameters. It was observed that shrinkage varies linearly with respect to moisture content, and the reduction in radial dimension of hawthorn samples was around 40% at the end of the drying process

Application of DC-DC Converters at Renewable Energy

Photovoltaics usually produce low voltage at their outputs. So, in order to inject their power into utility grids, the output voltage of solar panels should be increased to grid voltage level. Usually, the boost DC-DC converters will be connected between solar panels and grid-connected inverters to boost the panels\u27 output voltage to more than 320 V (for 380/220 utilities). Various DC-DC converter topologies have been proposed in the past three decades to boost the photovoltaic panels\u27 output voltage which will be discussed in this proposal. In order to increase the life span of photovoltaic panels, the DC-DC converts should absorb continuous low ripple current from solar panels. Maximum power point tracking (MPPT) is an algorithm implemented in photovoltaic (PV) inverters by DC-DC technology to continuously adjust the impedance seen by the solar array to keep the PV system operating at, or close to, the peak power point of the PV panel under varying conditions, like changing solar irradiance, temperature, and humidity. In this research work, various topologies of DC-DC converters that are suitable for renewable energy applications along with the advantages and disadvantages of control methods and the stability of converters with related control methods are discussed

On the Topology Induced by C*-Algebra-Valued Fuzzy Metric Spaces

We define the notion of C * -algebra-valued fuzzy metric spaces and we study the topology induced by these spaces.The authors are grateful to the Basque Government by the support, of this work through Grant IT1207-19