Search results for: phase center

Authors: Ching-Yi Yiu, Hui-Chen Hsu

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Objectives: Head and neck cancer (HNC) is a big global health problem in the world. Despite the development of diagnosis and treatment, the overall survival of HNC is still low. The well recognition of the interaction of the host immune system and cancer cells has led to realizing the processes of tumor initiation, progression and metastasis. Many systemic inflammatory responses have been shown to play a crucial role in cancer progression. The pre and post-treatment nutritional and immunological status of HNC patients is a reliable prognostic indicator of tumor outcomes and survivors. Methods: Between July 2020 to June 2022, We have enrolled 60 HNC patients, including 59 males and 1 female, in Chi Mei Medical Center, Liouying, Taiwan. The age distribution was from 37 to 81 years old (y/o), with a mean age of 57.6 y/o. We evaluated the pre-and post-treatment nutritional and immunological status of these HNC patients with body weight, body weight loss, body mass index (BMI), whole blood count including hemoglobin (Hb), lymphocyte, neutrophil and platelet counts, biochemistry including prealbumin, albumin, c-reactive protein (CRP), with the time period of before treatment, post-treatment 3 and 6 months. We calculated the neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) to assess how these biomarkers influence the outcomes of HNC patients. Results: We have carcinoma of the hypopharynx in 21 cases with 35％, carcinoma of the larynx in 9 cases, carcinoma of the tonsil and tongue every 6 cases, carcinoma soft palate and tongue base every 5 cases, carcinoma of buccal mucosa, retromolar trigone and mouth floor every 2 cases, carcinoma of the hard palate and low lip each 1 case. There were stage I 15 cases, stage II 13 cases, stage III 6 cases, stage IVA 10 cases, and stage IVB 16 cases. All patients have received surgery, chemoradiation therapy or combined therapy. We have wound infection in 6 cases, 2 cases of pharyngocutaneous fistula, flap necrosis in 2 cases, and mortality in 6 cases. In the wound infection group, the average BMI is 20.4 kg/m2; the average Hb is 12.9 g/dL, the average albumin is 3.5 g/dL, the average NLR is 6.78, and the average PLR is 243.5. In the PC fistula and flap necrosis group, the average BMI is 21.65 kg/m2; the average Hb is 11.7 g/dL, the average albumin is 3.15 g/dL, average NLR is 13.28, average PLR is 418.84. In the mortality group, the average BMI is 22.3 kg/m2; the average Hb is 13.58 g/dL, the average albumin is 3.77 g/dL, the average NLR is 6.06, and the average PLR is 275.5. Conclusion: HNC is a big challenging public health problem worldwide, especially in the high prevalence of betel nut consumption area Taiwan. Besides the definite risk factors of smoking, drinking and betel nut related, the other biomarkers may play significant prognosticators in the HNC outcomes. We concluded that the average BMI is less than 22 kg/m2, the average Hb is low than 12.0 g/dL, the average albumin is low than 3.3 g/dL, the average NLR is low than 3, and the average PLR is more than 170, the surgical complications and mortality will be increased, and the prognosis is poor in HNC patients.

Keywords: nutritional, immunological, neutrophil-to-lymphocyte ratio, paltelet-to-lymphocyte ratio.

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Authors: Narayana Murthy Akurathi, Vijaya Lakshmi Marella

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The literature is reviewed with regard to online Super critical fluid extraction (SFE) coupled directly with supercritical fluid chromatography (SFC) -mass spectrometry that have typically more sensitive than conventional LC-MS/MS and GC-MS/MS. It is becoming increasingly interesting to use on-line techniques that combine sample preparation, separation and detection in one analytical set up. This provides less human intervention, uses small amount of sample and organic solvent and yields enhanced analyte enrichment in a shorter time. The sample extraction is performed under light shielding and anaerobic conditions, preventing the degradation of thermo labile analytes. It may be able to analyze compounds over a wide polarity range as SFC generally uses carbon dioxide which was collected as a by-product of other chemical reactions or is collected from the atmosphere as it contributes no new chemicals to the environment. The diffusion of solutes in supercritical fluids is about ten times greater than that in liquids and about three times less than in gases which results in a decrease in resistance to mass transfer in the column and allows for fast high resolution separations. The drawback of SFC when using carbon dioxide as mobile phase is that the direct introduction of water samples poses a series of problems, water must therefore be eliminated before it reaches the analytical column. Hundreds of compounds analysed simultaneously by simple enclosing in an extraction vessel. This is mainly applicable for pharmaceutical industry where it can analyse fatty acids and phospholipids that have many analogues as their UV spectrum is very similar, trace additives in polymers, cleaning validation can be conducted by putting swab sample in an extraction vessel, analysing hundreds of pesticides with good resolution.

Keywords: super critical fluid extraction (SFE), super critical fluid chromatography (SFC), LCMS/MS, GCMS/MS

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Authors: Raymond Dominic Uzoh

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Starch fillers were extracted from three plant sources namely amora tuber (a wild variety of Irish potato), sweet potato and yam starch and their particle size, pH, amylose, and amylopectin percentage decomposition determined accordingly by high performance liquid chromatography (HPLC). The starch was introduced into natural rubber in liquid phase (through gelatinization) by the latex compounding method and compounded according to standard method. The prepared starch/natural rubber composites was characterized by Instron Universal testing machine (UTM) for tensile mechanical properties. The composites was further characterized by x-ray diffraction and crosslink density analysis. The particle size determination showed that amora starch granules have the highest particle size (156 × 47 μm) followed by yam starch (155× 40 μm) and then the sweet potato starch (153 × 46 μm). The pH test also revealed that amora starch has a near neutral pH of 6.9, yam 6.8, and sweet potato 5.2 respectively. Amylose and amylopectin determination showed that yam starch has a higher percentage of amylose (29.68), followed by potato (22.34) and then amora starch with the lowest value (14.86) respectively. The tensile mechanical properties testing revealed that yam starch produced the best tensile mechanical properties followed by amora starch and then sweet potato starch. The structure, crystallinity/amorphous nature of the product composite was confirmed by x-ray diffraction, while the nature of crosslinking was confirmed by swelling test in toluene solvent using the Flory-Rehner approach. This research study has rendered a workable strategy for enhancing interfacial interaction between a hydrophilic filler (starch) and hydrophobic polymeric matrix (natural rubber) yielding moderately good tensile mechanical properties for further exploitation development and application in the rubber processing industry.

Keywords: natural rubber, fillers, starch, amylose, amylopectin, crosslink density

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Authors: O. Delage, H. Bencherif, T. Portafaix, A. Bourdier

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The main purpose of time series analysis is to learn about the dynamics behind some time ordered measurement data. Two approaches are used in the literature to get a better knowledge of the dynamics contained in observation data sequences. The first of these approaches concerns time series decomposition, which is an important analysis step allowing patterns and behaviors to be extracted as components providing insight into the mechanisms producing the time series. As in many cases, time series are short, noisy, and non-stationary. To provide components which are physically meaningful, methods such as Empirical Mode Decomposition (EMD), Empirical Wavelet Transform (EWT) or, more recently, Empirical Adaptive Wavelet Decomposition (EAWD) have been proposed. The second approach is to reconstruct the dynamics underlying the time series as a trajectory in state space by mapping a time series into a set of Rᵐ lag vectors by using the method of delays (MOD). Takens has proved that the trajectory obtained with the MOD technic is equivalent to the trajectory representing the dynamics behind the original time series. This work introduces the singular spectrum decomposition (SSD), which is a new adaptive method for decomposing non-linear and non-stationary time series in narrow-banded components. This method takes its origin from singular spectrum analysis (SSA), a nonparametric spectral estimation method used for the analysis and prediction of time series. As the first step of SSD is to constitute a trajectory matrix by embedding a one-dimensional time series into a set of lagged vectors, SSD can also be seen as a reconstruction method like MOD. We will first give a brief overview of the existing decomposition methods (EMD-EWT-EAWD). The SSD method will then be described in detail and applied to experimental time series of observations resulting from total columns of ozone measurements. The results obtained will be compared with those provided by the previously mentioned decomposition methods. We will also compare the reconstruction qualities of the observed dynamics obtained from the SSD and MOD methods.

Keywords: time series analysis, adaptive time series decomposition, wavelet, phase space reconstruction, singular spectrum analysis

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Authors: H. F. Shi, C. L. Zhang

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Visible-light-responsive g-C3N4/NaNbO3 nanowires photocatalysts were fabricated by introducing polymeric g-C3N4 on NaNbO3 nanowires. The microscopic mechanisms of interface interaction, charge transfer and separation, as well as the influence on the photocatalytic activity of g-C3N4/NaNbO3 composite were systematic investigated. The HR-TEM revealed that an intimate interface between C3N4 and NaNbO3 nanowires formed in the g-C3N4/NaNbO3 heterojunctions. The photocatalytic performance of photocatalysts was evaluated for CO2 reduction under visible-light illumination. Significantly, the activity of g-C3N4/NaNbO3 composite photocatalyst for photoreduction of CO2 was higher than that of either single-phase g-C3N4 or NaNbO3. Such a remarkable enhancement of photocatalytic activity was mainly ascribed to the improved separation and transfer of photogenerated electron-hole pairs at the intimate interface of g-C3N4/NaNbO3 heterojunctions, which originated from the well-aligned overlapping band structures of C3N4 and NaNbO3. Pt loaded NaNbO3-xNx (Pt-NNON), a visible-light-sensitive photocatalyst, was synthesized by an in situ photodeposition method from H2PtCl6•6H2O onto NaNbO3-xNx (NNON) sample. Pt-NNON exhibited a much higher photocatalytic activity for gaseous 2-propanol (IPA) degradation under visible-light irradiation in contrast to NNON. The apparent quantum efficiency (AQE) of Pt-NNON sample for IPA photodegradation achieved up to 8.6% at the wavelength of 419 nm. The notably enhanced photocatalytic performance was attributed to the promoted charge separation and transfer capability in the Pt-NNON system. This work suggests that surface nanosteps possibly play an important role as an electron transfer at high way, which facilitates to the charge carrier collection onto Pt rich zones and thus suppresses recombination between photogenerated electrons and holes. This method can thus be considered as an excellent strategy to enhance photocatalytic activity of organic decomposition in addition to the commonly applied noble metal doping method.

Keywords: CO2 reduction, NaNbO3, nanowires, g-C3N4

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Authors: William C. Alexander

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The oscillating water column (OSC) wave energy converter (WEC) with deep water reactance (DWR) consists of a large hollow sphere filled with seawater at the base, referred to as the ‘stabilizer’, a hollow cylinder at the top of the device, with a said cylinder having a bottom open to the sea and a sealed top save for an orifice which leads to an air turbine, and a long, narrow rod connecting said stabilizer with said cylinder. A small amount of ballast at the bottom of the stabilizer and a small amount of floatation in the cylinder keeps the device upright in the sea. The floatation is set such that the mean water level is nominally halfway up the cylinder. The entire device is loosely moored to the seabed to keep it from drifting away. In the presence of ocean waves, seawater will move up and down within the cylinder, producing the ‘oscillating water column’. This gives rise to air pressure within the cylinder alternating between positive and negative gauge pressure, which in turn causes air to alternately leave and enter the cylinder through said top-cover situated orifice. An air turbine situated within or immediately adjacent to said orifice converts the oscillating airflow into electric power for transport to shore or elsewhere by electric power cable. Said oscillating air pressure produces large up and down forces on the cylinder. Said large forces are opposed through the rod to the large mass of water retained within the stabilizer, which is located deep enough to be mostly free of any wave influence and which provides the deepwater reactance. The cylinder and stabilizer form a spring-mass system which has a vertical (heave) resonant frequency. The diameter of the cylinder largely determines the power rating of the device, while the size (and water mass within) of the stabilizer determines said resonant frequency. Said frequency is chosen to be on the lower end of the wave frequency spectrum to maximize the average power output of the device over a large span of time (such as a year). The upper portion of the device (the cylinder) moves laterally (surge) with the waves. This motion is accommodated with minimal loading on the said rod by having the stabilizer shaped like a sphere, allowing the entire device to rotate about the center of the stabilizer without rotating the seawater within the stabilizer. A full-scale device of this type may have the following dimensions. The cylinder may be 16 meters in diameter and 30 meters high, the stabilizer 25 meters in diameter, and the rod 55 meters long. Simulations predict that this will produce 1,400 kW in waves of 3.5-meter height and 12 second period, with a relatively flat power curve between 5 and 16 second wave periods, as will be suitable for an open-ocean location. This is nominally 10 times higher power than similar-sized WEC spar buoys as reported in the literature, and the device is projected to have only 5% of the mass per unit power of other OWC converters.

Keywords: oscillating water column, wave energy converter, spar bouy, stabilizer

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Authors: Mohammed Badereldien, Rezk Diab, Mohamoud Ali, Ayman Aboelkassem

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The stone surfaces of historical architectural heritage in Egypt are under threat from of various environmental factors such as temperature fluctuation, humidity, pollution, and microbes. Due to these factors, the facades of buildings are deteriorating deformation and disfiguration of external decoration and the formation of black accretion also often from the stone works. The aim of this study is to evaluate the effectiveness of CaCO₃ nano-particles as consolidation and protection material for calcareous stone monuments. Selected tests were carried out in order to estimate the superficial consolidating and protective effect of the treatment. When applied the nanoparticles dispersed in the acrylic copolymer; poly ethylmethacrylate (EMA)/methylacrylate (MA) (70/30, respectively) (EMA)/methylacrylate (MA) (70/30, respectively). The synthesis process of CaCO₃ nanoparticles/polymer nano-composite was prepared using in situ emulsion polymerization system. The consolidation and protection were characterized by TEM, while the penetration depth, re-aggregating effects of the deposited phase, and the surface morphology before and after treatment were examined by SEM (Scanning Electron Microscopy). Improvement of the stones' mechanical properties was evaluated by compressive strength tests. Changes in water-interaction properties were evaluated by water absorption capillarity measurements, and colorimetric measurements were used to evaluate the optical appearance. Together the results appear to demonstrate that CaCO₃/polymer nanocomposite is an efficient material for the consolidation of limestone architecture and monuments. As compared with samples treated with pure acrylic copolymer without Calcium carbonate nanoparticles, for example, CaCO₃ nanoparticles are completely compatible, strengthening limestone against thermal aging and improving its mechanical properties.

Keywords: calcium carbonate nanoparticles, consolidation, nanocomposites, calcareous stone, colorimetric measurements, compressive strength

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Authors: Adetokunbo Ademola Falade, Oluwatoyin Olakunle Akinsete, Hussein Omeiza Aliu

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Solvent-aided dilution processes are often employed to recover bitumen by reducing its viscosity. In this study, methanol, toluene, and xylene were investigated as potential hydrocarbon solvents for solvent-aided hydrocarbon recovery of Agbabu bitumen. Solubility, Viscosity, and Saturate, Aromatic, Resin and Asphaltene (SARA) Analysis tests were carried out to determine the solubility of the bitumen in the solvents, the viscosity, and the SARA fraction of the natural bitumen and bitumen-solvent mixtures. Agbabu bitumen was found to have a high content of saturates and aromatics. Viscosity decreases as pressure increases, while solubility reduces as temperature increases. The experimental diffusivity of the sample decreases with temperature and increases with pressure, indicating that the presence of additional solvent molecules in the oil phase facilitates diffusion. Agbabu bitumen was found to be most soluble in toluene, and its viscosity was reduced most in it. Xylene exhibited a similar effect as toluene on the sample, though lesser but better than methanol. Methanol reduced the saturated content and significantly raised the asphaltene content, keeping the mixture viscosity high, a condition that, in turn, favors its colloidal stability. The colloidal instability index (CII) values, which account for the asphaltene stability of the mixture, show that the bitumen-methanol system with a CII of 0.874 will have mild asphaltene deposit issues while others are unstable. This approach of combining multiple tests with the CII can accurately predict the behavior of Agbabu bitumen in solvents and enhance the decision on the choice of bitumen recovery technology.

Keywords: asphaltene, bitumen, diffusivity, hydrocarbon solvent, SARA

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Authors: Yu-Chieh Chen, Li-Yun Wang, Chi-Chih Chen, Huy Hùng Đào, Ya-Mei Chen, Ming-Chu Cheng, Wen-Bin Chung, Hso-Chi Chaung, Guan-Ming Ke

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Many recent researches have demonstrated that CD154, a protein primarily expressed on activated T cell molecules, has potentially acted as a molecular adjuvant to improve the immunogenicity of subunit vaccines against viral infections. Classical swine fever (CSF) affects the swine industry worldwide that is one of the most devastating and highly contagious pig diseases. It is listed by the World Organization for Animal Health (OIE) as an infectious animal disease that must be reported. Although pigs vaccinated with subunit vaccines can be differentially diagnosed from those infected animals, subunit vaccines usually need adjuvants to enhance and elicit immune responses. In this study, CD154 was linked with CSFV E2 sequences and then expressed in CHO cells to produce the fusion protein as E2-CD154. The porcine specific CpG adjuvant was also used in one of the formulations. The specific pathogen-free pigs (SPF) at the age of 4-week-old were randomly separated into four groups, vaccinated with E2-CpG, E2-CD154, E2-CD154-CpG or the commercial Bayovac® CSF-E2 vaccine and boosted two weeks after primary vaccination. The results showed that the percentages of CD4+ and CD4+IL2+ in peripheral blood mononuclear cells (PBMC) in E2-CD154 vaccinated piglets seven days after primary vaccination were gained by 1-5% relative to the control group. In addition, the percentages of CD4+IFNγ+ T cells had slightly edged up 0.1-0.3% compared with the control group. Also, increased E2-specific IFNγ levels had edged up CD4+CD8+ T cells found in E2-CD154 and E2-CD154-CpG groups, particularly in the E2-CD154-CpG group. These results implicate that CD154 may enhance cellular immunity and synergistically act with species-specific CpG adjuvant as a dual-phase adjuvant. Therefore, the CD154 may be beneficial as a promising adjuvant in subunit vaccines.

Keywords: CD154, CpG adjuvant, cellular immunity, subunit vaccine, pig

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Authors: Tamar Grdzelishvili, Zaza Sinauridze

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Introduction: Preeclampsia is a complication of the second trimester of pregnancy, which is characterized by high morbidity and multiorgan damage. Many complex pathogenic mechanisms are now implicated to be responsible for this disease (1). Preeclampsia is one of the leading causes of maternal mortality worldwide. Statistics are enough to convince you of the seriousness of this pathology: about 100,000 women die of preeclampsia every year. It occurs in 3-14% (varies significantly depending on racial origin or ethnicity and geographical region) of pregnant women, in 75% of cases - in a mild form, and in 25% - in a severe form. During severe pre-eclampsia-eclampsia, perinatal mortality increases by 5 times and stillbirth by 9.6 times. Considering that the only way to treat the disease is to end the pregnancy, the main thing is timely diagnosis and prevention of the disease. Identification of high-risk pregnant women for PE and giving prophylaxis would reduce the incidence of preterm PE. First-trimester screening model developed by the Fetal Medicine Foundation (FMF), which uses the Bayes-theorem to combine maternal characteristics and medical history together with measurements of mean arterial pressure, uterine artery pulsatility index, and serum placental growth factor, has been proven to be effective and have superior screening performance to that of traditional risk factor-based approach for the prediction of PE (2) Methods: Retrospective single center screening study. The study population consisted of women from the Tbilisi maternity hospital “Pineo medical ecosystem” who met the following criteria: they spoke Georgian, English, or Russian and agreed to participate in the study after discussing informed consent and answering questions. Prior to the study, the informed consent forms approved by the Institutional Review Board were obtained from the study subjects. Early assessment of preeclampsia was performed between 11-13 weeks of pregnancy. The following were evaluated: anamnesis, dopplerography of the uterine artery, mean arterial blood pressure, and biochemical parameter: Pregnancy-associated plasma protein A (PAPP-A). Individual risk assessment was performed with performed by Fast Screen 3.0 software ThermoFisher scientific. Results: A total of 513 women were recruited and through the study, 51 women were diagnosed with preeclampsia (34.5% in the pregnant women with high risk, 6.5% in the pregnant women with low risk; P<0.000 1). Conclusions: First-trimester screening combining maternal factors with uterine artery Doppler, blood pressure, and pregnancy-associated plasma protein-A is useful to predict PE in a routine care setting. More patient studies are needed for final conclusions. The research is still ongoing.

Keywords: first-trimester, preeclampsia, screening, pregnancy-associated plasma protein

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Authors: Mansoor Soomro

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The evolution of power electronic equipment has been pivotal in making industrial processes productive, efficient and safe. Despite its attractive features, it has been due to nonlinear loads which make it vulnerable to power quality conditions. Harmonics is one of the power quality problem in which the harmonic frequency is integral multiple of supply frequency. Therefore, the supply voltage and supply frequency do not last within their tolerable limits. As a result, distorted current and voltage waveform may appear. Attributes of low power quality confirm that an electrical device or equipment is likely to malfunction, fail promptly or unable to operate under all applied conditions. The electrical power system is designed for delivering power reliably, namely maximizing power availability to customers. However, power quality events are largely untracked, and as a result, can take out a process as many as 20 to 30 times a year, costing utilities, customers and suppliers of load equipment, a loss of millions of dollars. The ill effects of current harmonics reduce system efficiency, cause overheating of connected equipment, result increase in electrical power and air conditioning costs. With the passage of time and the rapid growth of power electronic converters has highlighted the damages of current harmonics in the electrical power system. Therefore, it has become essential to address the bad influence of current harmonics while planning any suitable changes in the electrical installations. In this paper, an effort has been made to mitigate the effects of dominant 3rd order current harmonics. Passive filtering technique with six pulse multiplication converter has been employed to mitigate them. Since, the standards of power quality are to maintain the supply voltage and supply current within certain prescribed standard limits. For this purpose, the obtained results are validated as per specifications of IEEE 519-1992 and IEEE 519-2014 performance standards.

Keywords: current harmonics, power quality, passive filters, power electronic converters

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Authors: Susan Lanz, Gary T. Burke, Omid Omidvar

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The intention to transfer ownership control across family generations is acknowledged to be central to developing a theoretical understanding of how family businesses differ and are distinct as a business group. However, in practice, most business-owning families face challenges to transfer their business ownership from one family generation to the next. To date, researchers have paid little attention to how and when ownership is passed across family generations and what the dynamics of such transitions are. This is primarily due to the prevailing assumption that ownership transfer is an unimportant and legalistic issue that occurs within a wider family management succession process. Yet, the limited evidence available suggests that family ownership transfer occurs inside and outside of the management succession process and is a difficult process for business-owning families to navigate. As a result, many otherwise viable family businesses are closing, leading to unnecessary loss of jobs and knowledge. This qualitative paper examines how family members understand and navigate the ownership transfer process. This study uses an inductive qualitative research design, conducted through in-depth interviews within eight business-owning families. It draws on family development theory and shows how a wide range of family-related events and dynamics outside of family business involvement underlie and shape the ownership transfer process. The findings extend the theory on how these events trigger ownership transfer and how they shape the ownership meanings held within business-owning families. This study found that ownership transfer meanings extend beyond that of transferring the legal control and financial appropriation rights of shareholders. The study concludes there are three different stages in the process of ownership transfer -symbolic, re-balancing, and protectionist. Each stage creates distinct family social constructions of the rights of family members to hold business ownership, and each stage occurs within a specific family development phase.

Keywords: business-owning family, family development theory, ownership transfer, process

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Authors: Janice Keener, Christine Houlihan

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Over the last several years, there has been an increase in children identified as having Autism Spectrum Disorder (ASD). Specialists across several disciplines: mental health and medical professionals have been tasked with ensuring accurate and timely evaluations for children with suspected ASD. Due to the nature of the ASD symptom presentation, an interdisciplinary assessment and treatment approach best addresses the needs of the whole child. During the unprecedented COVID-19 Pandemic, clinicians were faced with how to continue with interdisciplinary assessments in a telehealth arena. Instruments that were previously used to assess ASD in-person were no longer appropriate measures to use due to the safety restrictions. For example, The Autism Diagnostic Observation Schedule requires examiners and children to be in very close proximity of each other and if masks or face shields are worn, they render the evaluation invalid. Similar issues arose with the various cognitive measures that are used to assess children such as the Weschler Tests of Intelligence and the Differential Ability Scale. Thus the need arose to identify measures that are able to be safely and accurately administered using safety guidelines. The incidence of ASD continues to rise over time. Currently, the Center for Disease Control estimates that 1 in 59 children meet the criteria for a diagnosis of ASD. The reasons for this increase are likely multifold, including changes in diagnostic criteria, public awareness of the condition, and other environmental and genetic factors. The rise in the incidence of ASD has led to a greater need for diagnostic and treatment services across the United States. The uncertainty of the diagnostic process can lead to an increased level of stress for families of children with suspected ASD. Along with this increase, there is a need for diagnostic clarity to avoid both under and over-identification of this condition. Interdisciplinary assessment is ideal for children with suspected ASD, as it allows for an assessment of the whole child over the course of time and across multiple settings. Clinicians such as Psychologists and Developmental Pediatricians play important roles in the initial evaluation of autism spectrum disorder. An ASD assessment may consist of several types of measures such as standardized checklists, structured interviews, and direct assessments such as the ADOS-2 are just a few examples. With the advent of telehealth clinicians were asked to continue to provide meaningful interdisciplinary assessments via an electronic platform and, in a sense, going to the family home and evaluating the clinical symptom presentation remotely and confidently making an accurate diagnosis. This poster presentation will review the benefits, limitations, and interpretation of these various instruments. The role of other medical professionals will also be addressed, including medical providers, speech pathology, and occupational therapy.

Keywords: Autism Spectrum Disorder Assessments, Interdisciplinary Evaluations , Tele-Assessment with Autism Spectrum Disorder, Diagnosis of Autism Spectrum Disorder

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Authors: Einat E. Peles, Shaul Schreiber, Miriam Adelson

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Background: Since established more than 50 years ago, methadone maintenance treatment (MMT) is the most effective treatment for opioid addiction, a chronic relapsing brain disorder that became an epidemic in western societies. Treatment includes daily individual optimal medication methadone dose (a long acting mu opioid receptor full agonist), accompanied with psychosocial therapy. It is well established that the longer retention in treatment the better outcome and survival occur. It reduces the likelihood to infectious diseases and overdose death that associated with drug injecting, enhanced social rehabilitation and eliminate criminal activity, and lead to healthy productive life. Aim: To evaluate predictors for long term retention in treatment we analyzed our prospective follow up of a major MMT clinic affiliated to a big tertiary medical center. Population Methods: Between June 25, 1993, and June 24, 2016, all 889 patients ( ≥ 18y) who ever admitted to the clinic were prospectively followed-up until May 2017. Duration in treatment from the first admission until the patient quit treatment or until the end of follow-up (24 years) was taken for calculating cumulative retention in treatment using survival analyses (Kaplan Meier) with log-rank and Cox regression for multivariate analyses. Results: Of the 889 patients, 25.2% were females who admitted to treatment at younger age (35.0 ± 7.9 vs. 40.6 ± 9.8, p < .0005), but started opioid usage at same age (22.3 ± 6.9). In addition to opioid use, on admission to MMT 58.5% had positive urine for benzodiazepines, 25% to cocaine, 12.4% to cannabis and 6.9% to amphetamines. Hepatitis C antibody tested positive in 55%, and HIV in 7.8% of the patients and 40%. Of all patients, 75.7% stayed at least one year in treatment, and of them, 67.7% stopped opioid usage (based on urine tests), and a net reduction observed in all other substance abuse (proportion of those who stopped minus proportion of those who have started). Long term retention up to 24 years was 8.0 years (95% Confidence Interval (CI) 7.4-8.6). Predictors for longer retention in treatment (Cox regression) were being older on admission ( ≥ 30y) Odds Ratio (OR) =1.4 (CI 1.1-1.8), not abusing opioids after one year OR=1.8 (CI 1.5-2.1), not abusing benzodiazepine after one year OR=1.7 (CI 1.4-2.1) and treating with methadone dose ≥ 100mg/day OR =1.8 (CI 1.5-2.3). Conclusions: Treating and following patients over 24 years indicate success of two main outcomes, high rate of retention after one year (75.7%) and high proportion of opiate abuse cessation (67.7%). As expected, longer cumulative retention was associated with patients treated with high adequate methadone dose that successfully result in opioid cessation. Based on these findings, in order to reduce morbidity and mortality, we find the establishment of more MMT clinics within a general hospital, a most urgent necessity.

Keywords: methadone maintenance treatment, epidemic, opioids, retention

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Authors: Fitim Sadiku, Mjellma Rexhepi, Kreshnik Grezda, Jonijana Sadiku Tigani, Merita Qorolli, Blerta Rexhepi-Kelmendi, Zelie Sadiku, Laura Cakolli

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Background: According to the European Alliance of Associations for Rheumatology (EULAR), biologics should be considered alongside traditional treatments in Ankylosing Spondylitis (AS) patients with persistently high disease activity that directly affects functional capacity. Unfortunately, Kosovo’s health system only offers continuous treatment with etanercept (ETN), and most of the patients with AS are referred to be treated with this biological substance. Objectives: This study aims to explore the relationship between comorbidity, disease activity, and functional capacity in AS patients undergoing ETN treatment in Kosovo. Methods: In this cross-sectional study, we included patients diagnosed with AS who were being treated with ETN 50mg per week for at least 6 months at the Rheumatology Clinic of the University Clinical Center of Kosovo. Patients under 18, pregnant women, and patients with spinal fractures were excluded. This study was approved by the Ethics Committee of the Faculty of Medicine, University of Prishtina and a consent form was signed by patients for participating in the study. We collected data (September-December 2023) about socio-demographics and disease history. Moreover, the presence of comorbidities was measured by the Comorbidity Charlson Index; the disease activity was measured by the Ankylosing Spondylitis Disease Activity Score (ASDAS), and the functional capacity was measured by the Bath Ankylosing Spondylitis Functional Index (BASFI). Results: A total of 31 out of the 39 patients with AS receiving etanercept were included aged 18 to above 65 years (M= 40 years, SD= 14.39), and 87% were male. Diagnose delay was, on average, 7 years from the first symptoms (min-max= 0-24), while the disease duration on average was 7.5 years (min-max= 1- 50). Treatment duration with etanercept was from 0.5 to 6 years. The results indicate a significant positive correlation between comorbidity and BASFI (r= .615, p= .01) and disease activity. Additionally, a significant positive correlation exists between disease activity and BASFI (r= .507, p= .004). Regression analysis highlights the significance of both comorbidity and disease activity as predictors of patients’ functional capacity F (1, 29) = 10.047, p= .05 and F(1, 29) = 17.678, p= .01. No notable gender differences were observed. The study found no significant variations in comorbidity, disease activity, and functional capacity concerning the duration of ETN treatment. Conclusion: We found that in Kosovo, it takes at least 7 years for individuals to be diagnosed with AS from the first-time symptoms are experienced. This study showed that there is a positive correlation between comorbidity and functional capacity, disease activity and functional capacity in patients with AS undergoing etanercept treatment. Furthermore, results showed that comorbidity and disease activity are predictors of the functional status of the patients with AS receiving ETN. Gender and treatment duration with etanercept did not show any significant variations in these patients.

Keywords: ankylosing spondilitis, etanercept, physical wellbeing, comorbidities

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Authors: Cory B. Lord

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Falls among the elderly population has become an area of concern in healthcare today. The negative impacts of falls lead to increased morbidity, mortality, and financial burdens for both patients and healthcare systems. Falls in the United States is reported at an annual rate of 36 million in those aged 65 and older. Each year, one out of four people in this age group will suffer a fall, with 20% of these falls causing injury. The setting for this Doctor of Nursing Practice (DNP) project was a memory care unit in an assisted living community, as these facilities house cognitively impaired older adults. These communities lack fall prevention programs; therefore, the need exists to add to the body of knowledge to positively impact this population. The objective of this project was to reduce fall rates through the implementation of the Center for Disease Control and Prevention (CDC) STEADI (stopping elderly accidents, deaths, and injuries) program. The DNP project performed was a quality improvement pilot study with a pre and post-test design. This program was implemented in the memory care setting over 12 weeks. The project included an educational session for staff and a fall risk assessment with appropriate resident referrals. The three aims of the DNP project were to reduce fall rates among the elderly aged 65 and older who reside in the memory care unit, increase staff knowledge of STEADI fall prevention measures after an educational session, and assess the willingness of memory care unit staff to adopt an evidence-based a fall prevention program. The Donabedian model was used as a guiding conceptual framework for this quality improvement pilot study. The fall rate data for 12 months before the intervention was evaluated and compared to post-intervention fall rates. The educational session comprised of a pre and post-test to assess staff knowledge of the fall prevention program and the willingness of staff to adopt the fall prevention program. The overarching goal was to reduce falls in the elderly population who live in memory care units. The results of the study showed, on average that the fall rate during the implementation period of STEADI (μ=6.79) was significantly lower when compared to the prior 12 months (μ= 9.50) (p=0.02, α = 0.05). The mean staff knowledge scores improved from pretest (μ=77.74%) to post-test (μ=87.42%) (p=0.00, α= 0.05) after the education session. The results of the willingness to adopt a fall prevention program were scored at 100%. In summation, implementing the STEADI fall prevention program can assist in reducing fall rates for residents aged 65 and older who reside in a memory care setting.

Keywords: dementia, elderly, falls, STEADI

Procedia PDF Downloads 119

Authors: Ravshan A. Ibadov, Sardor Kh. Ibragimov

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Objective. The aim of the study was to optimize the protocol of cardiopulmonary resuscitation (CPR) after cardiovascular surgical interventions. Methods. The experience of CPR conducted on patients after cardiovascular surgical interventions in the Department of Intensive Care and Resuscitation (DIR) of the Republican Specialized Scientific-Practical Medical Center of Surgery named after Academician V. Vakhidov is presented. The key to the new approach is the rapid elimination of reversible causes of cardiac arrest, followed by either defibrillation or electrical cardioversion (depending on the situation) before external heart compression, which may damage sternotomy. Careful use of adrenaline is emphasized due to the potential recurrence of hypertension, and timely resternotomy (within 5 minutes) is performed to ensure optimal cerebral perfusion through direct massage. Out of 32 patients, cardiac arrest in the form of asystole was observed in 16 (50%), with hypoxemia as the cause, while the remaining 16 (50%) experienced ventricular fibrillation caused by arrhythmogenic reactions. The age of the patients ranged from 6 to 60 years. All patients were evaluated before the operation using the ASA and EuroSCORE scales, falling into the moderate-risk group (3-5 points). CPR was conducted for cardiac activity restoration according to the American Heart Association and European Resuscitation Council guidelines (Ley SJ. Standards for Resuscitation After Cardiac Surgery. Critical Care Nurse. 2015;35(2):30-38). The duration of CPR ranged from 8 to 50 minutes. The ARASNE II scale was used to assess the severity of patients' conditions after CPR, and the Glasgow Coma Scale was employed to evaluate patients' consciousness after the restoration of cardiac activity and sedation withdrawal. Results. In all patients, immediate chest compressions of the necessary depth (4-5 cm) at a frequency of 100-120 compressions per minute were initiated upon detection of cardiac arrest. Regardless of the type of cardiac arrest, defibrillation with a manual defibrillator was performed 3-5 minutes later, and adrenaline was administered in doses ranging from 100 to 300 mcg. Persistent ventricular fibrillation was also treated with antiarrhythmic therapy (amiodarone, lidocaine). If necessary, infusion of inotropes and vasopressors was used, and for the prevention of brain edema and the restoration of adequate neurostatus within 1-3 days, sedation, a magnesium-lidocaine mixture, mechanical intranasal cooling of the brain stem, and neuroprotective drugs were employed. A coordinated effort by the resuscitation team and proper role allocation within the team were essential for effective cardiopulmonary resuscitation (CPR). All these measures contributed to the improvement of CPR outcomes. Conclusion. Successful CPR following cardiac surgical interventions involves interdisciplinary collaboration. The application of an optimized CPR standard leads to a reduction in mortality rates and favorable neurological outcomes.

Keywords: cardiac surgery, cardiac arrest, resuscitation, critically ill patients

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Authors: Sanjal Gavande, Thomas Mazzuchi, Shahram Sarkani

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In a complex aerospace operational environment, identifying failures in a procedure involving multiple human-machine interactions are difficult. These failures could lead to accidents causing loss of hardware or human life. The likelihood of failure further increases if operational procedures are tested for a novel system with multiple human-machine interfaces and with no prior performance data. The existing approach in the literature of reviewing complex operational tasks in a flowchart or tabular form doesn’t provide any insight into potential system failures due to human decision-making ability. To address these challenges, this research explores an agent-based simulation approach for reliability assessment and fault detection in complex human-machine systems while utilizing a human decision-making model. The simulation will predict the emergent behavior of the system due to the interaction between humans and their decision-making capability with the varying states of the machine and vice-versa. Overall system reliability will be evaluated based on a defined set of success-criteria conditions and the number of recorded failures over an assigned limit of Monte Carlo runs. The study also aims at identifying high-likelihood failure locations for the system. The research concludes that system reliability and failures can be effectively calculated when individual human and machine agent states are clearly defined. This research is limited to the operations phase of a system lifecycle process in an aerospace environment only. Further exploration of the proposed agent-based and human decision-making model will be required to allow for a greater understanding of this topic for application outside of the operations domain.

Keywords: agent-based model, complex human-machine system, human decision-making model, system reliability assessment

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Authors: Intisar Al Busaidi, Rashid Al Maamari, Daowoud Al Mahroqi, Mahvash Karimi

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In recent years, some research studies have been performed on the hybrid application of polymer and low salinity water flooding (LSWF). Numerous technical and economic benefits of low salinity polymer flooding (LSPF) have been reported. However, as with any EOR technology, there are various risks involved in using LSPF. Ions exchange between porous media and brine is one of the Crude oil/ brine/ rocks (COBR) reactions that is identified as a potential risk in LSPF. To the best of our knowledge, this conclusion was drawn based on bulk rheology measurements, and no explanation was provided on how water chemistry changed in the presence of polymer. Therefore, this study aimed to understand rock/ brine interactions with high and low salinity brine in the absence and presence of polymer with Omani reservoir core plugs. Many single-core flooding experiments were performed with low and high salinity polymer solutions to investigate the influence of partially hydrolyzed polyacrylic amide with different brine salinities on cation exchange reactions. Ion chromatography (IC), total organic carbon (TOC), rheological, and pH measurements were conducted for produced aqueous phase. A higher increase in pH and lower polymer adsorption was observed in LSPF compared with conventional polymer flooding. In addition, IC measurements showed that all produced fluids in the absence and presence of polymer showed elevated Ca²⁺, Mg²⁺, K+, Cl- and SO₄²⁻ ions compared to the injected fluids. However, the divalent cations levels, mainly Ca²⁺, were the highest and remained elevated for several pore volumes in the presence of LSP. The results are in line with rheological measurements where the highest viscosity reduction was recorded with the highest level of Ca²⁺ production. Despite the viscosity loss due to cation exchange reactions, LSP can be an attractive alternative to conventional polymer flooding in the Marmul field.

Keywords: polymer, ions, exchange, recovery, low salinity

Procedia PDF Downloads 102

Authors: Rui He, Seung-Eun Baik, Min-Jae Lee, Myong-Hoon Lee

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The polarizer is one of the most essential optical elements in LCDs. Currently, the most widely used polarizers for LCD is the derivatives of the H-sheet polarizer. There is a need for coatable polarizers which are much thinner and more stable than H-sheet polarizers. One possible approach to obtain thin, stable, and coatable polarizers is based on the use of highly ordered guest-host system. In our research, we aimed to fabricate coatable polarizer based on highly ordered liquid crystalline monomer and dichroic dye ‘guest-host’ system, in which the anisotropic absorption of light could be achieved by aligning a dichroic dye (guest) in the cooperative motion of the ordered liquid crystal (host) molecules. Firstly, we designed and synthesized a new reactive liquid crystalline monomer containing polymerizable acrylate groups as the ‘host’ material. The structure was confirmed by 1H-NMR and IR spectroscopy. The liquid crystalline behavior was studied by differential scanning calorimetry (DSC) and polarized optical microscopy (POM). It was confirmed that the monomers possess highly ordered smectic phase at relatively low temperature. Then, the photocurable ‘guest-host’ system was prepared by mixing the liquid crystalline monomer, dichroic dye and photoinitiator. Coatable polarizers were fabricated by spin-coating above mixture on a substrate with alignment layer. The in-situ photopolymerization was carried out at room temperature by irradiating UV light, resulting in the formation of crosslinked structure that stabilized the aligned dichroic dye molecules. Finally, the dichroic ratio (DR), order parameter (S) and polarization efficiency (PE) were determined by polarized UV/Vis spectroscopy. We prepared the coatable polarizers by using different type of dichroic dyes to meet the requirement of display application. The results reveal that the coatable polarizers at a thickness of 8μm exhibited DR=12~17 and relatively high PE (>96%) with the highest PE=99.3%, which possess potential for the LCD or flexible display applications.

Keywords: coatable polarizer, display, guest-host, liquid crystal

Procedia PDF Downloads 248

Authors: H. Shokouhmand, M. Tajerian

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A numerical investigation of laminar forced convection flows through a square cross section micro heat pipe by applying electrohydrodynamic (EHD) field has been studied. In the present study, pentane is selected as working fluid. Temperature and velocity profiles and heat transfer enhancement in the micro heat pipe by using EHD field at the two-dimensional and single phase fluid flow in steady state regime have been numerically calculated. At this model, only Coulomb force is considered. The study has been carried out for the Reynolds number 10 to 100 and EHD force field up to 8 KV. Coupled, non-linear equations governed on the model (continuity, momentum, and energy equations) have been solved simultaneously by CFD numerical methods. Steady state behavior of affecting parameters, e.g. friction factor, average temperature, Nusselt number and heat transfer enhancement criteria, have been evaluated. It has been observed that by increasing Reynolds number, the effect of EHD force became more significant and for smaller Reynolds numbers the rate of heat transfer enhancement criteria is increased. By obtaining and plotting the mentioned parameters, it has been shown that the EHD field enhances the heat transfer process. The numerical results show that by increasing EHD force field the absolute value of Nusselt number and friction factor increases and average temperature of fluid flow decreases. But the increasing rate of Nusselt number is greater than increasing value of friction factor, which makes applying EHD force field for heat transfer enhancement in micro heat pipes acceptable and applicable. The numerical results of model are in good agreement with the experimental results available in the literature.

Keywords: micro heat pipe, electrohydrodynamic force, Nusselt number, average temperature, friction factor

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Authors: Pranil Kumar Upadhayaya

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While peace is dividend to tourism, tourism can also be a vital force for world peace. The existing body of knowledge on a tripartite complex nexus between tourism, peace and conflict reveals that tourism is benefactor to peace and sensitive to conflict. By contextualizing the ongoing sporadic structural conflict in the transitional phase in the aftermath of a decade long (1996-2006), Maoist armed conflict in Nepal, the purpose of this study is to explore the potentials of tourism in peace-building. The outcomes of this research paper is based on the mixed methods of research (qualitative and quantitative). Though the armed conflict ended with the comprehensive peace agreement in 2006 but there is constant manifestations of non-violent structural conflicts, which continue to threaten the sustainability of tourism industry. With the persistent application of coping strategies, tourism is found resilient during the ongoing structural political conflict. The strong coping abilities of the private sector of tourism industry have also intersected with peace-building efforts with more reactive and less proactive (pro-peace) engagements. This paper ascertains about the application of the ‘theory of tourism security’ by Nepalese tourism industry while coping with conflict and reviving, and sustaining. It reveals that the multiple verities of tourism at present has heterogeneous degree of peace potentials. The opportunities of ‘peace through tourism’ can be promoted subject to its molding with responsible, sustainable and participatory characteristics. This paper comes out with pragmatic policy recommendations for strengthening the position of tourism as a true peace-builder: (a) a broad shift from mainstream conventional tourism to the community based rural with local participation and ownership to fulfill Nepal’s potentials for peace, and (b) building and applications of the managerial and operational codes of conducts for owners and workers (labor unions) at all tourism enterprises and strengthen their practices.

Keywords: code of conduct, community based tourism, conflict, peace-building, tourism

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Authors: Yebeen Ji, Jimin Yun, Kwonhoo Kim

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Magnesium alloys were limited for industrial applications due to having a limited slip system and high plastic anisotropy. It has been known that specific textures were formed during processing (rolling, etc.), and These textures cause poor formability. To solve these problems, many researchers have studied controlling texture by adding rare-earth elements. However, the high cost limits their use; therefore, alternatives are needed to replace them. Although Pb addition doesn’t directly improve magnesium properties, it has been known to suppress the diffusion of other alloying elements and reduce grain boundary energy. These characteristics are similar to the additions of rare-earth elements, and a similar texture behavior is expected as well. However, there is insufficient research on this. Therefore, this study investigates the behavior of texture and microstructure development after adding Pb to magnesium. This study compared and analyzed AZ61 alloy and Mg-15wt%Pb alloy to determine the effect of adding solute elements. The alloy was hot rolled and annealed to form a single phase and initial texture. Afterward, the specimen was set to contraction and elongate parallel to the rolling surface and the rolling direction and then subjected to high-temperature plane strain compression under the conditions of 723K and 0.05/s. Microstructural analysis and texture measurements were performed by SEM-EBSD. The peak stress in the true strain-stress curve after compression was higher in AZ61, but the shape of the flow curve was similar for both alloys. For both alloys, continuous dynamic recrystallization was confirmed to occur during the compression process. The basal texture developed parallel to the compressed surface, and the pole density was lower in the Mg-15wt%Pb alloy. It is confirmed that this change in behavior is because the orientation distribution of recrystallized grains has a more random orientation compared to the parent grains when Pb is added.

Keywords: Mg, texture, Pb, DRX

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Authors: Vahid Bairami Rad

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The intelligentization of agricultural fields can control the temperature, humidity, and variables affecting the growth of agricultural products online and on a mobile phone or computer. Smarting agricultural fields and gardens is one of the best and best ways to optimize agricultural equipment and has a 100 percent direct effect on the growth of plants and agricultural products and farms. Smart farms are the topic that we are going to discuss today, the Internet of Things and artificial intelligence. Agriculture is becoming smarter every day. From large industrial operations to individuals growing organic produce locally, technology is at the forefront of reducing costs, improving results and ensuring optimal delivery to market. A key element to having a smart agriculture is the use of useful data. Modern farmers have more tools to collect intelligent data than in previous years. Data related to soil chemistry also allows people to make informed decisions about fertilizing farmland. Moisture meter sensors and accurate irrigation controllers have made the irrigation processes to be optimized and at the same time reduce the cost of water consumption. Drones can apply pesticides precisely on the desired point. Automated harvesting machines navigate crop fields based on position and capacity sensors. The list goes on. Almost any process related to agriculture can use sensors that collect data to optimize existing processes and make informed decisions. The Internet of Things (IoT) is at the center of this great transformation. Internet of Things hardware has grown and developed rapidly to provide low-cost sensors for people's needs. These sensors are embedded in IoT devices with a battery and can be evaluated over the years and have access to a low-power and cost-effective mobile network. IoT device management platforms have also evolved rapidly and can now be used securely and manage existing devices at scale. IoT cloud services also provide a set of application enablement services that can be easily used by developers and allow them to build application business logic. Focus on yourself. These development processes have created powerful and new applications in the field of Internet of Things, and these programs can be used in various industries such as agriculture and building smart farms. But the question is, what makes today's farms truly smart farms? Let us put this question in another way. When will the technologies associated with smart farms reach the point where the range of intelligence they provide can exceed the intelligence of experienced and professional farmers?

Keywords: food security, IoT automation, wireless communication, hybrid lifestyle, arduino Uno

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Authors: Yang Shen, Yongpan Cheng, Jinliang Xu

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The effective blade cooling is of great significance for improving the performance of turbine. The mist cooling emerges as the promising way compared with the transitional single-phase cooling. In the mist cooling, the injected droplet will evaporate rapidly, and cool down the blade surface due to the absorbed latent heat, hence the lifetime for evaporating droplet becomes critical for design of cooling passages for the blade. So far there have been extensive studies on the droplet evaporation, but usually the isothermal model is applied for most of the studies. Actually the surface cooling effect can affect the droplet evaporation greatly, it can prolong the droplet evaporation lifetime significantly. In our study, a new theoretical model for sessile droplet evaporation with surface cooling effect is built up in toroidal coordinate. Three evaporation modes are analyzed during the evaporation lifetime, include “Constant Contact Radius”(CCR) mode、“Constant Contact Angle”(CCA) mode and “stick-slip”(SS) mode. The dimensionless number E0 is introduced to indicate the strength of the evaporative cooling, it is defined based on the thermal properties of the liquid and the atmosphere. Our model can predict accurately the lifetime of evaporation by validating with available experimental data. Then the temporal variation of droplet volume, contact angle and contact radius are presented under CCR, CCA and SS mode, the following conclusions are obtained. 1) The larger the dimensionless number E0, the longer the lifetime of three evaporation cases is; 2) The droplet volume over time still follows “2/3 power law” in the CCA mode, as in the isothermal model without the cooling effect; 3) In the “SS” mode, the large transition contact angle can reduce the evaporation time in CCR mode, and increase the time in CCA mode, the overall lifetime will be increased; 4) The correction factor for predicting instantaneous volume of the droplet is derived to predict the droplet life time accurately. These findings may be of great significance to explore the dynamics and heat transfer of sessile droplet evaporation.

Keywords: blade cooling, droplet evaporation, lifetime, theoretical analysis

Procedia PDF Downloads 137

Authors: S. Amirhossein Tabatabaei, Abdulghader A. Aldaeef, Mohammad T. Rayhani

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As the permafrost continues to melt in the northern regions due to global warming, a soil-water mixture is left behind with drastically lower strength; a phenomenon that directly impacts the resilience of existing structures and infrastructure systems. The frozen soil-structure interaction, which in ice-poor soils is controlled by both interface shear and ice-bonding, changes its nature into a sole frictional state. Adfreeze, the controlling mechanism in frozen soil-structure interaction, diminishes as the ground temperature approaches zero. The main purpose of this paper is to capture the altered behaviour of frozen interface with respect to rising temperature, especially near melting states. A series of pull-out tests are conducted on model piles inside a cold room to study how the strength parameters are influenced by the phase change in ice-poor soils. Steel model piles, embedded in artificially frozen cohesionless soil, are subjected to both sustained pull-out forces and constant rates of displacement to observe the creep behaviour and acquire load-deformation curves, respectively. Temperature, as the main variable of interest, is increased from a lower limit of -10°C up to the point of melting. During different stages of the temperature rise, both skin deformations and temperatures are recorded at various depths along the pile shaft. Significant reduction of pullout capacity and accelerated creep behaviour is found to be the primary consequences of rising temperature. By investigating the different pull-out capacities and deformations measured during step-wise temperature change, characteristics of the transition from frozen to unfrozen soil-structure interaction are studied.

Keywords: Adfreeze, frozen soil-structure interface, ice-poor soils, pull-out capacity, warming permafrost

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Authors: Sadman Durlov, Aditya Ganesh-Ram, Hamidreza Hekmatjou, Md Najmus Salehin, Nora Shayesteh Ameri

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In the field of additive manufacturing, tungsten stands out for its exceptional resistance to high temperatures, making it an ideal candidate for use in extreme conditions. However, its inherent brittleness and vulnerability to thermal cracking pose significant challenges to its manufacturability. This study explores the microstructural evolution of tungsten processed through layer-wise rolling in laser powder bed fusion additive manufacturing, utilizing a comprehensive approach that combines advanced simulation techniques with empirical research. We aim to uncover the complex processes of plastic deformation and microstructural transformations, with a particular focus on the dynamics of grain size, boundary evolution, and phase distribution. Our methodology employs a combination of simulation and experimental data, allowing for a detailed comparison that elucidates the key mechanisms influencing microstructural alterations during the rolling process. This approach facilitates a deeper understanding of the material's behavior under additive manufacturing conditions, specifically in terms of deformation and recrystallization. The insights derived from this research not only deepen our theoretical knowledge but also provide actionable strategies for refining manufacturing parameters to improve the tungsten components' mechanical properties and functional performance. By integrating simulation with practical experimentation, this study significantly enhances the field of materials science, offering a robust framework for the development of durable materials suited for challenging operational environments. Our findings pave the way for optimizing additive manufacturing techniques and expanding the use of tungsten across various demanding sectors.

Keywords: additive manufacturing, layer wise rolling, refractory materials, in-situ microstructure modifications

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Authors: Md Iqbal Hossain, Tahmeed Ahmed, Kenneth H. Brown

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Objective: To assess the effect of community-based follow up, with or without food-supplementation and/or psychosocial stimulation, as an alternative to current hospital-based follow-up of children with moderate-acute-malnutrition (WHZ < -2 to -3) (MAM). Design/methods: The study was conducted at the ICDDR,B Dhaka Hospital and in four urban primary health care centers of Dhaka, Bangladesh during 2005-2007. The efficacy of five different randomly assigned interventions was compared with respect to the rate of completion of follow-up, growth and morbidity in 227 MAM children aged 6-24 months who were initially treated at ICDDR,B for diarrhea and/or other morbidities. The interventions were: 1) Fortnightly follow-up care (FFC) at the ICDDR,B’s outpatient-unit, including growth monitoring, health education, and micro-nutrient supplementation (H-C, n=49). 2) FFC at community follow-up unit (CNFU) [established in the existing urban primary health-care centers close to the residence of the child] but received the same regimen as H-C (C-C, n=53). 3) As per C-C plus cereal-based supplementary food (SF) (C-SF, n=49). The SF packets were distributed on recruitment and at every visit in CNFU [@1 packet/day for 6–11 and 2 packets/day for 12-24 month old children. Each packet contained 20g toasted rice-powder, 10g toasted lentil-powder, 5g molasses, and 3g soy bean oil, to provide a total of ~ 150kcal with 11% energy from protein]. 4) As per C-C plus psychosocial stimulation (PS) (C-PS, n=43). PS consisted of child-stimulation and parental-counseling conducted by trained health workers. 5) As per C-C plus both SF+PS (C-SF+PS, n=33). Results: A total of 227children (48.5% female), with a mean ± SD age of 12.6 ±3.8 months, and WHZ of - 2.53±0.28 enrolled. Baseline characteristics did not differ by treatment group. The rate of spontaneous attendance at scheduled follow-up visits gradually decreased in all groups. Follow-up attendance and gain in weight and length were greater in groups C-SF, C-SF+PS, and C-PS than C-C, and these indicators were observed least in H-C. Children in the H-C group more often suffered from diarrhea (25 % vs. 4-9%) and fever (28% vs. 8-11%) than other groups (p < 0.05). Children who attended at least five of the total six scheduled follow-up visits gained more in weight (median: 0.86 vs. 0.62 kg, p=0.002), length (median: 2.4 vs. 2.0 cm, p=0.009) than those who attended fewer. Conclusions: Community-based service delivery, especially including supplementary food with or without psychosocial stimulation, permits better rehabilitation of children with MAM compared to current hospital outpatients-based care. By scaling the community-based follow-up including food supplementation with or without psychosocial stimulation, it will be possible to rehabilitate a greater number of MAM children in a better way.

Keywords: community-based management, moderate acute malnutrition, psychosocial stimulation, supplementary food

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Authors: Patricia M. Boechler, Heather M. Gautreau

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In this research study, postsecondary students completed an information learning task in an avatar-based 3D virtual learning environment. Three factors were of interest in relation to learning; 1) the influence of collaborative vs. independent conditions, 2) the influence of the spatial arrangement of the virtual environment (linear, random and clustered), and 3) the relationship of individual differences such as spatial skill, general computer experience and video game experience to learning. Students completed pretest measures of prior computer experience and prior spatial skill. Following the premeasure administration, students were given instruction to move through the virtual environment and study all the material within 10 information stations. In the collaborative condition, students proceeded in randomly assigned pairs, while in the independent condition they proceeded alone. After this learning phase, all students individually completed a multiple choice test to determine information retention. The overall results indicated that students in pairs did not perform any better or worse than independent students. As far as individual differences, only spatial ability predicted the performance of students. General computer experience and video game experience did not. Taking a closer look at the pairs and spatial ability, comparisons were made on pairs high/matched spatial ability, pairs low/matched spatial ability and pairs that were mismatched on spatial ability. The results showed that both high/matched pairs and mismatched pairs outperformed low/matched pairs. That is, if a pair had even one individual with strong spatial ability they would perform better than pairs with only low spatial ability individuals. This suggests that, in virtual environments, the specific individuals that are paired together are important for performance outcomes. The paper also includes a discussion of trends within the data that have implications for virtual environment education.

Keywords: avatar-based, virtual environment, paired learning, individual differences

Procedia PDF Downloads 109

Authors: Amira Abdelrasoul

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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 93