Research on Powering a Personal Heating Garment with a Hybrid Power Supply

Due to the extensive contribution of the fossil fuels’ combustion to the global warming, increasing attention has been drawn to reduce the carbon footprint of all sectors by moving toward green technologies. Accordingly, personal comfort systems (PCSs) are considered as a green substitute for the conventional heating, ventilation, and air conditioning (HVAC) systems in the buildings. Precisely, PCSs can address the thermal comfort of each individual in shared spaces, such as office buildings, with remarkably lower energy consumption than the HVAC systems. To clarify, they save energy by conditioning only the air surrounding each individual, leaving the unoccupied points of the buildings unconditioned. However, their main drawback is that they are mostly powered either by a fossil fuel based power supply (i.e. public electricity) or batteries, which to some extent offsets their eco-friendly feature. Regarding batteries, although they are not considered as a fossil fuel based power supply, they can cause negative environmental impact due to their constitutive elements (e.g. cobalt). Accordingly, in this thesis, it was proposed to develop a hybrid power supply comprising a renewable power source called a thermoelectric generator (TEG) and a rechargeable battery to reduce the carbon footprint of the PCSs. To illustrate, a TEG is considered as a promising thermal energy harvester, which captures the waste ambient heat and converts it into electricity. To put it another way, it employs the temperature difference between a hot and a cold object to generate electricity. In this research, this temperature difference was provided by a candle and the ambient air as the heat and cold sources, respectively. The main reason for using a candle as the heat source was that at room temperature none of the existing internal heat sources (e.g. radiators, hot pipe works) could provide the required temperature difference along the thermoelectric (TE) legs. As a result, the TE legs could not generate enough electricity to power a PCS. Regarding the rechargeable battery, it mainly served as a storage system to store the generated electricity by the TEG to release it on demand. In fact, this storage system performed a pivotal role between the TEG (as a green energy supply) and the electricity demand. To clarify, the generated electricity by a TEG is variable, depending on the temperature difference along its legs. Thus, to provide a reliable power for the studied PCS, usage of a storage system was inevitable. In addition, due to the low output current of the TEGs at the room temperature, the storage system also performed as a backup power supply to provide a constant current for the PCS. To develop the TEG part of the hybrid power supply, initially the life cycle impact of 14 thermoelectric materials were numerically studied from cradle to gate (i.e. raw material’s extraction to manufacturing the final material). The main aim of this numerical study was to select the most environmental friendly material out of the three TE types of inorganic, organic, and hybrid. The employed software for this life cycle impact assessment (LCIA) was GaBi v.4.4, and the results proved the greatest environmental damage of the inorganic type compared with the other two types. However, Bi2Te3 was an exceptional inorganic TE material that its life cycle impact was not only less than that of the other studied inorganic TE materials, but also far less than that of the studied organic and hybrid ones. According, an off-the-shelf TEG consisted of Bi2Te3 was selected for this research, and different integrating patterns were determined to couple six of that together. These patterns were considered based on providing enough temperature difference along the TE legs. Accordingly, three different patterns were developed namely, coating either the top half, or the bottom half, or fully the legs with the integrating substrate. To further improve the temperature difference along the legs, the thermal conductivity of the integrating substrate was manipulated by adding different fillers to it. Then, the thermoelectric effects of all of the developed samples were studied both numerically (i.e. computational modelling by COMSOL) and experimentally (i.e. laboratory tests). Based on the outcomes of both studies, coating only the top half of the legs with a low thermal conductivity substrate called polydimethylsiloxane (PDMS) resulted in the highest output power compared with the other two patterns. Accordingly, the TEG part of the hybrid power supply was fabricated with respect to the achieved optimal integrating substrate. Then, to further improve the temperature difference along the TE legs, two different heatsinks (pin-shaped and bumpy-shaped) were developed, and their performances were studied in the laboratory under three air flow conditions (0,1.2, and 2.4 m/s). The results proved the superiority of the pin-shaped heatsink to the bumpy-shaped one after being attached to the PDMS-based integrating substrate. Next, six of the considered off-the-shelf TEG were coupled together from the top half of their legs using the optimal developed PDMS-based integrating substrate. After that, the pre-developed pin-shaped heatsink was attached to the integrating substrate. Then, the integrated TEGs were coupled with a rechargeable battery to heat a pair of pre-developed heating armbands (i.e. the studied PCS). To test the heating performance of the armbands, they were tested in-field on eight subjects served as office workers in the heating season of March in the UK. The results revealed that at roughly 15 °C to 16 °C ambient temperature, 75% of the subjects felt warmer after 30 min of wearing the armbands. To specify, the armbands improved their average comfort level from slightly uncomfortable to slightly comfortable after 30 min of wearing them. Thus, not only this thesis developed a PCS concerning its conditioning performance, but also it addressed the sustainability aspect of its power supply. Accordingly, this thesis paves the way for further research on developing different types of renewable power supplies for any green technologies, including PCSs

Effective Factors on Needle Stick Injuries in Health Care Workers

Aims: Needle stick accidents are a serious health risk for blood-borne infections among health care workers. This study was conducted to evaluate the frequency of needle stick injuries in health care workers and its related factors. Instrument & Methods: This cross-sectional study was carried on HCWs of Shahid Beheshti Hospital of Kashan City, Iran (270 individuals), from September 2013 to March 2014. Due to the low number of samples, all those who had the experience of needle stick injuries and confirmed to participate were entered to the study. A researcher-made questionnaire with 20 questions was used. Data were analyzed by SPSS 16 software using descriptive statistics. Findings: The most injuries of needle sticks (75.2) were superficial and the most common device for NSIs was the needle of syringe (51.8). Blood sampling was the most common activity during NSIs (28.4). The most common contamination was blood and its products (69.5). 61 participants (43.3) used gloves during NSIs. 118 participants (83.7) were vaccinated completely against hepatitis B, and 19 participants (13.5) had incomplete HBV vaccination. 4 participants (2.8) had no history of vaccination against hepatitis B. Conclusion: Needle stick injuries among health care workers of Kashan Hospital are relatively high

Differentiation of definitive endoderm from human induced pluripotent stem cells on hMSCs feeder in a defined medium

Background: The Definitive Endoderm (DE) differentiation using the undefined media and non-human feeders can cause contaminations in the generated cells for therapeutic applications. Therefore, generating safer and more appropriate DE cells is needed. This study compared five different methods to establish an appropriate method for inducing an efficient DE differentiation from Human Induced Pluripotent Stem Cells (hiPSCs) on an appropriate feeder in a more defined medium. Methods: Human Induced Pluripotent Stem Cells (hiPSCs) were cultured on inactivated feeders. Passaged hiPSCs, without feeder, were incubated for three days with Activin-A and different endodermal differentiation media including 1-FBS, 2-B27, 3- ITS and albumin fraction-V, 4-B27 and ITS and 5-like the third medium. The feeder cells in the first four methods were Mouse Embryonic Fibroblasts (MEFs) and in the fifth method were human adult bone marrow Mesenchymal Stem Cells (hMSCs). DE markers FOXA2, SOX17 and CXCR4 and also pluripotency marker OCT4 were evaluated using qRT-PCR, as well as FOXA2 by the immunocytochemistry. Results: QRT-PCR analysis showed that after three days, the expression levels of DE and pluripotency markers in the differentiated hiPSCs among all five groups did not have any significant differences. Similarly, the immunocytochemistry analysis demonstrated that the differentiated hiPSCs expressed FOXA2, with no significant differences. Conclusion: Despite this similarity in the results, the third differentiation medium has more defined and cost effective components. Furthermore, hMSC, a human feeder, is safer than MEF. Therefore, the fifth method is preferable among other DE differentiation methods and can serve as a fundamental method helping the development of regenerative medicine. © 2016, Avicenna Journal of Medical Biotechnology. All rights reserved

Relationship of some risk factors and symptoms in patients with acute coronary syndrome

Acute coronary syndrome (ACS) is one of the major causes of death in the worldwide. Clinical manifestations are different. So it's necessary to have knowledge about the types of symptoms experienced by patients with ACS. This study was performed to assay the Relationship of some risk factors and symptoms in patients with acute coronary syndrome. This cross-sectional study, were studied 294 patients with acute coronary syndrome at least 24 hours after admission had survived. Data was collected by a questionnaire that included demographic data form and check list of some symptoms and history of risk factors. There was a significant relationship between STEMI with vomiting (OR=1.94) and anxiety (OR=1.83) and UA with vomiting (OR=0.42). Between sex with weakness (OR=2.29) and anxiety (OR=1.82), diabetes with dyspenea (OR=1.8), weakness (OR=1.02) and tinnitus (OR=2.06) and hyperlipidemia with weakness (OR=2.35) and tinnitus (OR=2.49) was available significant difference. The findings of this study indicate that the appearance of symptoms of acute coronary syndrome were different as for ECG changes and risk factors, and more focused on those symptoms that they are common with any other diseases. Since, many of the symptoms of acute coronary syndrome can be potentially dangerous and life threatening, accurate diagnosis and timely action is crucial for the patients

The effects of vitamin D supplementation on signaling pathway of inflammation and oxidative stress in diabetic hemodialysis: A randomized, double-blind, placebo-controlled trial

Objective: This study was carried out to determine the effects of vitamin D supplementation on signaling pathway of inflammation and oxidative stress in diabetic hemodialysis (HD) patients. Methods: This randomized double-blind placebo-controlled clinical trial was conducted among 60 diabetic HD patients. Subjects were randomly allocated into two groups to intake either vitamin D supplements at a dosage of 50,000 IU (n = 30) or placebo (n = 30) every 2 weeks for 12 weeks. Gene expression of inflammatory cytokines and biomarkers of oxidative stress were assessed in peripheral blood mononuclear cells (PBMCs) of diabetic HD patients with RT-PCR method. Results: Results of RT-PCR indicated that after the 12-week intervention, compared to the placebo, vitamin D supplementation downregulated gene expression of interleukin (IL)-1β (P = 0.02), tumor necrosis factor alpha (TNF-α) (P = 0.02) and interferon gamma (IFN-γ) (P = 0.03) in PBMCs of diabetic HD patients. Additionally, vitamin D supplementation, compared to the placebo, downregulated gene expression of transforming growth factor beta (TGF-β) (P = 0.04), protein kinase C (PKC) (P = 0.001), and mitogen-activated protein kinases 1 (MAPK1) (P = 0.02) in PBMCs of diabetic HD patients. Although not significant, vitamin D supplementation let to a reduction of nuclear factor kappa B (NF-kB) (p = 0.75) expression in PBMCs isolated from diabetic patients compared to the placebo group. There was no statistically significant change following supplementation with vitamin D on gene expression of interleukin (IL)-4, IL-6, and vascular endothelial growth factor (VEGF) in PBMCs of diabetic HD patients. Conclusions: Overall, we found that vitamin D supplementation for 12 weeks among diabetic HD patients had beneficial effects on few gene expression related to inflammation and oxidative stress. © 2018 Haddad Kashani, Seyed Hosseini, Nikzad, Soleimani, Soleimani, Tamadon, Keneshlou and Asemi

Void fraction measurement of gas-liquid two-phase flow with a 12-electrode contactless resistivity array sensor under different excitation patterns

This work focuses on the void fraction measurement of gas–liquid two-phase flow by a 12-electrode contactless resistivity array sensor. Such a sensor, which can realize different excitation patterns, is developed here. Five different excitation patterns (with 1, 2, 3, 4 or 5 electrodes) and three two-phase distributions (bubble flow, stratified flow and annular flow) are investigated. Two data processing approaches, the data average method and the principal component regression (PCR) method, are used to establish models of void fraction measurement and hence to implement it. Experiments on void fraction measurement are carried out with the 12-electrode contactless resistivity array sensor. The results show that the void fraction measurement performances are different under different excitation patterns. Among the five different excitation patterns studied, the one with five electrodes has the best performance and the absolute values of void fraction measurement errors of the three two-phase distributions are all less than 5.0% (using the data average method) and 3.0% (using the PCR method). Research results indicate that the 5-electrode excitation pattern + PCR combination is a new effective way to implement void fraction measurement of gas–liquid two-phase flow with the 12-electrode contactless resistivity array sensor.<br/

An Image Reconstruction Algorithm for A 12-electrode Capacitively Coupled Electrical Resistance Tomography System Under 2-electrode Excitation Pattern

An image reconstruction algorithm, which is developed for a 12-electrode capacitively coupled electrical resistance tomography (CCERT) system under 2-electrode excitation strategy, is proposed. Based on L-curve and Reginska’s method, truncated singular value decomposition (TSVD) is used to reconstruct the initial image. The algebraic reconstruction technique (ART) algorithm is used to obtain the final reconstructed image. Image reconstruction experiments are conducted by a 12-electrode CCERT system. The proposed algorithm (TSVD + ART) is compared with conventional linear back projection (LBP), Tikhonov, Landweber, ART, simultaneous iterative reconstruction technique (SIRT), total variation (TV), conjugate gradient (CG), and TSVD to evaluate its image reconstruction performance. Image reconstruction results show the proposed algorithm (TSVD + ART) can effectively exploit the advantages of 2-electrode excitation strategy and hence realize higher quality image reconstruction. Under 2-electrode excitation strategy, the proposed algorithm has an obvious advantage over conventional image reconstruction algorithms. Under 1-electrode excitation strategy, the image reconstruction performance is comparable or slightly improved compared with that of conventional image reconstruction algorithms. Image reconstruction results also indicate the TSVD is effective to obtain the initial reconstructed image. The quality of the initial reconstructed image can be significantly improved compared with that of classic LBP, either under 2-electrode excitation strategy or 1-electrode excitation strategy

Clinical trial of the effects of coenzyme Q10 supplementation on glycemic control and markers of lipid profiles in diabetic hemodialysis patients

Abstract Purpose: The current study was conducted to determine the effects of coenzyme Q10 (CoQ10) supplementation on glycemic control and markers of lipid profiles risk in diabetic hemodialysis (HD) patients. Methods: This randomized, double blind, placebo-controlled clinical trial was performed among 60 diabetic HD patients. Subjects were randomly allocated into two groups to take either 120 mg/day of CoQ10 supplements or placebo (n= 30each group) for 12 weeks. Results: After 12 weeks of intervention, CoQ10 supplementation, compared with the placebo, resulted in a significant decrease in serum insulin concentrations (− 2.5 ± 4.0 vs.+ 2.8 ± 5.3 μIU/mL, P < 0.001), homeostasis model of assessment estimated insulin resistance (− 0.9 ± 2.1 vs. + 1.2 3.0, P = 0.002), and significant increase in the quantitative insulin sensitivity check index (+ 0.009 ± 0.01 vs. − 0.02 ± 0.05, P = 0.003). In addition, a trend toward a greater decrease in serum triglycerides (− 5 ± 53 vs. + 17 ± 44, P = 0.078) and VLDL-cholesterol levels (− 0.9 ± 10 vs. + 3 ± 9, P = 0.078) was observed in the CoQ10 group compared to the placebo group. We did not observe any significant effect of CoQ10 supplementation on fasting glucose, HbA1c and other lipid profiles compared with the placebo. Conclusions: Overall, our study supported that CoQ10 supplementation to diabetic HD patients for 12 weeks had beneficial effects on markers of insulin metabolism, but did not affect fasting glucose, HbA1c, and lipid profiles. Keywords: Coenzyme Q10 supplementation · Hemodialysis · Glycemic control · Lipid profile

On the Image Reconstruction of Capacitively Coupled Electrical Resistance Tomography (CCERT) with Entropy Priors

Regularization with priors is an effective approach to solve the ill-posed inverse problem of electrical tomography. Entropy priors have been proven to be promising in radiation tomography but have received less attention in the literature of electrical tomography. This work aims to investigate the image reconstruction of capacitively coupled electrical resistance tomography (CCERT) with entropy priors. Four types of entropy priors are introduced, including the image entropy, the projection entropy, the image-projection joint entropy, and the cross-entropy between the measurement projection and the forward projection. Correspondingly, objective functions with the four entropy priors are developed, where the first three are implemented under the maximum entropy strategy and the last one is implemented under the minimum cross-entropy strategy. Linear back-projection is adopted to obtain the initial image. The steepest descent method is utilized to optimize the objective function and obtain the final image. Experimental results show that the four entropy priors are effective in regularization of the ill-posed inverse problem of CCERT to obtain a reasonable solution. Compared with the initial image obtained by linear back projection, all the four entropy priors make sense in improving the image quality. Results also indicate that cross-entropy has the best performance among the four entropy priors in the image reconstruction of CCERT