Search results for: micro and small enterprises
Commenced in January 2007
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Edition: International
Paper Count: 6893

Search results for: micro and small enterprises

2303 Poverty Status and Determinants of Income Diversification among Rural Households of Pakistan

Authors: Saba Javed, Abdul Majeed Nadeem, Imran Qaiser, Muhammad Asif Kamran, Azka Amin

Abstract:

This study is designed to determine the poverty status and determinants of income diversification in rural areas of Pakistan using cross sectional data of Pakistan Social and Living Standards Measurement (PSLM) for 2010-2011. The variables used for measuring income diversification are demographic indicators, poverty status, and income of households. Foster-Greer-Thorbecke (FGT) poverty measures show that 43.1% poor and 56.9% non-poor resided in rural areas of Pakistan. A Tobit model was employed to examine the determinants of livelihood diversification among households. The result showed that age, gender, marital status, household size and province have significant impact on income diversification. The data show that non-poor and female headed household with higher family size diversify more as compared to poor, male headed household with small size of family members. The place of residence (province used as proxy for place) also plays important role for income diversification as Sindh Province was found more diversified as compared to Punjab and Khyber Pakhtoon Kha (KPK). It is recommended to improve the ways of income diversification among rural household to reduce poverty among them. This can be done by more investment in education with universal access for poor and remote localities households.

Keywords: poverty, income diversification, rural Pakistan, Tobit regression model, FGT

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2302 TCTN2 Maintains the Transition Zone Stability and Controls the Entrance of the Ciliary Membrane Protein into Primary Cilia

Authors: Rueyhung Weng, Chia-En Huang, Jung-Chi-Liao

Abstract:

The transition zone (TZ) serves as a diffusion barrier to regulate the ins and outs of the proteins recruited to the primary cilia. TCTN2 is one of the TZ proteins and its mutation causes Joubert syndrome, a serious multi-organ disease. Despite its important medical relevance, the functions of TCTN2 remain elusive. Here we created a TCTN2 gene deleted retinal pigment epithelial cells (RPE1) using CRISPR/Cas9-based genome editing technique and used this knockout line to reveal roles of TCTN2. TCTN2 knockout RPE1 cells displayed a significantly reduced ciliogenesis or a shortened primary cilium length in the cilium-remaining population. Intraflagellar transport protein IFT88 aberrantly accumulated at the tip of TCTN2 deficient cells. Guanine nucleotide exchange factor Arl13B was mostly absent from the ciliary compartment, with a small population localizing at the ciliary tip. The deficient TZ was corroborated with the mislocalization of two other TZ proteins TMEM67 and MKS1. In addition, TCTN2 deficiency induced TZ impairment led to the suppression of Sonic hedgehog signaling in response to Smoothened (Smo) agonist. Together, depletion of TCTN2 destabilizes other TZ proteins and considerably alters the localization of key transport and signaling-associated proteins, including IFT88, Arl13B, and Smo.

Keywords: CRISPR/Cas9, primary cilia, Sonic hedgehog signaling, transition zone

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2301 The Relationship between EFL Learners' Self-Regulation and Willingness to Communicate

Authors: Mania Nosratinia, Zahra Deris

Abstract:

The purpose of the present study was to investigate the relationship between EFL learners' self-regulation (SR) and willingness to communicate (WTC). To this end, 520 male and female EFL learners, ranging between 19 and 34 years old (Mage = 26), majoring in English Translation, English Language Teaching and English Literature at Islamic Azad University, Fars Province, were randomly selected. They were given two questionnaires: Self-Regulation Questionnaire devised by Brown, Miller, and Lawendowski (1999) and Willingness to Communicate Scale devised by McCroskey and Baer (1985). Preliminarily, pertinent analyses were performed on the data to check the assumptions of normality, linearity, and homoscedasticity. Since the assumption of normality was violated, Spearman's rank-order correlation was employed to probe the relationships between SR and WTC. The results indicated a significant and positive correlation between the two variables, ρ = .56, n = 520, p < .05, which signified a large effect size supplemented by a very small confidence interval (0.503 – 0.619). The results of the Kruskal-Wallis tests indicated that there is a statistically significant difference in WTC score between the different levels of SR, χ2(2) = 157.843, p = 0.000 with a mean rank SR score of 128.13 for low-SR level, 286.64 for mid-SR level, and 341.12 for high-SR level. Also, a post-hoc comparison through running a Dwass-Steel-Critchlow-Fligner indicated significant differences among the SR level groups on WTC scores. Given the findings of the study, the obtained results may help EFL teachers, teacher trainers, and material developers to possess a broader perspective towards the TEFL practice and to take practical steps towards the attainments of the desired objectives and effective instruction.

Keywords: EFL learner, self-regulation, willingness to communicate, relationship

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2300 Metal Binding Phage Clones in a Quest for Heavy Metal Recovery from Water

Authors: Tomasz Łęga, Marta Sosnowska, Mirosława Panasiuk, Lilit Hovhannisyan, Beata Gromadzka, Marcin Olszewski, Sabina Zoledowska, Dawid Nidzworski

Abstract:

Toxic heavy metal ion contamination of industrial wastewater has recently become a significant environmental concern in many regions of the world. Although the majority of heavy metals are naturally occurring elements found on the earth's surface, anthropogenic activities such as mining and smelting, industrial production, and agricultural use of metals and metal-containing compounds are responsible for the majority of environmental contamination and human exposure. The permissible limits (ppm) for heavy metals in food, water and soil are frequently exceeded and considered hazardous to humans, other organisms, and the environment as a whole. Human exposure to highly nickel-polluted environments causes a variety of pathologic effects. In 2008, nickel received the shameful name of “Allergen of the Year” (GILLETTE 2008). According to the dermatologist, the frequency of nickel allergy is still growing, and it can’t be explained only by fashionable piercing and nickel devices used in medicine (like coronary stents and endoprostheses). Effective remediation methods for removing heavy metal ions from soil and water are becoming increasingly important. Among others, methods such as chemical precipitation, micro- and nanofiltration, membrane separation, conventional coagulation, electrodialysis, ion exchange, reverse and forward osmosis, photocatalysis and polymer or carbon nanocomposite absorbents have all been investigated so far. The importance of environmentally sustainable industrial production processes and the conservation of dwindling natural resources has highlighted the need for affordable, innovative biosorptive materials capable of recovering specific chemical elements from dilute aqueous solutions. The use of combinatorial phage display techniques for selecting and recognizing material-binding peptides with a selective affinity for any target, particularly inorganic materials, has gained considerable interest in the development of advanced bio- or nano-materials. However, due to the limitations of phage display libraries and the biopanning process, the accuracy of molecular recognition for inorganic materials remains a challenge. This study presents the isolation, identification and characterisation of metal binding phage clones that preferentially recover nickel.

Keywords: Heavy metal recovery, cleaning water, phage display, nickel

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2299 Physical, Chemical and Mechanical Properties of Different Varieties of Jatropha curcas Cultivated in Pakistan

Authors: Mehmood Ali, Attaullah Khan, Md. Abul Kalam

Abstract:

Petroleum crude oil reserves are going to deplete in future due to the consumption of fossil fuels in transportation and energy generating sector. Thus, increasing the fossil fuel prices and also causing environmental degradation issues such as climate change and global warming due to air pollution. Therefore, to tackle these issues the environmentally friendly fuels are the potential substitute with lower emissions of toxic gases. A non-edible vegetable oilseed crop, Jatropha curcas, from different origins such as Malaysia, Thailand and India were cultivated in Pakistan. The harvested seeds physical, chemical and mechanical properties were measured, having an influence on the post-harvesting machines design parameters for dehulling, storing bins, drying, oil extraction from seeds with a screw expeller and in-situ transesterification reaction to produce biodiesel fuel. The seed variety from Thailand was found better in comparison of its properties with other varieties from Malaysia and India. The seed yield from these three varieties i.e. Malaysia, Thailand and India were 829, 943 and 735 kg/ acre/ year respectively. While the oil extraction yield from Thailand variety seed was found higher (i.e. 32.61 % by wt.) as compared to other two varieties from Malaysia and India were 27.96 and 24.96 % by wt respectively. The physical properties investigated showed the geometric mean diameter of seeds from three varieties Malaysia, Thailand and India were 11.350, 10.505 and 11.324 mm, while the sphericity of seeds were found 0.656, 0.664 and 0.655. The bulk densities of the powdered seeds from three varieties Malaysia, Thailand and India, were found as 0.9697, 0.9932 and 0.9601 g/cm³ and % passing was obtained with sieve test were 78.7, 87.1 and 79.3 respectively. The densities of the extracted oil from three varieties Malaysia, Thailand and India were found 0.902, 0.898 and 0.902 g/ mL with corresponding kinematic viscosities 54.50, 49.18 and 48.16 mm2/sec respectively. The higher heating values (HHV) of extracted oil from Malaysia, Thailand and India seed varieties were measured as 40.29, 36.41 and 34.27 MJ/ kg, while the HHV of de-oiled cake from these varieties were 21.23, 20.78 and 17.31 MJ/kg respectively. The de-oiled cake can be used as compost with nutrients and carbon content to enhance soil fertility to grow future Jatropha curcas oil seed crops and also can be used as a fuel for heating and cooking purpose. Moreover, the mechanical parameter micro Vickers hardness of Malaysia seed was found lowest 16.30 HV measured with seed in a horizontal position to the loading in comparison to other two varieties as 25.2 and 18.7 HV from Thailand and India respectively. The fatty acid composition of three varieties of seed oil showed the presence of C8-C22, required to produce good quality biodiesel fuel. In terms of physicochemical properties of seeds and its extracted oil, the variety from Thailand was found better as compared to the other two varieties.

Keywords: biodiesel, Jatropha curcas, mechanical property, physico-chemical properties

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2298 Exploring Heidegger’s Fourfold through Architecture-Dwelling for Imaginary Fictional Characters in Drawings

Authors: Hassan Wajid

Abstract:

Architecture design studio with all its accouterments, especially pedagogies, has been committed to awakening the students to the true meaning of the concept of Dwelling. The real task is how to make them unlearn the associations of “dwelling as a rented or owned accommodation by the road with a car parked in front of a garage door and replace it by the fundamental experiential-phenomenological manifestations of Light, Space, Gravity and Time through assigned readings and small theoretical challenges resulting in drawings and models. The primary challenge for teachers remained the introduction of the act or desire of ‘Dwelling’ philosophically. The academic link had been offered by Albert Hofstadter's Poetry, Language, through which Martin Heidegger’s fourfold concept of ‘Building Dwelling, Thinking’ primarily served to guide us through this trajectory in helping to build an intellectual framework as justification of the term “dwelling” in its various meanings. Gaston Bachelard’s Poetics of Space and Merleau-Ponti’s Phenomenology of Perception also got assigned as reading. Four fictional characters created by two master short story writers G Maupassant, and O Henry were introduced as DwellersClients in search of their respective dwellings as drawn imaginations in the studio four-fold of Light, Space, Gravity, and Time and at the same time aspire to understand thoroughly Heidegger’s Four-Fold of Earth, Sky, Divinities and Mortals. asserting its place in the corresponding story and its unique character as the Dweller.

Keywords: dwelling, imagination, architectural manifestation, phenomenological

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2297 Fluorescent Analysis of Gold Nanoclusters-Wool Keratin Addition to Copper Ions

Authors: Yao Xing, Hong Ling Liu, Wei Dong Yu

Abstract:

With the increase of global population, it is of importance for the safe water supply, while, the water-monitoring method with the capability of rapidness, low-cost, green and robustness remains unsolved. In this paper, gold nanoclusters-wool keratin is added into copper ions measured by fluorescent method in order to probe copper ions in aqueous solution. The fluorescent results show that gold nanoclusters-wool keratin exhibits high stability of pHs, while it is sensitive to temperature and time. Based on Gauss fitting method, the results exhibit that the slope of gold nanoclusters-wool keratin with pH resolution under acidic condition is higher compared to it under alkaline solutions. Besides, gold nanoclusters-wool keratin added into copper ions shows a fluorescence turn-off response transferring from red to blue under UV light, leading to the dramatically decreased fluorescent intensity of gold nanoclusters-wool keratin solution located at 690 nm. Moreover, the limited concentration of copper ions tested by gold nanoclusters-wool keratin system is around 1 µmol/L, which meets the need of detection standards. The fitting slope of Stern-Volmer plot at low concentration of copper ions is larger than it at high concentrations, which indicates that aggregated gold nanoclusters are from small amounts to large numbers with the increasing concentration of copper ions. It is expected to provide novel method and materials for copper ions testing with low cost, high efficiency, and easy operability.

Keywords: gold nanoclusters, copper ions, wool keratin, fluorescence

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2296 Study for Utilization of Industrial Solid Waste, Generated by the Discharge of Casting Sand Agglomeration with Clay, Blast Furnace Slag and Sugar Cane Bagasse Ash in Concrete Composition

Authors: Mario Sergio de Andrade Zago, Javier Mazariegos Pablos, Eduvaldo Paulo Sichieri

Abstract:

This research project accomplished a study on the technical feasibility of recycling industrial solid waste generated by the discharge of casting sand agglomeration with clay, blast furnace slag and sugar cane bagasse ash. For this, the plan proposed a methodology that initially establishes a process of solid waste encapsulation, by using solidification/stabilization technique on Portland cement matrices, in which the residuals act as small and large aggregates on the composition of concrete, and later it presents the possibility of using this concrete in the manufacture of concrete pieces (concrete blocks) for paving. The results obtained in this research achieved the objective set with great success, regarding the manufacturing of concrete pieces (blocks) for paving urban roads, whenever there is special vehicle traffic or demands capable of producing accentuated abrasion effects (surpassing the 50 MPa required by the regulation), which probes the technical practicability of using waste from sand casting agglomeration with clay and blast furnace slag used in this study, unlocking usage possibilities for construction.

Keywords: industrial solid waste, solidification/stabilization, Portland cement, reuse, bagasse ash in the sugar cane, concrete

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2295 Distribution Pattern of Faecal Egg output and Herbage Larval Populations of Gastrointestinal Nematodes in Naturally Infected Scottish Blackface Lambs in East Scotland

Authors: M. Benothman, M. Stear, S. Mitchel, O. Abuargob, R. Vijayan, Sateesh Kumar

Abstract:

Parasitic gastroenteritis caused by gastrointestinal nematodes (GIN) is a serious pathological complication in lambs. The dispersion pattern of GIN influences their transmission dynamics. There is no proper study on this aspect in Scottish Blackface lambs in Scotland. This study undertaken on 758 naturally infected, weaned, straight bred Scottish Blackface lambs in high land pasture in East Scotland extending over three months (August, September and October) in a year, and for three successive years demonstrated that the distribution of faecal egg counts (FEC) followed negative binomial distribution, with the exception of a few samples. The inverse index of dispersion (k) ranged between 0.19 ± 0.51 and 1.09 ± 0.08. Expression of low k values resulting from aggregation in a few individuals, suggested that a small proportion of animals with heavy parasitic influx significantly influenced the level of pasture contamination and parasite transmission. There was no discernible trend in the mean faecal egg count (FEC) and mean herbage larval population (HLP) in different months and in different years. Teladorsagia was the highest pasture contaminant (85.14±14.30 L3/kdh) followed by Nematodirus (53.00±13.96), Ostertagia (28.21±10.18) and Cooperia (11.43±5.55). The results of this study would be useful in instituting gastrointestinal nematode control strategies for sheep in cool temperate agro-ecological zones.

Keywords: blackface lamb, faecal egg count, Gastrointestinal nematodes, herbage larval population, Scotland

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2294 Computational Characterization of Electronic Charge Transfer in Interfacial Phospholipid-Water Layers

Authors: Samira Baghbanbari, A. B. P. Lever, Payam S. Shabestari, Donald Weaver

Abstract:

Existing signal transmission models, although undoubtedly useful, have proven insufficient to explain the full complexity of information transfer within the central nervous system. The development of transformative models will necessitate a more comprehensive understanding of neuronal lipid membrane electrophysiology. Pursuant to this goal, the role of highly organized interfacial phospholipid-water layers emerges as a promising case study. A series of phospholipids in neural-glial gap junction interfaces as well as cholesterol molecules have been computationally modelled using high-performance density functional theory (DFT) calculations. Subsequent 'charge decomposition analysis' calculations have revealed a net transfer of charge from phospholipid orbitals through the organized interfacial water layer before ultimately finding its way to cholesterol acceptor molecules. The specific pathway of charge transfer from phospholipid via water layers towards cholesterol has been mapped in detail. Cholesterol is an essential membrane component that is overrepresented in neuronal membranes as compared to other mammalian cells; given this relative abundance, its apparent role as an electronic acceptor may prove to be a relevant factor in further signal transmission studies of the central nervous system. The timescales over which this electronic charge transfer occurs have also been evaluated by utilizing a system design that systematically increases the number of water molecules separating lipids and cholesterol. Memory loss through hydrogen-bonded networks in water can occur at femtosecond timescales, whereas existing action potential-based models are limited to micro or nanosecond scales. As such, the development of future models that attempt to explain faster timescale signal transmission in the central nervous system may benefit from our work, which provides additional information regarding fast timescale energy transfer mechanisms occurring through interfacial water. The study possesses a dataset that includes six distinct phospholipids and a collection of cholesterol. Ten optimized geometric characteristics (features) were employed to conduct binary classification through an artificial neural network (ANN), differentiating cholesterol from the various phospholipids. This stems from our understanding that all lipids within the first group function as electronic charge donors, while cholesterol serves as an electronic charge acceptor.

Keywords: charge transfer, signal transmission, phospholipids, water layers, ANN

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2293 An Experimental Study on the Influence of Brain-Break in the Classroom on the Physical Health and Academic Performance of Fourth Grade Students

Authors: Qian Mao, Xiaozan Wang, Jiarong Zhong, Xiaolin Zou

Abstract:

Introduction: As a result of the decline of students' physical health level and the increase of study pressure, students’ academic performance is not so good. Objective: This study aims to verify whether the Brain-Break intervention in the fourth-grade classroom of primary school can improve students' physical health and academic performance. Methods: According to the principle of no difference in pre-test data, students from two classes of grade four in Fuhai Road Primary School, Fushan district, Yantai city, Shandong province, were selected as experimental subjects, including 50 students in the experimental class (25 males and 25 females) and 50 students in the control class (24 males and 26 females). The content of the experiment was that the students were asked to perform a 4-minute Brain-Berak program designed by the researcher in the second class in the morning and the afternoon, and the intervention lasted for 12 weeks. In addition, the lung capacity, 50-meter run, sitting body forward bend, one-minute jumping rope and one-minute sit-ups stipulated in the national standards for physical fitness of students (revised in 2014) were selected as the indicators of physical health. The scores of Chinese, Mathematics, and English in the unified academic test of the municipal education bureau were selected as the indicators of academic performance. The independent-sample t-test was used to compare and analyze the data of each index between the two classes. The paired-sample t-test was used to compare and analyze the data of each index in the two classes. This paper presents only results with significant differences. Results: in terms of physical health, lung capacity (P=0.002, T= -2.254), one-minute rope skipping (P=0.000, T=3.043), and one-minute sit-ups (P=0.045, T=6.153) were significantly different between the experimental class and the control class. In terms of academic performance, there is a significant difference between the Chinese performance of the experimental class and the control class (P=0.009, T=4.833). Conclusion: Adding Brain-Berak intervention in the classroom can effectively improve the cardiorespiratory endurance (lung capacity), coordination (jumping rope), and abdominal strength (sit-ups) of fourth-grade students. At the same time, it can also effectively improve their Chinese performance. Therefore, it is suggested to promote micro-sports in the classroom of primary schools throughout the country so as to help students improve their physical health and academic performance.

Keywords: academic performance, brain break, fourth grade, physical health

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2292 Electrochemically Reduced Graphene Oxide Modified Boron-Doped Diamond Paste Electrode on Paper-Based Analytical Device for Simultaneous Determination of Norepinephrine and Serotonin

Authors: Siriwan Nantaphol, Robert B. Channon, Takeshi Kondo, Weena Siangproh, Orawon Chailapakul, Charles S. Henry

Abstract:

In this work, we demonstrate a novel electrochemically reduced graphene oxide (ERGO) modified boron-doped diamond paste (BDDP) electrode on paper-based analytical devices (PADs) for simultaneous determination of norepinephrine (NE) and serotonin (5-HT). The BDD paste electrode was easily constructed by filling BDD paste in small channels, which made in transparency film sheets using a CO₂ laser etching 
system. The counter and reference electrodes were fabricated on paper by in-house screen-printing and then combined with BDD paste microelectrode. The electrochemical characterization of the device was investigated by cyclic voltammetry (CV). Differential pulse voltammetry (DPV) was employed for the simultaneous determination of NE and 5-HT. The ERGO-modified BDDP electrode displayed excellent electrocatalytic activities toward the oxidation of NE and 5-HT and strong function for resolving the overlapping voltammetric responses of NE and 5-HT into two well-defined voltammetric peaks. This device was capable of simultaneously detecting NE and 5-HT in wide concentration ranges and with a low limit of detections. In addition, it has the advantages in terms of ease of use, low cost, and disposability.

Keywords: boron-doped diamond paste electrode, electrochemically reduced graphene oxide, norepinephrine, paper-based analytical device, serotonin

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2291 Influences of Thermal Treatments on Dielectric Behaviors of Carbon Nanotubes-BaTiO₃ Hybrids Reinforced Polyvinylidene Fluoride Composites

Authors: Benhui Fan, Fahmi Bedoui, Jinbo Bai

Abstract:

Incorporated carbon nanotube-BaTiO₃ hybrids (H-CNT-BT) with core-shell structure, a better dispersion of CNTs can be achieved in a semi-crystalline polymeric matrix, polyvinylidene fluoride (PVDF). Carried by BT particles, CNTs are easy to mutually connect which helps to obtain an extremely low percolation threshold (fc). After thermal treatments, the dielectric constants (ε’) of samples further increase which depends on the conditions of thermal treatments such as annealing temperatures, annealing durations and cooling ways. Thus, in order to study more comprehensively about the influence of thermal treatments on composite’s dielectric behaviors, in situ synchrotron X-ray is used to detect re-crystalline behavior of PVDF. Results of wide-angle X-ray diffraction (WAXD) and small-angle X-ray scattering (SAXS) show that after the thermal treatment, the content of β polymorph (the polymorph with the highest ε’ among all the polymorphs of PVDF’s crystalline structure) has increased nearly double times at the interfacial region of CNT-PVDF, and the thickness of amorphous layers (La) in PVDF’s long periods (Lp) has shrunk around 10 Å. The evolution of CNT’s network possibly occurs in the procedure of La shrinkage, where the strong interfacial polarization may be aroused and increases ε’ at low frequency. Moreover, an increase in the thickness of crystalline lamella may also arouse more orientational polarization and improve ε’ at high frequency.

Keywords: dielectric properties, thermal treatments, carbon nanotubes, crystalline structure

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2290 Prevalence of High Risk Human Papillomavirus in Cervical Dysplasia and Cancer Samples from Twin Cities in Pakistan

Authors: Sana Gul, Sheeba Murad, Aneela Javed

Abstract:

Introduction: Human Papilloma Virus (HPV) is small DNA virus mostly infecting mucosa and cutaneous keratinocytes. So far, more than 200 Human papillomaviruses are known. HPV have been divided into high- and low-risk on the basis of their oncogenic potential. High risk HPV is considered to be the main etiological cause for cervical cancer. Objective: Current study was designed to screen the local cervical cancer patients from the twin cities of Pakistan for the occurance of high risk HPV. Methodology: A total of 67 formalin fixed paraffin-embedded samples of cervical cancer biopsies were obtained from the government hospitals in Islamabad and Rawalpindi. Cervical cancer biopsies were examined for the presence of HPV DNA. Polymerase chain reaction (PCR) was used for the amplification of a region in the HPV-L1 gene for the general detection of the Papilloma virus and for the genotype specific detection of high risk HPV 16 and 18 using the GP5/GP6 primers and genotype specific primers respectively. Results: HPV DNA was detected in 59 out of 67 samples analyzed. 30 samples showed the presence of HPV16 while 22 samples were positive for HPV 18 . HPV subtype could not be determined in 7 samples. Conclusion: Our results show a strong association between HPV infection and cervical cancer among women in twin cities of Pakistan. One way to minimize the disease burden in relation to HPV infection in Pakistani population is the use of prophylactic vaccines and routine screening. An early diagnosis of HPV infection will allow better health management to reduce the risk of developing cervical cancer.

Keywords: cervical cancer, Pakistan, human papillomavirus, HPV 16

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2289 Investigating English Dominance in a Chinese-English Dual Language Program: Teachers' Language Use and Investment

Authors: Peizhu Liu

Abstract:

Dual language education, also known as immersion education, differs from traditional language programs that teach a second or foreign language as a subject. Instead, dual language programs adopt a content-based approach, using both a majority language (e.g., English, in the case of the United States) and a minority language (e.g., Spanish or Chinese) as a medium of instruction to teach math, science, and social studies. By granting each language of instruction equal status, dual language education seeks to educate not only meaningfully but equitably and to foster tolerance and appreciation of diversity, making it essential for immigrants, refugees, indigenous peoples, and other marginalized students. Despite the cognitive and academic benefits of dual language education, recent literature has revealed that English is disproportionately privileged across dual language programs. Scholars have expressed concerns about the unbalanced status of majority and minority languages in dual language education, as favoring English in this context may inadvertently reaffirm its dominance and moreover fail to serve the needs of children whose primary language is not English. Through a year-long study of a Chinese-English dual language program, the extensively disproportionate use of English has also been observed by the researcher. However, despite the fact that Chinese-English dual language programs are the second-most popular program type after Spanish in the United States, this issue remains underexplored in the existing literature on Chinese-English dual language education. In fact, the number of Chinese-English dual language programs being offered in the U.S. has grown rapidly, from 8 in 1988 to 331 as of 2023. Using Norton and Darvin's investment model theory, the current study investigates teachers' language use and investment in teaching Chinese and English in a Chinese-English dual language program at an urban public school in New York City. The program caters to a significant number of minority children from working-class families. Adopting an ethnographic and discourse analytic approach, this study seeks to understand language use dynamics in the program and how micro- and macro-factors, such as students' identity construction, parents' and teachers' language ideologies, and the capital associated with each language, influence teachers' investment in teaching Chinese and English. The research will help educators and policymakers understand the obstacles that stand in the way of the goal of dual language education—that is, the creation of a more inclusive classroom, which is achieved by regarding both languages of instruction as equally valuable resources. The implications for how to balance the use of the majority and minority languages will also be discussed.

Keywords: dual language education, bilingual education, language immersion education, content-based language teaching

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2288 Palygorskite Bearing Calcic-Soils from Western Thar Desert: Implications for Late Quaternary Monsoonal Fluctuations

Authors: A. Hameed, N. Upreti, P. Srivastava

Abstract:

Main objective the present study is to investigate microscopic, sub-microscopic, clay mineralogical and geochemical characteristics of three calcic soil profiles from the western Thar Desert for the last 30 ka paleoclimatic information. Thin-sections of the soils show weakly to moderately developed pedofeatures dominated by powdery to well-indurated pedogenic calcium carbonate. Sub-microscopy of the representative calcretes show extensive growth of fibrous palygorskite in pore spaces of micritic and sparitic nodules. XRD of the total clay ( < 2 µm) and fine clay ( < 0.2 µm) fractions of the soils show dominance of smectite, palygorskite, chlorite, mica, kaolinite and small amounts of quartz and feldspar. Formation of the palygorskite is attributed to pedogenic processes associated with Bw, Bss and Bwk horizons during drier conditions over the last 30 ka. Formation of palygorskite was mainly favoured by strongly evaporating percolating water and precipitation of secondary calcite, high pH (9-10), high Mg, Si and low Al activities during pedogenesis. Age estimate and distribution of calcretes, palygorskite, and illuvial features indicate fluctuating monsoonal strength during MIS3-MIS1 stages. The pedogenic features in calcic soils of western Thar suggest relatively arid conditions during MIS3-MIS2 transition and LGM time that changed to relatively wetter conditions during post LGM time and again returned to dry conditions at ~4 ka in MIS1.

Keywords: palygorskite, clay minerals, Thar, aridisol, late quaternary

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2287 Types of School Aggression Amongst Bulgarian Students in the Age Group of 12–18 Years-Old

Authors: Yolanda Zografova, Ekaterina Dimitrova, Tsvetelina Panchelieva, Victoria Nedeva-Atanasova

Abstract:

Aggression and violence amongst school-aged children are widely spread phenomenon, which is expanding both on a global level and in Bulgaria. The purpose of the paper is to reveal the overall range of different types and manifestations of school aggression in a specific age group (12 to 18 years old students) from the 5th to the 12th grade according to the Bulgarian education system. In addition, the research investigates the dynamics of aggressive behaviour in two parallel lines – a horizontal one (with students from the same age) and a vertical one (with students from different grade). In the current study based on the original authors’ inventory (School Aggression Questionnaire), the three main types of aggression are measured – physical, verbal and indirect. The sample consists of 300 students from schools in a big metropolitan city, a mid-sized town, and a small town. Results show that the predominant aggression type is the verbal one, but this is the predominant type for the girls in the sample, not for the boys. Another result is that the higher the school grade, the lower levels of overall aggression is shown by the students. The study of such a multi-dimensional phenomenon as the aggression will provide up-to-date scientific knowledge, important both for the development of science on these topics, and useful for public interests in relation to the balanced development of children and adolescents at school. The results provide an excellent base for the development of prevention and intervention programs in order to reduce school aggression.

Keywords: educational psychology, School aggression, interpersonal relations, school aggression questionnaire, types of aggression

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2286 Structure and Tribological Properties of Moisture Insensitivity Si Containing Diamond-Like Carbon Film

Authors: Mingjiang Dai, Qian Shi, Fang Hu, Songsheng Lin, Huijun Hou, Chunbei Wei

Abstract:

A diamond-like carbon (DLC) is considered as a promising protective film since its high hardness and excellent tribological properties. However, DLC films are very sensitive to the environmental condition, its friction coefficient could dramatic change in high humidity, therefore, limited their further application in aerospace, the watch industry, and micro/nano-electromechanical systems. Therefore, most studies focus on the low friction coefficient of DLC films at a high humid environment. However, this is out of satisfied in practical application. An important thing was ignored is that the DLC coated components are usually used in the diversed environment, which means its friction coefficient may evidently change in different humid condition. As a result, the invalidation of DLC coated components or even sometimes disaster occurred. For example, DLC coated minisize gears were used in the watch industry, and the customer may frequently transform their locations with different weather and humidity even in one day. If friction coefficient is not stable in dry and high moisture conditions, the watch will be inaccurate. Thus, it is necessary to investigate the stable tribological behavior of DLC films in various environments. In this study, a-C:H:Si films were deposited by multi-function magnetron sputtering system, containing one ion source device and a pair of SiC dual mid-frequent targets and two direct current Ti/C targets. Hydrogenated carbon layers were manufactured by sputtering the graphite target in argon and methane gasses. The silicon was doped in DLC coatings by sputtering silicon carbide targets and the doping content were adjusted by mid-frequent sputtering current. The microstructure of the film was characterized by Raman spectrometry, X-ray photoelectron spectroscopy, and transmission electron microscopy while its friction behavior under different humidity conditions was studied using a ball-on-disc tribometer. The a-C:H films with Si content from 0 to 17at.% were obtained and the influence of Si content on the structure and tribological properties under the relative humidity of 50% and 85% were investigated. Results show that the a-C:H:Si film has typical diamond-like characteristics, in which Si mainly existed in the form of Si, SiC, and SiO2. As expected, the friction coefficient of a-C:H films can be effectively changed after Si doping, from 0.302 to 0.176 in RH 50%. The further test shows that the friction coefficient value of a-C:H:Si film in RH 85% is first increase and then decrease as a function of Si content. We found that the a-C:H:Si films with a Si content of 3.75 at.% show a stable friction coefficient of 0.13 in different humidity environment. It is suggestion that the sp3/sp2 ratio of a-C:H films with 3.75 at.% Si was higher than others, which tend to form the silica-gel-like sacrificial layers during friction tests. Therefore, the films deliver stable low friction coefficient under controlled RH value of 50 and 85%.

Keywords: diamond-like carbon, Si doping, moisture environment, table low friction coefficient

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2285 The Influence of Online Audience Response on Journalists

Authors: Raja Arslan Ahmad Khan

Abstract:

Audience feedback and data play an increasingly crucial role, particularly in the digital age. The advent of digital media and the digitalization of news have given rise to novel forms of audience feedback, markedly different from traditional channels. The engagement of online audiences challenges the conventional role of journalists, introducing a dynamic where audiences can wield both direct and indirect influence. This struggle between the audience and journalists is evident in their contributions and interactions. Media professionals are grappling with challenges such as derogatory remarks, hate speech, online harassment, audience hostility, and attacks from online audiences. The influence of online audiences extends to shaping journalists' daily routines and work practices. Consequently, this study seeks to analyze the impact of online audience feedback on journalists at a routine level within the Malaysian context. Employing a Hierarchy of Influence model as a theoretical framework, the study will utilize a quantitative approach with a snowball survey method. The study's findings aim to enhance our understanding of how online audiences influence journalists and their work practices, encompassing aspects like journalists' autonomy and integrity, editorial decision-making, performance and accountability, daily routines, work practices, as well as the psychological and emotional costs they bear. It's important to note that the study has limitations due to the use of the snowball survey method and its focus within the specific context of Malaysia, making it relatively small in scale.

Keywords: online audiences, feedback, influence, journalists, Malaysia

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2284 Preliminary Study of the Hydrothermal Polymetallic Ore Deposit at the Karancs Mountain, North-East Hungary

Authors: Eszter Kulcsar, Agnes Takacs, Gabriella B. Kiss, Peter Prakfalvi

Abstract:

The Karancs Mountain is part of the Miocene Inner Carpathian Volcanic Belt and is located in N-NE Hungary, along the Hungarian-Slovakian border. The 14 Ma old andesitic-dacitic units are surrounded by Oligocene sedimentary units (sandstone, siltstone). The host rocks of the mineralisation are siliceous and/or argillaceous volcanic units, quartz veins, hydrothermal breccia, and strongly silicified vuggy rocks, found in the various altered volcanic units. The hydrothermal breccia consists of highly silicified vuggy quartz clasts in quartz matrix. The hydrothermal alteration of the host units shows structural control at the deeper levels. The main ore minerals are galena, pyrite, marcasite, sphalerite, hematite, magnetite, arsenopyrite, anglesite and argentite The mineralisation was first mentioned in 1944 and the first exploration took place between 1961 and 1962 in the area. The first ore geological studies were performed between 1984-1985. The exploration programme was limited only to surface sampling; no drilling programme was performed. Petrographical and preliminary fluid inclusion studies were performed on calcite samples from a galena-bearing vein. Despite the early discovery of the mineralisation, no detailed description is available, thus its size, characteristics, and origin have remained unknown. The aim of this study is to examine the mineralisation, describe the characteristics in detail and to test the possible gold content of the various quartz veins and breccias. Finally, we also investigate the potential relation of the hydrothermal mineralisation to the surrounding similar mineralisations with similar ages (e.g. W-Mátra Mountains in Hungary, Banska Bystrica, Banska Stiavnica in Slovakia) in order to place the mineralisation within the volcanic-hydrothermal evolution of the Miocene Inner Carpathian Belt. As first steps, the study includes field mapping, traditional petrological and ore microscopy; X-ray diffraction analysis; SEM-EDS and EMPA studies on ore minerals, to obtain mineral chemical information. Fluid inclusion petrography and microthermometry and micro-Raman-spectroscopy studies are also planned on quartz-hosted inclusions to investigate the physical and chemical properties of the ore-forming fluid.

Keywords: epithermal, Karancs Mountain, Hungary, Miocene Inner Carpathian volcanic belt, polimetallic ore deposit

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2283 Hybrid Collaborative-Context Based Recommendations for Civil Affairs Operations

Authors: Patrick Cummings, Laura Cassani, Deirdre Kelliher

Abstract:

In this paper we present findings from a research effort to apply a hybrid collaborative-context approach for a system focused on Marine Corps civil affairs data collection, aggregation, and analysis called the Marine Civil Information Management System (MARCIMS). The goal of this effort is to provide operators with information to make sense of the interconnectedness of entities and relationships in their area of operation and discover existing data to support civil military operations. Our approach to build a recommendation engine was designed to overcome several technical challenges, including 1) ensuring models were robust to the relatively small amount of data collected by the Marine Corps civil affairs community; 2) finding methods to recommend novel data for which there are no interactions captured; and 3) overcoming confirmation bias by ensuring content was recommended that was relevant for the mission despite being obscure or less well known. We solve this by implementing a combination of collective matrix factorization (CMF) and graph-based random walks to provide recommendations to civil military operations users. We also present a method to resolve the challenge of computation complexity inherent from highly connected nodes through a precomputed process.

Keywords: Recommendation engine, collaborative filtering, context based recommendation, graph analysis, coverage, civil affairs operations, Marine Corps

Procedia PDF Downloads 125
2282 Evaluation of Environmental, Social, and Governance Factors by U.S. Tolling Authorities in Bond Issuance Disclosures

Authors: Nicolas D. Norboge

Abstract:

Purchasers of municipal bonds in primary and secondary markets are increasingly expecting issuers to disclose environmental, social, and governance factors (ESG) inissuance and continuing disclosure documents. U.S. tolling authorities are slowly catching up with other transportation sectors, such as public transit, in integrating ESG factors into their bond disclosure documents. A systematic mixed-methods evaluation of publicly available bond disclosure documents from 2010-2022 suggest that only a small number of U.S. tolling authorities disclosedall ESG factors; however, the pace has accelerated significantly from 2020-2022. Because many tolling authorities have a direct financial stake in the growth of passenger vehicle miles traveled on their toll facilities, and in turn the burning of more climate-warming fossil fuels, one crucial questionthat remains is how bond purchasers will view increasedESG transparency. Recent moves by large institutional investors, credit rating agencies, and regulators suggestan expectation of ESG disclosure is a trend likely to endure. This researchsuggests tolling authorities will need to proactively consider these emerging trends and carefully adapt their disclosure practiceswhere possible. Building on these findings, this research also provides a basic sketch framework for how issuers can responsibly position themselves within the changing global municipal debt marketplace.

Keywords: debt policy, ESG, municipal bonds, public-private partnerships, public tolling authorities, transportation finance, and policy

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2281 An Advanced Exponential Model for Seismic Isolators Having Hardening or Softening Behavior at Large Displacements

Authors: Nicolò Vaiana, Giorgio Serino

Abstract:

In this paper, an advanced Nonlinear Exponential Model (NEM), able to simulate the uniaxial dynamic behavior of seismic isolators having a continuously decreasing tangent stiffness with increasing displacement in the relatively large displacements range and a hardening or softening behavior at large displacements, is presented. The mathematical model is validated by comparing the experimental force-displacement hysteresis loops obtained during cyclic tests, conducted on a helical wire rope isolator and a recycled rubber-fiber reinforced bearing, with those predicted analytically. Good agreement between the experimental and simulated results shows that the proposed model can be an effective numerical tool to predict the force-displacement relationship of seismic isolation devices within the large displacements range. Compared to the widely used Bouc-Wen model, unable to simulate the response of seismic isolators at large displacements, the proposed one allows to avoid the numerical solution of a first order nonlinear ordinary differential equation for each time step of a nonlinear time history analysis, thus reducing the computation effort. Furthermore, the proposed model can simulate the smooth transition of the hysteresis loops from small to large displacements by adopting only one set of five parameters determined from the experimental hysteresis loops having the largest amplitude.

Keywords: base isolation, hardening behavior, nonlinear exponential model, seismic isolators, softening behavior

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2280 Effect of Intrinsic Point Defects on the Structural and Optical Properties of SnO₂ Thin Films Grown by Ultrasonic Spray Pyrolysis Method

Authors: Fatiha Besahraoui, M'hamed Guezzoul, Kheira Chebbah, M'hamed Bouslama

Abstract:

SnO₂ thin film is characterized by Atomic Force Microscopy (AFM) and Photoluminescence Spectroscopies. AFM images show a dense surface of columnar grains with a roughness of 78.69 nm. The PL measurements at 7 K reveal the presence of PL peaks centered in IR and visible regions. They are attributed to radiative transitions via oxygen vacancies, Sn interstitials, and dangling bonds. A bands diagram model is presented with the approximate positions of intrinsic point defect levels in SnO₂ thin films. The integrated PL measurements demonstrate the good thermal stability of our sample, which makes it very useful in optoelectronic devices functioning at room temperature. The unusual behavior of the evolution of PL peaks and their full width at half maximum as a function of temperature indicates the thermal sensitivity of the point defects present in the band gap. The shallower energy levels due to dangling bonds and/or oxygen vacancies are more sensitive to the temperature. However, volume defects like Sn interstitials are thermally stable and constitute deep and stable energy levels for excited electrons. Small redshifting of PL peaks is observed with increasing temperature. This behavior is attributed to the reduction of oxygen vacancies.

Keywords: transparent conducting oxide, photoluminescence, intrinsic point defects, semiconductors, oxygen vacancies

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2279 Detecting Nitrogen Deficiency and Potato Leafhopper (Hemiptera, Cicadellidae) Infestation in Green Bean Using Multispectral Imagery from Unmanned Aerial Vehicle

Authors: Bivek Bhusal, Ana Legrand

Abstract:

Detection of crop stress is one of the major applications of remote sensing in agriculture. Multiple studies have demonstrated the capability of remote sensing using Unmanned Aerial Vehicle (UAV)-based multispectral imagery for detection of plant stress, but none so far on Nitrogen (N) stress and PLH feeding stress on green beans. In view of its wide host range, geographical distribution, and damage potential, Potato leafhopper- Empoasca fabae (Harris) has been emerging as a key pest in several countries. Monitoring methods for potato leafhopper (PLH) damage, as well as the laboratory techniques for detecting Nitrogen deficiency, are time-consuming and not always easily affordable. A study was initiated to demonstrate if the multispectral sensor attached to a drone can detect PLH stress and N deficiency in beans. Small-plot trials were conducted in the summer of 2023, where cages were used to manipulate PLH infestation in green beans (Provider cultivar) at their first-trifoliate stage. Half of the bean plots were introduced with PLH, and the others were kept insect-free. Half of these plots were grown with the recommended amount of N, and the others were grown without N. Canopy reflectance was captured using a five-band multispectral sensor. Our findings indicate that drone imagery could detect stress due to a lack of N and PLH damage in beans.

Keywords: potato leafhopper, nitrogen, remote sensing, spectral reflectance, beans

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2278 Revolutions and Cyclic Patterns in Chinese Town Planning: The Case-Study of Shenzhen

Authors: Domenica Bona

Abstract:

Colin Chant and David Goodman argue that historians of Chinese pre-industrial cities tend to underestimate revolutions and overestimate cyclic patterns: periods of peace and prosperity in the earl part of each d nast , followed b peasants’ rebellions and upheavals. Boyd described these cyclic patterns as part of the background of Chinese town planning and architecture. Thus old ideals of city planning-square plan, southward orientation and a palace along the central axis - are revived again and again in the ascendant phases of several d nastic c cles (e.g. Chang’an, Kaifen, and Beijing). Along this line of thought, m paper questions the relationship between the “magic square rule” and modern Chinese urban- planning. As a matter of fact, the classical theme of “cosmic Taoist urbanism” is still a reference for planning cities and new urban developments, whenever there is the intention to express nationalist ideals and “cultural straightforwardness.” Besides, some case studies can be related to “modern d nasties”: the first Republic under the Kuo Min Tang, the red People’s Republic and the post-Maoist open country of Deng Xiao Ping. Considering the project for the new capital of Nanjing in the Thirties, Beijing’s Tianan Men area in the ifties, and Shenzhen’s utian CBD in late 20th century, I argue that cyclic patterns are still in place, though with deformations related to westernization, private interests and lack of spirituality. How far new Chinese cities are - or simply seem to be - westernized? Symbolism, invisible frameworks, repeating features and behavioural patterns make urban China just “superficiall” western. This can be well noticed in cities previousl occupied b foreigners, like Hong Kong, or in newly founded ones, like Shenzhen, where both Asians and non-Asian people can feel the gender-shift from New-York-like landscapes to something else. Current planning in main metropolitan areas shows a blurred relationship between public policies and private investments: two levels of decisions and actions, one addressing the larger scale and infrastructures, the other concerning the micro scale and development of single plots. While zoning is instrumental in this process, master plans are often laid out over a very poor cartography, so much that any relation between the formal characters of new cities and the centuries-old structure of the related territory gets lost.

Keywords: China, contemporary cities, cultural heritage, shenzhen, urban planning

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2277 Chongqing, a Megalopolis Disconnected with Its Rivers: An Assessment of Urban-Waterside Disconnect in a Chinese Megacity and Proposed Improvement Strategies, Chongqing City as a Case Study

Authors: Jaime E. Salazar Lagos

Abstract:

Chongqing is located in southwest China and is becoming one of the most significant cities in the world. Its urban territories and metropolitan-related areas have one of the largest urban populations in China and are partitioned and shaped by two of the biggest and longest rivers on Earth, the Yangtze and Jialing Rivers, making Chongqing a megalopolis intersected by rivers. Historically, Chongqing City enjoyed fundamental connections with its rivers; however, current urban development of Chongqing City has lost effective integration of the riverbanks within the urban space and structural dynamics of the city. Therefore, there exists a critical lack of physical and urban space conjoined with the rivers, which diminishes the economic, tourist, and environmental development of Chongqing. Using multi-scale satellite-map site verification the study confirmed the hypothesis and urban-waterside disconnect. Collected data demonstrated that the Chongqing urban zone, an area of 5292 square-kilometers and a water front of 203.4 kilometers, has only 23.49 kilometers of extension (just 11.5%) with high-quality physical and spatial urban-waterside connection. Compared with other metropolises around the world, this figure represents a significant lack of spatial development along the rivers, an issue that has not been successfully addressed in the last 10 years of urban development. On a macro scale, the study categorized the different kinds of relationships between the city and its riverbanks. This data was then utilized in the creation of an urban-waterfront relationship map that can be a tool for future city planning decisions and real estate development. On a micro scale, we discovered there are three primary elements that are causing the urban-waterside disconnect: extensive highways along the most dense areas and city center, large private real estate developments that do not provide adequate riverside access, and large industrial complexes that almost completely lack riverside utilization. Finally, as part of the suggested strategies, the study concludes that the most efficient and practical way to improve this situation is to follow the historic master-planning of Chongqing and create connective nodes in critical urban locations along the river, a strategy that has been used for centuries to handle the same urban-waterside relationship. Reviewing and implementing this strategy will allow the city to better connect with the rivers, reducing the various impacts of disconnect and urban transformation.

Keywords: Chongqing City, megalopolis, nodes, riverbanks disconnection, urban

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2276 Comparison of Physicochemical Properties of DNA-Ionic Liquids Complexes

Authors: Ewelina Nowak, Anna Wisla-Swider, Gohar Khachatryan, Krzysztof Danel

Abstract:

Complexes of ionic liquids with different heterocyclic-rings were synthesized by ion exchange reactions with pure salmon DNA. Ionic liquids (ILs) like 1-hexyl-3-methylimidazolium chloride, 1-butyl-4-methylpyridinium chloride and 1-ethyl-1-methylpyrrolidinium bromide were used. The ILs were built into helical state and confirmed by IR spectrometric techniques. Patterns of UV-Vis, photoluminescence, IR, and CD spectra indicated inclusion of small molecules into DNA structure. Molecular weight and radii of gyrations values of ILs-DNA complexes chains were established by HPSEC–MALLS–RI method. Modification DNA with 1-ethyl-1-methylpyrrolidinium bromide gives more uniform material and leads to elimination of high molecular weight chains. Thus, the incorporation DNA double helical structure with both 1-hexyl-3-methylimidazolium chloride and 1-butyl-4-methylpyridinium chloride exhibited higher molecular weight values. Scanning electron microscopy images indicate formation of nanofibre structures in all DNA complexes. Fluorescence depends strongly on the environment in which the chromophores are inserted and simultaneously on the molecular interactions with the biopolymer matrix. The most intensive emission was observed for DNA-imidazole ring complex. Decrease in intensity UV-Vis peak absorption is a consequence of a reduction in the spatial order of polynucleotide strands and provides different π–π stacking structure. Changes in optical properties confirmed by spectroscopy methods make DNA-ILs complexes potential biosensor applications.

Keywords: biopolymers, biosensors, cationic surfactant, DNA, DNA-gels

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2275 Feasibility Study on a Conductive-Type Cooling System for an Axial Flux Permanent Magnet Generator

Authors: Yang-Gyun Kim, Eun-Taek Woo, Myeong-Gon Lee, Yun-Hyun Cho, Seung-Ho Han

Abstract:

For the sustainable development of wind energy, energy industries have invested in the development of highly efficient wind turbines such as an axial flux permanent magnet (AFPM) generator. The AFPM generator, however, has a history of overheating on the surface of the stator, so that power production decreases significantly. A proper cooling system, therefore, is needed. Although a convective-type cooling system has been developed, the size of the air blower must be increased when the generator’s capacity exceeds 2.5 MW. In this paper, we proposed a newly developed conductive-type cooling system using a heat pipe wound to the stator of a 2.5 MW AFPM generator installed on an offshore wind turbine. The numerical results showed that the temperatures on the stator surface using convective-type cooling system and the proposed conductive-type cooling system at thermal saturation were 60 and 76°C, respectively, which met the requirements for power production. The temperatures of the permanent magnet cased by the radiant heating from the stator surface were 53°C and 66°C, respectively, in each case. As a result, the permanent magnet did not reach the malfunction temperature. Although the cooling temperatures in the case of the conductive-type cooling system were higher than that of the convective-type cooling system, the relatively small size of the water pump and radiators make a light-weight design of the AFPM generator possible.

Keywords: wind turbine, axial flux permanent magnet (AFPM) generator, conductive-type cooling system

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2274 Chatter Prediction of Curved Thin-walled Parts Considering Variation of Dynamic Characteristics Based on Acoustic Signals Acquisition

Authors: Damous Mohamed, Zeroudi Nasredine

Abstract:

High-speed milling of thin-walled parts with complex curvilinear profiles often encounters machining instability, commonly referred to as chatter. This phenomenon arises due to the dynamic interaction between the cutting tool and the part, exacerbated by the part's low rigidity and varying dynamic characteristics along the tool path. This research presents a dynamic model specifically developed to predict machining stability for such curved thin-walled components. The model employs the semi-discretization method, segmenting the tool trajectory into small, straight elements to locally approximate the behavior of an inclined plane. Dynamic characteristics for each segment are extracted through experimental modal analysis and incorporated into the simulation model to generate global stability lobe diagrams. Validation of the model is conducted through cutting tests where acoustic intensity is measured to detect instabilities. The experimental data align closely with the predicted stability limits, confirming the model's accuracy and effectiveness. This work provides a comprehensive approach to enhancing machining stability predictions, thereby improving the efficiency and quality of high-speed milling operations for thin-walled parts.

Keywords: chatter, curved thin-walled part, semi-discretization method, stability lobe diagrams

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