Elasticity investigation of thin cellular structure films for piezoelectric sensors

Sensor Review ◽  
2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Ewa Klimiec ◽  
Piotr Zachariasz ◽  
Halina Kaczmarek ◽  
Bogusław Królikowski ◽  
Sławomir Mackiewicz
Keyword(s):  
Electric Charge ◽  
Polymer Films ◽  
Cellular Structure ◽  
Early Stage ◽  
Pressure Sensors ◽  
Ultrasonic Waves ◽  
Homogeneous Distribution ◽  
Simple Method ◽  
Content Type ◽  
Air Cavities

Purpose This paper aims to present the details of isotactic polypropylene (it-PP) films with a cellular structure (air-cavities) dedicated to pressure sensors. The polymer composites (thin films enriched with 5 and 10 wt% of mineral fillers as Sillikolloid P 87 and glass beads) should exhibit suitable structural elasticity within specific stress ranges. After the deformation force is removed, the sensor material must completely restore its original shape and size. Design/methodology/approach Estimating the stiffness tensor element (C33) for polymer films (nonpolar space-charge electrets) by broadband resonance ultrasound spectroscopy is a relatively simple method of determining the safe stress range generated in thin pressure sensors. Therefore, ultrasonic and piezoelectric studies were carried out on four composite it-PP films. First, the longitudinal velocity (vL) of ultrasonic waves passing through the it-PP film in the z-direction (thickness) was evaluated from the ω-position of mechanical resonance of the so-called insertion loss function. In turn, the d33 coefficient was calculated from accumulated piezoelectric charge density response to mechanical stress. Findings Research is at an early stage; however, it can be seen that the mechanical orientation of the it-PP film improves its piezoelectric properties. Moreover, the three-year electric charge stability of the it-PP film seems promising. Originality/value Ultrasonic spectroscopy can be successfully handled as a validation method in the small-lot production of polymer films with the air-cavities structure intended for pressure sensors. The structural repeatability of polymer films is strongly related to a homogeneous distribution of the electric charge on the electret surface.

Self-powered flexible pressure sensors based on nanopatterned polymer films

Sensor Review ◽  
2020 ◽  
Vol 40 (6) ◽  
pp. 629-635
Author(s):  
Man Zhang ◽  
Liangping Xia ◽  
Suihu Dang ◽  
Lifang Shi ◽  
Axiu Cao ◽  
...  
Keyword(s):  
Polymer Films ◽  
Pressure Sensor ◽  
Nanoimprint Lithography ◽  
Mechanical Energy ◽  
Electrical Power ◽  
Pressure Sensors ◽  
The Self ◽  
Content Type ◽  
Self Powered ◽  
Flexible Pressure Sensor

Purpose The pressure sensors can convert external pressure or mechanical deformation into electrical power and signal, which cannot only detect pressure or strain changes but also harvest energy as a self-powered sensor. This study aims to develop a self-powered flexible pressure sensor based on regular nanopatterned polymer films. Design/methodology/approach In this paper, the self-powered flexible pressure sensor is mainly composed of two nanopatterned polymer films and one conductive electrode layer between them, which is a sandwich structure. The regular nanostructures increase the film roughness and contact area to enhance the friction effect. To enhance the performance of the pressure sensor, different nanostructures on soft polymer sensitive layers are fabricated using UV nanoimprint lithography to generate more triboelectric charges. Findings Finally, the self-powered flexible pressure sensor is prepared, which consists of sub-200 nm resolution regular nanostructures on the surface of the elastic layer and an indium tin oxide electrode thin film. By converting the friction mechanical energy into electrical power, a maximum power of 423.8 mW/m2 and the sensitivity of 0.8 V/kPa at a frequency of 5 Hz are obtained, which proves the excellent sensing performance of the sensor. Originality/value The acquired electrical power and pressure signal by the sensor would be processed in the signal process circuit, which is capable of immediately and sustainably driving the highly integrated self-powered sensor system. Results of the experiments show that this new pressure sensor is a potential method for personal pressure monitoring, featured as being wearable, cost-effective, non-invasive and user-friendly.

Gamma knife surgery for vestibular schwannoma: 10-year experience of 195 cases

2005 ◽  
Vol 102 (Special_Supplement) ◽  
pp. 87-97 ◽  
Author(s):  
Wen-Yuh Chung ◽  
Kang-Du Liu ◽  
Cheng-Ying Shiau ◽  
Hsiu-Mei Wu ◽  
Ling-Wei Wang ◽  
...  
Keyword(s):  
Mr Imaging ◽  
Gamma Knife ◽  
Vestibular Schwannoma ◽  
Tumor Volume ◽  
Radiation Effect ◽  
Gamma Knife Surgery ◽  
Homogeneous Distribution ◽  
Content Type ◽  
Fine Print

Object. The authors conducted a study to determine the optimal radiation dose for vestibular schwannoma (VS) and to examine the histopathology in cases of treatment failure for better understanding of the effects of irradiation. Methods. A retrospective study was performed of 195 patients with VS; there were 113 female and 82 male patients whose mean age was 51 years (range 11–82 years). Seventy-two patients (37%) had undergone partial or total excision of their tumor prior to gamma knife surgery (GKS). The mean tumor volume was 4.1 cm3 (range 0.04–23.1 cm3). Multiisocenter dose planning placed a prescription dose of 11 to 18.2 Gy on the 50 to 94% isodose located at the tumor margin. Clinical and magnetic resonance (MR) imaging follow-up evaluations were performed every 6 months. A loss of central enhancement was demonstrated on MR imaging in 69.5% of the patients. At the latest MR imaging assessment decreased or stable tumor volume was demonstrated in 93.6% of the patients. During a median follow-up period of 31 months resection was avoided in 96.8% of cases. Uncontrolled tumor swelling was noted in five patients at 3.5, 17, 24, 33, and 62 months after GKS, respectively. Twelve of 20 patients retained serviceable hearing. Two patients experienced a temporary facial palsy. Two patients developed a new trigeminal neuralgia. There was no treatment-related death. Histopathological examination of specimens in three cases (one at 62 months after GKS) revealed a long-lasting radiation effect on vessels inside the tumor. Conclusions. Radiosurgery had a long-term radiation effect on VSs for up to 5 years. A margin 12-Gy dose with homogeneous distribution is effective in preventing tumor progression, while posing no serious threat to normal cranial nerve function.

scholarly journals Relationship between vaginal group B streptococcus colonization in the early stage of pregnancy and preterm birth: a retrospective cohort study

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Sho Tano ◽  
Takuji Ueno ◽  
Michinori Mayama ◽  
Takuma Yamada ◽  
Takehiko Takeda ◽  
...  
Keyword(s):  
Cohort Study ◽  
Preterm Birth ◽  
Retrospective Cohort Study ◽  
Retrospective Cohort ◽  
Early Stage ◽  
Group B Streptococcus ◽  
Multivariable Logistic Regression Analysis ◽  
Simple Method ◽  
Group B ◽  
Singleton Pregnancies

Abstract Background Although infection and inflammation within the genital tract during pregnancy is considered a major risk factor for spontaneous preterm birth (PTB), there are few studies on association between vaginal microorganisms in the early stage of pregnancy and PTB. The aim of this study was to investigate relationship between vaginal Group B streptococcus (GBS) colonization, a leading cause of infection during pregnancy, in the early stage of pregnancy and PTB. Methods This single-center, retrospective cohort study utilized data from 2009 to 2017 obtained at TOYOTA Memorial Hospital. Women with singleton pregnancies who underwent vaginal culture around 14 weeks of gestation during their routine prenatal check-up were included. Vaginal sampling for Gram staining and culture was performed regardless of symptoms. GBS colonization was defined as positive for GBS latex agglutination assay. Statistical analysis was performed to determine the factors associated with PTB. Results Overall 1079 singleton pregnancies were included. GBS (5.7%) and Candida albicans (5.5%) were the most frequently observed microorganisms. The incidence of PTB (before 34 and before 37 weeks of gestation) were significantly higher in the GBS-positive group than in the GBS-negative group (6.6% vs 0.5%, p = 0.001 and 9.8% vs 4.3%, p = 0.047). Our multivariable logistic regression analysis revealed that GBS colonization was a factor associated with PTB before 34 and before 37 weeks of gestation (Odds ratio [OR] 15.17; 95% confidence interval [CI] 3.73–61.74), and OR 2.42; 95%CI 1.01–5.91, respectively). Conclusions The present study found that vaginal GBS colonization in the early stage of pregnancy was associated with PTB. Our study indicates that patients at a high risk for PTB can be extracted by a simple method using conventional culture method.

Quality of life in breast cancer sufferers

2016 ◽  
Vol 29 (7) ◽  
pp. 721-732 ◽  
Author(s):  
Ahmed Essmat Shouman ◽  
Nahla Fawzy Abou El Ezz ◽  
Nivine Gado ◽  
Amal Mahmoud Ibrahim Goda
Keyword(s):  
Breast Cancer ◽  
Quality Of Life ◽  
Family Income ◽  
Early Stage ◽  
Functional Domain ◽  
Related Factors ◽  
Specific Patient ◽  
Content Type ◽  
Factors Affecting

Purpose – The purpose of this paper is to measure health-related quality of life (QOL) among patients with early stage cancer breast under curative treatment at department of oncology and nuclear medicine at Ain Shams University Hospitals. Identify factors affecting QOL among these patients. Design/methodology/approach – A cross-sectional study measured QOL among early stage female breast cancer (BC) patients and determined the main factors affecting their QOL. Three interviewer administered questionnaires were used. Findings – The physical domain mostly affected in BC patients and the functional domain least. Socio-demographic factors that significantly affected BC patients QOL scores were patient age, education, having children and family income. Specific patient characteristics include caregiver presence – a factor that affected different QOL scores. Age at diagnosis, affection in the side of the predominant hand, post-operative chemotherapy and difficulty in obtaining the medication were the disease-related factors that affected QOL scores. Originality/value – The final model predicting QOL for early stage female BC patients included age, education and difficulty in obtaining the medication as determinants for total QOL score. Carer presence was the specific patient characteristic that affected different QOL scores.

Antecedents of growth-oriented entrepreneurship before and during the Greek economic crisis

2017 ◽  
Vol 24 (3) ◽  
pp. 528-544 ◽  
Author(s):  
Ioannis Giotopoulos ◽  
Alexandra Kontolaimou ◽  
Aggelos Tsakanikas
Keyword(s):  
Work Experience ◽  
Early Stage ◽  
New Ventures ◽  
High Growth ◽  
Content Type ◽  
Crisis Period ◽  
Individual Level ◽  
Level Data ◽  
The Social ◽  
Before And After

Purpose The purpose of this paper is to explore potential drivers of high-growth intentions of early-stage entrepreneurs in Greece before and after the onset of the financial crisis of 2008. Design/methodology/approach To this end, the authors use individual-level data retrieved from Global Entrepreneurship Monitor annual surveys (2003-2015). Findings The results show that high-growth intentions of Greek entrepreneurs are driven by different factors in the crisis compared to the non-crisis period. Male entrepreneurs and entrepreneurs with significant work experience seem to be more likely to be engaged in growth-oriented new ventures during the crisis period. The same appears to hold for entrepreneurs who are motivated by an opportunity and also perceive future business opportunities in adverse economic conditions. On the other hand, the educational level and the social contacts of founders with other entrepreneurs are found to drive ambitious Greek entrepreneurship in the years before the crisis, while they were insignificant after the crisis outbreak. Originality/value Based on the concept of ambitious entrepreneurship, this study contributes to the literature by investigating the determinants of entrepreneurial high-growth expectations in the Greek context emphasizing the crisis period in comparison to the pre-crisis years.

Challenges faced by youth social entrepreneurs in Malaysia: career transition to become a social entrepreneur

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Nur Raihan Che Nawi ◽  
Mohd Mursyid Arshad ◽  
Steven Eric Krauss ◽  
Ismi Arif Ismail
Keyword(s):  
Social Entrepreneurship ◽  
Early Stage ◽  
Career Transition ◽  
Social Enterprises ◽  
Social Entrepreneur ◽  
Social Entrepreneurs ◽  
Content Type ◽  
Data Saturation ◽  
Analyse Data ◽  
Voice Recorder

Purpose The practice of social entrepreneurship has grown rapidly around the world, including in Malaysia where it is still considered to be at an early stage. Nevertheless, little is known about the career transition among youth who choose careers as social entrepreneurs. The purpose of this study is to explore the challenges faced by youth social entrepreneurs who run social enterprises in Malaysia. Design/methodology/approach This study used a qualitative approach to collect and analyse data to answer the research questions. Seven youth social entrepreneurs were interviewed until data saturation was met. An interview guide was created for the purposes of conducting the interviews. The interviews were recorded using a voice recorder. Data were transcribed verbatim and grouped in order to identify the codings, categories and themes. Findings The findings show the career transition to become a social entrepreneur, as well as the major challenges that youth social entrepreneurs face, which include acclimatising to the life and career of a social entrepreneur and not getting support from family. Practical implications The study findings are also significant for presenting valuable data on the experience of the developing social entrepreneur. The qualitative nature of the study provides valuable experiential insight into the lives and struggles of young social entrepreneurs in Malaysia. The findings will allow local authorities and social entrepreneurship regulatory agencies to design initiatives and plan actions intended to overcome the challenges. Originality/value This study makes an original contribution by showing that the process of career development as a social entrepreneur has given meaning to the informants. Despite presenting many challenges, social entrepreneurship has reinforced the role of youth social entrepreneurs, especially in relation to social responsibility.

Geochemical evaluation of the in-situ regolith of Madengi hills of Dodoma, Tanzania. Implication on bedrock mapping and delineating gold mineralization target

2021 ◽  
pp. geochem2021-074
Author(s):  
Godson Godfray
Keyword(s):  
Gold Mineralization ◽  
Early Stage ◽  
Shear Zones ◽  
Soil Geochemistry ◽  
Residual Soils ◽  
Content Type ◽  
Geochemical Evaluation ◽  
Supplementary Material ◽  
Pathfinder Elements

Successful gold exploration projects depend on a piece of clear information on the association between gold, trace elements, and mineralization controlling factors. The use of soil geochemistry has been an important tool in pinpointing exploration targets during the early stage of exploration. This study aimed to establish the gold distribution, the elemental association between gold and its pathfinder elements such as Cu, Zn, Ag, Ni, Co, Mn, Fe, Cd, V, Cr, Ti, Sc, In, and Se and identify lithologies contributing to the overlying residual soils. From cluster analysis, a high similarity level of 53.93% has been shown with Ag, Cd, and Se at a distance level of 0.92. Au and Se have a similarity level of 65.87% and a distance level of 0.68, hence is proposed to be the most promising pathfinder element. PCA, FA, and the Pearson's correlation matrix of transformed data of V, Cu, Ni, Fe, Mn, Cr, and Co and a stronger correlation between Pb and U, Th, Na, K, Sn, Y, Ta and Be shows that source gold mineralization might be associated with both hornblende gneisses interlayered with quartzite, tonalite, and tonalitic orthogneiss. From the contour map and gridded map of Au and its pathfinder elements, it has been noted that their anomalies and target generated are localized in the Northern part of the area. The targets trend ESE to WNW nearly parallel to the shear zones as a controlling factor of Au mineralization emplacement.Supplementary material:https://doi.org/10.6084/m9.figshare.c.5721965

A collaborative application of design thinking and Taguchi approach in restaurant service design for food wellbeing

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
G. Rejikumar ◽  
Asokan-Ajitha Aswathy ◽  
Ajay Jose ◽  
Mathew Sonia
Keyword(s):  
Food Industry ◽  
Design Thinking ◽  
Service Design ◽  
Service Research ◽  
Taguchi Approach ◽  
Simple Method ◽  
Content Type ◽  
Wellbeing Index ◽  
Food Movement ◽  
Practical Implications

PurposeInnovative restaurant service designs impart food wellbeing to diners. This research comprehends customer aspirations and concerns in a restaurant-dining experience to develop a service design that enhances the dining experience using the design thinking approach and evaluates its efficiency using the Taguchi method of robust design.Design/methodology/approachThe sequential incidence technique defines diners' needs, which, followed by brainstorming sessions, helped create multiple service designs with important attributes. Prototype narration, as a scenario, acted as the stimulus for evaluators to respond to the WHO-5 wellbeing index scale. Scenario-based Taguchi experiment with nine foodservice attributes in two levels and the wellbeing score as the response variable helped identify levels of critical factors that develop better FWB.FindingsThe study identified the best combination of factors and their preferred levels to maximize FWB in a restaurant. Food serving hygiene, followed by information about cuisine specification, and food movement in the restaurant, were important to FWB. The experiment revealed that hygiene perceptions are critical to FWB, and service designs have a significant role in it. Consumers prefer detailed information about the ingredients and recipe of the food they eat; being confident that there will be no unacceptable ingredients added to the food inspires their FWB.Research limitations/implicationsTheoretically, this study contributes to the growing body of literature on design thinking and transformative service research, especially in the food industry.Practical implicationsThis paper details a simple method to identify and evaluate important factors that optimize FWB in a restaurant. The proposed methodology will help service designers and technology experts devise settings that consider customer priorities and contribute to their experience.Originality/valueThis study helps to understand the application of design thinking and the Taguchi approach for creating robust service designs that optimize FWB.

Benefits and challenges to applying IPD: experiences from a Norwegian mega-project

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Monique Rieger Rodrigues ◽  
Søren Munch Lindhard
Keyword(s):  
Early Stage ◽  
Lessons Learned ◽  
Structured Interviews ◽  
Main Concept ◽  
Content Type ◽  
Positive Effects ◽  
Collaboration And Communication ◽  
Traditional Construction ◽  
Supporting Element ◽  
Early Phases

Purpose The traditional construction delivery method is challenged by low trust and collaboration issues, resulting in increased project costs. The integrated project delivery (IPD) method is developed, through a contractual agreement, to overcome these challenges by creating a common set of terms, expectations and project goals. Design/methodology/approach A singular construction case was followed during a four-month period. Data collection consisted of contract documents and a series of semi-structured interviews with representatives from the owner, design-group and contractors. Findings The IPD contract was found to have a number of positive effects; it improved project behavior (e.g. trust, collaboration and communication), increased ownership among project participants and improved buildability of the design, leading to fewer surprises and interruptions in the construction phase. The study also revealed a number of challenges including contractual and legal challenges and involving too many participants in the early phases. Moreover, co-location was identified as a particular important supporting element, to build relations and improve collaboration. Originality/value This research identified lessons learned from the application, as well as initial barriers and persistent barriers for implementing IPD. To improve IPD application the top three lessons were as follows: 1) the contractual documents should be adapted and signed at an early stage as this increases financial transparency, 2) cost estimates should be carried as an iterative process and project main concept be freezed at an early stage to increase understanding and minimize risks, 3) only the most important project developers should be involved in the early phases, to avoid going into detailed design issues before the main concept is completed.

Stock markets' reaction to COVID-19: evidence from the six WHO regions

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Anas Ali Al-Qudah ◽  
Asma Houcine
Keyword(s):  
Stock Returns ◽  
Stock Markets ◽  
Early Stage ◽  
Eastern Mediterranean ◽  
Abnormal Returns ◽  
Western Pacific ◽  
Content Type ◽  
Panel Data Regression ◽  
Daily Stock Returns ◽  
The Impact

PurposeThis study investigates the effects of the COVID-19 outbreak on daily stock returns for the six major affected WHO Regions, namely: Africa, Americas, Eastern Mediterranean, Europe, South-East Asia and Western Pacific.Design/methodology/approachThis study uses an event study method and panel-data regression models to examine the effect of the daily increase in the number of COVID-19 confirmed cases on daily stock returns from 1 March to 1 August 2020 for the leading stock market in major affected countries in the WHO regions.FindingsThe results reveal an adverse impact of the daily increasing number of COVID-19 cases on stock returns and stock markets fell quickly in response to the pandemic. The findings also suggest that negative market reaction was strong during the early stage of the outbreak between the 26th and 35th days after the initial confirmed cases. We further find that stock markets in the Western Pacific region experienced more negative abnormal returns as compared to other regions. The results also confirm that feelings of fear among investors turned out to be a mediator and a transmission channel for the effect of COVID-19 outbreak on the stock markets.Research limitations/implicationsThis study contributes to financial literature in two ways. First, we contribute to existing literature that has examined the effect of various catastrophes and crises on the stock markets Second, we contribute to the recent emerging literature that examines the impact of COVID-19 on financial markets.Practical implicationsThe study may have implications for policymakers to deal with this outbreak without triggering uncertainty in stock markets and reassure investors' confidence. The study may also be of interest to investors, managers, financial analysts by revealing how the stock markets quickly respond to outbreaks.Originality/valueThis study is the first study to examine the impact of the COVID-19 outbreak on the leading stock markets of the WHO regions.

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