Search results for: electrical impedance of skin
Commenced in January 2007
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Edition: International
Paper Count: 3399

Search results for: electrical impedance of skin

1839 Single Ion Conductors for Lithium-Ion Battery Application

Authors: Seyda Tugba Gunday Anil, Ayhan Bozkurt

Abstract:

Next generation lithium batteries are taking more attention and single-ion polymer electrolytes are expected to play a significant role in the development of these kinds of energy storage systems. In the present work we used a different strategy to design of novel solid single-ion conducting inorganic polymer electrolytes based on lithium polyvinyl alcohol oxalate borate (Li(PVAOB), lithium polyacrylic acid oxalate borate (LiPAAOB) and poly (ethylene glycol) methacrylate (PEGMA). Free radical polymerization was used to convert PEGMA into PPEGMA and LiPAAOB is prepared from poly (acrylic acid), oxalic acid and boric acid. Blend polymer electrolytes were produced by mixing of LiPAAOB or Li (PVAOB with PPEGMA at different stoichiometric ratios to enhance the single ion conductivity of the systems. To exploit the flexible chemistry and increase the segmental mobility of the blend electrolyte, the composition was changed up to 80% with respect to the guest polymer, PPEGMA. FT-IR and differential scanning calorimeter techniques confirmed the interaction between the host and guest polymers. TGA verified that the thermal stability of the blends increased up to approximately 200 C. Scanning electron microscopy images confirm the homogeneity of the blend electrolytes. CV studies showed that electrochemical stability electrochemical stability window is approximately 5 V versus Li/Li⁺. The effect of PPEGMA on to the Lithium-ion conductivity was investigated using dielectric impedance analyzer. The maximum single ion conductivity was measured as 1.3 × 10⁻⁴ S/cm at 100 C for the sample LiPAAOB-80PPEGMA. Clearly, the results confirmed the positive effect to the increment in ionic conductivity of the blend electrolytes with the addition of PPEGMA.

Keywords: single-ion conductor, inorganic polymer, blends, polymer electrolyte

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1838 Predictors of Survival of Therapeutic Hypothermia Based on Analysis of a Consecutive American Inner City Population over 4 Years

Authors: Jorge Martinez, Brandon Roberts, Holly Payton Toca

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Background: Therapeutic hypothermia (TH) is the international standard of care for all comatose patients after cardiac arrest, but criticism focuses on poor outcomes. We sought to develop criteria to identify American urban patients more likely to benefit from TH. Methods: Retrospective chart review of 107 consecutive adults undergoing TH in downtown New Orleans from 2010-2014 yielded records for 99 patients with all 44 survivors or families contacted up to four years. Results: 69 males and 38 females with a mean age of 60.2 showed 63 dead (58%) and 44 survivors (42%). Presenting cardiac rhythm was divided into shockable (Pulseless Ventricular Tachycardia, Ventricular Fibrillation) and non-shockable (Pulseless Electrical Activity, Asystole). Presenting in shockable rhythms with ROSC <20 minutes were 21 patients with 15 (71%) survivors (p=.001). Time >20 minutes until ROSC in shockable rhythms had 5 patients with 3 survivors (78%, p=0.001). Presenting in non-shockable rhythms with ROSC <20 minutes were 54 patients with 18 survivors (33%, p=.001). ROSC >20 minutes in non-shockable rhythms had 19 patients with 2 survivors (8%, p=.001). Survivors of shockable rhythms showed 19 (100%) living post TH. 15 survivors (79%, n=19, p=.001) had CPC score 1 or 2 with 4 survivors (21%, n=19) having a CPC score of 3. A total of 25 survived non-shockable rhythm. Acute survival of patients with non-shockable rhythm showed 18 expired <72 hours (72%, n=25) with long-term survival of 4 patients (5%, n=74) and CPC scores of 1 or 2 (p=.001). Interestingly, patients with time to ROSC <20 minutes exhibiting more than one loss of sustained ROSC showed 100% mortality (p=.001). Patients presenting with shockable >20 minutes ROSC had overall survival of 70% (p=.001), but those undergoing >3 cardiac rhythm changes had 100% mortality (p=.001). Conclusion: Patients presenting with shockable rhythms undergoing TH had overall acute survival of 70% followed by long-term survival of 100% after 4 years. In contrast, patients presenting with non-shockable rhythm had long-term survival of 5%. TH is not recommended for patients presenting with non-shockable rhythm and requiring greater than 20 minutes for restoration of ROSC.

Keywords: cardiac rhythm changes, Pulseless Electrical Activity (PEA), Therapeutic Hypothermia (TH)

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1837 MICA-TM Peptide Selectively Binds to HLAs Associated with Behçet's Disease

Authors: Sirilak Kongkaew, Pathumwadee Yodmanee, Nopporn Kaiyawet, Arthitaya Meeprasert, Thanyada Rungrotmongkol, Toshikatsu Kaburaki, Hiroshi Noguchi, Fujio Takeuch, Nawee Kungwan, Supot Hannongbua

Abstract:

Behçet’s disease (BD) is a genetic autoimmune expressed by multisystemic inflammatory disorder mostly occurred at the skin, joints, gastrointestinal tract, and genitalia, including ocular, oral, genital, and central nervous systems. Most BD patients in Japan and Korea were strongly indicated by the genetic factor namely HLA-B*51 (especially, HLA-B*51:01) marker in HMC class I, while HLA-A*26:01 allele has been detected from the BD patients in Greek, Japan, and Taiwan. To understand the selective binding of the MICA-TM peptide towards the HLAs associated with BD, the molecular dynamics simulations were applied on the four HLA alleles (B*51:01, B*35:01, A*26:01, and A*11:01) in complex with such peptide. As a result, the key residues in the binding groove of HLA protein which play an important role in the MICA-TM peptide binding and stabilization were revealed. The Van der Waals force was found to be the main protein-protein interaction. Based on the binding free energy prediction by MM/PBSA method, the MICA-TM peptide interacted stronger to the HLA alleles associated to BD in the identical class by 7-12 kcal/mol. The obtained results from the present study could help to differentiate the HLA alleles and explain a source of Behçet’s disease.

Keywords: Behçet’s disease, MD simulations, HMC class I, autoimmune

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1836 Ageing, the Reality, and Its Gender Dimension

Authors: Forhana Rahman Noor, Shafia Jannat Khanam

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The image of old age in Bangladesh is associated with graying of hair, wrinkling of skin, with poor physical health, and decreased ability to work. The common expression “bura hoechi”, to be aged, means to be limited in terms of performing economically productive activities, known as ‘work’. For ‘old-old’ age, there is a saying, “uthan akhon onek dure”, which literally means “even the courtyard is like a very distant place (for an old person).” Traditionally, Bengali society had a structure caring the life of older people. It was common in the joint families of Bangladeshi culture. The situation has been changing. Complexities of the societies with growing rapid urbanization are influencing the traditional respects and caring structure of the elderly persons and facing social challenges. Bangladesh is projected to have 10 percent of its population of age 60 years and above in the year 2025. The ageing process is expected to accelerate in the next century, mainly because the large cohorts born in 1950s and 1960s respectively will be joining the ranks of 60 years and over during this period. The decline in mortality, particularly at young ages, also means that a higher proportion of the large cohorts will survive to old age. The country does not have enough policy or strategy to face this upcoming challenge for the aged persons which needs immediate attention.

Keywords: ageing, gender, dimension, elderly population, Bangladesh

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1835 Determination of Aflatoxins in Edible-Medicinal Plant Samples by HPLC with Fluorescence Detector and KOBRA-Cell

Authors: Isil Gazioglu, Abdulselam Ertas

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Aflatoxins (AFs) are secondary toxic metabolites of Aspergillus flavus and A. parasiticus. AFs can be absorbed through the skin. Potent carcinogens like AFs should be completely absent from cosmetics, this can be achieved by careful quality control of the raw plant materials. Regulatory limits for aflatoxins have been established in many countries, and reliable testing methodology is needed to implement and enforce the regulatory limits. In this study, ten medicinal plant samples (Bundelia tournefortti, Capsella bursa-pastoris, Carduus tenuiflorus, Cardaria draba, Malva neglecta, Malvella sharardiana, Melissa officinalis, Sideritis libanotica, Stakys thirkei, Thymus nummularius) were investigated for aflatoxin (AF) contaminations by employing an HPLC assay for the determination of AFB1, B2, G1 and G2. The samples were extracted with 70% (v/v) methanol in water before further cleaned up with an immunoaffinity column and followed by the detection of AFs by using an electrochemically post-column derivatization with Kobra-Cell and fluorescence detector. The extraction procedure was optimized in order to obtain the best recovery. The method was successfully carried out with all medicinal plant samples. The results revealed that five (50%) of samples were contaminated with AFs. The association between particular samples and the AF contaminated could not be determined due to the low frequency of positive samples.

Keywords: aflatoxin B1, HPLC-FLD, KOBRA-Cell, mycotoxin

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1834 Climate Adaptive Building Shells for Plus-Energy-Buildings, Designed on Bionic Principles

Authors: Andreas Hammer

Abstract:

Six peculiar architecture designs from the Frankfurt University will be discussed within this paper and their future potential of the adaptable and solar thin-film sheets implemented facades will be shown acting and reacting on climate/solar changes of their specific sites. The different aspects, as well as limitations with regard to technical and functional restrictions, will be named. The design process for a “multi-purpose building”, a “high-rise building refurbishment” and a “biker’s lodge” on the river Rheine valley, has been critically outlined and developed step by step from an international studentship towards an overall energy strategy, that firstly had to push the design to a plus-energy building and secondly had to incorporate bionic aspects into the building skins design. Both main parameters needed to be reviewed and refined during the whole design process. Various basic bionic approaches have been given [e.g. solar ivyᵀᴹ, flectofinᵀᴹ or hygroskinᵀᴹ, which were to experiment with, regarding the use of bendable photovoltaic thin film elements being parts of a hybrid, kinetic façade system.

Keywords: bionic and bioclimatic design, climate adaptive building shells [CABS], energy-strategy, harvesting façade, high-efficiency building skin, photovoltaic in building skins, plus-energy-buildings, solar gain, sustainable building concept

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1833 Using Deep Learning in Lyme Disease Diagnosis

Authors: Teja Koduru

Abstract:

Untreated Lyme disease can lead to neurological, cardiac, and dermatological complications. Rapid diagnosis of the erythema migrans (EM) rash, a characteristic symptom of Lyme disease is therefore crucial to early diagnosis and treatment. In this study, we aim to utilize deep learning frameworks including Tensorflow and Keras to create deep convolutional neural networks (DCNN) to detect images of acute Lyme Disease from images of erythema migrans. This study uses a custom database of erythema migrans images of varying quality to train a DCNN capable of classifying images of EM rashes vs. non-EM rashes. Images from publicly available sources were mined to create an initial database. Machine-based removal of duplicate images was then performed, followed by a thorough examination of all images by a clinician. The resulting database was combined with images of confounding rashes and regular skin, resulting in a total of 683 images. This database was then used to create a DCNN with an accuracy of 93% when classifying images of rashes as EM vs. non EM. Finally, this model was converted into a web and mobile application to allow for rapid diagnosis of EM rashes by both patients and clinicians. This tool could be used for patient prescreening prior to treatment and lead to a lower mortality rate from Lyme disease.

Keywords: Lyme, untreated Lyme, erythema migrans rash, EM rash

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1832 Chemical Composition and Biological Properties of Algerian Honeys

Authors: Ouchemoukh Salim, Amessis-Ouchemoukh Nadia, Guenaoui Nawel, Moumeni Lynda, Zaidi Hicham, Otmani Amar, Sadou Dyhia

Abstract:

Honey is a hive food rich in carbohydrates and water and it also has a lot of nutrients (enzymes, minerals, organic acids, phytochemicals...). It is used in different nutritional and therapeutic fields. Algerian honey was studied for its physicochemical parameters, nutritional values (moisture, brix, pH, electrical conductivity, and amounts of HMF, proteins, proline, total phenolic compounds and flavonoids) and some biological activities (antioxidant, anti-inflammatory and enzymatic anti-browning). The antioxidant activities of the samples were estimated using different methods (ABTS, DPPH free radicals scavenging, reducing power, and chelating ferrous activity). All honeys were acidic (3.45≤pH≤4.65). The color varied from mimosa yellow to dark brown. The specific rotation was levorotatory in most honey samples, and the electrical conductivity, hydroxymethylfurfural, and proline values agreed with the international honey requirements. For anti-inflammatory activity, the results showed that the inhibiting capacity of the denaturation of the BSA of the honey analyzed varied from 15 to 75 % with a maximum of activity at the concentration of 0,5 mg/ml. All honey exhibited enzymatic anti-browning on different slices of fruits. In fact, the results showed that the controls have the greatest browning unit compared to the honeys studied and PPO and POD enzymes had the lowest enzyme activity. High significant correlations were found between the color of honey, its antioxidant content and its biological activities (antioxidant, anti-inflammatory and enzymatic anti-browning). The dark color of honey is a good indicator of the best biological properties, therefore, the best nutritional and therapeutic values.

Keywords: honey, physico-chemical parameters, bioactive compounds, biological properties

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1831 Determination of Temperature Dependent Characteristic Material Properties of Commercial Thermoelectric Modules

Authors: Ahmet Koyuncu, Abdullah Berkan Erdogmus, Orkun Dogu, Sinan Uygur

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Thermoelectric modules are integrated to electronic components to keep their temperature in specific values in electronic cooling applications. They can be used in different ambient temperatures. The cold side temperatures of thermoelectric modules depend on their hot side temperatures, operation currents, and heat loads. Performance curves of thermoelectric modules are given at most two different hot surface temperatures in product catalogs. Characteristic properties are required to select appropriate thermoelectric modules in thermal design phase of projects. Generally, manufacturers do not provide characteristic material property values of thermoelectric modules to customers for confidentiality. Common commercial software applied like ANSYS ICEPAK, FloEFD, etc., include thermoelectric modules in their libraries. Therefore, they can be easily used to predict the effect of thermoelectric usage in thermal design. Some software requires only the performance values in different temperatures. However, others like ICEPAK require three temperature-dependent equations for material properties (Seebeck coefficient (α), electrical resistivity (β), and thermal conductivity (γ)). Since the number and the variety of thermoelectric modules are limited in this software, definitions of characteristic material properties of thermoelectric modules could be required. In this manuscript, the method of derivation of characteristic material properties from the datasheet of thermoelectric modules is presented. Material characteristics were estimated from two different performance curves by experimentally and numerically in this study. Numerical calculations are accomplished in ICEPAK by using a thermoelectric module exists in the ICEPAK library. A new experimental setup was established to perform experimental study. Because of similar results of numerical and experimental studies, it can be said that proposed equations are approved. This approximation can be suggested for the analysis includes different type or brand of TEC modules.

Keywords: electrical resistivity, material characteristics, thermal conductivity, thermoelectric coolers, seebeck coefficient

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1830 Environmental Fate and Toxicity of Aged Titanium Dioxide Nano-Composites Used in Sunscreen

Authors: Danielle Slomberg, Jerome Labille, Riccardo Catalano, Jean-Claude Hubaud, Alexandra Lopes, Alice Tagliati, Teresa Fernandes

Abstract:

In the assessment and management of cosmetics and personal care products, sunscreens are of emerging concern regarding both human and environmental health. Organic UV blockers in many sunscreens have been evidenced to undergo rapid photodegradation, induce dermal allergic reactions due to skin penetration, and to cause adverse effects on marine systems. While mineral UV-blockers may offer a safer alternative, their fate and impact and resulting regulation are still under consideration, largely related to the potential influence of nanotechnology-based products on both consumers and the environment. Nanometric titanium dioxide (TiO₂) UV-blockers have many advantages in terms of sun protection and asthetics (i.e., transparency). These UV-blockers typically consist of rutile nanoparticles coated with a primary mineral layer (silica or alumina) aimed at blocking the nanomaterial photoactivity and can include a secondary organic coating (e.g., stearic acid, methicone) aimed at favouring dispersion of the nanomaterial in the sunscreen formulation. The nanomaterials contained in the sunscreen can leave the skin either through a bathing of everyday usage, with subsequent release into rivers, lakes, seashores, and/or sewage treatment plants. The nanomaterial behaviour, fate and impact in these different systems is largely determined by its surface properties, (e.g. the nanomaterial coating type) and lifetime. The present work aims to develop the eco-design of sunscreens through the minimisation of risks associated with nanomaterials incorporated into the formulation. All stages of the sunscreen’s life cycle must be considered in this aspect, from its manufacture to its end-of-life, through its use by the consumer to its impact on the exposed environment. Reducing the potential release and/or toxicity of the nanomaterial from the sunscreen is a decisive criterion for its eco-design. TiO₂ UV-blockers of varied size and surface coating (e.g., stearic acid and silica) have been selected for this study. Hydrophobic TiO₂ UV-blockers (i.e., stearic acid-coated) were incorporated into a typical water-in-oil (w/o) formulation while hydrophilic, silica-coated TiO₂ UV-blockers were dispersed into an oil-in-water (o/w) formulation. The resulting sunscreens were characterised in terms of nanomaterial localisation, sun protection factor, and photo-passivation. The risk to the direct aquatic environment was assessed by evaluating the release of nanomaterials from the sunscreen through a simulated laboratory aging procedure. The size distribution, surface charge, and degradation state of the nano-composite by-products, as well as their nanomaterial concentration and colloidal behaviour were determined in a variety of aqueous environments (e.g., seawater and freshwater). Release of the hydrophobic nanocomposites into the aqueous environment was driven by oil droplet formation while hydrophilic nano-composites were readily dispersed. Ecotoxicity of the sunscreen by-products (from both w/o and o/w formulations) and their risk to marine organisms were assessed using coral symbiotes and tropical corals, evaluating both lethal and sublethal toxicities. The data dissemination and provided risk knowledge from the present work will help guide regulation related to nanomaterials in sunscreen, provide better information for consumers, and allow for easier decision-making for manufacturers.

Keywords: alteration, environmental fate, sunscreens, titanium dioxide nanoparticles

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1829 Advanced Eales’ Disease with Neovascular Glaucoma at First Presentation: Case Report

Authors: Mohammed A. Alfayyadh, Halla A. AlAbdulhadi, Mahdi H. Almubarak

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Purpose: Eales’ disease is an idiopathic vasculitis that affects the peripheral retina. It is characterized by recurrent vitreous hemorrhage as a complication of retinal neovascularization. It is more prevalent in India and affects young males. Here we present a patient with neovascular glaucoma as a rare first presentation of Eales’ disease. Observations: This is a 24-year-old Indian gentleman, who complained of a sudden decrease in vision in the left eye over less than 24 hours, along with frontal headache and eye pain for the last three weeks. Ocular examination revealed peripheral retinal ischemia in the right eye, very high intraocular pressure, rubeosis iridis, vitreous hemorrhage and extensive retinal ischemia in the left eye, vascular sheathing and neovascularization in both eyes. Purified protein derivative skin test was positive. The patient was managed with anti-glaucoma, intravitreal anti-vascular endothelial growth factor and laser photocoagulation. Systemic steroids and anti-tuberculous therapy were also initiated. Conclusions: Neovascular glaucoma is an infrequent complication of Eales’ disease. However, the lack of early detection of the disease in the early stages might lead to such serious complication.

Keywords: case report, Eales’ disease, mycobacterium tuberculosis, neovascular glaucoma

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1828 Improving the Accuracy of Oral Care Performed by ICU Nurses for Cancer Patients

Authors: Huang Wei-Yi

Abstract:

Purpose: Oral cancer patients undergoing skin flap reconstruction may have wounds in the oral cavity, leading to accumulation of blood, clots, and secretions. Inadequate oral care by nursing staff can result in oral infections and pain. Methods: An investigation revealed that ICU nurses' knowledge and adherence to oral care standards were below acceptable levels. Key issues identified included lack of hands-on training opportunities, insufficient experience, absence of oral care standards and regular audits, no in-service education programs, and a lack of oral care educational materials. Interventions: The following measures were implemented: 1) in-service education programs, 2) development of care standards, 3) creation of a monitoring plan, 4) bedside demonstration teaching, and 5) revision of educational materials. Results: The intervention demonstrated that ICU nurses' knowledge and adherence to oral care standards improved, leading to better quality oral care and reduced pain for patients. Conclusion: Through in-service education, bedside demonstrations, establishment of oral care standards, and regular audits, the oral care skills of ICU nurses were significantly enhanced, resulting in improved oral care quality and decreased patient pain.

Keywords: oral care, ICU, improving, oral cancer

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1827 Ground Track Assessment Using Electrical Resistivity Tomography Application

Authors: Noryani Natasha Yahaya, Anas Ibrahim, Juraidah Ahmad, Azura Ahmad, Mohd Ikmal Fazlan Rosli, Zailan Ramli, Muhd Sidek Muhd Norhasri

Abstract:

The subgrade formation is an important element of the railway structure which holds overall track stability. Conventional track maintenance involves many substructure component replacements, as well as track re-ballasting on a regular basis is partially contributed to the embankment's long-term settlement problem. For subgrade long-term stability analysis, the geophysical method is commonly being used to diagnose those hidden sources/mechanisms of track deterioration problems that the normal visual method is unable to detect. Electrical resistivity tomography (ERT) is one of the applicable geophysical tools that are helpful in railway subgrade inspection/track monitoring due to its flexibility and reliability of the analysis. The ERT was conducted at KM 23.0 of Pinang Tunggal track to investigate the subgrade of railway track through the characterization/mapping on track formation profiling which was directly generated using 2D analysis of Res2dinv software. The profiles will allow examination of the presence and spatial extent of a significant subgrade layer and screening of any poor contact of soil boundary. Based on the finding, there is a mix/interpretation/intermixing of an interlayer between the sub-ballast and the sand. Although the embankment track considered here is at no immediate risk of settlement effect or any failure, the regular monitoring of track’s location will allow early correction maintenance if necessary. The developed data of track formation clearly shows the similarity of the side view with the assessed track. The data visualization in the 2D section of the track embankment agreed well with the initial assumption based on the main element structure general side view.

Keywords: ground track, assessment, resistivity, geophysical railway, method

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1826 Flexible PVC Based Nanocomposites With the Incorporation of Electric and Magnetic Nanofillers for the Shielding Against EMI and Thermal Imaging Signals

Authors: H. M. Fayzan Shakir, Khadija Zubair, Tingkai Zhao

Abstract:

Electromagnetic (EM) waves are being used widely now a days. Cell phone signals, WIFI signals, wireless telecommunications etc everything uses EM waves which then create EM pollution. EM pollution can cause serious effects on both human health and nearby electronic devices. EM waves have electric and magnetic components that disturb the flow of charged particles in both human nervous system and electronic devices. The shielding of both humans and electronic devices are a prime concern today. EM waves can cause headaches, anxiety, suicide and depression, nausea, fatigue and loss of libido in humans and malfunctioning in electronic devices. Polyaniline (PANI) and polypyrrole (PPY) were successfully synthesized using chemical polymerizing using ammonium persulfate and DBSNa as oxidant respectively. Barium ferrites (BaFe) were also prepared using co-precipitation method and calcinated at 10500C for 8h. Nanocomposite thin films with various combinations and compositions of Polyvinylchloride, PANI, PPY and BaFe were prepared. X-ray diffraction technique was first used to confirm the successful fabrication of all nano fillers and particle size analyzer to measure the exact size and scanning electron microscopy is used for the shape. According to Electromagnetic Interference theory, electrical conductivity is the prime property required for the Electromagnetic Interference shielding. 4-probe technique is then used to evaluate DC conductivity of all samples. Samples with high concentration of PPY and PANI exhibit remarkable increased electrical conductivity due to fabrication of interconnected network structure inside the Polyvinylchloride matrix that is also confirmed by SEM analysis. Less than 1% transmission was observed in whole NIR region (700 nm – 2500 nm). Also, less than -80 dB Electromagnetic Interference shielding effectiveness was observed in microwave region (0.1 GHz to 20 GHz).

Keywords: nanocomposites, polymers, EMI shielding, thermal imaging

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1825 Modeling of Bipolar Charge Transport through Nanocomposite Films for Energy Storage

Authors: Meng H. Lean, Wei-Ping L. Chu

Abstract:

The effects of ferroelectric nanofiller size, shape, loading, and polarization, on bipolar charge injection, transport, and recombination through amorphous and semicrystalline polymers are studied. A 3D particle-in-cell model extends the classical electrical double layer representation to treat ferroelectric nanoparticles. Metal-polymer charge injection assumes Schottky emission and Fowler-Nordheim tunneling, migration through field-dependent Poole-Frenkel mobility, and recombination with Monte Carlo selection based on collision probability. A boundary integral equation method is used for solution of the Poisson equation coupled with a second-order predictor-corrector scheme for robust time integration of the equations of motion. The stability criterion of the explicit algorithm conforms to the Courant-Friedrichs-Levy limit. Trajectories for charge that make it through the film are curvilinear paths that meander through the interspaces. Results indicate that charge transport behavior depends on nanoparticle polarization with anti-parallel orientation showing the highest leakage conduction and lowest level of charge trapping in the interaction zone. Simulation prediction of a size range of 80 to 100 nm to minimize attachment and maximize conduction is validated by theory. Attached charge fractions go from 2.2% to 97% as nanofiller size is decreased from 150 nm to 60 nm. Computed conductivity of 0.4 x 1014 S/cm is in agreement with published data for plastics. Charge attachment is increased with spheroids due to the increase in surface area, and especially so for oblate spheroids showing the influence of larger cross-sections. Charge attachment to nanofillers and nanocrystallites increase with vol.% loading or degree of crystallinity, and saturate at about 40 vol.%.

Keywords: nanocomposites, nanofillers, electrical double layer, bipolar charge transport

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1824 Amniotic Fluid Mesenchymal Stem Cells Selected for Neural Specificity Ameliorates Chemotherapy Induced Hearing Loss and Pain Perception

Authors: Jan F. Talts, Amit Saxena, Kåre Engkilde

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Chemotherapy-induced peripheral neuropathy (CIPN) is one of the most frequent side effects caused by anti-neoplastic agents, with a prevalence from 19 % to 85 %. Clinically, CIPN is a mostly sensory neuropathy leading to pain and to motor and autonomic changes. Due to its high prevalence among cancer patients, CIPN constitutes a major problem for both cancer patients and survivors, especially because currently, there is no single effective method of preventing CIPN. Hearing loss is the most common form of sensory impairment in humans and can be caused by ototoxic chemical compounds such as chemotherapy (platinum-based antineoplastic agents).In rodents, single or repeated cisplatin injections induce peripheral neuropathy and hearing impairment mimicking human disorder, allowing studying the efficacy of new pharmacological candidates in chemotherapy-induced hearing loss and peripheral neuropathy. RNA sequencing data from full term amniotic fluid (TAF) mesenchymal stemcell (MSC) clones was used to identify neural-specific markers present on TAF-MSC. Several prospective neural markers were tested by flow cytometry on cultured TAF-MSC. One of these markers was used for cell-sorting using Tyto MACSQuant cell sorter, and the neural marker positive cell population was expanded for several passages to the final therapeutic product stage. Peripheral neuropathy and hearing loss was induced in mice by administration of cisplatin in three week-long cycles. The efficacy of neural-specific TAF-MSC in treating hearing loss and pain perception was evaluated by administration of three injections of 3 million cells/kg by intravenous route or three injections of 3 million cells/kg by intra-arterial route after each cisplatin cycle treatment. Auditory brainstem responses (ABR) are electric potentials recorded from scalp electrodes, and the first ABR wave represents the summed activity of the auditory nerve fibers contacting the inner hair cells. For ABR studies, mice were anesthetized, then earphones were placed in the left ear of each mouse, an active electrode was placed in the vertex of the skull, a reference electrode under the skin of the mastoid bone, and a ground electrode in the neck skin. The stimuli consisted of tone pips of five frequencies (2, 4, 6, 12, 16, and 24 kHz) at various sound levels (from 0 to 90 dB) ranging to cover the mouse auditory frequency range. The von Frey test was used to assess the onset and maintenance of mechanical allodynia over time. Mice were placed in clear plexiglass cages on an elevated mesh floor and tested after 30 min of habituation. Mechanical paw withdrawal threshold was examined using an electronic von Frey anesthesiometer. Cisplatin groups treated with three injections of 3 million cells/kg by intravenous route and three injections of 3 million cells/kg by intra-arterial route after each cisplatin cycle treatment presented, a significant increase of hearing acuity characterized by a decrease of ABR threshold and a decrease of neuropathic pain characterized by an increase of von Frey paw withdrawal threshold compared to controls only receiving cisplatin. This study shows that treatment with MSCselected for neural specificity presents significant positive efficacy on the chemotherapy-induced neuropathic pain and the chemotherapy-induced hearing loss.

Keywords: mesenchymal stem cell, peripheral neuropathy, amniotic fluid, regenerative medicine

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1823 Ground Water Contamination by Tannery Effluents and Its Impact on Human Health in Peshawar, Pakistan

Authors: Fawad Ali, Muhammad Ateeq, Ikhtiar Khan

Abstract:

Ground water, a major source of drinking water supply in Peshawar has been severely contaminated by leather tanning industry. Effluents from the tanneries contain high concentration of chromium besides several other chemical species. Release of untreated effluents from the tanning industry has severely damaged surface and ground water, agriculture soil as well as vegetables and crops. Chromium is a well-known carcinogenic and mutagenic agent. Once in the human food chain, it causes multiple problems to the exposed population including various types of cancer, skin dermatitis, and DNA damage. In order to assess the extent of chromium and other heavy metals contamination, water samples were analyzed for heavy metals using Graphite Furnace Atomic Absorption Spectrometer (GFAAS, Analyst 700, Perkin Elmer). Total concentration of chromium was above the permissible limit (0.048 mg/l) in 85% of the groundwater (drinking water) samples. The concentration of cobalt, manganese, cadmium, nickel, lead, zinc and iron was also determined in the ground water, surface water, agriculture soil, and vegetables samples from the affected area.

Keywords: heavy metals, soil, groundwater, tannery effluents, food chain

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1822 Sensitive Electrochemical Sensor for Simultaneous Detection of Endocrine Disruptors, Bisphenol A and 4- Nitrophenol Using La₂Cu₂O₅ Modified Glassy Carbon Electrode

Authors: S. B. Mayil Vealan, C. Sekar

Abstract:

Bisphenol A (BIS A) and 4 Nitrophenol (4N) are the most prevalent environmental endocrine-disrupting chemicals which mimic hormones and have a direct relationship to the development and growth of animal and human reproductive systems. Moreover, intensive exposure to the compound is related to prostate and breast cancer, infertility, obesity, and diabetes. Hence, accurate and reliable determination techniques are crucial for preventing human exposure to these harmful chemicals. Lanthanum Copper Oxide (La₂Cu₂O₅) nanoparticles were synthesized and investigated through various techniques such as scanning electron microscopy, high-resolution transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and electrochemical impedance spectroscopy. Cyclic voltammetry and square wave voltammetry techniques are employed to evaluate the electrochemical behavior of as-synthesized samples toward the electrochemical detection of Bisphenol A and 4-Nitrophenol. Under the optimal conditions, the oxidation current increased linearly with increasing the concentration of BIS A and 4-N in the range of 0.01 to 600 μM with a detection limit of 2.44 nM and 3.8 nM. These are the lowest limits of detection and the widest linear ranges in the literature for this determination. The method was applied to the simultaneous determination of BIS A and 4-N in real samples (food packing materials and river water) with excellent recovery values ranging from 95% to 99%. Better stability, sensitivity, selectivity and reproducibility, fast response, and ease of preparation made the sensor well-suitable for the simultaneous determination of bisphenol and 4 Nitrophenol. To the best of our knowledge, this is the first report in which La₂Cu₂O₅ nano particles were used as efficient electron mediators for the fabrication of endocrine disruptor (BIS A and 4N) chemical sensors.

Keywords: endocrine disruptors, electrochemical sensor, Food contacting materials, lanthanum cuprates, nanomaterials

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1821 Testing of Complicated Bus Bar Protection Using Smart Testing Methodology

Authors: K. N. Dinesh Babu

Abstract:

In this paper, the protection of a complicated bus arrangement with a dual bus coupler and bus sectionalizer using low impedance differential protection applicable for very high voltages like 220kV and 400kV is discussed. In many power generation stations, several operational procedures are implemented to utilize the transfer bus as the main bus and to facilitate the maintenance of circuit breakers and current transformers (in each section) without shutting down the bay(s). Owing to this fact, the complications in operational philosophy have thrown challenges for the bus bar protection implementation. Many bus topologies allow any one of the main buses available in the station to be used as an auxiliary bus. In such a system, pre-defined precautions and procedures are made as guidelines, which are followed before assigning any bus as an auxiliary bus. The procedure involves shifting of links, changing rotary switches, insertion of test block, and so on, thereby causing unreliable operation. This kind of unreliable operation or inadvertent procedural lapse may result in the isolation of the bus bar from the grid due to the unpredictable operation of the bus bar protection relay, which is a commonly occurring phenomenon due to manual mistakes. With the sophisticated configuration and implementation of logic in modern intelligent electronic devices, the operator is free to select the transfer arrangement without sacrificing the protection required by a bus differential system for a reliable operation, and labor-intensive processes are completely eliminated. This paper deals with the procedure to test the security logic for such special scenarios using Megger make SMRT, bus bar protection relay to assure system stability and get rid of all the specific operational precautions/procedure.

Keywords: bus bar protection, by-pass isolator, blind spot, breaker failure, intelligent electronic device, end fault, bus unification, directional principle, zones of protection, breaker re-trip, under voltage security, smart megger relay tester

Procedia PDF Downloads 63
1820 Occupational Health and Safety Implications of Flower Farming on the Local Communities in Central Uganda

Authors: Charles Owenda Omulo

Abstract:

This study examines Occupational Health and Safety implications in flower farms in Central Uganda. An exploratory sequential mixed method design and methodology was employed, with multiple data collection methods, including interviews, focus group discussions, and surveys. The findings show that occupational health and safety issues remain a major problem in flower farms. While the majority of workers agreed that the farms provided them with protective equipment, the data collected from the workers point to either the improper use or ineffectiveness of this equipment. A number of workers reported skin irritations, sore and painful eyes, stiff necks, back pains, and occasional headaches that were presumably argued to have arisen from their work environment. The study also found that farms have been adjusting in an attempt to correct some of these anomalies. These included the use of biological approaches to control pests and diseases and restricting the use of some chemical formulations that are deemed to be harmful to applicators and the environment. Alongside these efforts, the study recommends increased vigilance by the flower farm owners in the provision of personal protective equipment to workers.

Keywords: flower farms, personal protective equipment, agrochemicals, rural communities, occupational health and safety

Procedia PDF Downloads 57
1819 Application of Electrical Resistivity Surveys on Constraining Causes of Highway Pavement Failure along Ajaokuta-Anyigba Road, North Central Nigeria

Authors: Moroof, O. Oloruntola, Sunday Oladele, Daniel, O. Obasaju, Victor, O Ojekunle, Olateju, O. Bayewu, Ganiyu, O. Mosuro

Abstract:

Integrated geophysical methods involving Vertical Electrical Sounding (VES) and 2D resistivity survey were deployed to gain an insight into the influence of the two varying rock types (mica-schist and granite gneiss) underlying the road alignment to the incessant highway failure along Ajaokuta-Anyigba, North-central Nigeria. The highway serves as a link-road for the single largest cement factory in Africa (Dangote Cement Factory) and two major ceramic industries to the capital (Abuja) via Lokoja. 2D Electrical Resistivity survey (Dipole-Dipole Array) and Vertical Electrical Sounding (VES) (Schlumberger array) were employed. Twenty-two (22) 2D profiles were occupied, twenty (20) conducted about 1 m away from the unstable section underlain by mica-schist with profile length each of approximately 100 m. Two (2) profiles were conducted about 1 m away from the stable section with a profile length of 100 m each due to barriers caused by the drainage system and outcropping granite gneiss at the flanks of the road. A spacing of 2 m was used for good image resolution of the near-surface. On each 2D profile, a range of 1-3 VES was conducted; thus, forty-eight (48) soundings were acquired. Partial curve matching and WinResist software were used to obtain the apparent and true resistivity values of the 1D survey, while DiprofWin software was used for processing the 2-D survey. Two exposed lithologic sections caused by abandoned river channels adjacent to two profiles as well as the knowledge of the geology of the area helped to constrain the VES and 2D processing and interpretation. Generally, the resistivity values obtained reflect the parent rock type, degree of weathering, moisture content and competency of the tested area. Resistivity values < 100; 100 – 950; 1000 – 2000 and > 2500 ohms-m were interpreted as clay, weathered layer, partly weathered layer and fresh basement respectively. The VES results and 2-D resistivity structures along the unstable segment showed similar lithologic characteristics and sequences dominated by clayey substratum for depths range of 0 – 42.2 m. The clayey substratum is a product of intensive weathering of the parent rock (mica-schist) and constitutes weak foundation soils, causing highway failure. This failure is further exacerbated by several heavy-duty trucks which ply the section round the clock due to proximity to two major ceramic industries in the state and lack of drainage system. The two profiles on the stable section show 2D structures that are remarkably different from those of the unstable section with very thin topsoils, higher resistivity weathered substratum (indicating the presence of coarse fragments from the parent rock) and shallow depth to the basement (1.0 – 7. 1 m). Also, the presence of drainage and lower volume of heavy-duty trucks are contributors to the pavement stability of this section of the highway. The resistivity surveys effectively delineated two contrasting soil profiles of the subbase/subgrade that reflect variation in the mineralogy of underlying parent rocks.

Keywords: clay, geophysical methods, pavement, resistivity

Procedia PDF Downloads 164
1818 Smart Wheel Chair: A Design to Accommodate Vital Sign Monitoring

Authors: Stephanie Nihan, Jayson M. Fadrigalan, Pyay P. San, Steven M. Santos, Weihui Li

Abstract:

People of all ages who use wheelchairs are left with the inconvenience of not having an easy way to take their vital signs. Typically, patients are required to visit the hospital in order to take the vital signs. VitalGO is a wheel chair system that equipped with medical devices to take vital signs and then transmit data to a mobile application for convenient, long term health monitoring. The vital signs include oxygen saturation, heart rate, and blood pressure, breathing rate and body temperature. Oxygen saturation and heart rate are monitored through pulse oximeter. Blood pressure is taken through a radar sensor. Breathing rate is derived through thoracic impedance while body temperature is measured through an infrared thermometer. The application receives data through bluetooth and stores in a database for review in a simple graphical interface. The application will have the ability to display this data over various time intervals such as a day, week, month, 3 months, 6 months and a year. The final system for the mobile app can also provide an interface for both the user and their physician(s) to record notes or keep record of daily symptoms that a patient might be having. The user’s doctor will be granted access by the user to view the patient information for assistance with a more accurate diagnosis. Also, this wheelchair accessory conveniently includes a foldable table/desk as somewhere to place an electronic device that may be used to access the app. The foldable table will overall contribute to the wheelchair user’s increased comfort and will give them somewhere to place food, a book, or any other form of entertainment that would normally be hard to juggle on their lap.

Keywords: wheel chair, vital sign, mobile application, telemedicine

Procedia PDF Downloads 330
1817 The Relation between Vitamin C and Oral Health

Authors: Mai Ashraf Talaat

Abstract:

Background: Vitamin C (ascorbic acid) is an essential nutrient for the development and repair of all body tissues. It can be obtained from a healthy diet or through supplementation. Due to its importance, vitamin C has become a mainstay in the treatment and prevention of many diseases and in maintaining immune, skin, bone and overall health. This review article aims to discuss the studies and case reports conducted to evaluate the effect of Vitamin C on oral health and the recent advances in oral medicine that involve the use of vitamin C. Data/Sources: The review was conducted for clinical studies, case reports and published literature in the English language that addresses this topic. An extensive search in the electronic databases of PubMed, PubMed Central, Web of Science, National Library of Medicine and ResearchGate was performed. Conclusion: Vitamin C is thought to treat periodontal diseases and gingival enlargement. It also affects biofilm formation and therefore, it helps in reducing caries incidence. Recently, vitamin C mesotherapy has been used to treat inflamed gingiva, bleeding gums and gingival hyperpigmentation. More research and randomized controlled trials are needed on this specific topic for more accurate judgment. Clinical significance: A minimally invasive approach - the usage of vitamin C in dental care could drastically reduce the need for surgical intervention.

Keywords: oral health, periodontology, vitamin C, Gingivitis

Procedia PDF Downloads 77
1816 Control Algorithm Design of Single-Phase Inverter For ZnO Breakdown Characteristics Tests

Authors: Kashif Habib, Zeeshan Ayyub

Abstract:

ZnO voltage dependent resistor was widely used as components of the electrical system for over-voltage protection. It has a wide application prospect in superconducting energy-removal, generator de-excitation, overvoltage protection of electrical & electronics equipment. At present, the research for the application of ZnO voltage dependent resistor stop, it uses just in the field of its nonlinear voltage current characteristic and overvoltage protection areas. There is no further study over the over-voltage breakdown characteristics, such as the combustion phenomena and the measure of the voltage/current when it breakdown, and the affect to its surrounding equipment. It is also a blind spot in its application. So, when we do the feature test of ZnO voltage dependent resistor, we need to design a reasonable test power supply, making the terminal voltage keep for sine wave, simulating the real use of PF voltage in power supply conditions. We put forward the solutions of using inverter to generate a controllable power. The paper mainly focuses on the breakdown characteristic test power supply of nonlinear ZnO voltage dependent resistor. According to the current mature switching power supply technology, we proposed power control system using the inverter as the core. The power mainly realize the sin-voltage output on the condition of three-phase PF-AC input, and 3 control modes (RMS, Peak, Average) of the current output. We choose TMS320F2812M as the control part of the hardware platform. It is used to convert the power from three-phase to a controlled single-phase sin-voltage through a rectifier, filter, and inverter. Design controller produce SPWM, to get the controlled voltage source via appropriate multi-loop control strategy, while execute data acquisition and display, system protection, start logic control, etc. The TMS320F2812M is able to complete the multi-loop control quickly and can be a good completion of the inverter output control.

Keywords: ZnO, multi-loop control, SPWM, non-linear load

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1815 Morphology and Permeability of Biomimetic Cellulose Triacetate-Impregnated Membranes: in situ Synchrotron Imaging and Experimental Studies

Authors: Amira Abdelrasoul

Abstract:

This study aimed to ascertain the controlled permeability of biomimetic cellulose triacetate (CTA) membranes by investigating the electrical oscillatory behavior across impregnated membranes (IM). The biomimetic CTA membranes were infused with a fatty acid to induce electrical oscillatory behavior and, hence, to ensure controlled permeability. In situ synchrotron radiation micro-computed tomography (SR-μCT) at the BioMedical Imaging and Therapy (BMIT) Beamline at the Canadian Light Source (CLS) was used to evaluate the main morphology of IMs compared to neat CTA membranes to ensure fatty acid impregnation inside the pores of the membrane matrices. A monochromatic beam at 20 keV was used for the visualization of the morphology of the membrane. The X-ray radiographs were recorded by means of a beam monitor AA-40 (500 μm LuAG scintillator, Hamamatsu, Japan) coupled with a high-resolution camera, providing a pixel size of 5.5 μm and a field of view (FOV) of 4.4 mm × 2.2 mm. Changes were evident in the phase transition temperatures of the impregnated CTA membrane at the melting temperature of the fatty acid. The pulsations of measured voltages were related to changes in the salt concentration of KCl in the vicinity of the electrode. Amplitudes and frequencies of voltage pulsations were dependent on the temperature and concentration of the KCl solution, which controlled the permeability of the biomimetic membranes. The presented smart biomimetic membrane successfully combined porous polymer support and impregnating liquid not only imitate the main barrier properties of the biological membranes but could be easily modified to achieve some new properties, such as facilitated and active transport, regulation by chemical, physical and pharmaceutical factors. These results open new frontiers for the facilitation and regulation of active transport and permeability through biomimetic smart membranes for a variety of biomedical and drug delivery applications.

Keywords: biomimetic, membrane, synchrotron, permeability, morphology

Procedia PDF Downloads 95
1814 Bioremediation of Sea Food Waste in Solid State Fermentation along with Production of Bioactive Agents

Authors: Rahul Warmoota, Aditya Bhardwaj, Steffy Angural, Monika Rana, Sunena Jassal, Neena Puri, Naveen Gupta

Abstract:

Seafood processing generates large volumes of waste products such as skin, heads, tails, shells, scales, backbones, etc. Pollution due to conventional methods of seafood waste disposal causes negative implications on the environment, aquatic life, and human health. Moreover, these waste products can be used for the production of high-value products which are still untapped due to inappropriate management. Paenibacillus sp. AD is known to act on chitinolytic and proteinaceous waste and was explored for its potential to degrade various types of seafood waste in solid-state fermentation. Effective degradation of seafood waste generated from a variety of sources such as fish scales, crab shells, prawn shells, and a mixture of such wastes was observed. 30 to 40 percent degradation in terms of decrease in the mass was achieved. Along with the degradation, chitinolytic and proteolytic enzymes were produced, which can have various biotechnological applications. Apart from this, value-added products such as chitin oligosaccharides and peptides of various degrees of polymerization were also produced, which can be used for various therapeutic purposes. Results indicated that Paenibacillus sp. AD can be used for the development of a process for the infield degradation of seafood waste.

Keywords: chitin, chitin-oligosaccharides, chitinase, protease, biodegradation, crab shells, prawn shells, fish scales

Procedia PDF Downloads 94
1813 C2N2 Adsorption on the Surface of a BN Nanosheet: A DFT Study

Authors: Maziar Noei

Abstract:

Calculation showed that when the nanosheet is doped by Si, the adsorption energy is about -85.62 to -87.43kcal/mol and also the amount of HOMO/LUMO energy gap (Eg) will reduce significantly. Boron nitride nanosheet is a suitable adsorbent for cyanogen and can be used in separation processes cyanogen. It seems that nanosheet (BNNS) is a suitable semiconductor after doping. The doped BNNS in the presence of cyanogens (C2N2) an electrical signal is generating directly and, therefore, can potentially be used for cyanogen sensors.

Keywords: nanosheet, DFT, cyanogen, sensors

Procedia PDF Downloads 277
1812 Effect of Annealing Temperature on the Photoelectric Work Function of Silver-Zinc Oxide Contact Materials

Authors: Bouchou Aïssa, Mohamed Akbi

Abstract:

Contact materials used for electrical breakers are often made with silver alloys. Mechanical and thermo dynamical properties as well as electron emission of such complicated alloys present a lack of reliable and accurate experimental data. This paper deals mainly with electron work function (EWF) measurements about silver-metal oxide (Ag-MeO) electrical contacts (Ag-ZnO (92/8), before and after surface heat treatments at 296 K  813 K, under UHV conditions (residual gas pressure of 1.4 x 10-7 mbar). The electron work function (EWF) of silver zinc oxide materials was measured photoelectrically, using both Fowler’s method of isothermal curves and linearized Fowler plots. In this paper, we present the development of a method for measuring photoelectric work function of contact materials. Also reported in this manuscript are the results of experimental work whose purpose has been the buildup of a reliable photoelectric system and associated monochromatic ultra-violet radiations source, and the photoelectric measurement of the electron work functions (EWF) of contact materials. In order to study the influence of annealing temperature on the EWF, a vacuum furnace was used for heating the metallic samples up to 800 K. The EWF of the silver – zinc oxide materials were investigated to study the influence of annealing temperature on the EWF. In the present study, the photoelectric measurements about Ag-ZnO(92/8) contacts have shown a linear decrease of the EWF with increasing temperature, i.e. the temperature coefficient is constant and negative: for the first annealing # 1, in the temperature range [299 K  823 K]. On the contrary, a linear increase was observed with increasing temperature (i.e. , being constant and positive), for the next annealing # 2, in the temperature range [296 K  813 K]. The EWFs obtained for silver-zinc oxide Ag-ZnO(92/8) show an obvious dependence on the annealing temperature which is strongly associated with the evolution of the arrangement on ZnO nano particles on the Ag-ZnO contact surface as well as surface charge distribution.

Keywords: Photoemission, Electron work function, Fowler methods, Ag-ZnO contact materials, Vacuum heat treatment

Procedia PDF Downloads 413
1811 Modified 'Perturb and Observe' with 'Incremental Conductance' Algorithm for Maximum Power Point Tracking

Authors: H. Fuad Usman, M. Rafay Khan Sial, Shahzaib Hamid

Abstract:

The trend of renewable energy resources has been amplified due to global warming and other environmental related complications in the 21st century. Recent research has very much emphasized on the generation of electrical power through renewable resources like solar, wind, hydro, geothermal, etc. The use of the photovoltaic cell has become very public as it is very useful for the domestic and commercial purpose overall the world. Although a single cell gives the low voltage output but connecting a number of cells in a series formed a complete module of the photovoltaic cells, it is becoming a financial investment as the use of it fetching popular. This also reduced the prices of the photovoltaic cell which gives the customers a confident of using this source for their electrical use. Photovoltaic cell gives the MPPT at single specific point of operation at a given temperature and level of solar intensity received at a given surface whereas the focal point changes over a large range depending upon the manufacturing factor, temperature conditions, intensity for insolation, instantaneous conditions for shading and aging factor for the photovoltaic cells. Two improved algorithms have been proposed in this article for the MPPT. The widely used algorithms are the ‘Incremental Conductance’ and ‘Perturb and Observe’ algorithms. To extract the maximum power from the source to the load, the duty cycle of the convertor will be effectively controlled. After assessing the previous techniques, this paper presents the improved and reformed idea of harvesting maximum power point from the photovoltaic cells. A thoroughly go through of the previous ideas has been observed before constructing the improvement in the traditional technique of MPP. Each technique has its own importance and boundaries at various weather conditions. An improved technique of implementing the use of both ‘Perturb and Observe’ and ‘Incremental Conductance’ is introduced.

Keywords: duty cycle, MPPT (Maximum Power Point Tracking), perturb and observe (P&O), photovoltaic module

Procedia PDF Downloads 174
1810 Influence of Magnetic Field on Microstructure and Properties of Copper-Silver Composites

Authors: Engang Wang

Abstract:

The Cu-alloy composites are a kind of high-strength and high-conductivity Cu-based alloys, which have excellent mechanical and electrical properties and is widely used in electronic, electrical, machinery industrial fields. However, the solidification microstructure of the composites, such as the primary or second dendrite arm spacing, have important rule to its tensile strength and conductivity, and that is affected by its fabricating method. In this paper, two kinds of directional solidification methods; the exothermic powder method (EP method) and liquid metal cooling method (LMC method), were used to fabricate the Cu-alloy composites with applied different magnetic fields to investigate their influence on the solidifying microstructure of Cu-alloy, and further the fabricated Cu-alloy composites was drawn to wires to investigate the influence of fabricating method and magnetic fields on the drawing microstructure of fiber-reinforced Cu-alloy composites and its properties. The experiment of Cu-Ag alloy under directional solidification and horizontal magnetic fields with different processing parameters show that: 1) For the Cu-Ag alloy with EP method, the dendrite is directionally developed in the cooling copper mould and the solidifying microstructure is effectively refined by applying horizontal magnetic fields. 2) For the Cu-Ag alloy with LMC method, the primary dendrite arm spacing is decreased and the content of Ag in the dendrite increases as increasing the drawing velocity of solidification. 3) The dendrite is refined and the content of Ag in the dendrite increases as increasing the magnetic flux intensity; meanwhile, the growth direction of dendrite is also affected by magnetic field. The research results of Cu-Ag alloy in situ composites by drawing deforming process show that the micro-hardness of alloy is higher by decreasing dendrite arm spacing. When the dendrite growth orientation is consistent with the axial of the samples. the conductivity of the composites increases with the second dendrite arm spacing increases. However, its conductivity reduces with the applied magnetic fields owing to disrupting the dendrite growth orientation.

Keywords: Cu-Ag composite, magnetic field, microstructure, solidification

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