Fabrication and characterization of epoxy/silica functionally graded composite material

NASA Astrophysics Data System (ADS)

Misra, N.; Kapusetti, G.; Pattanayak, D. K.; Kumar, A.

2011-09-01

Increased use of composites in aerospace and defense application induces the search for heat resistant material. In present study silica reinforced epoxy functionally graded material using quartz fabric is prepared with different thickness. The gradation in silica : epoxy matrix is maintained with one side pure epoxy to opposite side pure silica. Thermal and mechanical behaviour of the composites were studied. It was found that the temperature gradient of 350°C to 950°C could be maintained for 2 to 5 min if the thickness of insulating silica layer is increased from 0.5 mm to 16 mm. Mechanical properties such as flexural modulus and strength of FGM composites were also evaluated. Strength and modulus decreased with increase of insulating layer.

Synthesis and microwave absorbing characteristics of functionally graded carbonyl iron/polyurethane composites

NASA Astrophysics Data System (ADS)

Yang, R. B.; Liang, W. F.; Wu, C. H.; Chen, C. C.

2016-05-01

Radar absorbing materials (RAMs) also known as microwave absorbers, which can absorb and dissipate incident electromagnetic wave, are widely used in the fields of radar-cross section reduction, electromagnetic interference (EMI) reduction and human health protection. In this study, the synthesis of functionally graded material (FGM) (CI/Polyurethane composites), which is fabricated with semi-sequentially varied composition along the thickness, is implemented with a genetic algorithm (GA) to optimize the microwave absorption efficiency and bandwidth of FGM. For impedance matching and broad-band design, the original 8-layered FGM was obtained by the GA method to calculate the thickness of each layer for a sequential stacking of FGM from 20, 30, 40, 50, 60, 65, 70 and 75 wt% of CI fillers. The reflection loss of the original 8-layered FGM below -10 dB can be obtained in the frequency range of 5.12˜18 GHz with a total thickness of 9.66 mm. Further optimization reduces the number of the layers and the stacking sequence of the optimized 4-layered FGM is 20, 30, 65, 75 wt% with thickness of 0.8, 1.6, 0.6 and 1.0 mm, respectively. The synthesis and measurement of the optimized 4-layered FGM with a thickness of 4 mm reveal a minimum reflection loss of -25.2 dB at 6.64 GHz and its bandwidth below - 10 dB is larger than 12.8 GHz.

PREFACE: 12th International Symposium on Multiscale, Multifunctional and Functionally Graded Materials (FGM 2012)

NASA Astrophysics Data System (ADS)

Zhou, Zhangjian; Li, Jingfeng; Zhang, Lianmeng; Ge, Changchun

2013-03-01

The 12th International Symposium on Multiscale, Multifunctional and Functionally Graded Materials (FGM-2012) was held in Beijing, China, from 22-36 October 2012. This was part of a series of conferences organized every two years endorsed by International Advisory Committee for FGM's, which serves as a forum for scientists, educators, engineers and young students interested in the development of functionally graded materials (FGM). The series continues from the previous international symposium on FGM held in Sendai, Japan (1990), San Francisco, USA (1992), Lausanne, Switzerland (1994), Tsukuba, Japan (1996), Dresden, Germany (1998), Estes Park, USA (2000), Beijing, China (2002), Leuven, Belgium (2004), Hawaii, USA (2006), Sendai, Japan (2008) and Guimaraes, Portugal (2010). Functionally graded materials are non-uniform materials which are designed with embodied continuous spatial variations in composition and microstructure for the specific purpose of adjusting their thermal, structural, mechanical, biological or functional response to specific application conditions. Such multi-phase materials cover a range of space and time scales, and are best understood by means of a comprehensive multiscale, multiphysics approach. These kinds of materials are presently in the forefront of materials research, receiving worldwide attention. They have a broad range of applications including for example, biomedical, biomechanical, automotive, aerospace, mechanical, civil, nuclear, and naval engineering. New applications are continuously being discovered and developed. The objective of the FGM-2012 intends to provide opportunities for exchanging ideas and discussing state-of-the-art theories, techniques and applications in the fields of multiscale, multifunctional and FGM, through invited lectures, oral and poster presentations. FGM-2012 was organized and hosted by University of Science and Technology Beijing, China, together with Tsing-hua University and Wuhan University of Technology, and was supported by National Natural Science Foundation of China. On behalf of the organizing committee of FGM-2012, I express my great appreciation to their support of the symposium. Nearly 100 scholars and students from Japan, Brazil, Germany, Russia, United States of America, Portugal, France, Switzerland, Turkey, Singapore, China, and so on, attended FGM-2012, and 57 of the presented papers were collected and selected for publication. The subjects of these papers cover simulation and characterization, advanced fabrication technology, novel application of FGM and layer materials. I cordially thank all of the authors and attendees for their support, and my appreciation is also given to the advisory committee, organizing committee, and the conference volunteers for their hard work. Professor Zhangjian Zhou Proceedings Editor Beijing, December 2012 Committees International Advisory Committee Professor Glaucio H Paulino, USA Professor Marek-Jerzy Pindera, USA Professor Jeong-Ho Kim, USA Professor Emer Fazil Erdogan, USA Professor Dr Monika Willert-Porada, Germany Professor Emer Wolfgang G J Bunk, Germany Professor Omer Van Der Biest, Belgium Professor Michael M Gasik, Finland Professor Evgeny Levashov, Russia Professor Lianmeng Zhang, China Professor Qingjie Zhang, China Professor Wei Pan, China Professor Chang-Chun Ge, China Professor Jing-Feng Li, China Professor Zhangjian Zhou, China Associate Professor Serkan Dag, Turkey Professor Fernando A Rochinha, Brazil Professor Emilio C N Silva, Brazil Professor Luis August Rocha, Portugal Dr Sasa Novak, Slovenia Dr Masayuki Niino, Japan Professor Akira Kawasaki, Japan Professor Ichiro Shiota, Japan Dr Akinaga Kumakawa, Japan Dr Yoshikazu Shinohara, Japan Professor Kiyotaka Matsuura, Japan Professor Yoshinari Miyamoto, Japan Professor Takashi Goto, Japan Professor Yoshimi Watanabe, Japan Professor Kazuhiro Hasezaki, Japan Professor Soshu Kirihara, Japan Professor Emer Toshio Hirai, Japan Mr Choji Endou, Japan Dr Seiichi Uemura, Japan Local Organizing Committee Professor Changchun Ge (Chairman) Professor Xuanhui Qu Professor Jingfeng Li Professor Wei Pan Professor Lianmeng Zhang; Professor Qingjie Zhang Professor Qiang Shen Professor Jianghong Gong Dr Xianhui Li Dr Min Xia

High temperature thermo-physical properties of SPS-ed W-Cu functional gradient materials

NASA Astrophysics Data System (ADS)

Galatanu, Magdalena; Enculescu, Monica; Galatanu, Andrei

2018-02-01

The divertor of a fusion reactor like DEMO requires materials able to withstand high heat fluxes and neutron irradiation for several years. For the water cooling concept of this essential part of the reactor, the most likely plasma facing material will be W, while the heatsink material considered is CuCrZr or an improved version of such a Cu-based alloy. To realize W-Cu alloy joints able to withstand thousands of thermal cycles can be difficult due to the difference between the thermal expansion coefficients of these materials. In this work we investigate the possibility to realize such joints by using W-Cu functional gradient materials (FGMs) produced from nanometric and micrometric metallic powders mixtures and consolidated by spark plasma sintering at about 900 °C. Morphological and thermal properties investigations, performed for typical compositions, shows that the best results are obtained using powders with micrometric dimensions. A resulting 1 mm thick, 3 layers W-Cu FGM produced by this simple method shows a remarkable almost constant thermal conductivity value of 200 W m-1 K-1, from room temperature up to 1000 °C.

The use of functionally graded dental crowns to improve biocompatibility: a finite element analysis.

PubMed

Mahmoudi, Mojtaba; Saidi, Ali Reza; Hashemipour, Maryam Alsadat; Amini, Parviz

2018-02-01

In post-core crown restorations, the significant mismatch between stiffness of artificial crowns and dental tissues leads to stress concentration at the interfaces. The aim of the present study was to reduce the destructive stresses by using a class of inhomogeneous materials called functionally graded materials (FGMs). For the purpose of the study, a 3-dimentional computer model of a premolar tooth and its surrounding tissues were generated. A post-core crown restoration with various crown materials, homogenous and FGM materials, were simulated and analyzed by finite element method. Finite element and statistical analysis showed that, in case of oblique loading, a significant difference (p < 0.05) was found at the maximum von Mises stresses of the crown margin between FGM and homogeneous crowns. The maximum von Mises stresses of the crown margin generated by FGM crowns were lower than those generated by homogenous crowns (70.8 vs. 46.3 MPa) and alumina crown resulted in the highest von Mises stress at the crown margin (77.7 MPa). Crown materials of high modulus of elasticity produced high stresses at the cervical region. FGM crowns may reduce the stress concentration at the cervical margins and consequently reduce the possibility of fracture.

VPS Process for Copper Components in Thrust Chamber Assemblies

NASA Technical Reports Server (NTRS)

Elam, Sandra; Holmes, Richard; Hickman, Robert; McKechnie, Tim; Thom, George

2005-01-01

For several years, NASA's Marshall Space Flight Center (MSFC) has been working with Plasma Processes, Inc., (PPI) to fabricate thrust chamber liners with GRCop-84. Using the vacuum plasma spray (VPS) process, chamber liners of a variety of shapes and sizes have been created. Each has been formed as a functional gradient material (FGM) that creates a unique protective layer of NiCrAlY on the GRCop-84 liner s hot wall surface. Hot-fire testing was successfully conducted on a subscale unit to demonstrate the liner's durability and performance. Similar VPS technology has also been applied to create functional gradient coatings (FGC) on copper injector faceplates. Protective layers of NiCrAlY and zirconia were applied to both coaxial and impinging faceplate designs. Hot-fire testing is planned for these coated injectors in April 2005. The resulting material systems for both copper alloy components allows them to operate at higher temperatures with improved durability and operating margins.

Mapping the lack of public initiative against female genital mutilation in Denmark.

PubMed

Christoffersen, Gro Møller; Bruhn, Peter James; de Neergaard, Rosanna; Engel, Susanne; Naeser, Vibeke

2018-04-07

Female genital mutilation (FGM) is a harmful practice prevalent in 35 countries, mainly in Africa, as well as in some Middle Eastern countries and a few Asian countries. FGM comprises all procedures that involve partial or complete resection of, or other injury to, external female genitalia for non-medical reasons. The practice of FGM has spread to Western countries due to migration. The European Institute for Gender Equality recommend that FGM be combatted by nationally coordinated efforts through implementation of national action plans, guidelines for professionals as well as comprehensive research in the field. FGM was outlawed in Denmark 2003, but no national actions plan has been implemented. Instead, the task of combatting FGM is currently under the responsibility of local governments in the form of the 98 municipalities. The aim of this study is to investigate the Danish municipalities' efforts to prevent FGM on the local level, and whether these initiatives are in accordance with international recommendations and standards. All 98 Danish municipalities were invited to respond to a questionnaire regarding FGM in their respective municipalities. The inclusion process and questionnaire was designed after a pilot study, which included 29 municipalities. The questionnaire consisted of four overall areas of focus: "action plan", "registration", "information material" and "preventive initiatives". Demographic data were gathered from the 2017 census by Statistics Denmark. Risk countries were defined as countries with a tradition for FGM, identified from the 2016 UNICEF definition. A total of 67 municipalities participated in the study. At the time of census, 1.8% of the Danish population was immigrants with origins in risk countries. A total of 10.4% of the responding municipalities indicated to have implemented a specific action plan against FGM. A total of 7,5% had implemented specific preventive initiatives against FGM. Registration of reported FGM cases were indicated to be performed in 73.1% of the responding municipalities; however, only 17.9% stated to perform registration of FGM specifically as such, and not as general child abuse. Our study shows that the current situation of FGM registration and prevention being under local administrative responsibility in the 98 Danish municipalities has led to a severe lack of coordinated public initiative against FGM.

Inter-instrument calibration using magnetic field data from Flux Gate Magnetometer (FGM) and Electron Drift Instrument (EDI) onboard Cluster

NASA Astrophysics Data System (ADS)

Nakamura, R.; Plaschke, F.; Teubenbacher, R.; Giner, L.; Baumjohann, W.; Magnes, W.; Steller, M.; Torbert, R. B.; Vaith, H.; Chutter, M.; Fornaçon, K.-H.; Glassmeier, K.-H.; Carr, C.

2013-07-01

We compare the magnetic field data obtained from the Flux-Gate Magnetometer (FGM) and the magnetic field data deduced from the gyration time of electrons measured by the Electron Drift Instrument (EDI) onboard Cluster to determine the spin axis offset of the FGM measurements. Data are used from orbits with their apogees in the magnetotail, when the magnetic field magnitude was between about 20 nT and 500 nT. Offset determination with the EDI-FGM comparison method is of particular interest for these orbits, because no data from solar wind are available in such orbits to apply the usual calibration methods using the Alfvén waves. In this paper, we examine the effects of the different measurement conditions, such as direction of the magnetic field relative to the spin plane and field magnitude in determining the FGM spin-axis offset, and also take into account the time-of-flight offset of the EDI measurements. It is shown that the method works best when the magnetic field magnitude is less than about 128 nT and when the magnetic field is aligned near the spin-axis direction. A remaining spin-axis offset of about 0.4 ~ 0.6 nT was observed between July and October 2003. Using multi-point multi-instrument measurements by Cluster we further demonstrate the importance of the accurate determination of the spin-axis offset when estimating the magnetic field gradient.

Interinstrument calibration using magnetic field data from the flux-gate magnetometer (FGM) and electron drift instrument (EDI) onboard Cluster

NASA Astrophysics Data System (ADS)

Nakamura, R.; Plaschke, F.; Teubenbacher, R.; Giner, L.; Baumjohann, W.; Magnes, W.; Steller, M.; Torbert, R. B.; Vaith, H.; Chutter, M.; Fornaçon, K.-H.; Glassmeier, K.-H.; Carr, C.

2014-01-01

We compare the magnetic field data obtained from the flux-gate magnetometer (FGM) and the magnetic field data deduced from the gyration time of electrons measured by the electron drift instrument (EDI) onboard Cluster to determine the spin-axis offset of the FGM measurements. Data are used from orbits with their apogees in the magnetotail, when the magnetic field magnitude was between about 20 and 500 nT. Offset determination with the EDI-FGM comparison method is of particular interest for these orbits, because no data from solar wind are available in such orbits to apply the usual calibration methods using the Alfvén waves. In this paper, we examine the effects of the different measurement conditions, such as direction of the magnetic field relative to the spin plane and field magnitude in determining the FGM spin-axis offset, and also take into account the time-of-flight offset of the EDI measurements. It is shown that the method works best when the magnetic field magnitude is less than about 128 nT and when the magnetic field is aligned near the spin-axis direction. A remaining spin-axis offset of about 0.4 ∼ 0.6 nT was observed for Cluster 1 between July and October 2003. Using multipoint multi-instrument measurements by Cluster we further demonstrate the importance of the accurate determination of the spin-axis offset when estimating the magnetic field gradient.

Female genital mutilation and cutting: a systematic literature review of health professionals' knowledge, attitudes and clinical practice.

PubMed

Zurynski, Yvonne; Sureshkumar, Premala; Phu, Amy; Elliott, Elizabeth

2015-12-10

The World Health Organisation (WHO) estimates that 100-140 million girls and women have undergone female genital mutilation or cutting (FGM/C). FGM/C is an ancient cultural practice prevalent in 26 countries in Africa, the Middle East and Asia. With increased immigration, health professionals in high income countries including UK, Europe, North America and Australia care for women and girls with FGM/C. FGM/C is relevant to paediatric practice as it is usually performed in children, however, health professionals' knowledge, clinical practice, and attitudes to FGM/C have not been systematically described. We aimed to conduct a systematic review of the literature to address this gap. The review was conducted according to guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement and registered with the PROSPERO International Prospective Register of Systematic Reviews (CRD42015015540, http://www.crd.york.ac.uk/PROSPERO/). Articles published in English 2000-2014 which used quantitative methods were reviewed. Of 159 unique articles, 18 met inclusion criteria. The methodological quality was poor - six studies met seven of the eight quality criteria. Study participants included mainly obstetricians, gynaecologists and midwives (15 studies). We found no papers that studied paediatricians specifically, but two papers reported on subgroups of paediatricians within a mixed sample of health professionals. The 18 articles covered 13 different countries: eight from Africa and 10 from high income countries. Most health professionals were aware of the practice of FGM/C, but few correctly identified the four FGM/C categories defined by WHO. Knowledge about FGM/C legislation varied: 25% of professionals in a Sudanese study, 46 % of Belgian labour ward staff and 94 % of health professionals from the UK knew that FGM/C was illegal in their country. Health professionals from high income countries had cared for women or girls with FGM/C. The need to report children with FGM/C, or at risk of FGM/C, to child protection authorities was mentioned by only two studies. Further research is needed to determine health professionals' attitudes, knowledge and practice to support the development of educational materials and policy to raise awareness and to prevent this harmful practice.

Quadratic Solid⁻Shell Finite Elements for Geometrically Nonlinear Analysis of Functionally Graded Material Plates.

PubMed

Chalal, Hocine; Abed-Meraim, Farid

2018-06-20

In the current contribution, prismatic and hexahedral quadratic solid⁻shell (SHB) finite elements are proposed for the geometrically nonlinear analysis of thin structures made of functionally graded material (FGM). The proposed SHB finite elements are developed within a purely 3D framework, with displacements as the only degrees of freedom. Also, the in-plane reduced-integration technique is combined with the assumed-strain method to alleviate various locking phenomena. Furthermore, an arbitrary number of integration points are placed along a special direction, which represents the thickness. The developed elements are coupled with functionally graded behavior for the modeling of thin FGM plates. To this end, the Young modulus of the FGM plate is assumed to vary gradually in the thickness direction, according to a volume fraction distribution. The resulting formulations are implemented into the quasi-static ABAQUS/Standard finite element software in the framework of large displacements and rotations. Popular nonlinear benchmark problems are considered to assess the performance and accuracy of the proposed SHB elements. Comparisons with reference solutions from the literature demonstrate the good capabilities of the developed SHB elements for the 3D simulation of thin FGM plates.

An analytical method for free vibration analysis of functionally graded beams with edge cracks

NASA Astrophysics Data System (ADS)

Wei, Dong; Liu, Yinghua; Xiang, Zhihai

2012-03-01

In this paper, an analytical method is proposed for solving the free vibration of cracked functionally graded material (FGM) beams with axial loading, rotary inertia and shear deformation. The governing differential equations of motion for an FGM beam are established and the corresponding solutions are found first. The discontinuity of rotation caused by the cracks is simulated by means of the rotational spring model. Based on the transfer matrix method, then the recurrence formula is developed to get the eigenvalue equations of free vibration of FGM beams. The main advantage of the proposed method is that the eigenvalue equation for vibrating beams with an arbitrary number of cracks can be conveniently determined from a third-order determinant. Due to the decrease in the determinant order as compared with previous methods, the developed method is simpler and more convenient to analytically solve the free vibration problem of cracked FGM beams. Moreover, free vibration analyses of the Euler-Bernoulli and Timoshenko beams with any number of cracks can be conducted using the unified procedure based on the developed method. These advantages of the proposed procedure would be more remarkable as the increase of the number of cracks. A comprehensive analysis is conducted to investigate the influences of the location and total number of cracks, material properties, axial load, inertia and end supports on the natural frequencies and vibration mode shapes of FGM beams. The present work may be useful for the design and control of damaged structures.

Application of C/C composites to the combustion chamber of rocket engines. Part 1: Heating tests of C/C composites with high temperature combustion gases

NASA Astrophysics Data System (ADS)

Tadano, Makoto; Sato, Masahiro; Kuroda, Yukio; Kusaka, Kazuo; Ueda, Shuichi; Suemitsu, Takeshi; Hasegawa, Satoshi; Kude, Yukinori

1995-04-01

Carbon fiber reinforced carbon composite (C/C composite) has various superior properties, such as high specific strength, specific modulus, and fracture strength at high temperatures of more than 1800 K. Therefore, C/C composite is expected to be useful for many structural applications, such as combustion chambers of rocket engines and nose-cones of space-planes, but C/C composite lacks oxidation resistivity in high temperature environments. To meet the lifespan requirement for thermal barrier coatings, a ceramic coating has been employed in the hot-gas side wall. However, the main drawback to the use of C/C composite is the tendency for delamination to occur between the coating layer on the hot-gas side and the base materials on the cooling side during repeated thermal heating loads. To improve the thermal properties of the thermal barrier coating, five different types of 30-mm diameter C/C composite specimens constructed with functionally gradient materials (FGM's) and a modified matrix coating layer were fabricated. In this test, these specimens were exposed to the combustion gases of the rocket engine using nitrogen tetroxide (NTO) / monomethyl hydrazine (MMH) to evaluate the properties of thermal and erosive resistance on the thermal barrier coating after the heating test. It was observed that modified matrix and coating with FGM's are effective in improving the thermal properties of C/C composite.

Structural kinematics based damage zone prediction in gradient structures using vibration database

NASA Astrophysics Data System (ADS)

Talha, Mohammad; Ashokkumar, Chimpalthradi R.

2014-05-01

To explore the applications of functionally graded materials (FGMs) in dynamic structures, structural kinematics based health monitoring technique becomes an important problem. Depending upon the displacements in three dimensions, the health of the material to withstand dynamic loads is inferred in this paper, which is based on the net compressive and tensile displacements that each structural degree of freedom takes. These net displacements at each finite element node predicts damage zones of the FGM where the material is likely to fail due to a vibration response which is categorized according to loading condition. The damage zone prediction of a dynamically active FGMs plate have been accomplished using Reddy's higher-order theory. The constituent material properties are assumed to vary in the thickness direction according to the power-law behavior. The proposed C0 finite element model (FEM) is applied to get net tensile and compressive displacement distributions across the structures. A plate made of Aluminum/Ziconia is considered to illustrate the concept of structural kinematics-based health monitoring aspects of FGMs.

The Influence of Al2O3 Powder Morphology on the Properties of Cu-Al2O3 Composites Designed for Functionally Graded Materials (FGM)

NASA Astrophysics Data System (ADS)

Strojny-Nędza, Agata; Pietrzak, Katarzyna; Węglewski, Witold

2016-08-01

In order to meet the requirements of an increased efficiency applying to modern devices and in more general terms science and technology, it is necessary to develop new materials. Combining various types of materials (such as metals and ceramics) and developing composite materials seem to be suitable solutions. One of the most interesting materials includes Cu-Al2O3 composite and gradient materials (FGMs). Due to their potential properties, copper-alumina composites could be used in aerospace industry as rocket thrusters and components in aircraft engines. The main challenge posed by copper matrix composites reinforced by aluminum oxide particles is obtaining the uniform structure with no residual porosity (existing within the area of the ceramic phase). In the present paper, Cu-Al2O3 composites (also in a gradient form) with 1, 3, and 5 vol.% of aluminum oxide were fabricated by the hot pressing and spark plasma sintering methods. Two forms of aluminum oxide (αAl2O3 powder and electrocorundum) were used as a reinforcement. Microstructural investigations revealed that near fully dense materials with low porosity and a clear interface between the metal matrix and ceramics were obtained in the case of the SPS method. In this paper, the properties (mechanical, thermal, and tribological) of composite materials were also collected and compared. Technological tests were preceded by finite element method analyses of thermal stresses generated in the gradient structure, and additionally, the role of porosity in the formation process of composite properties was modeled. Based on the said modeling, technological conditions for obtaining FGMs were proposed.

Vibration analysis of FG cylindrical shells with power-law index using discrete singular convolution technique

NASA Astrophysics Data System (ADS)

Mercan, Kadir; Demir, Çiǧdem; Civalek, Ömer

2016-01-01

In the present manuscript, free vibration response of circular cylindrical shells with functionally graded material (FGM) is investigated. The method of discrete singular convolution (DSC) is used for numerical solution of the related governing equation of motion of FGM cylindrical shell. The constitutive relations are based on the Love's first approximation shell theory. The material properties are graded in the thickness direction according to a volume fraction power law indexes. Frequency values are calculated for different types of boundary conditions, material and geometric parameters. In general, close agreement between the obtained results and those of other researchers has been found.

Refined hierarchical kinematics quasi-3D Ritz models for free vibration analysis of doubly curved FGM shells and sandwich shells with FGM core

NASA Astrophysics Data System (ADS)

Fazzolari, Fiorenzo A.; Carrera, Erasmo

2014-02-01

In this paper, the Ritz minimum energy method, based on the use of the Principle of Virtual Displacements (PVD), is combined with refined Equivalent Single Layer (ESL) and Zig Zag (ZZ) shell models hierarchically generated by exploiting the use of Carrera's Unified Formulation (CUF), in order to engender the Hierarchical Trigonometric Ritz Formulation (HTRF). The HTRF is then employed to carry out the free vibration analysis of doubly curved shallow and deep functionally graded material (FGM) shells. The PVD is further used in conjunction with the Gauss theorem to derive the governing differential equations and related natural boundary conditions. Donnell-Mushtari's shallow shell-type equations are given as a particular case. Doubly curved FGM shells and doubly curved sandwich shells made up of isotropic face sheets and FGM core are investigated. The proposed shell models are widely assessed by comparison with the literature results. Two benchmarks are provided and the effects of significant parameters such as stacking sequence, boundary conditions, length-to-thickness ratio, radius-to-length ratio and volume fraction index on the circular frequency parameters and modal displacements are discussed.

Obstetric outcomes for women with female genital mutilation at an Australian hospital, 2006-2012: a descriptive study.

PubMed

Varol, Nesrin; Dawson, Angela; Turkmani, Sabera; Hall, John J; Nanayakkara, Susie; Jenkins, Greg; Homer, Caroline S E; McGeechan, Kevin

2016-10-28

Women, who have been subjected to female genital mutilation (FGM), can suffer serious and irreversible physical, psychological and psychosexual complications. They have more adverse obstetric outcomes as compared to women without FGM. Exploratory studies suggest radical change to abandonment of FGM by communities after migration to countries where FGM is not prevalent. Women who had been subjected to FGM as a child in their countries of origin, require specialised healthcare to reduce complications and further suffering. Our study compared obstetric outcomes in women with FGM to women without FGM who gave birth in a metropolitan Australian hospital with expertise in holistic FGM management. The obstetric outcomes of one hundred and ninety-six women with FGM who gave birth between 2006 and 2012 at a metropolitan Australian hospital were analysed. Comparison was made with 8852 women without FGM who gave birth during the same time period. Data were extracted from a database specifically designed for women with FGM and managed by midwives specialised in care of these women, and a routine obstetric database, ObstetriX. The accuracy of data collection on FGM was determined by comparing these two databases. All women with FGM type 3 were deinfibulated antenatally or during labour. The outcome measures were (1) maternal: accuracy and grade of FGM classification, caesarean section, instrumental birth, episiotomy, genital tract trauma, postpartum blood loss of more than 500 ml; and (2) neonatal: low birth weight, admission to a special care nursery, stillbirth. The prevalence of FGM in women who gave birth at the metropolitan hospital was 2 to 3 %. Women with FGM had similar obstetric outcomes to women without FGM, except for statistically significant higher risk of first and second degree perineal tears, and caesarean section. However, none of the caesarean sections were performed for FGM indications. The ObstetriX database was only 35 % accurate in recording the correct FGM type. Women with FGM had similar obstetric outcomes to women without FGM in an Australian metropolitan hospital with expertise in FGM management. Specialised FGM services with clinical practice guideline and education of healthcare professionals may increase the detection rate of FGM and improve obstetric management of women with FGM.

Modeling the Capillary Pressure for the Migration of the Liquid Phase in Granular Solid-Liquid-Vapor Systems: Application to the Control of the Composition Profile in W-Cu FGM Materials

NASA Astrophysics Data System (ADS)

Missiaen, Jean-Michel; Raharijaona, Jean-Joël; Delannay, Francis

2016-11-01

A model is developed to compute the capillary pressure for the migration of the liquid phase out or into a uniform solid-liquid-vapor system. The capillary pressure is defined as the reduction of the overall interface energy per volume increment of the transferred fluid phase. The model takes into account the particle size of the solid particle aggregate, the packing configuration (coordination number, porosity), the volume fractions of the different phases, and the values of the interface energies in the system. The model is used for analyzing the stability of the composition profile during processing of W-Cu functionally graded materials combining a composition gradient with a particle size gradient. The migration pressure is computed with the model in two stages: (1) just after the melting of copper, i.e., when sintering and shape accommodation of the W particle aggregate can still be neglected and (2) at high temperature, when the system is close to full density with equilibrium particle shape. The model predicts well the different stages of liquid-phase migration observed experimentally.

Thermomechanical response of metal-ceramic graded composites for high-temperature aerospace applications

NASA Astrophysics Data System (ADS)

Deierling, Phillip Eugene

Airframes operating in the hypersonic regime are subjected to complex structural and thermal loads. Structural loads are a result of aggressive high G maneuvers, rapid vehicle acceleration and deceleration, and dynamic pressure, while thermal loads are a result of aerodynamic heating. For such airframes, structural members are typically constructed from steel, titanium and nickel alloys. However, with most materials, rapid elevations in temperature lead to undesirable changes in material properties. In particular, reductions in strength and stiffness are observed, along with an increase in thermal conductivity, specific heat and thermal expansion. Thus, hypersonic airframes are typically designed with external insulation, active cooling or a thermal protection system (TPS) added to the structure to protect the underling material from the effects of temperature. Such thermal protection may consist of adhesively bonded, pinned, and bolted thermal protection layers over exterior panels. These types of attachments create abrupt changes in thermal expansion and stiffness that make the structure susceptible to cracking and debonding as well as adding mass to the airframe. One of the promising materials concepts for extreme environments that was introduced in the past is the so-called Spatially Tailored Advanced Thermal Structures (STATS). The concept of STATS is rooted in functionally graded materials (FGMs), in which a directional variation of material properties exists. These materials are essentially composites and consist of two or more phases of distinct materials in which the volume fractions of each phase continuously change in space. Here, the graded material will serve a dual-purpose role as both the structural/skin member and thermal management with the goal of reducing the weight of the structure while maintaining structural soundness. This is achieved through the ability to tailor material properties to create a desired or enhanced thermomechanical response through spatial variation (e.g. grading). The objective of this study is to present a computational framework for modeling and evaluating the thermomechanical response of STATS and FGMs for highly maneuverable hypersonic (Mach > 5) airframes. To meet the objective of this study, four key steps have been defined to study the thermomechanical response of such materials in extreme environments. They involve: (1) modeling of graded microstructures; (2) validation of analytical and numerical modeling techniques for graded microstructures; (3) determination of effective properties of variable composition composites; (4) parametric studies to evaluate the performance of FGMs for use in the hypersonic operating environment; (5) optimization of the material spatial grading in hypersonic panels aiming to improve the thermomechanical performance. Modeling of graded microstructures, representing particulate reinforced FGMs, has been accomplished using power law distribution functions to specify the spatial variation of the constituents. Artificial microstructures consisting of disks and spheres have been generated using developed algorithms. These algorithms allow for the creation of dense packing fractions up to 0.61 and 0.91 for 2D and 3D geometry, respectively. Effective properties of FGMs are obtained using micromechanics models and finite element analysis of representative volume elements (RVEs). Two approaches have been adopted and compared to determine the proper RVE for materials with graded microstructures. In the first approach, RVEs are generated by considering regions that have a uniform to slow variation in material composition (i.e., constant volume fraction), resulting in statistically homogenous piecewise RVEs of the graded microstructure neglecting interactions from neighboring cells. In the second approach, continuous RVEs are generated by considering the entire FGM. Here it is presumed that modeling of the complete variation in a microstructure may influence the surrounding layers due to the interactions of varying material composition, particularly when there is a steep variation in material composition along the grading direction. To determine these effects of interlayer interactions, FGM microstructures were generated using three different types of material grading functions, linear, quadratic and square root, providing uniform, gradual and steep variations, respectively. Two- and three-dimensional finite element analysis was performed to determine the effective temperature-dependent material properties of the composite over a wide temperature range. The outcome of the computational analysis show that the similar effective properties are obtained by each of the modeling approaches. Furthermore, the obtained computational results for effective elastic, thermal, and thermal expansion properties are consistent with the known analytical bounds. Resulting effective temperature-dependent material properties were used to evaluate the time-dependent thermostructural response and effectiveness of FGM structural panels. Structural panels are subjected to time- and spatial-dependent thermal and mechanical loads resulting from hypersonic flight over a representative trajectory. Mechanical loads are the by-product of aggressive maneuvering at high air speeds and angles of attack. Thermal loads as a result of aerodynamic heating are applied to the material systems as laminar, turbulent and transitional heat flux on the outer surface. Laminar and turbulent uniform heat fluxes are used to evaluate the effectiveness of FGM panels graded in the through-thickness direction only. Transitional heat fluxes are used to evaluate the effectiveness of FGMs graded in two principal directions, e.g., through-thickness and the surface parallel to flow. The computational results indicate that when subjected to uniform surface heat flux, the graded material system can eliminate through-thickness temperature gradients that are otherwise present in traditional thermal protection systems. Furthermore, two-dimensional graded material systems can also eliminate through-thickness temperature gradients and significantly reduce in-plane surface temperature gradients when subjected to non-uniform surface aerodynamic heating.

Process Of Bonding Copper And Tungsten

DOEpatents

Slattery, Kevin T.; Driemeyer, Daniel E.; Davis, John W.

2000-07-18

Process for bonding a copper substrate to a tungsten substrate by providing a thin metallic adhesion promoting film bonded to a tungsten substrate and a functionally graded material (FGM) interlayer bonding the thin metallic adhesion promoting film to the copper substrate. The FGM interlayer is formed by sintering a stack of individual copper and tungsten powder blend layers having progressively higher copper content/tungsten content, by volume, ratio values in successive powder blend layers in a lineal direction extending from the tungsten substrate towards the copper substrate. The resulting copper to tungsten joint well accommodates the difference in the coefficient of thermal expansion of the materials.

Wsbnd Cu functionally graded material: Low temperature fabrication and mechanical characterization

NASA Astrophysics Data System (ADS)

Yusefi, Ali; Parvin, Nader; Mohammadi, Hossein

2018-04-01

In this study, we fabricated and characterized a Wsbnd Cu functionally graded material (FGM) with 11 layers, including a pure copper layer. Samples were prepared by mixing a mechanically alloyed Nisbnd Mnsbnd Cu powder with W and Cu powders, stacking the powders, pressing the stacked layers, and finally sintering at 1000 °C. The utilization of a Nisbnd Mnsbnd Cu system may reduce the cost but without losing the good sintering behavior and physical and mechanical properties. The composition of the material was analyzed based on scanning electron microscopy images and by energy dispersive X-ray spectroscopy mapping, which indicated that in the presence of Ni and Mn, the Cu atoms could diffuse into the W particles. All of the layers had a very high relative density, thereby indicating their densification and excellent sintering behavior. We also found that the porosity values in the Cu phase remained unchanged at approximately 2.39% across the FGM. Mechanical measurements showed that the hardness (72%), modulus of elasticity (61%), and ultimate tensile strength (58%) increased with the W content across the Wsbnd Cu FGM, whereas the fracture toughness (KIC) varied in the opposite manner (minimum of 4.52 MPa/m0.5).

Female genital mutilation/cutting: will it continue?

PubMed

Mohammed, Ghada F; Hassan, Magdy M; Eyada, Moustafa M

2014-11-01

Female genital mutilation/cutting (FGM/C) is a prevalent, deeply rooted traditional practice in Egypt. Specification of the motives behind the continuation of FGM/C in Egyptian community and evaluation of the sexual function in women with FGM/C. This cross-sectional study, involved 2,106 sexually active female participants with FGM/C. Full history-taking and general examination to evaluate the type of FGM/C were conducted. Sexual function was assessed by using the Female Sexual Function Index (FSFI) questionnaire. Enumerate and specify the motivational factors and its percent among the participants. The correlation between FGM/C and FSFI domain scores was done with Pearson's correlation. Tradition, cleanliness, and virginity were the most common motives empowering the continuation of FGM/C (100%), followed by men's wish, esthetic factors, marriage, and religion factors (45.2-100%). Type I FGM/C was the most common, followed by type II. There was only negative correlation between the type II FGM/C and sexual satisfaction. No statistically significant difference between type I and non-FGM/C was found. FGM/C remains high. A variety of socio-cultural myths, religious misbelievers, and hygienic and esthetic concerns were behind the FGM/C. Overall, a large proportion of the participants supported the continuation of FGM/C in spite of adverse effect and sexual dysfunction associated with FGM/C. © 2014 International Society for Sexual Medicine.

Female Genital Mutilation in Sierra Leone: Forms, Reliability of Reported Status, and Accuracy of Related Demographic and Health Survey Questions

PubMed Central

Grant, Donald S.; Berggren, Vanja

2013-01-01

Objective. To determine forms of female genital mutilation (FGM), assess consistency between self-reported and observed FGM status, and assess the accuracy of Demographic and Health Surveys (DHS) FGM questions in Sierra Leone. Methods. This cross-sectional study, conducted between October 2010 and April 2012, enrolled 558 females aged 12–47 from eleven antenatal clinics in northeast Sierra Leone. Data on demography, FGM status, and self-reported anatomical descriptions were collected. Genital inspection confirmed the occurrence and extent of cutting. Results. All participants reported FGM status; 4 refused genital inspection. Using the WHO classification of FGM, 31.7% had type Ib; 64.1% type IIb; and 4.2% type IIc. There was a high level of agreement between reported and observed FGM prevalence (81.2% and 81.4%, resp.). There was no correlation between DHS FGM responses and anatomic extent of cutting, as 2.7% reported pricking; 87.1% flesh removal; and 1.1% that genitalia was sewn closed. Conclusion. Types I and II are the main forms of FGM, with labia majora alterations in almost 5% of cases. Self-reports on FGM status could serve as a proxy measurement for FGM prevalence but not for FGM type. The DHS FGM questions are inaccurate for determining cutting extent. PMID:24204384

Recyclable fluorescent gold nanocluster membrane for visual sensing of copper(II) ion in aqueous solution.

PubMed

Lin, Zhijin; Luo, Fenqiang; Dong, Tongqing; Zheng, Liyan; Wang, Yaxian; Chi, Yuwu; Chen, Guonan

2012-05-21

Recently, metal-selective fluorescent chemosensors have attracted intense attention for their simple and real-time tracking of metal ions in environmental samples. However, most of the existing fluorescent sensors are one-off sensors and thus suffer from large amount of reagent consumption, significant experimental cost and raising the risk of environmental pollution. In this paper, we developed a green (low reagent consumption, low-toxicity reagent use), recyclable, and visual sensor for Cu(2+) in aqueous solution by using a fluorescent gold nanoclusters membrane (FGM) as the sensing unit, basing on our findings on gold nanoclusters (Au NCs) that the bovine serum albumin (BSA)-coated Au NCs exhibit excellent membrane-forming ability under the isoelectric point of BSA, and thus enable us to obtain a new type of sensing membrane (i.e. FGM) by denaturing Au NCs; the fluorescence of FGM can be significantly quenched by Cu(2+) ion, and the quenched fluorescence can be totally recovered by histidine; the as-prepared FGM is very stable and recyclable, which makes it an ideal sensing material.

An exploration of attitudes towards female genital mutilation (FGM) in men and women accessing FGM clinical services in London: a pilot study.

PubMed

Larsson, Martina; Cohen, Pollyanna; Hann, Gayle; Creighton, Sarah M; Hodes, Deborah

2018-03-21

This pilot study researched the attitudes towards and the knowledge of female genital mutilation (FGM) in adult women with FGM and their partners. The participant population consisted of English-speaking women and men over 18 years old attending specialist FGM clinics in two London hospitals. The participants completed a questionnaire on the attitudes and the knowledge of FGM, which were adapted with permission from the United Nations Children's Fund and the United States Agency for International Development household surveys. 54 participants (51 women, 3 men) took part in the surveys. 89% of participants thought that FGM should be stopped (95%CI: 0.81-0.97) and 72% said they knew FGM is illegal in the United Kingdom (UK). 15% reported that FGM caused no danger, or were unaware of any danger to women's health. This study demonstrates the opposition to FGM by participants, but some lack of knowledge regarding the legal and health implications. The exploration of attitudes in diaspora community groups is often cited as key to safeguarding girls from FGM. This is one of the first UK studies of individuals from FGM-practising communities, and we recommend use of the study questionnaires for a multicentre, cross-community study. Impact statement What is already known about this subject? Women and children are affected by female genital mutilation (FGM) globally and in the United Kingdom (UK). The majority of knowledge on practices and the attitudes towards FGM comes from UNICEF and USAID research in Africa and there is scant data on FGM practices in diaspora communities in the UK. What do the results of this study add? This study provides an appropriate questionnaire and protocol for use in community-based national research to improve healthcare for women by collecting up-to-date data on the attitudes towards FGM among the members of FGM-practising communities in the UK. What are the implications of these findings for clinical practice and further research? The implications of the results of this study are that health professionals need to understand that patients do not always know the law on FGM, even after a consultation. Health and social care professionals are placed in a unique position to work with community members to educate men and women to end FGM.

Geographic Variation and Factors Associated with Female Genital Mutilation among Reproductive Age Women in Ethiopia: A National Population Based Survey

PubMed Central

Setegn, Tesfaye; Lakew, Yihunie; Deribe, Kebede

2016-01-01

Background Female genital mutilation (FGM) is a common traditional practice in developing nations including Ethiopia. It poses complex and serious long-term health risks for women and girls and can lead to death. In Ethiopia, the geographic distribution and factors associated with FGM practices are poorly understood. Therefore, we assessed the spatial distribution and factors associated with FGM among reproductive age women in the country. Method We used population based national representative surveys. Data from two (2000 and 2005) Ethiopian demographic and health surveys (EDHS) were used in this analysis. Briefly, EDHS used a stratified, two-stage cluster sampling design. A total of 15,367 (from EDHS 2000) and 14,070 (from EDHS 2005) women of reproductive age (15–49 years) were included in the analysis. Three outcome variables were used (prevalence of FGM among women, prevalence of FGM among daughters and support for the continuation of FGM). The data were weighted and descriptive statistics (percentage change), bivariate and multivariable logistic regression analyses were carried out. Multicollinearity of variables was assessed using variance inflation factors (VIF) with a reference value of 10 before interpreting the final output. The geographic variation and clustering of weighted FGM prevalence were analyzed and visualized on maps using ArcGIS. Z-scores were used to assess the statistical difference of geographic clustering of FGM prevalence spots. Result The trend of FGM weighted prevalence has been decreasing. Being wealthy, Muslim and in higher age categories are associated with increased odds of FGM among women. Similarly, daughters from Muslim women have increased odds of experiencing FGM. Women in the higher age categories have increased odds of having daughters who experience FGM. The odds of FGM among daughters decrease with increased maternal education. Mass media exposure, being wealthy and higher paternal and maternal education are associated with decreased odds of women’s support of FGM continuation. FGM prevalence and geographic clustering showed variation across regions in Ethiopia. Conclusion Individual, economic, socio-demographic, religious and cultural factors played major roles in the existing practice and continuation of FGM. The significant geographic clustering of FGM was observed across regions in Ethiopia. Therefore, targeted and integrated interventions involving religious leaders in high FGM prevalence spot clusters and addressing the socio-economic and geographic inequalities are recommended to eliminate FGM. PMID:26741488

Geographic Variation and Factors Associated with Female Genital Mutilation among Reproductive Age Women in Ethiopia: A National Population Based Survey.

PubMed

Setegn, Tesfaye; Lakew, Yihunie; Deribe, Kebede

2016-01-01

Female genital mutilation (FGM) is a common traditional practice in developing nations including Ethiopia. It poses complex and serious long-term health risks for women and girls and can lead to death. In Ethiopia, the geographic distribution and factors associated with FGM practices are poorly understood. Therefore, we assessed the spatial distribution and factors associated with FGM among reproductive age women in the country. We used population based national representative surveys. Data from two (2000 and 2005) Ethiopian demographic and health surveys (EDHS) were used in this analysis. Briefly, EDHS used a stratified, two-stage cluster sampling design. A total of 15,367 (from EDHS 2000) and 14,070 (from EDHS 2005) women of reproductive age (15-49 years) were included in the analysis. Three outcome variables were used (prevalence of FGM among women, prevalence of FGM among daughters and support for the continuation of FGM). The data were weighted and descriptive statistics (percentage change), bivariate and multivariable logistic regression analyses were carried out. Multicollinearity of variables was assessed using variance inflation factors (VIF) with a reference value of 10 before interpreting the final output. The geographic variation and clustering of weighted FGM prevalence were analyzed and visualized on maps using ArcGIS. Z-scores were used to assess the statistical difference of geographic clustering of FGM prevalence spots. The trend of FGM weighted prevalence has been decreasing. Being wealthy, Muslim and in higher age categories are associated with increased odds of FGM among women. Similarly, daughters from Muslim women have increased odds of experiencing FGM. Women in the higher age categories have increased odds of having daughters who experience FGM. The odds of FGM among daughters decrease with increased maternal education. Mass media exposure, being wealthy and higher paternal and maternal education are associated with decreased odds of women's support of FGM continuation. FGM prevalence and geographic clustering showed variation across regions in Ethiopia. Individual, economic, socio-demographic, religious and cultural factors played major roles in the existing practice and continuation of FGM. The significant geographic clustering of FGM was observed across regions in Ethiopia. Therefore, targeted and integrated interventions involving religious leaders in high FGM prevalence spot clusters and addressing the socio-economic and geographic inequalities are recommended to eliminate FGM.

Scale-dependent effects on wave propagation in magnetically affected single/double-layered compositionally graded nanosize beams

NASA Astrophysics Data System (ADS)

Ebrahimi, Farzad; Barati, Mohammad Reza

2018-04-01

This article deals with the wave propagation analysis of single/double layered functionally graded (FG) size-dependent nanobeams in elastic medium and subjected to a longitudinal magnetic field employing nonlocal elasticity theory. Material properties of nanobeam change gradually according to the sigmoid function. Applying an analytical solution, the acoustical and optical dispersion relations are explored for various wave number, nonlocality parameter, material composition, elastic foundation constants, and magnetic field intensity. It is found that frequency and phase velocity of waves propagating in S-FGM nanobeam are significantly affected by these parameters. Also, presence of cut-off and escape frequencies in wave propagation analysis of embedded S-FGM nanobeams is investigated.

Female Genital Mutilation/Cutting among Women of Somali and Kurdish Origin in Finland.

PubMed

Koukkula, Mimmi; Keskimäki, Ilmo; Koponen, Päivikki; Mölsä, Mulki; Klemetti, Reija

2016-09-01

The tradition of female genital mutilation/cutting (FGM/C) has spread in Europe as a result of immigration. Although it is known to have negative health impacts, the exact prevalence of FGM/C and its health effects in Finland are unknown. This study explores the prevalence of FGM/C, the sociodemographic characteristics associated with it, and its health effects among women of Somali and Kurdish origin in Finland. Data were obtained from the Migrant Health and Well Being Study carried out in 2010-2012. This study uses data from interviews with Somali (N = 165) and Kurdish origin (N = 224) women. The participation rate was 37 percent for Somali and 54 percent for Kurdish origin women. The prevalence of FGM/C was 69 percent among those of Somali origin and 32 percent among those of Kurdish origin. Having no education and older age were significantly associated with FGM/C, as was marriage amongst women of Somali origin, and the practice of Islam among women of Kurdish origin. Reporting good self-perceived health was more common among women without FGM/C. Outpatient visits to medical doctors were less common among women of Somali origin with FGM/C, compared with women without FGM/C. About 26 percent of Somali origin and 39 percent of Kurdish origin women with FGM/C reported reproductive or other health problems because of FGM/C. FGM/C is more common in Finland than previously assumed, particularly among women of Kurdish origin. Women with FGM/C need improved access to culturally competent health services to address the health impacts of FGM/C. Education and outreach to immigrant communities to prevent future FGM/C are also urgently needed. © 2016 Wiley Periodicals, Inc.

Female genital mutilation reversal: a general approach.

PubMed

Anand, Mallika; Stanhope, Todd J; Occhino, John A

2014-07-01

Female genital mutilation (FGM) is a violation of human rights; yet, more than 100 million females are estimated to have undergone the procedure worldwide. There is an increased need for physician education in treating FGM. Female pelvic surgeons have a unique opportunity to treat this population of patients. Here, we depict the classification of FGM and a general approach to FGM reversal. We specifically address the procedure of type III FGM reversal, or defibulation. In this video, we first highlight the importance of the problem of FGM. Next, we present the classification of FGM using an original, simple, schematic diagram highlighting they key anatomic structures involved in the four types of FGM. We then present a simple case of reversal of type III FGM, a procedure also known as defibulation. After depicting the surgical procedure, we discuss clinical results and summarize key principles of the defibulation procedure. Our patient was a 25-year-old woman who had undergone type III FGM as a child in Somalia. She desired restoration of vaginal function. We performed a reversal, and her postoperative course was uncomplicated. By 6 weeks postoperatively, she was able to engage in sexual intercourse without dyspareunia. FGM is a problem at the doorsteps of female pelvic medicine and reconstructive surgery. Our video demonstrates a basic surgical approach that can be applied to simple cases of type III FGM presenting to the female pelvic surgeon.

Health care-seeking patterns for female genital mutilation/cutting among young Somalis in Norway.

PubMed

Mbanya, Vivian N; Gele, Abdi A; Diaz, Esperanza; Kumar, Bernadette

2018-04-18

Female genital mutilation/cutting (FGM/C) is a great concern, considering all the potential health implications. Use of health care services related to FGM/C by women who have been subjected to FGM/C in Norway remains to be understood. This study aims to explore the health care-seeking patterns for FGM/C-related health care problems, among young Somalis in Norway. A cross-sectional study involving 325 young Somalis in Oslo was conducted in 2014 using respondent-driven sampling (RDS) technique. The RDS was initiated by a small number of recruited seeds, who were given coded coupons to recruit their peers to participate in the study. Eligible recruiters who participated in the study and redeemed their coupons created the first wave of respondents. The first wave further recruited their peers, the second wave. The cycle continued to attain the needed samples. Using interviews and structured questionnaires, data on socio-demographic, FGM/C status and FGM/C-related use of health care were obtained. Logistic regressions were used to compute the odds ratio (OR) and the confidence interval (CI) for the associations between demographic variables, to circumcision status and health care-seeking for FGM/C. This study will focus on the 159 female participants of the total 325. While 51.6% of the 159 women were subjected to FGM/C, only 20.3% of them used health care services for FGM/C-related problems. Women's FGM/C status was associated with age ≥ 12 years at migration, experience of stigma regarding FGM/C practice (p <  0.05), support of FGM/C practice, and place of birth of women (p <  0.05). Only one-fifth of the women with FGM/C sought care for FGM/C-related health problems. Our study does not provide the answers to why only a few of them sought care for FGM/C. However, as a large proportion of women did not seek care, it is important to investigate the reasons for this. For, we propose to conduct further research targeting girls and women who have undergone FGM/C to assess challenges in accessing health care services for proper intervention.

Female genital mutilation: Australian law, policy and practical challenges for doctors.

PubMed

Mathews, Ben

2011-02-07

The issue of whether medical practitioners should perform "ritual nicks" as a method of meeting demand for female genital mutilation (FGM) has recently been debated in the United States and Australia. Due to increasing numbers of people arriving and settling in Australia from African nations in which FGM is customary, demand for FGM in Australia is present and may be increasing. Australian law clearly prohibits performance of any type of FGM. FGM is also prohibited by the most recent policy of the Royal Australian and New Zealand College of Obstetricians and Gynaecologists (RANZCOG). For legal, medical and social reasons, the RANZCOG policy is sound, and medical practitioners should not administer FGM in any form. Development of an evidence base regarding incidence of and attitudes towards FGM, and the need for post-FGM treatment, would help inform sound policy and practical responses. Strategies adopted in African nations to abolish FGM may assist in refining educational and supportive efforts.

Evidence-based policy responses to strengthen health, community and legislative systems that care for women in Australia with female genital mutilation / cutting.

PubMed

Varol, Nesrin; Hall, John J; Black, Kirsten; Turkmani, Sabera; Dawson, Angela

2017-05-18

The physical and psychological impact of female genital mutilation / cutting (FGM/C) can be substantial, long term, and irreversible. Parts of the health sector in Australia have developed guidelines in the management of FGM/C, but large gaps exist in community and professional knowledge of the consequences and treatment of FGM/C. The prevalence of FGM/C amongst Australian women is unknown. Our article reviews the literature on research on FGM/C in Australia, which focuses on health system response to women and girls with FGM/C. Recommendations are made for policy reform in health, legislation, and community programs to provide the best healthcare, protect children, and help communities abandon this harmful practice. Midwives and doctors in Australia acknowledged a lack of knowledge on FGM/C, clinical guidelines and consequences for maternity care. In a metropolitan Australian hospital with specialised FGM/C care, women with FGM/C had similar obstetric outcomes as women without FGM/C, underlining the importance of holistic FGM/C clinics. Greater focus on integration of refugee and migrant populations into their new cultures may be an important way of facilitating the abandonment of this practice, as is education of communities that practise FGM/C, and experts involved in the care and protection of children. Men could be important advocates for protecting women and girls from violence and FGM/C through a man-to-man strategy with programs focussing on men's health and other personal issues, education, and communication. The Australian Government has identified gender-based violence as an area of priority and has been implementing a National plan to reduce violence against women and their children 2010-2022. A multidisciplinary network of experts on FGM/C could be established within this taskforce to develop well-defined and rapid referral pathways to care for and protect these children, as well as coordinate education and prevention programs to help communities abandon this harmful practice. Countries of migration can be part of the solution for abandonment of FGM/C through community interventions and implementation of national and coordinated training in FGM/C of experts involved in the care and protection of children and women. The global focus on collaboration on research, training and prevention programs should be fostered between countries of FGM/C prevalence and migration.

Knowledge, attitude, and experience of health professionals of female genital mutilation (FGM): A qualitative study in Iraqi Kurdistan Region.

PubMed

Shabila, Nazar P; Ahmed, Hamdia M; Safari, Kolsoom

2017-11-01

We aimed to assess the knowledge, attitude, and experience of health professionals of female genital mutilation (FGM). The study involved content analysis of semistructured interviews with 21 health professionals. The participants had poor knowledge regarding different aspects of FGM including its types, prevalence, and complications as well as the existing legislation that prohibits FGM. They believed that FGM is mainly practiced for religious reasons and to reduce sexual desire/arousal. Health professionals are apparently not involved in performing FGM, and they do not support its continuation. Health professionals can take a leading role in raising the awareness of women and combating FGM.

Mechanical and microstructural characterization of W–Cu FGM fabricated by one-step sintering method through PM route

NASA Astrophysics Data System (ADS)

Gupta, Rajat; Kumar, Rohit; Chaubey, A. K.; Kanpara, Shailesh; Khirwadkar, S. S.

2018-03-01

Five layer W-Cu functionally graded material (FGM) for components in nuclear fusion application was fabricated by a one-step resistance sintering process, known as spark plasma sintering (SPS). In this study effect of sintering temperature (Ts) on physical, mechanical and surface property was investigated. Detailed microstructural study revealed that the graded structure of the composite layers with varying composition from 0 to 100 wt% W and Cu in opposite directions could be well densified after the SPS process. It also indicates that the fine microstructure within functionally graded layers can be maintained because of short sintering time. The sample sintered at 1050°C shows more than 90% theoretical density, hardness greater than 239±5 Hv and excellent surface scratch resistance. The result demonstrates that SPS is promising and more suitable process for fabrication of W-Cu FGM.

Fashion garment manufacturing - FGM and cyclability theory

NASA Astrophysics Data System (ADS)

Mendes, F. D.; Dos Santos, M. C. L.

2017-10-01

This article, derived from an ongoing research, presents the possibilities of reducing the inappropriate disposal of textile residues generated by the fabric cutting sector of the Fashion Garment Manufacturing (FGM). The raw material used is very varied, resulting in a large number of productive processes. FGM produces clothing that has as its main features a short life cycle, a high rate of diversification and differentiation, and small production batches, resulting in few similar parts. The production process is differentiated according to the characteristics of the fabric and the look of the garment. During the production process, at least 10% of textile waste is generated during the cutting process, which is constantly discarded in an inadequate way. The Cyclability theory is researched aiming at the possibility of reduction in the generation of waste and elimination of inappropriate disposal. The case study presents the action research carried out in three small Brazilian companies to study the applicability of the Cyclability theory.

Missed opportunities for diagnosis of female genital mutilation.

PubMed

Abdulcadir, Jasmine; Dugerdil, Adeline; Boulvain, Michel; Yaron, Michal; Margairaz, Christiane; Irion, Olivier; Petignat, Patrick

2014-06-01

To investigate missed opportunities for diagnosing female genital mutilation (FGM) at an obstetrics and gynecology (OB/GYN) department in Switzerland. In a retrospective study, we included 129 consecutive women with FGM who attended the FGM outpatient clinic at the Department of Gynecology and Obstetrics at the University Hospitals of Geneva between 2010 and 2012. The medical files of all women who had undergone at least 1 previous gynecologic exam performed by an OB/GYN doctor or a midwife at the study institution were reviewed. The type of FGM reported in the files was considered correct if it corresponded to that reported by the specialized gynecologist at the FGM clinic, according to WHO classification. In 48 (37.2%) cases, FGM was not mentioned in the medical file. In 34 (26.4%) women, the diagnosis was correct. FGM was identified but erroneously classified in 28 (21.7%) cases. There were no factors (women's characteristics or FGM type) associated with missed diagnosis. Opportunities to identify FGM are frequently missed. Measures should be taken to improve FGM diagnosis and care. Copyright © 2014 International Federation of Gynecology and Obstetrics. Published by Elsevier Ireland Ltd. All rights reserved.

Socioeconomic and Reproductive Health Outcomes of Female Genital Mutilation.

PubMed

Refaei, Mansoureh; Aghababaei, Soodabeh; Pourreza, Abolghasem; Masoumi, Seyedeh Zahra

2016-11-01

Female genital mutilation (FGM) is one of the important aspects of reproductive health. The economic, social and health consequences of FGM threaten the achievement of sustainable development goals. The purpose of this study was to assess the economic, social and reproductive health consequences of FGM from the perspective of individual, family, community and health system. In this study, we reviewed 1536 articles from 1979 to 2015. Fifty-one studies were directly related to our goal. Research papers, review articles, case studies and books on the research topic were used. The results of this review showed that most studies on FGM, have investigated health complications of FGM, and few studies have addressed its socioeconomic aspects. The complications from the FGM can impose a significant economic burden on individuals, society and health system. Social consequences of FGM are more irritating than health consequences, so to tackle this practice; its social aspects should be more emphasized. Significant short and long term consequences of FGM threaten women's reproductive health; Reproductive health is one of the essential prerequisites of sustainable development. Sustainable development will be achieved if women are healthy. This practice can threaten achieving sustainable development. In Iran, FGM is performed in some areas, but there are no official statistics about it and there has yet been no plan to deal with FGM. FGM is a form of social injustice which women suffer. Ending FGM requires a deep and long-term commitment. Knowing its consequences and its effects on individual, families, the health system and community will help supporters to continue fighting this practice. Any money spent on eliminating this harmful practice, compared with the costs of complications, would not be wasteful.  It seems that further studies are needed to assess socioeconomic effects of FGM and the relationship between type of FGM and induced complications. Such studies will help policymakers to tackle this practice.

Female genital mutilation among mothers and daughters in Harar, eastern Ethiopia.

PubMed

Oljira, Teshome; Assefa, Nega; Dessie, Yadeta

2016-12-01

To assess the practice of female genital mutilation (FGM) among mothers and daughters, and to investigate sociodemographic factors influencing the practice of FGM in Harar, Ethiopia. A community-based cross-sectional study was conducted among women aged 15 years or older who had at least one living daughter younger than 12 years via the Harar Health and Demographic Surveillance System 2013. Data were collected through face-to-face interviews. The practice of FGM was compared between mothers and their daughters. Whether the daughter had undergone FGM was included as an outcome variable in bivariate and multivariate analyses. Among 842 mothers, 669 (79.5%) reported that they had undergone FGM themselves, and 160 (19.0%) that their daughter had undergone FGM. Traditional practitioners were said to be the major performers of FGM by 151 (94.4%) mothers. Mothers whose daughter was mutilated mentioned social acceptance (144 [90.0%] women) and better marriage prospects (96 [60.0%]) as the major benefits. Genital mutilation of daughters was significantly associated with maternal age, education to grade 1-4, and FGM experience. Amhara ethnic origin was significantly associated with a reduced likelihood of FGM among daughters. Over one generation, the incidence of FGM has reduced. Increasing advocacy against FGM and enforcement of law should be emphasized. Copyright © 2016 International Federation of Gynecology and Obstetrics. Published by Elsevier Ireland Ltd. All rights reserved.

Female Genital Mutilation/Cutting: Innovative Training Approach for Nurse-Midwives in High Prevalent Settings.

PubMed

Kimani, Samuel; Esho, Tammary; Kimani, Violet; Muniu, Samuel; Kamau, Jane; Kigondu, Christine; Karanja, Joseph; Guyo, Jaldesa

2018-01-01

Female genital mutilation/cutting (FGM/C) has no medical benefits and is associated with serious health complications. FGM/C including medicalization is illegal in Kenya. Capacity building for nurse-midwives to manage and prevent FGM/C is therefore critical. Determine the current FGM/C knowledge and effect of training among nurse-midwives using an electronic tool derived from a paper-based quiz on FGM/C among nurse-midwives. Nurse-midwives ( n =26) were assessed pre- and post-FGM/C training using a quiz comprising 12 questions. The quiz assessed the following factors: definition, classification, determining factors, epidemiology, medicalization, prevention, health consequences, and nurse-midwives' roles in FGM/C prevention themes. The scores for individuals and all the questions were computed and compared using SPSS V22. The mean scores for the quiz were 64.8%, improving to 96.2% p < 0.05 after training. Before the training, the following proportions of participants correctly answered questions demonstrating their knowledge of types of cutting (84.6%), link with health problems (96.2%), FGM/C-related complications (96.2%), communities that practice FGM/C (61.5%), medicalization (43.6%), reinfibulation (46.2%), dissociation from religion (46.2%), and the law as it relates to FGM/C (46.2%). The participants demonstrated knowledge of FGM/C-related complications with the proportion of nurse-midwives correctly answering questions relating to physical impact (69.2%), psychological impact (69.2%), sexual impact (57.7%), and social impact (38.5%). Additionally, participant awareness of NM roles in managing FGM/C included the following: knowledge of the nurse-midwife as counselor (69.2%), advocate (80.8%), leader (26.9%), role model (42.3%), and caregiver (34.6%). These scores improved significantly after training. Substantial FGM/C-related knowledge was demonstrated by nurse-midwives. They, however, showed challenges in preventing/rejecting medicalization of FGM/C, and there were knowledge gaps concerning sexual and social complications, as well as the specific roles of NM. This underscores the need to implement innovative FGM/C training interventions to empower health professionals to better respond to its management and prevention.

Female Genital Mutilation/Cutting: Innovative Training Approach for Nurse-Midwives in High Prevalent Settings

PubMed Central

Esho, Tammary; Kimani, Violet; Kamau, Jane; Kigondu, Christine; Karanja, Joseph; Guyo, Jaldesa

2018-01-01

Background Female genital mutilation/cutting (FGM/C) has no medical benefits and is associated with serious health complications. FGM/C including medicalization is illegal in Kenya. Capacity building for nurse-midwives to manage and prevent FGM/C is therefore critical. Objective Determine the current FGM/C knowledge and effect of training among nurse-midwives using an electronic tool derived from a paper-based quiz on FGM/C among nurse-midwives. Methods Nurse-midwives (n=26) were assessed pre- and post-FGM/C training using a quiz comprising 12 questions. The quiz assessed the following factors: definition, classification, determining factors, epidemiology, medicalization, prevention, health consequences, and nurse-midwives' roles in FGM/C prevention themes. The scores for individuals and all the questions were computed and compared using SPSS V22. Results The mean scores for the quiz were 64.8%, improving to 96.2% p < 0.05 after training. Before the training, the following proportions of participants correctly answered questions demonstrating their knowledge of types of cutting (84.6%), link with health problems (96.2%), FGM/C-related complications (96.2%), communities that practice FGM/C (61.5%), medicalization (43.6%), reinfibulation (46.2%), dissociation from religion (46.2%), and the law as it relates to FGM/C (46.2%). The participants demonstrated knowledge of FGM/C-related complications with the proportion of nurse-midwives correctly answering questions relating to physical impact (69.2%), psychological impact (69.2%), sexual impact (57.7%), and social impact (38.5%). Additionally, participant awareness of NM roles in managing FGM/C included the following: knowledge of the nurse-midwife as counselor (69.2%), advocate (80.8%), leader (26.9%), role model (42.3%), and caregiver (34.6%). These scores improved significantly after training. Conclusion Substantial FGM/C-related knowledge was demonstrated by nurse-midwives. They, however, showed challenges in preventing/rejecting medicalization of FGM/C, and there were knowledge gaps concerning sexual and social complications, as well as the specific roles of NM. This underscores the need to implement innovative FGM/C training interventions to empower health professionals to better respond to its management and prevention. PMID:29736171

Immunomodulating and anti-allergic effects of Negroamaro and Koshu Vitis vinifera fermented grape marc (FGM).

PubMed

Marzulli, Giuseppe; Magrone, Thea; Vonghia, Luisa; Kaneko, Masahiro; Takimoto, Hiroaki; Kumazawa, Yoshio; Jirillo, Emilio

2014-01-01

Polyphenols contained in FGM from Negroamaro (N) and Koshu (K) Vitis vinifera have been shown to exhibit several immunomodulating activities. For instance, mice affected by experimental colitis when administered with K-FGM showed an attenuation of the inflammatory process. In murine asthma, K-FGM reduced IgE production and eosinophil number in bronchial alveolar lavage fluid. In vitro, both N- and K-FGM were able to induce T regulatory cells in terms of Foxp-3 molecule expression and release of interleukin-10. In another set of experiments both N- and K-FGM were able to balance rate of proliferation/apoptosis/necrosis of normal human peripheral lymphocytes, thus indicating the property of these compounds to maintain immune homeostatic mechanisms in the host. On the other hand, N- and K-FGM inhibited human basophil degranulation, thus, confirming our previous results obtained with rat basophilic leukemia cells. Finally, N- and K-FGM also decreased oxidative burst of human polymorphonuclear cells and monocytes.Taken together, these findings imply the potential clinical usefulness of FGM administration in inflammatory/allergic conditions, such as chronic asthma.

Ceramic-Based 4D Components: Additive Manufacturing (AM) of Ceramic-Based Functionally Graded Materials (FGM) by Thermoplastic 3D Printing (T3DP).

PubMed

Scheithauer, Uwe; Weingarten, Steven; Johne, Robert; Schwarzer, Eric; Abel, Johannes; Richter, Hans-Jürgen; Moritz, Tassilo; Michaelis, Alexander

2017-11-28

In our study, we investigated the additive manufacturing (AM) of ceramic-based functionally graded materials (FGM) by the direct AM technology thermoplastic 3D printing (T3DP). Zirconia components with varying microstructures were additively manufactured by using thermoplastic suspensions with different contents of pore-forming agents (PFA), which were co-sintered defect-free. Different materials were investigated concerning their suitability as PFA for the T3DP process. Diverse zirconia-based suspensions were prepared and used for the AM of single- and multi-material test components. All of the samples were sintered defect-free, and in the end, we could realize a brick wall-like component consisting of dense (<1% porosity) and porous (approx. 5% porosity) zirconia areas to combine different properties in one component. T3DP opens the door to the AM of further ceramic-based 4D components, such as multi-color, multi-material, or especially, multi-functional components.

Ceramic-Based 4D Components: Additive Manufacturing (AM) of Ceramic-Based Functionally Graded Materials (FGM) by Thermoplastic 3D Printing (T3DP)

PubMed Central

Weingarten, Steven; Johne, Robert; Schwarzer, Eric; Richter, Hans-Jürgen; Michaelis, Alexander

2017-01-01

In our study, we investigated the additive manufacturing (AM) of ceramic-based functionally graded materials (FGM) by the direct AM technology thermoplastic 3D printing (T3DP). Zirconia components with varying microstructures were additively manufactured by using thermoplastic suspensions with different contents of pore-forming agents (PFA), which were co-sintered defect-free. Different materials were investigated concerning their suitability as PFA for the T3DP process. Diverse zirconia-based suspensions were prepared and used for the AM of single- and multi-material test components. All of the samples were sintered defect-free, and in the end, we could realize a brick wall-like component consisting of dense (<1% porosity) and porous (approx. 5% porosity) zirconia areas to combine different properties in one component. T3DP opens the door to the AM of further ceramic-based 4D components, such as multi-color, multi-material, or especially, multi-functional components. PMID:29182541

Topology optimized design of functionally graded piezoelectric ultrasonic transducers

NASA Astrophysics Data System (ADS)

Rubio, Wilfredo Montealegre; Buiochi, Flávio; Adamowski, Julio Cezar; Silva, Emílio C. N.

2010-01-01

This work presents a new approach to systematically design piezoelectric ultrasonic transducers based on Topology Optimization Method (TOM) and Functionally Graded Material (FGM) concepts. The main goal is to find the optimal material distribution of Functionally Graded Piezoelectric Ultrasonic Transducers, to achieve the following requirements: (i) the transducer must be designed to have a multi-modal or uni-modal frequency response, which defines the kind of generated acoustic wave, either short pulse or continuous wave, respectively; (ii) the transducer is required to oscillate in a thickness extensional mode or piston-like mode, aiming at acoustic wave generation applications. Two kinds of piezoelectric materials are mixed for producing the FGM transducer. Material type 1 represents a PZT-5A piezoelectric ceramic and material type 2 represents a PZT-5H piezoelectric ceramic. To illustrate the proposed method, two Functionally Graded Piezoelectric Ultrasonic Transducers are designed. The TOM has shown to be a useful tool for designing Functionally Graded Piezoelectric Ultrasonic Transducers with uni-modal or multi-modal dynamic behavior.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stoynov, Y.

Functionally graded materials (FGM) are extensively used in modern industry. They are composite materials with continuously varying properties in one or more special dimensions, according to the specific purpose. In view of the wide range of applications of FGM, stress analysis is important for their structural integrity and reliable service life. In this study we will consider functionally graded magneto-electro-elastic materials with one or more cracks subjected to SH waves. We assume that the material properties vary in one and the same way, described by an inhomogeneity function. The boundary value problem is reduced to a system of integro-differential equationsmore » based on the existence of fundamental solutions. Different inhomogeneity classes are used to obtain a wave equation with constant coefficients. Radon transform is applied to derive the fundamental solution in a closed form. Program code in FORTRAN 77 is developed and validated using available examples from literature. Simulations show the dependence of stress field concentration near the crack tips on the frequency of the applied time-harmonic load for different types of material inhomogeneity.« less

Female genital mutilation: knowledge, attitude and practices of Flemish midwives.

PubMed

Cappon, Sien; L'Ecluse, Charlotte; Clays, Els; Tency, Inge; Leye, Els

2015-03-01

health professionals in Belgium are confronted with female genital mutilation (FGM). To date, no survey to assess knowledge, attitudes and practices on FGM was conducted among midwives in the Northern region of Belgium. the objective of this study was to assess the knowledge, attitude and practices of Flemish midwives regarding female genital mutilation (FGM). we used a quantitative design, using KAP study (semi-structured questionnaire). labour wards, maternity wards and maternal intensive care units (MIC) in 56 hospitals in Flemish region of Belgium. 820 midwives, actively working in labour wards, maternity wards and maternal intensive care units (MIC). 820 valid questionnaires (40.9%) were returned. More than 15% of the respondents were recently confronted with FGM. They were mostly faced with the psychological and sexual complications caused by FGM. Few respondents were aware of existing guidelines regarding FGM in their hospitals (3.5%). The results also showed that only 20.2% was aware of the exact content of the law. The majority of midwives condemned the harmful traditional practice: FGM was experienced as a form of violence against women or a violation of human rights. Only 25.9% declared that FGM forms a part of their midwifery program. The vast majority of respondents (92.5%) indicated a need for more information on the subject. this study indicated that midwives in Flanders are confronted with FGM and its complications and highlighted the gaps in the knowledge of Flemish midwives regarding FGM. This may interfere with the provision of adequate care and prevention of FGM for the new-born daughter. there is an important need for appropriate training of (student)midwives concerning FGM as well as for the development and dissemination of clear guidelines in Flemish hospitals. Copyright © 2014 Elsevier Ltd. All rights reserved.

Effect of female genital mutilation/cutting; types I and II on sexual function: case-controlled study.

PubMed

Ismail, Sahar A; Abbas, Ahmad M; Habib, Dina; Morsy, Hanan; Saleh, Medhat A; Bahloul, Mustafa

2017-08-30

The existing literature is contradictory regarding effects of female genital mutilation/cutting (FGM/C) on sexual functions. The aim of this study was to explore the impact of type I and II FGM/C on sexual function of Egyptian women. We recruited 197 cut women and 197 control women from those visiting Assiut University hospitals for different reasons. We asked each woman to fill the Arabic female sexual function index (FSFI) (a self reported 19-item questionnaire assessing the main domains of female sexual function). Genital Examination was done to confirm the type of FGM. Female sexual dysfunction (FSD) was found in 83.8% of FGM/C cases in contrast to 64.5% of the control. The total FSFI score in the FGM/C group (19.82 ± 7.1) was significantly lower than in the control group (23.34 ± 8.1). Concerning the types of FGM/C, type 73.6% of cases had type I and 26.4% had type II. Type I FGM/C was performed mainly by physicians (62.1%) while type II was performed mainly by midwives (44.4%). FSD was found in 83.4% of FGM/C I cases and in 84.6% of FGM/C II cases. There was no statistically significant difference between the two types of FGM/C as regards total and individual domain scores except for the pain domain. There were significantly lower total and individual domain scores in both FGM/C types except for the desire domain compared to control. In this study, FGM/C was associated with reduced scores of FSFI on all domains scores, and among both types I and II, both were associated with sexual dysfunction.

The history and role of the criminal law in anti-FGM campaigns: Is the criminal law what is needed, at least in countries like Great Britain?

PubMed

Berer, Marge

2015-11-01

The history of campaigns against female genital mutilation (FGM) began in the 1920s. From the beginning, it was recognised that FGM was considered an important rite of passage between childhood and adulthood for girls, based on the importance of controlling female sexuality to maintain chastity and family honour, and to make girls marriageable. How to separate the "cut" from these deeply held norms is a question not yet adequately answered, yet I believe the answer is key to stopping the practice. Since the 1994 ICPD, national and international action against FGM has grown and resolutions have been passed in global forums which define FGM as a form of violence and a violation of children's human rights. These resolutions have contributed to building consensus against FGM and developing national legislation criminalising FGM. Prosecutions or arrests involving FGM have been reported in several African countries and Great Britain, but apart from France, there have been very few. This paper summarises this history and how FGM has been criminalised. It argues that criminalisation may not be the best means of stopping FGM, but can have serious harmful effects itself. It calls for community-led educational information and more support for dialogue within FGM-practising communities, and argues that what is important is addressing the sexual and reproductive health consequences of FGM and gaining the understanding of women who have experienced it and their families as to why they should not make their daughters and grand-daughters go through it too. Copyright © 2015 Elsevier Inc. All rights reserved.

Spatial modelling and mapping of female genital mutilation in Kenya.

PubMed

Achia, Thomas N O

2014-03-25

Female genital mutilation/cutting (FGM/C) is still prevalent in several communities in Kenya and other areas in Africa, as well as being practiced by some migrants from African countries living in other parts of the world. This study aimed at detecting clustering of FGM/C in Kenya, and identifying those areas within the country where women still intend to continue the practice. A broader goal of the study was to identify geographical areas where the practice continues unabated and where broad intervention strategies need to be introduced. The prevalence of FGM/C was investigated using the 2008 Kenya Demographic and Health Survey (KDHS) data. The 2008 KDHS used a multistage stratified random sampling plan to select women of reproductive age (15-49 years) and asked questions concerning their FGM/C status and their support for the continuation of FGM/C. A spatial scan statistical analysis was carried out using SaTScan™ to test for statistically significant clustering of the practice of FGM/C in the country. The risk of FGM/C was also modelled and mapped using a hierarchical spatial model under the Integrated Nested Laplace approximation approach using the INLA library in R. The prevalence of FGM/C stood at 28.2% and an estimated 10.3% of the women interviewed indicated that they supported the continuation of FGM. On the basis of the Deviance Information Criterion (DIC), hierarchical spatial models with spatially structured random effects were found to best fit the data for both response variables considered. Age, region, rural-urban classification, education, marital status, religion, socioeconomic status and media exposure were found to be significantly associated with FGM/C. The current FGM/C status of a woman was also a significant predictor of support for the continuation of FGM/C. Spatial scan statistics confirm FGM clusters in the North-Eastern and South-Western regions of Kenya (p<0.001). This suggests that the fight against FGM/C in Kenya is not yet over. There are still deep cultural and religious beliefs to be addressed in a bid to eradicate the practice. Interventions by government and other stakeholders must address these challenges and target the identified clusters.

Psychological impact of female genital mutilation among adolescent Egyptian girls: a cross-sectional study.

PubMed

Ahmed, Magdy R; Shaaban, Mohamed M; Meky, Heba K; Amin Arafa, Mohamed E; Mohamed, Tamer Y; Gharib, Waleed F; Ahmed, Abeer B

2017-08-01

Worldwide, at least 200 million women and girls have undergone female genital mutilation (FGM). The medical and sexual consequences have been documented, but the psychological impact has not been studied to the same extent. The aim of this study was to explore the relationship between FGM and psychiatric problems among adolescent girls. A total of 204 girls, aged 14-19 years, were included in a cross-sectional study conducted at Suez Canal University Hospitals. All participants completed an Arabic-validated, structured questionnaire covering nine symptom scales. Sociodemographic data were also collected. Main outcome measures were the prevalence of psychiatric problems among adolescent girls who had undergone FGM. Overall, 66.2% of girls had undergone FGM. The percentage in rural areas was 91.8%, compared with 43.0% in urban areas. There were no significant differences between the FGM and non-FGM groups as regards religion, educational and socioeconomic levels. FGM girls had a significantly higher level of psychological problems with regard to somatisation, depression, anxiety, phobic anxiety and hostility compared with non-FGM girls (p < .0001). FGM is a traumatic experience that may leave a lasting psychological mark and a negative impact on the psychological status of affected girls.

Digital fabrication of multi-material biomedical objects.

PubMed

Cheung, H H; Choi, S H

2009-12-01

This paper describes a multi-material virtual prototyping (MMVP) system for modelling and digital fabrication of discrete and functionally graded multi-material objects for biomedical applications. The MMVP system consists of a DMMVP module, an FGMVP module and a virtual reality (VR) simulation module. The DMMVP module is used to model discrete multi-material (DMM) objects, while the FGMVP module is for functionally graded multi-material (FGM) objects. The VR simulation module integrates these two modules to perform digital fabrication of multi-material objects, which can be subsequently visualized and analysed in a virtual environment to optimize MMLM processes for fabrication of product prototypes. Using the MMVP system, two biomedical objects, including a DMM human spine and an FGM intervertebral disc spacer are modelled and digitally fabricated for visualization and analysis in a VR environment. These studies show that the MMVP system is a practical tool for modelling, visualization, and subsequent fabrication of biomedical objects of discrete and functionally graded multi-materials for biomedical applications. The system may be adapted to control MMLM machines with appropriate hardware for physical fabrication of biomedical objects.

[Excision: the new prohibition that divides the society. Press review: Senegal].

PubMed

1999-12-01

Approximately 700,000 women in Senegal have suffered female genital mutilation (FGM). Now, following a vote upon legislation banning FGM, public opinion in the country over the practice is more divided than ever. The practitioners of FGM are not taking the law seriously, while politicians hesitate to openly condemn the practice, which still occurs widely in rural zones. Most of the 140 parliamentarians do not believe that laws alone can successfully end FGM in Senegal. Some deputies and feminists believe that several years of sensitization on the issue will be needed to effectively reduce the frequency with which FGM is practiced. Only optimists believe FGM will disappear on its own. The debate threatens to resurface in some areas during the year 2000 presidential election. One deputy from the governing party, originally from southern Senegal, states that he dares not tell his constituency that the president himself created the anti-FGM legislation, especially when locally elected leaders finance villages¿ FGM-related celebrations. According to a scholar of the Koran, FGM is an Islamic practice, but it is not taught in the Koran. FGM is therefore a cultural practice borne from individual choice. In Kolda, 650 km south of Dakar, the practitioners of such mutilation argue that they would rather be imprisoned than abandon the practice they consider to be an immutable component of their cultural history.

Are obstetric outcomes affected by female genital mutilation?

PubMed

Balachandran, Aswini A; Duvalla, Swapna; Sultan, Abdul H; Thakar, Ranee

2018-03-01

Female genital mutilation (FGM) has been associated with adverse obstetric and neonatal outcomes, such as postpartum haemorrhage (PPH), perineal trauma, genital fistulae, obstructed labour and stillbirth. The prevalence of FGM has increased in the UK over the last decade. There are currently no studies available that have explored the obstetric impact of FGM in the UK. The aim of our study was to investigate the obstetric and neonatal outcomes of women with FGM when compared with the general population. We conducted a retrospective case-control study of consecutive pregnant women with FGM over a 5-year period between 1 January 2009 and 31 December 2013. Each woman with FGM was matched for age, ethnicity, parity and gestation with subsequent patients without FGM (control cohort) over the same 5-year period. Outcomes assessed were mode of delivery, duration of labour, estimated blood loss, analgaesia, perineal trauma and foetal outcomes. A total of 242 eligible women (121 FGM, 121 control) were identified for the study. There was a significant increase in the use of episiotomy in the FGM group (p = 0.009) and a significant increase in minor PPH in the control group during caesarean sections (p = 0.0001). There were no differences in all other obstetric and neonatal parameters. In our unit, FGM was not associated with an increased incidence of adverse obstetric and foetal morbidity or mortality.

Attitudes and awareness of female genital mutilation: a questionnaire-based study in a Kenyan hospital.

PubMed

Livermore, L; Monteiro, R; Rymer, J

2007-11-01

There are considerable efforts in Kenya to increase awareness of the issues and health risks associated with female genital mutilation (FGM) through educational programmes. The Kenyan government formally outlawed FGM in 2001. This questionnaire-based study aimed to explore attitudes and awareness of FGM in Kenya with particular reference to the law, health complications and educational programmes. A significant decline in the prevalence of FGM was demonstrated and awareness of health complications of FGM shown to be the main factor causing this trend. The need for further efforts to eradicate the practice and the importance of religion and culture in shaping social attitudes was evident. The outlawing of FGM was considered a positive advance but may have the detrimental effect of deterring women from seeking medical assistance for complications relating to FGM.

Multidisciplinary approach to the management of children with female genital mutilation (FGM) or suspected FGM: service description and case series.

PubMed

Creighton, Sarah M; Dear, Joanna; de Campos, Claudia; Williams, Louise; Hodes, Deborah

2016-02-29

To describe the first dedicated clinic in the UK for children with suspected or confirmed female genital mutilation (FGM) including referral patterns, clinical findings and subsequent management. A prospective study of all children seen in a dedicated multidisciplinary FGM clinic for children over a 1-year period. Patients aged under 18 years referred for clinical assessment or for a second opinion on Digital Versatile Disc (DVD) images. Data were collected on reasons for referral, demography, genital examination findings including FGM type, and clinical recommendations. 38 children were referred of whom 18 (47%) had confirmed FGM; most frequently type 4 (61%). Social care and police referred 78% of cases. According to UK law FGM had been performed illegally in three cases. Anonymous information given to the police led to the referral of six children, none of whom had had FGM. Mandatory reporting and increased media attention may increase the numbers of referrals of children with suspected FGM. This patient group have complex needs and management in a dedicated multidisciplinary service is essential. Paediatricians and gynaecologists should have the skills to carry out the consultation and detect all types of FGM including type 4 which was the most common type seen in this series. This is the first dedicated FGM service for children in the UK and similar clinics in high-prevalence areas should be established. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

Process Of Bonding Copper And Tungsten

DOEpatents

Slattery, Kevin T.; Driemeyer, Daniel E.

1999-11-23

Process for bonding a copper substrate to a tungsten substrate by providing a thin metallic adhesion promoting film bonded to a tungsten substrate and a functionally graded material (FGM) interlayer bonding the thin metallic adhesion promoting film to the copper substrate. The FGM interlayer is formed by thermal plasma spraying mixtures of copper powder and tungsten powder in a varied blending ratio such that the blending ratio of the copper powder and the tungsten powder that is fed to a plasma torch is intermittently adjusted to provide progressively higher copper content/tungsten content, by volume, ratio values in the interlayer in a lineal direction extending from the tungsten substrate towards the copper substrate. The resulting copper to tungsten joint well accommodates the difference in the coefficient of thermal expansion of the materials.

Female genital mutilation and pregnancy: associated risks.

PubMed

Gayle, Claudine; Rymer, Janice

2016-09-22

Female genital mutilation (FGM) is a traditional practice that has no medical benefit and severe health consequences for girls and women. This article discusses the risks to patients who are pregnant and have had FGM. It will describe urinary tract infections caused by FGM, and how this condition increases the risk of preterm labour and delivery. It will also address the difficulty in vaginal examinations that can be caused by FGM and instances when this can delay diagnosis and treatment. In addition, it will explore a number of intrapartum risks caused by FGM and the role of deinfibulation in pregnancy. Finally, it will look at the link between maternal and fetal morbidity and mortality, and FGM.

Geography and correlates of attitude toward Female Genital Mutilation (FGM) in Sudan: What can we learn from successive Sudan opinion poll data?

PubMed

Hamilton, Alexander; Kandala, Ngianga-Bakwin

2016-02-01

In Sudan, prevalence of FGM is declining; likely as a result of changing attitude surrounding FGM, as more women believe the practice should be discontinued amid growing awareness about its health dangers. DFID Sudan opinion poll data collected from 2012 to 2014 was used. Bayesian geo-additive mixed models were used to map the spatial distribution of the likelihood of pro-FGM attitude at the state-level accounting for associated risk factors. During 2012 to 2014, the overall proportion of pro-FGM was 27.5% and 18.3% respectively with striking variations within states. People with pro-FGM attitude were more likely to be un-educated, living in rural settings with strong tribal identity. Individuals from Darfur were more likely to be pro-FGM when compared to the North state. The decrease in the practice of cutting observed between the 2006 and 2010 Sudanese Household Surveys and the resulting shift in attitude make a compelling case for public health policy to eradicate the FGM practice. Copyright © 2015. Published by Elsevier Ltd.

Female genital mutilation and efforts to achieve Millennium Development Goals 3, 4, and 5 in southeast Nigeria.

PubMed

Lawani, Lucky O; Onyebuchi, Azubuike K; Iyoke, Chukwuemeka A; Okeke, Nwabunike E

2014-05-01

To determine the prevalence of female genital mutilation (FGM), the common forms of FGM, reasons for the practice, associated obstetric outcomes, and how these have affected efforts to achieve Millennium Development Goals (MDGs) 3, 4, and 5 in southeast Nigeria. A prospective descriptive study of parturients in southeast Nigeria was conducted from January to December 2012. All primigravid women attending delivery services at 2 health institutions during the study period were recruited, examined, and classified using the 2008 WHO classification for FGM. The mean age of the 516 participants was 27.24±4.80 years and most (66.3%) had undergone FGM. Type II FGM was the most common form, accounting for 59.6% of cases. Most FGM procedures were performed in infancy (97.1%) and for cultural reasons (60.8%). Women who had undergone FGM had significantly higher risk for episiotomy, perineal tear, hemorrhage, cesarean delivery, neonatal resuscitation, fresh stillbirth/early neonatal death, and longer hospitalization, with higher risk ratios associated with higher degrees of FGM. FGM is still a common practice in southeast Nigeria, where its association with adverse reproductive outcomes militates against efforts to achieve MDGs 3, 4, and 5. Copyright © 2014 International Federation of Gynecology and Obstetrics. Published by Elsevier Ireland Ltd. All rights reserved.

Female Genital Mutilation in Kenya: are young men allies in social change programmes?

PubMed

Brown, Eleanor; Mwangi-Powell, Faith; Jerotich, Miriam; le May, Victoria

2016-05-01

The Girl Summit held in 2014 aimed to mobilise greater effort to end Female Genital Mutilation (FGM) within a generation, building on a global movement which viewed the practice as a severe form of violence against women and girls and a violation of their rights. The UN, among others, endorse "comprehensive" strategies to end FGM, including legalistic measures, social protection and social communications. FGM is a sensitive issue and difficult to research, and rapid ethnographic methods can use existing relations of trust within social networks to explore attitudes towards predominant social norms which posit FGM as a social necessity. This study used Participatory Ethnographic Evaluation Research (PEER) to understand young men's (18-25 years) perceptions of FGM, demand for FGM among future spouses, and perceptions of efforts to end FGM in a small town in West Pokot, Kenya, where FGM is reported to be high (between 85% to 96%). Twelve PEER researchers were recruited, who conducted two interviews with their friends, generating a total of 72 narrative interviews. The majority of young men who viewed themselves as having a "modern" outlook and with aspirations to marry "educated" women were more likely not to support FGM. Our findings show that young men viewed themselves as valuable allies in ending FGM, but that voicing their opposition to the practice was often difficult. More efforts are needed by multi-stakeholders - campaigners, government and local leaders - to create an enabling environment to voice that opposition. Copyright © 2016 Elsevier Inc. All rights reserved.

Female genital mutilation in children presenting to Australian paediatricians

PubMed Central

Zurynski, Yvonne; Sureshkumar, Premala; Cherian, Sarah; Deverell, Marie; Elliott, Elizabeth J

2017-01-01

Objective The WHO reports that female genital mutilation/cutting (FGM/C) is an ancient cultural practice prevalent in many countries. FGM/C has been reported among women resident in Australia. Our paper provides the first description of FGM/C in Australian children. Design Cross-sectional survey conducted in April–June 2014. Setting Paediatricians and other child health specialists recruited through the Australian Paediatric Surveillance Unit were asked to report children aged <18 years with FGM/C seen in the last 5 years, and to provide data for demographics, FGM/C type, complications and referral for each case. Participants Of 1311 eligible paediatricians/child health specialists, 1003 (76.5%) responded. Results Twenty-three (2.3%) respondents had seen 59 children with FGM/C and provided detailed data for 31. Most (89.7%) were identified during refugee screening and were born in Africa. Three (10.3%) were born in Australia: two had FGM/C in Australia and one in Indonesia. All parents were born overseas, mainly Africa (98.1%). Ten children had WHO FGM/C type I, five type II, five type III and six type IV. Complications in eight children included recurrent genitourinary infections, menstrual, sexual, fertility and psychological problems. Nineteen children (82.6%) were referred to obstetrics/gynaecology: 16 (69.9%) to social work and 13 (56.5%) to child protection. Conclusions This study confirms that FGM/C is seen in paediatric clinical practice within Australia. Paediatricians need cultural awareness, education and resources to help them identify children with FGM/C and/or at risk of FGM/C, to enable appropriate referral and counselling of children, families and communities to assist in the prevention of this practice. PMID:28082321

Female Genital Mutilation/Cutting in the United States: Updated Estimates of Women and Girls at Risk, 2012

PubMed Central

Stupp, Paul; Okoroh, Ekwutosi; Besera, Ghenet; Goodman, David; Danel, Isabella

2016-01-01

Objectives In 1996, the U.S. Congress passed legislation making female genital mutilation/cutting (FGM/C) illegal in the United States. CDC published the first estimates of the number of women and girls at risk for FGM/C in 1997. Since 2012, various constituencies have again raised concerns about the practice in the United States. We updated an earlier estimate of the number of women and girls in the United States who were at risk for FGM/C or its consequences. Methods We estimated the number of women and girls who were at risk for undergoing FGM/C or its consequences in 2012 by applying country-specific prevalence of FGM/C to the estimated number of women and girls living in the United States who were born in that country or who lived with a parent born in that country. Results Approximately 513,000 women and girls in the United States were at risk for FGM/C or its consequences in 2012, which was more than three times higher than the earlier estimate, based on 1990 data. The increase in the number of women and girls younger than 18 years of age at risk for FGM/C was more than four times that of previous estimates. Conclusion The estimated increase was wholly a result of rapid growth in the number of immigrants from FGM/C-practicing countries living in the United States and not from increases in FGM/C prevalence in those countries. Scientifically valid information regarding whether women or their daughters have actually undergone FGM/C and related information that can contribute to efforts to prevent the practice in the United States and provide needed health services to women who have undergone FGM/C are needed. PMID:26957669

Female Genital Mutilation/Cutting in the United States: Updated Estimates of Women and Girls at Risk, 2012.

PubMed

Goldberg, Howard; Stupp, Paul; Okoroh, Ekwutosi; Besera, Ghenet; Goodman, David; Danel, Isabella

2016-01-01

In 1996, the U.S. Congress passed legislation making female genital mutilation/cutting (FGM/C) illegal in the United States. CDC published the first estimates of the number of women and girls at risk for FGM/C in 1997. Since 2012, various constituencies have again raised concerns about the practice in the United States. We updated an earlier estimate of the number of women and girls in the United States who were at risk for FGM/C or its consequences. We estimated the number of women and girls who were at risk for undergoing FGM/C or its consequences in 2012 by applying country-specific prevalence of FGM/C to the estimated number of women and girls living in the United States who were born in that country or who lived with a parent born in that country. Approximately 513,000 women and girls in the United States were at risk for FGM/C or its consequences in 2012, which was more than three times higher than the earlier estimate, based on 1990 data. The increase in the number of women and girls younger than 18 years of age at risk for FGM/C was more than four times that of previous estimates. The estimated increase was wholly a result of rapid growth in the number of immigrants from FGM/C-practicing countries living in the United States and not from increases in FGM/C prevalence in those countries. Scientifically valid information regarding whether women or their daughters have actually undergone FGM/C and related information that can contribute to efforts to prevent the practice in the United States and provide needed health services to women who have undergone FGM/C are needed.

Decline of Supportive Attitudes among Husbands toward Female Genital Mutilation and Its Association to Those Practices in Yemen

PubMed Central

Al-Khulaidi, Ghadah Abdulmajid; Nakamura, Keiko; Seino, Kaoruko; Kizuki, Masashi

2013-01-01

Objectives To elucidate the attitudes of women and their husband’s towards female genital mutilation (FGM) and their associations with the continuation of FGM upon their daughters. Methods Subjects were 10,345 (in 1997) and 11,252 (in 2003) ever married women aged 15 to 49 years from the Yemen Demographic Health Surveys. Performances of FGM on the most-recently-born daughters were investigated. Attitudes of women and their husbands were assessed by their opinions on the continuation of FGM. The association between the attitudes of women and their husbands and performance of FGM on the most-recently-born daughters were investigated after adjusting for age and education of the women. Findings The percentage among the most-recently-born daughters who received FGM of women who had undergone FGM declined from 61.9% in 1997 to 56.5% in 2003 (p<0.001). The percentages of women who had undergone FGM and who supported the continuation of FGM and of husbands who also supported its continuation decreased from 78.2% and 60.1% in 1997 to 70.9% and 49.5% in 2003, respectively (both p<0.001). When the women or the husbands did not agree with FGM, it was less likely to be performed on their daughter than when the women or the husbands agreed in 1997 (odds ratio=0.11, 95% confidence interval 0.07-0.16 and odds ratio=0.07, 95% confidence interval 0.04-0.12, respectively) and in 2003 (odds ratio=0.12, 95% confidence interval 0.09-0.16 and odds ratio=0.11, 95% confidence interval 0.07-0.16, respectively). Conclusion Non-supportive attitudes of women and their husbands towards the continuation of FGM have become common and were associated with their decision not to perform FGM upon their daughters. PMID:24367582

Daughters at Risk of Female Genital Mutilation: Examining the Determinants of Mothers’ Intentions to Allow Their Daughters to Undergo Female Genital Mutilation

PubMed Central

Pashaei, Tahereh; Ponnet, Koen; Moeeni, Maryam; Khazaee-pool, Maryam; Majlessi, Fereshteh

2016-01-01

Female genital mutilation (FGM) is still a common practice in many countries in Africa and the Middle East. Understanding the determinants of FGM can lead to more active interventions to prevent this harmful practice. The goal of this study is to explore factors associated with FGM behavior among Iranian mothers and their daughters. Based on Ajzen’s theory of planned behavior, we examined the predictive value of attitudes, subjective norms, perceived behavioral control and several socio-demographic variables in relation to mothers’ intentions to mutilate their daughters. A paper-and-pencil survey was conducted among 300 mothers (mean age = 33.20, SD = 9.09) who had at least one daughter and who lived in Ravansar, a county in Kermanshah Province in Iran. Structural equation modeling was used to investigate the relationships among the study variables. Our results indicate that attitude is the strongest predictor of mothers’ intentions to allow their daughters to undergo FGM, followed by subjective norms. Compared to younger mothers, older mothers have more positive attitudes toward FGM, perceive themselves as having more control over their behavior and demonstrate a greater intention to allow their daughter to undergo FGM. Furthermore, we found that less educated mothers and mothers living in rural areas had more positive attitudes toward FGM and feel more social pressure to allow FGM. The model accounts for 93 percent of the variance in the mothers’ intentions to allow their daughters to undergo FGM. Intervention programs that want to decrease FGM might focus primarily on converting mothers’ neutral or positive feelings toward FGM into negative attitudes and on alleviating the perceived social pressure to mutilate one’s daughter. Based on our findings, we provide recommendations about how to curtail mothers’ intentions to allow their daughters to undergo FGM. PMID:27031613

Decline of supportive attitudes among husbands toward female genital mutilation and its association to those practices in Yemen.

PubMed

Al-Khulaidi, Ghadah Abdulmajid; Nakamura, Keiko; Seino, Kaoruko; Kizuki, Masashi

2013-01-01

To elucidate the attitudes of women and their husband's towards female genital mutilation (FGM) and their associations with the continuation of FGM upon their daughters. Subjects were 10,345 (in 1997) and 11,252 (in 2003) ever married women aged 15 to 49 years from the Yemen Demographic Health Surveys. Performances of FGM on the most-recently-born daughters were investigated. Attitudes of women and their husbands were assessed by their opinions on the continuation of FGM. The association between the attitudes of women and their husbands and performance of FGM on the most-recently-born daughters were investigated after adjusting for age and education of the women. The percentage among the most-recently-born daughters who received FGM of women who had undergone FGM declined from 61.9% in 1997 to 56.5% in 2003 (p<0.001). The percentages of women who had undergone FGM and who supported the continuation of FGM and of husbands who also supported its continuation decreased from 78.2% and 60.1% in 1997 to 70.9% and 49.5% in 2003, respectively (both p<0.001). When the women or the husbands did not agree with FGM, it was less likely to be performed on their daughter than when the women or the husbands agreed in 1997 (odds ratio=0.11, 95% confidence interval 0.07-0.16 and odds ratio=0.07, 95% confidence interval 0.04-0.12, respectively) and in 2003 (odds ratio=0.12, 95% confidence interval 0.09-0.16 and odds ratio=0.11, 95% confidence interval 0.07-0.16, respectively). Non-supportive attitudes of women and their husbands towards the continuation of FGM have become common and were associated with their decision not to perform FGM upon their daughters.

Female genital mutilation: an injury, physical and mental harm.

PubMed

Utz-Billing, I; Kentenich, H

2008-12-01

This article gives an overview over the huge topic of 'female genital mutilation' (FGM). FGM means non-therapeutic, partial or complete removal or injury of each of the external female genitals. It concerns about 130 million women around the world. FGM is performed in about 30 countries, most of which are located in Africa. Four types of FGM are distinguished: type I stands for the removal of the clitoral foreskin, type II means the removal of the clitoris with partial or total excision of the labia minora. Type III is the extreme type of FGM. Not only the clitoris but also the labia minora and majora were removed. The orificium vaginae is sewn up, leaving only a small opening for urine or menstruation blood. Other types like pricking, piercing of clitoris or vulva, scraping of the vagina, etc. were defined as type IV of FGM. The mentioned reasons for FGM are: encouragement of the patriarchal family system, method for birth control, guarantee of moral behaviour and faithfulness to the husband, protection of women from suspicions and disgrace, initiation ritual, symbol of feminity and beauty, hygienic, health and economic advantages. Acute physical consequences of FGM include bleeding, wound infections, sepsis, shock, micturition problems and fractures. Chronic physical problems like anemia, infections of the urinary tract, incontinence, infertility, pain, menstruation problems and dyspareunia are frequent. Women also have a higher risk for HIV infections. During pregnancy and delivery, examinations and vaginal application of medicine are more difficult. Women have a higher risk for a prolonged delivery, wound infections, a postpartum blood loss of more than 500 mL, perineal tears, a resuscitation of the infant and an inpatient perinatal death. Mental consequences after FGM include the feelings of incompleteness, fear, inferiority and suppression. Women report chronic irritability and nightmares. They have a higher risk for psychiatric and psychosomatic diseases. FGM carried out by doctors, nurses or midwives is also called medicalisation of FGM and is definitely unacceptable. Regarding human rights, FGM refuses women the right of freedom from bodily harm. Specific laws that ban FGM exist in many countries in Europe, Africa, USA, Canada, New Zealand and Australia.

Spatial modelling and mapping of female genital mutilation in Kenya

PubMed Central

2014-01-01

Background Female genital mutilation/cutting (FGM/C) is still prevalent in several communities in Kenya and other areas in Africa, as well as being practiced by some migrants from African countries living in other parts of the world. This study aimed at detecting clustering of FGM/C in Kenya, and identifying those areas within the country where women still intend to continue the practice. A broader goal of the study was to identify geographical areas where the practice continues unabated and where broad intervention strategies need to be introduced. Methods The prevalence of FGM/C was investigated using the 2008 Kenya Demographic and Health Survey (KDHS) data. The 2008 KDHS used a multistage stratified random sampling plan to select women of reproductive age (15–49 years) and asked questions concerning their FGM/C status and their support for the continuation of FGM/C. A spatial scan statistical analysis was carried out using SaTScan™ to test for statistically significant clustering of the practice of FGM/C in the country. The risk of FGM/C was also modelled and mapped using a hierarchical spatial model under the Integrated Nested Laplace approximation approach using the INLA library in R. Results The prevalence of FGM/C stood at 28.2% and an estimated 10.3% of the women interviewed indicated that they supported the continuation of FGM. On the basis of the Deviance Information Criterion (DIC), hierarchical spatial models with spatially structured random effects were found to best fit the data for both response variables considered. Age, region, rural–urban classification, education, marital status, religion, socioeconomic status and media exposure were found to be significantly associated with FGM/C. The current FGM/C status of a woman was also a significant predictor of support for the continuation of FGM/C. Spatial scan statistics confirm FGM clusters in the North-Eastern and South-Western regions of Kenya (p < 0.001). Conclusion This suggests that the fight against FGM/C in Kenya is not yet over. There are still deep cultural and religious beliefs to be addressed in a bid to eradicate the practice. Interventions by government and other stakeholders must address these challenges and target the identified clusters. PMID:24661558

A Tradition in Transition: Factors Perpetuating and Hindering the Continuance of Female Genital Mutilation/Cutting (FGM/C) Summarized in a Systematic Review

PubMed Central

Berg, Rigmor C.; Denison, Eva

2013-01-01

Understanding the forces underpinning female genital mutilation/cutting (FGM/C) is a necessary first step to prevent the continuation of a practice that is associated with health complications and human rights violations. To this end, a systematic review of 21 studies was conducted. Based on this review, the authors reveal six key factors that underpin FGM/C: cultural tradition, sexual morals, marriageability, religion, health benefits, and male sexual enjoyment. There were four key factors perceived to hinder FGM/C: health consequences, it is not a religious requirement, it is illegal, and the host society discourse rejects FGM/C. The results show that FGM/C appears to be a tradition in transition. PMID:23489149

A survey of Australian midwives' knowledge, experience, and training needs in relation to female genital mutilation.

PubMed

Turkmani, Sabera; Homer, Caroline; Varol, Nesrin; Dawson, Angela

2018-02-01

Female genital mutilation (FGM) involves partial or total removal of the external female genitalia or any other injury for non-medical reasons. Due to international migration patterns, health professionals in high income countries are increasingly caring for women with FGM. Few studies explored the knowledge and skills of midwives in high income countries. To explore the knowledge, experience and needs of midwives in relation to the care of women with FGM. An online self-administered descriptive survey was designed and advertised through the Australian College of Midwives' website. Of the 198 midwives (24%) did not know the correct classification of FGM. Almost half of the respondents (48%) reported they had not received FGM training during their midwifery education. Midwives (8%) had been asked, or knew of others who had been asked to perform FGM in Australia. Many midwives were not clear about the law or health data related to FGM and were not aware of referral paths for affected women. As frontline providers, midwives must have appropriate up-to-date clinical skills and knowledge to ensure they are able to provide women with FGM the care they need and deserve. Midwives have a critical role to play in the collection of FGM related data to assist with health service planning and to prevent FGM by working closely with women and communities they serve to educate and advocate for its abandonment. Therefore, addressing educational gaps and training needs are key strategies to deliver optimal quality of care. Copyright © 2017 Australian College of Midwives. Published by Elsevier Ltd. All rights reserved.

Obstetric care of women with female genital mutilation attending a specialized clinic in a tertiary center.

PubMed

Abdulcadir, Jasmine; Dugerdil, Adeline; Yaron, Michal; Irion, Olivier; Boulvain, Michel

2016-02-01

To study the obstetric outcomes of women attending a specialized clinic for women with female genital mutilation (FGM). The medical charts of women with FGM who consecutively attended a specialized clinic between 2010 and 2012 were reviewed retrospectively. The present study focused on women attending for obstetric reasons. The outcome measures were type of delivery, reason for cesarean delivery or assisted delivery, blood loss, episiotomy, perineal tear, duration of the second stage of labor, postpartum complications, weight of the neonate, and Apgar score. Outcomes were compared between women with FGM type III who underwent defibulation, and patients with FGM type I and II. The clinic was attended by 129 women, 84 perinatally. Obstetric outcomes were similar to average outcomes for women without FGM presenting at the same department and in Switzerland generally. Specifically, 20 women had a cesarean delivery. An assisted delivery was performed for 18 patients; among these, only eight had experienced obstructed labor. No statistically significant differences were found for the outcome measures when women with FGM type III were compared to FGM type I and II. Routine obstetric follow-up combined with specialized care for women with FGM, including defibulation, can avoid inappropriate obstetric practices and reduce obstetric complications known to be associated with FGM. Copyright © 2015 International Federation of Gynecology and Obstetrics. Published by Elsevier Ireland Ltd. All rights reserved.

A retrospective analysis of 34 potentially missed cases of female genital mutilation in the emergency department.

PubMed

Fawcett, Richard John; Kernohan, George

2017-09-12

To discover if healthcare professionals working within an ED are able to make a diagnosis of female genital mutilation (FGM) in those patients who have previously undergone the procedure and report it as per UK law. A retrospective analysis of patients' notes who were assigned an FGM code during the period of May 2015 to August 2016. Single-centre, large UK major trauma centre offering a tertiary FGM clinic. Any woman coded during the study period as having undergone FGM. Number of FGM cases identified by the ED. Mean age, presenting complaint, discharge diagnosis, genitourinary exam and defibulation status. 34 patients were identified as having undergone FGM, 19 had previously attended ED and none had their FGM identified during their ED attendance. The age range of those identified was 23 to 40 years. None had undergone defibulation. This study demonstrates that the identification of FGM victims by an ED is very poor, and more work needs to be done to increase awareness of the subject by front-line staff. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Interventions for healthcare providers to improve treatment and prevention of female genital mutilation: a systematic review.

PubMed

Balfour, Julie; Abdulcadir, Jasmine; Say, Lale; Hindin, Michelle J

2016-08-19

Studies on healthcare providers' awareness, knowledge and attitudes regarding female genital mutilation (FGM) have shown a lack of awareness of the prevalence, diagnosis, and management of FGM. Our objective was to systematically review the literature on interventions improving healthcare providers' capacities of prevention and treatment of FGM. Systematic review of the published and grey literature on interventions aimed at improving healthcare providers' capacities of prevention and treatment of FGM (1995-2015). Outcomes observed were knowledge and attitudes about FGM, medicalization, and prevention. Only two studies met our inclusion criteria. They reported on educational interventions aimed at increasing caregivers' knowledge on FGM. One was conducted with 59 providers, in Mali; the other one with 11 certified nurse-midwives in the United States. The studies report basic statistics regarding the improvement of healthcare professionals' knowledge, attitude on FGM and medicalization of the practice. Neither conducted multivariable analysis nor evaluated the training effects on the quality of the care offered, the clinical outcomes and the satisfaction of women attended, and prevention. As health care providers are essential in prevention and treatment of FGM, developing effective interventions is crucial.

High Temperature Materials for Chemical Propulsion Applications

NASA Technical Reports Server (NTRS)

Elam, Sandra; Hickman, Robert; O'Dell, Scott

2007-01-01

Radiation or passively cooled thrust chambers are used for a variety of chemical propulsion functions including apogee insertion, reaction control for launch vehicles, and primary propulsion for planetary spacecraft. The performance of these thrust chambers is limited by the operating temperature of available materials. Improved oxidation resistance and increased operating temperatures can be achieved with the use of thermal barrier coatings such as zirconium oxide (ZrO2) and hafnium oxide (HfO2). However, previous attempts to include these materials showed cracking and spalling of the oxide layer due to poor bonding. Current research at NASA's Marshall Space Flight Center (MSFC) has generated unique, high temperature material options for in-space thruster designs that are capable of up to 2500 C operating temperatures. The research is focused on fabrication technologies to form low cost Iridium,qF_.henium (Ir/Re) components with a ceramic hot wall created as an integral, functionally graded material (FGM). The goal of this effort is to further de?celop proven technologies for embedding a protective ceramic coating within the Ir/Re liner to form a robust functional gradient material. Current work includes the fabrication and testing of subscale samples to evaluate tensile, creep, thermal cyclic/oxidation, and thermophysical material properties. Larger test articles have also being fabricated and hot-fire tested to demonstrate the materials in prototype thrusters at 1O0 lbf thrust levels.

Facts and controversies on female genital mutilation and Islam.

PubMed

Rouzi, Abdulrahim A

2013-02-01

Female genital mutilation (FGM) is a very ancient traditional and cultural ritual. Strategies and policies have been implemented to abandon this practice. However, despite commendable work, it is still prevalent, mainly in Muslim countries. FGM predates Islam. It is not mentioned in the Qur'an (the verbatim word of God in Islam). Muslim religious authorities agree that all types of mutilation, including FGM, are condemned. 'Sensitivity' to cultural traditions that erroneously associate FGM with Islam is misplaced. The principle of 'do no harm', endorsed by Islam, supersedes cultural practices, logically eliminating FGM from receiving any Islamic religious endorsement.

Understanding the motivations of health-care providers in performing female genital mutilation: an integrative review of the literature.

PubMed

Doucet, Marie-Hélène; Pallitto, Christina; Groleau, Danielle

2017-03-23

Female genital mutilation (FGM) is a traditional harmful practice that can cause severe physical and psychological damages to girls and women. Increasingly, trained health-care providers carry out the practice at the request of families. It is important to understand the motivations of providers in order to reduce the medicalization of FGM. This integrative review identifies, appraises and summarizes qualitative and quantitative literature exploring the factors that are associated with the medicalization of FGM and/or re-infibulation. Literature searches were conducted in PubMed, CINAHL and grey literature databases. Hand searches of identified studies were also examined. The "CASP Qualitative Research Checklist" and the "STROBE Statement" were used to assess the methodological quality of the qualitative and quantitative studies respectively. A total of 354 articles were reviewed for inclusion. Fourteen (14) studies, conducted in countries where FGM is largely practiced as well as in countries hosting migrants from these regions, were included. The main findings about the motivations of health-care providers to practice FGM were: (1) the belief that performing FGM would be less harmful for girls or women than the procedure being performed by a traditional practitioner (the so-called "harm reduction" perspective); (2) the belief that the practice was justified for cultural reasons; (3) the financial gains of performing the procedure; (4) responding to requests of the community or feeling pressured by the community to perform FGM. The main reasons given by health-care providers for not performing FGM were that they (1) are concerned about the risks that FGM can cause for girls' and women's health; (2) are preoccupied by the legal sanctions that might result from performing FGM; and (3) consider FGM to be a "bad practice". The findings of this review can inform public health program planners, policy makers and researchers to adapt or create strategies to end medicalization of FGM in countries with high prevalence of this practice, as well as in countries hosting immigrants from these regions. Given the methodological limitations in the included studies, it is clear that more robust in-depth qualitative studies are needed, in order to better tackle the complexity of this phenomenon and contribute to eradicating FGM throughout the world.

The mothering experience of women with FGM/C raising 'uncut' daughters, in Ivory Coast and in Canada.

PubMed

Koukoui, Sophia; Hassan, Ghayda; Guzder, Jaswant

2017-04-05

While Female Genital Cutting (FGM/C) is a deeply entrenched cultural practice, there is now mounting evidence for a gradual decline in prevalence in a number of geographical areas in Africa and following migration to non-practicing countries. Consequently, there is now a growing number of women with FGM/C who are raising 'uncut' daughters. This study used a qualitative methodology to investigate the experience of women with FGM/C raising daughters who have not been subjected to the ritual. The aim of this study was to shed light on mothers' perception of the meaning and cultural significance of the practice and to gain insight into their mothering experience of 'uncut' girls. To this end, in-depth interviews were conducted with fifteen mothers living in Abidjan, Ivory Coast and in Montreal, Canada (8 and 7, respectively). Thirteen mothers intrinsically refused to perpetuate FGM/C onto their daughters and two diasporic mothers were in favour of FGM/C but forewent the practice for fear of legal repercussions. Whether the eschewing of FGM/C was deliberate or legally imposed, raising 'uncut' daughters had significant consequences in terms of women's mothering experiences. Mothers faced specific challenges pertaining to community and family pressure to have daughters undergo FGM/C, and expressed concerns regarding their daughters' sexuality. Conversely, women's narratives were also infused with pride and hope for their daughters, and revealed an accrued dialogue between the mother-daughter dyad about cultural norms and sexuality. Interestingly, women's mothering experience was also bolstered by the existence of informal networks of support between mothers with FGM/C whose daughters were 'uncut'. These communities of mothers engaged in open dialogue about the consequences of FGM/C and offered reciprocal solidarity and support in their decision to forego FGM/C for their children. Women with FGM/C who are raising 'uncut' daughters in their homeland and in their country of immigration vastly report a positive experience. However, they also face specific challenges related to immigration, psychosocial, and psychosexual considerations, which must be tackled from a multidisciplinary perspective.

Psychopathological sequelae of female genital mutilation and their neuroendocrinological associations.

PubMed

Köbach, Anke; Ruf-Leuschner, Martina; Elbert, Thomas

2018-06-13

Anecdotal evidence suggests the frequently traumatic nature of female genital mutilation (FGM). At present, systematic research on the psychological sequelae of this tradition has remained limited. The study provides preliminary, high-quality psychodiagnostic data on potential psychopathological consequences of FGM, with a focus on posttraumatic stress disorder (PTSD), shutdown dissociation and other stress-related variables. We investigated a convenience sample of N = 167 women, supported by the women's affairs headquarters in Jijiga (capital of the Ethiopian Somali Region) and a local Ethiopian non-governmental organization. Our main outcome measures were PTSD (PSS-I) and shutdown dissociation (ShuD). We also assessed depression and anxiety (HSCL-25), major depression, substance abuse and dependence, suicidality and psychotic disorders (M.I.N.I.; sub-scales A., B., K., and L.). In addition, we collected hair samples to assess hair cortisol concentrations (HCC) as a neuroendocrinological measure. The majority of women endured FGM (FGM I: 36%, FGM II/III: 52%) and, regardless of the level of the physical invasiveness, almost all women reported having felt intense fear and/or helplessness. FGM II/III, the more invasive form, was associated with a greater vulnerability to PTSD symptoms (p < .001) and shutdown dissociation (p < .001). Symptoms of depression (p < .05) and anxiety (p < .01) were also elevated. Random forest regression with conditional inference trees revealed evidence of an alteration of the cortisol levels in relation to the age when FGM was experienced (< 1 year) and the invasiveness of the procedure. More extensive forms of FGM are associated with more severe psychopathological symptoms - particularly with an increased vulnerability to PTSD. Higher hair cortisol levels in women who experienced FGM before their first year of age or had more severe forms of FGM indicate long-term neuroendocrinological consequences of FGM and trauma in general on the stress system.

Female genital mutilation in children presenting to Australian paediatricians.

PubMed

Zurynski, Yvonne; Phu, Amy; Sureshkumar, Premala; Cherian, Sarah; Deverell, Marie; Elliott, Elizabeth J

2017-06-01

The WHO reports that female genital mutilation/cutting (FGM/C) is an ancient cultural practice prevalent in many countries. FGM/C has been reported among women resident in Australia. Our paper provides the first description of FGM/C in Australian children. Cross-sectional survey conducted in April-June 2014. Paediatricians and other child health specialists recruited through the Australian Paediatric Surveillance Unit were asked to report children aged <18 years with FGM/C seen in the last 5 years, and to provide data for demographics, FGM/C type, complications and referral for each case. Of 1311 eligible paediatricians/child health specialists, 1003 (76.5%) responded. Twenty-three (2.3%) respondents had seen 59 children with FGM/C and provided detailed data for 31. Most (89.7%) were identified during refugee screening and were born in Africa. Three (10.3%) were born in Australia: two had FGM/C in Australia and one in Indonesia. All parents were born overseas, mainly Africa (98.1%). Ten children had WHO FGM/C type I, five type II, five type III and six type IV. Complications in eight children included recurrent genitourinary infections, menstrual, sexual, fertility and psychological problems. Nineteen children (82.6%) were referred to obstetrics/gynaecology: 16 (69.9%) to social work and 13 (56.5%) to child protection. This study confirms that FGM/C is seen in paediatric clinical practice within Australia. Paediatricians need cultural awareness, education and resources to help them identify children with FGM/C and/or at risk of FGM/C, to enable appropriate referral and counselling of children, families and communities to assist in the prevention of this practice. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

Estimating the prevalence of female genital mutilation in Portugal.

PubMed

Teixeira, A L; Lisboa, M

2016-10-01

Due to globalized migratory processes, female genital mutilation/cutting (FGM/C) has spread to other countries, including countries in Europe, where, with a few exceptions, it remains a concealed problem. To the authors' knowledge, this is the first national extensive study to estimate the prevalence of FGM/C in Portugal. Prevalence estimation. Using extrapolation of country-of-origin prevalence data and the 2011 Census data, this study estimated: the prevalence of FGM/C in Portugal among women of reproductive age (15-49 years) and among all women aged ≥15 years; and the number of girls aged <15 years living in Portugal who have undergone or will probably undergo FGM/C. It is estimated that 6576 women aged ≥15 years living in Portugal have undergone FGM/C, with cases distributed unevenly throughout the national territory. In addition, it is estimated that 1830 girls aged <15 years living in Portugal have undergone or are likely to undergo FGM/C. This study estimated that more than 6000 women living in Portugal have undergone FGM/C, and many girls remain at risk. These two groups need different types of interventions. Awareness of the number and geographical dispersion of cases of FGM/C will enable more informed and targeted definition of public health policies for protection of females who have undergone or are at risk of undergoing FGM/C. Copyright © 2016 The Royal Society for Public Health. Published by Elsevier Ltd. All rights reserved.

Midwives' experiences of caring for women with female genital mutilation: Insights and ways forward for practice in Australia.

PubMed

Dawson, A J; Turkmani, S; Varol, N; Nanayakkara, S; Sullivan, E; Homer, C S E

2015-09-01

Female genital mutilation (FGM) has serious health consequences, including adverse obstetric outcomes and significant physical, sexual and psychosocial complications for girls and women. Migration to Australia of women with FGM from high-prevalence countries requires relevant expertise to provide women and girls with FGM with specialised health care. Midwives, as the primary providers of women during pregnancy and childbirth, are critical to the provision of this high quality care. To provide insight into midwives' views of, and experiences working with, women affected by FGM. A descriptive qualitative study was undertaken using focus group discussions with midwives from four purposively selected antenatal clinics and birthing units in three hospitals in urban New South Wales. The transcripts were analysed thematically. Midwives demonstrated knowledge and recalled skills in caring for women with FGM. However, many lacked confidence in these areas. Participants expressed fear and a lack of experience caring for women with FGM. Midwives described practice issues, including the development of rapport with women, working with interpreters, misunderstandings about the culture of women, inexperience with associated clinical procedures and a lack of knowledge about FGM types and data collection. Midwives require education, training and supportive supervision to improve their skills and confidence when caring for women with FGM. Community outreach through improved antenatal and postnatal home visitation can improve the continuity of care provided to women with FGM. Copyright © 2015 Australian College of Midwives. Published by Elsevier Ltd. All rights reserved.

The Obstetric Consequences of Female Genital Mutilation/Cutting: A Systematic Review and Meta-Analysis

PubMed Central

Berg, Rigmor C.; Underland, Vigdis

2013-01-01

Various forms of female genital mutilation/cutting (FGM/C) have been performed for millennia and continue to be prevalent in parts of Africa. Although the health consequences following FGM/C have been broadly investigated, divergent study results have called into question whether FGM/C is associated with obstetric consequences. To clarify the present state of empirical research, we conducted a systematic review of the scientific literature and quantitative meta-analyses of the obstetric consequences of FGM/C. We included 44 primary studies, of which 28 were comparative, involving almost 3 million participants. The methodological study quality was generally low, but several studies reported the same outcome and were sufficiently similar to warrant pooling of effect sizes in meta-analyses. The meta-analyses results showed that prolonged labor, obstetric lacerations, instrumental delivery, obstetric hemorrhage, and difficult delivery are markedly associated with FGM/C, indicating that FGM/C is a factor in their occurrence and significantly increases the risk of delivery complications. There was no significant difference in risk with respect to cesarean section and episiotomy. These results can make up the background documentation for health promotion and health care decisions that inform work to reduce the prevalence of FGM/C and improve the quality of services related to the consequences of FGM/C. PMID:23878544

Female genital mutilation in Greece.

PubMed

Vrachnis, N; Salakos, N; Iavazzo, C; Iliodromiti, Z; Bakalianou, K; Kouiroukidou, P; Creatsas, G

2012-01-01

The number of migrants and refugees with a female genital mutilation (FGM) living in Greece is rising. This study explores the characteristics and psychosexual issues of women with FGM who were examined in the 2nd Department of Obstetrics and Gynecology, University of Athens Medical School, Greece during the year 2009. The women were asked to fill out an anonymous questionnaire asking for demographic data, obstetric history, current complaints, and psychosexual problems. The results are presented and discussed, as FGM is a new reality for Greece. Healthcare providers have to familiarize themselves with issues related to FGM and improve their skills in transcultural care, so as to manage and support women with FGM adequately.

The relationship between female genital mutilation and HIV transmission in sub-Saharan Africa.

PubMed

Olaniran, Abimbola A

2013-12-01

Female genital mutilation (FGM) is an age-old practice that has since been linked with many health problems. This review aims to highlight some of the controversies trailing the relationship between FGM and HIV transmission in sub-Saharan Africa. A literature search was conducted on the subject matter. This was done using articles published in English while limiting the geographical coverage to sub-Saharan Africa. Three themes were noted. These themes include: Direct causal link between FGM and HIV transmission; indirect causal link between FGM and HIV transmission and a negative or no association between FGM and HIV transmission. While many of the arguments are within scientific reasoning, the researches supporting the views seem to lack the necessary objectivity. This study underscored the need for a more objective lens in viewing and conducting research on the relationship between FGM and HIV transmission in sub-Saharan Africa.

Female genital mutilation/cutting: risk management and strategies for social workers and health care professionals

PubMed Central

Costello, Susan

2015-01-01

Female genital mutilation/cutting (FGM/C) is a traditional practice originating in Africa. Its worst forms cause irreparable harm to girls and women and have no medical justification. Based on a literature review of global responses to FGM/C and conversations with Australian women who migrated from FGM/C practicing countries, this paper provides some background on FGM/C and its epidemiology, outlining its prevalence, types, and health risks and complications for women and girls. It discusses risk-prevention strategies, first, for health practitioners in identifying, screening, and supporting women affected by FGM/C and, second, for welfare and social workers and health care professionals to identify, work with, and prevent girls from being cut. Consistent with international trends in addressing the risks of FGM/C, the paper suggests practice responses for coordinated responses between professionals, communities from practicing countries, and governments of different countries. PMID:26719732

Estimates of first-generation women and girls with female genital mutilation in the European Union, Norway and Switzerland.

PubMed

Van Baelen, Luk; Ortensi, Livia; Leye, Els

2016-12-01

Female genital mutilation (FGM) is the practice of partial or total removal of female genitalia for non-medical reasons. The procedure has no known health benefits but can cause serious immediate and long-term obstetric, gynaecological and sexual health problems. Health workers in Europe are often unaware of the consequences of FGM and lack the knowledge to treat women adequately. Our goal was to estimate the number of first-generation girls and women in the European Union, Norway and Switzerland who have undergone FGM. Before migration from FGM-practicing countries began, FGM was an unknown phenomenon in Europe. Secondary analysis of data from the 2011 EU census and extrapolation from age-specific FGM prevalence rates in the immigrants' home countries to these data were used to provide our estimates. Estimates based on census and other demographic data were compared to our results for Belgium. In 2011 over half a million first-generation women and girls in the EU, Norway and Switzerland had undergone FGM before immigration. One in two was living in the UK or France, one in two was born in East-Africa. For the first time, scientific evidence gives a reliable estimate of the number of first-generation women and girls in Europe coming from countries where FGM is practiced. The use of census data proves reliable for policy makers to guide their actions, e.g., regarding training needs for health workers who might be confronted with women who have undergone FGM, or the need for reconstructive surgery.

Bibliometric analysis of literature on female genital mutilation: (1930 - 2015).

PubMed

Sweileh, Waleed M

2016-10-10

Female genital mutilation/cutting (FGM/C) is a common harmful traditional practice in many communities in Africa and to a lesser extent in Middle East and other regions in the world. In order to better understand publishing on this topic, we conducted a bibliometric study on FGM/C. Bibliometric analyses can be used as an indicator of the extent of interaction of researchers, health authorities, and communities with a particular health issue. Scopus database was used to retrieve data on FGM/C. Keywords used were "female genital mutilation", "female genital circumcision", "female genital cutting" and "female circumcision". Specifically, the number of publications, top productive countries and institutions, highly cited articles, citation analysis, co-authorships, international collaboration, role of African countries, top active authors, and journals involved in publishing articles on FGM/C were reviewed and analyzed. We indirectly assessed the impact of publications using total number of citations received, average number of citations per article, Hirsch-index, percentage of highly cited articles, and journal's impact factor. One thousand and thirty-five publications on FGM/C were retrieved. The h-index of retrieved articles was 37. A steep rise in number of publications was noticed in mid-1990s and again in 2012. More than half of retrieved articles were published from 2006 - 2015. A total of 65 countries contributed. The top ten productive countries included ones from Northern America, Europe and Africa. Nigeria and Egypt were the most active African countries in FGM/C publications. At least nine African academic institutions were actively involved on FGM/C publications. Articles on FGM/C that received the highest number of citations were those that focused on negative physical and psychosexual consequences of FGM/C. Journal topic areas were obstetrics/gynecology, public health, and psychological sociology. Collaboration between African and European countries on FGM/C research was evident. Bibliometric analysis reveals that research publications on FGM/C have been increasing since the l970s, with collaboration between African and Western countries, and articles are being published in higher impact journals, not only obstetrics, but also public health and social sciences. FGM/C research can be helpful to international health agencies and governments not only to document negative outcomes, but also to identify best practices, and to note gaps in implementation and practice.

What do we know about assessing healthcare students and professionals' knowledge, attitude and practice regarding female genital mutilation? A systematic review.

PubMed

Abdulcadir, Jasmine; Say, Lale; Pallitto, Christina

2017-05-22

Improving healthcare providers' capacities of prevention and treatment of female genital mutilation (FGM) is important given the fact that 200 million women and girls globally are living with FGM. However, training programs are lacking and often not evaluated. Validated and standardized tools to assess providers' knowledge, attitude and practice (KAP) regarding FGM are lacking. Therefore, little evidence exists on the impact of training efforts on healthcare providers' KAP on FGM. The aim of our paper is to systematically review the available published and grey literature on the existing quantitative tools (e.g. scales, questionnaires) measuring healthcare students' and providers' KAP on FGM. We systematically reviewed the published and grey literature on any quantitative assessment/measurement/evaluation of KAP of healthcare students and providers about FGM from January 1 st , 1995 to July 12 th , 2016. Twenty-nine papers met our inclusion criteria. We reviewed 18 full text questionnaires implemented and administered to healthcare professionals (students, nurses, midwives and physicians) in high and low income countries. The questionnaires assessed basic KAP on FGM. Some included personal and cultural beliefs, past clinical experiences, personal awareness of available clinical guidelines and laws, previous training on FGM, training needs, caregiver's confidence in management of women with FGM, communication and personal perceptions. Identified gaps included the medical, psychological or surgical treatments indicated to improve girls and women's health; correct diagnosis, recording ad reporting capacities; clitoral reconstruction and psychosexual care of circumcised women. Cultural and personal beliefs on FGM were investigated only in high prevalence countries. Few questionnaires addressed care of children, child protection strategies, treatment of short-term complications, and prevention. There is a need for implementation and testing of interventions aimed at improving healthcare professionals' and students' capacities of diagnosis, care and prevention of FGM. Designing tools for measuring the outcomes of such interventions is a critical aspect. A unique, reproducible and standardized questionnaire could be created to measure the effect of a particular training program. Such a tool would also allow comparisons between settings, countries and interventions. An ideal tool would test the clinical capacities of providers in managing complications and communicating with clients with FGM as well as changes in KAP.

Female Genital Mutilation as a Concern for Special Operations and Tactical Emergency Medical Support Medics.

PubMed

Wittich, Arthur C

Female genital mutilation (FGM), frequently called female genital cutting or female circumcision, is the intentional disfigurement of the external genitalia in young girls and women for the purpose of reducing libido and ensuring premarital virginity. This traditional, nontherapeutic procedure to suppress libido and prevent sexual intercourse before marriage has been pervasive in Northern Africa, the Middle East, and the Arabian peninsula for over 2,500 years. FGM permanently destroys the genital anatomy while frequently causing multiple and serious complications. The International Federation of Gynecology and Obstetrics proposed a classification system of FGM according to the specific genital anatomy removed and the extensiveness of genital disfigurement. Although it has been ruled illegal in most countries, FGM continues to be performed worldwide. With African, Asian, and Middle Eastern immigration to the United States and Europe, western countries are experiencing FGM in regions where these immigrants have concentrated. As deployments of Special Operations Forces (SOF) increase to regions in which FGM is pervasive, and as African, Asian, and Middle Eastern immigration to the United States increases, SOF and Tactical Emergency Medical Support (TEMS) medics will necessarily be called upon to evaluate and treat complications resulting from FGM. The purpose of this article is to educate SOF/TEMS medical personnel about the history, geographic regions, classification of procedures, complications, and medical treatment of patients with FGM. 2017.

African, male attitudes on female genital mutilation: an Australian survey.

PubMed

Shahid, Usama; Rane, Ajay

2017-11-01

Female genital mutilation (FGM) is a traditional practice where female genital organs are altered for non-medical reasons. The custom is outlawed in Australia and associated with an array of medical consequences. Due to the recent influx of migrants from regions endemic to FGM, the practice is becoming a growing concern locally. This federal government funded study aimed to elicit the poorly understood perceptions that young, Sub-Saharan African, migrant males residing in Townsville, Australia have on FGM. Through piloted questionnaires we found that amongst the 67 participants, 23.9% believed that FGM should be allowed under Australian Law. The independent predictors of supportive attitudes in favour of FGM were having resided in Australia for five or less years (p = .016, 95% CI 0.99-8.09) and coming from a basic educational background (high school or TAFE) (p = .003, 95% CI 1.3-12.4). This study also found that participant perceptions on FGM were amenable to change through educational interventional strategies. Impact statement Female genital mutilation (FGM) is a traditional practice where female genital organs are altered for non-medical reasons. The role that males play in the continuation of this outlawed practice remains poorly understood. No research has ever been conducted in Australia looking at the perception that young, migrant males have on FGM. Several European-based studies have examined the perceptions of older, poorly educated, migrant male cohorts. Generally, these studies show that the attitudinal support for FGM and intention to practice remains relatively high amongst these cohorts. This study examined the attitudes of a young, Sub-Saharan African, migrant, male cohort residing in Australia. This adds to the literature base by establishing the perceptions and associated socio-demographic variables of this unique and influential subset of the migrant population. This directly facilitates the development of interventional strategies against FGM by highlighting those most likely to have an attitudinal support in favour of FGM. Consequentially, this 'at risk' group can be more effectively focussed on interventional programmes and be further investigated in larger scale studies.

Non-invasive assessment of adrenocortical activity as a measure of stress in giraffe (Giraffa camelopardalis).

PubMed

Bashaw, Meredith J; Sicks, Florian; Palme, Rupert; Schwarzenberger, Franz; Tordiffe, Adrian S W; Ganswindt, Andre

2016-10-18

Numbers of giraffes are declining rapidly in their native habitat. As giraffe research and conservation efforts increase, the demand for more complete measures of the impact of conservation interventions and the effects of captive environments on animal health and welfare have risen. We compared the ability of six different enzyme immunoassays to quantify changes in fecal glucocorticoid metabolites (FGM) resulting from three sources: adrenocorticotropic hormone stimulation test, transport, and time of day that samples were collected. Two male giraffes underwent ACTH injections; all six assays detected FGM increases following injection for Giraffe 1, while only three assays detected FGM increases following injection for Giraffe 2. Consistent with other ruminant species, the two 11-oxoetiocholanolone assays (one for 11,17-dioxoandrostanes and the other for 3α,11-oxo metabolites) measured the most pronounced and prolonged elevation of FGM, while an assay for 3β,11β-diol detected peaks of smaller magnitude and duration. Both of the 11-oxoetiocholanolone assays detected significant FGM increases after transport in Giraffes 3-7, and preliminary data suggest FGM detected by the assay for 11,17-dioxoandrostanes may differ across time of day. We conclude the assay for 11,17-dioxoandrostanes is the most sensitive assay tested for FGM in giraffes and the assay for FGM with a 5β-3α-ol-11-one structure is also effective. 11-oxoetiocholanolone enzyme immunoassays have now been demonstrated to be successful in a wide variety of ruminant species, providing indirect evidence that 5β-reduction may be a common metabolic pathway for glucocorticoids in ruminants. As FGM peaks were detected in at least some giraffes using all assays tested, giraffes appear to excrete a wide variety of different FGM. The assays validated here will provide a valuable tool for research on the health, welfare, and conservation of giraffes.

Stop female genital mutilation: appeal to the international dermatologic community.

PubMed

Morrone, Aldo; Hercogova, Jana; Lotti, Torello

2002-05-01

Female genital mutilation (FGM) is a traditional cultural practice, but also a form of violence against girls, which affects their lives as adult women. FGM comprises a wide range of procedures: the excision of the prepuce; the partial or total excision of the clitoris (clitoridectomy) and labia; or the stitching and narrowing of the vaginal orifice (infibulation). The number of girls and women who have been subjected to FGM is estimated at around 137 million worldwide and 2 million girls per year are considered at risk. Most females who have undergone mutilation live in 28 African countries. Globalization and international migration have brought an increased presence of circumcised women in Europe and developed countries. Healthcare specialists need to be made aware and trained in the physical, psychosexual, and cultural aspects and effects of FGM and in the response to the needs of genitally mutilated women. Health education programs targeted at immigrant communities should include information on sexuality, FGM, and reproduction. Moreover, healthcare workers should both discourage women from performing FGM on their daughters and receive information on codes of conduct and existing laws. The aim is the total eradication of all forms of FGM.

Surgical reconstruction in female genital mutilation

PubMed Central

Gültekin, İsmail Burak; Altınboğa, Orhan; Dur, Rıza; Kara, Osman Fadıl; Küçüközkan, Tuncay

2016-01-01

Female genital mutilation (FGM) is an unusual condition for our country. However, an increase in FGM in future days can be predicted with the increasing numbers of exchange students coming from African countries, migration of refugees and socioeconomic relations with the African countries. We want to share our experience of two FGM victims admitted to our clinic with the request of reconstructive vulvar surgery before their marriage. Both women had WHO Type III FGM. Physical examination findings and surgical reconstruction techniques were presented. PMID:27274899

Effects of female genital mutilation/cutting on the sexual function of Sudanese women: a cross-sectional study.

PubMed

Rouzi, Abdulrahim A; Berg, Rigmor C; Sahly, Nora; Alkafy, Susan; Alzaban, Faten; Abduljabbar, Hassan

2017-07-01

Female genital mutilation/cutting (FGM/C) is a cultural practice that involves several types of removal or other injury to the external female genitalia for nonmedical reasons. Although much international research has focused on the health consequences of the practice, little is known about sexual functioning among women with various types of FGM/C. To assess the impact of FGM/C on the sexual functioning of Sudanese women. This is a cross-sectional study conducted at Doctor Erfan and Bagedo Hospital, Jeddah, Saudi Arabia. Eligible women completed a survey and a clinical examination, which documented and verified women's type of FGM/C. The main outcome measure was female sexual function, as assessed by the Arabic Female Sexual Function Index. A total of 107 eligible women completed the survey and the gynecological examination, which revealed that 39% of the women had FGM/C Type I, 25% had Type II, and 36% had Type III. Reliability of self-report of the type of FGM/C was low, with underreporting of the extent of the procedure. The results showed that 92.5% of the women scored lower than the Arabic Female Sexual Function Index cut-off point for sexual dysfunction. The multivariable regression analyses showed that sexual dysfunction was significantly greater with more extensive type of FGM/C, across all sexual function domains (desire, arousal, lubrication, orgasm, satisfaction, and pain) and overall. The study documents that a substantial proportion of women subjected to FGM/C experience sexual dysfunction. It shows that the anatomical extent of FGM/C is related to the severity of sexual dysfunction. Copyright © 2017 Elsevier Inc. All rights reserved.

Type I female genital mutilation: a cause of completely closed vagina.

PubMed

Rouzi, Abdulrahim A; Sahly, Nora; Alhachim, Estabraq; Abduljabbar, Hassan

2014-09-01

Female genital mutilation (FGM) ranges in severity from a nick of the clitoris to partial or total removal of the external genitalia. Sexual complications after FGM include sexual dysfunction, difficult intercourse, and dyspareunia. We report a case of Type I FGM presenting as complete vaginal closure and urinary retention. A 16-year-old adolescent was referred for obliterated vagina and urinary retention. She had recurrent urinary tract infections, difficulty in voiding, and cyclic hematuria. At the age of 1 year she had been taken by her mother to a pediatric surgeon to have a Type I FGM procedure. On examination, the urethral meatus and vaginal orifices were completely closed by the FGM scar. She underwent uneventful surgical opening of the vagina. A normal vaginal orifice was created and normal flow of urine and menses occurred. Type I FGM can present as complete vaginal closure and urinary retention. Proper diagnosis and treatment are of paramount importance. © 2014 International Society for Sexual Medicine.

Non-invasive monitoring of glucocorticoid metabolites in banded mongooses (Mungos mungo) in response to physiological and biological challenges.

PubMed

Laver, Peter N; Ganswindt, André; Ganswindt, Stefanie B; Alexander, Kathleen A

2012-11-01

Free-ranging banded mongooses are infected by the novel pathogen, Mycobacterium mungi in northern Botswana. A reliable method for determining stress-related physiological responses in banded mongooses will increase our understanding of the stress response in M. mungi infection. Therefore, our aim was to examine the suitability of four enzyme immunoassays (EIAs) for monitoring adrenocortical endocrine function in captive and free-ranging banded mongooses based on fecal glucocorticoid metabolite (FGM) analysis. A conducted adrenocorticotropic hormone challenge revealed suitability of a valid measurement of FGM levels in banded mongoose feces for all four tested EIAs, with an 11-oxoetiocholanolone assay detecting 11,17-dioxoandrostanes (11,17-DOA) performing best. Subsequent analyses using only this EIA showed the expected decrease in FGM concentrations 48 h after administering dexamethasone sodium phosphate. Furthermore, captive mongooses showed higher FGM concentrations during reproductive activity, agonistic encounters and depredation events. Finally, a late-stage, tuberculosis-infected moribund mongoose in a free-ranging troop had a 54-fold elevation in FGM levels relative to the rest of the troop. Measurements of gastrointestinal transit times and FGM metabolism post-defecation indicate that the time delay of FGM excretion approximately corresponded with food transit time and that FGM metabolism is minimal up to 8h post-defecation. The ability to reliably assess adrenocortical endocrine function in banded mongoose now provides a solid basis for advancing our understanding of infectious disease and endocrinology in this species. Copyright © 2012 Elsevier Inc. All rights reserved.

Deinfibulation for preventing or treating complications in women living with type III female genital mutilation: A systematic review and meta-analysis.

PubMed

Okusanya, Babasola O; Oduwole, Olabisi; Nwachuku, Nuria; Meremikwu, Martin M

2017-02-01

Deinfibulation is a surgical procedure carried out to re-open the vaginal introitus of women living with type III female genital mutilation (FGM). To assess the impact of deinfibulation on gynecologic or obstetric outcomes by comparing women who were deinfibulated with women with type III FGM or women without FGM. Major databases including CENTRAL, MEDLINE, and Scopus were searched until August 2015. We included nonrandomized studies that compared obstetric outcomes of women with deinfibulation, type III FGM (not deinfibulated during labor), and no FGM. Quality of evidence was determined following the GRADE methodology. Summary measures were calculated using odds ratios at 95% confidence intervals. We found no randomized controlled trials. We included four case-control studies. The quality of evidence was very low. Compared with women with type III FGM at delivery, deinfibulated women had a significant reduction in the risk of having a cesarean delivery or postpartum hemorrhage. Compared with women without FGM, deinfibulated women had a similar risk of episiotomy, cesarean delivery, vaginal lacerations, postpartum hemorrhage, and blood loss at vaginal delivery. The length of second stage of labor, mean maternal hospital stay, and Apgar scores less than 7 were also comparable. Low-quality evidence suggests deinfibulation improves birth outcomes for women with type III FGM. CRD42015024466. © 2017 International Federation of Gynecology and Obstetrics. The World Health Organization retains copyright and all other rights in the manuscript of this article as submitted for publication.

Tailoring vibration mode shapes using topology optimization and functionally graded material concepts

NASA Astrophysics Data System (ADS)

Montealegre Rubio, Wilfredo; Paulino, Glaucio H.; Nelli Silva, Emilio Carlos

2011-02-01

Tailoring specified vibration modes is a requirement for designing piezoelectric devices aimed at dynamic-type applications. A technique for designing the shape of specified vibration modes is the topology optimization method (TOM) which finds an optimum material distribution inside a design domain to obtain a structure that vibrates according to specified eigenfrequencies and eigenmodes. Nevertheless, when the TOM is applied to dynamic problems, the well-known grayscale or intermediate material problem arises which can invalidate the post-processing of the optimal result. Thus, a more natural way for solving dynamic problems using TOM is to allow intermediate material values. This idea leads to the functionally graded material (FGM) concept. In fact, FGMs are materials whose properties and microstructure continuously change along a specific direction. Therefore, in this paper, an approach is presented for tailoring user-defined vibration modes, by applying the TOM and FGM concepts to design functionally graded piezoelectric transducers (FGPT) and non-piezoelectric structures (functionally graded structures—FGS) in order to achieve maximum and/or minimum vibration amplitudes at certain points of the structure, by simultaneously finding the topology and material gradation function. The optimization problem is solved by using sequential linear programming. Two-dimensional results are presented to illustrate the method.

For the sake of purity (and control). Female genital mutilation.

PubMed

Gilbert, D

1993-01-01

In 1973 approximately 1 million girls will be victimized by female genital mutilation (FGM), widely practiced in more than 20 African nations from Mauritania to the Ivory Coast in the west, to Egypt and North Tanzania in the east, as well as in Oman, Bahrain, North and South Yemen, and the United Arab Emirates. FGM takes place among the Moslem populations of the Philippines, Indonesia, and Malaysia and the Jewish Falashas in Ethiopia. FGM is practiced on babies just a few days old to girls right before marriage or young women pregnant with their first child. The most extreme mutilation is called infibulation. In Somalia, almost 100% of the women are infibulated, and so are more than 80% of the women in north and central Sudan. In Ethiopia/Eritrea, Mali, and Sierra Leone, 90% of the women have undergone some form of genital mutilation. The rate reaches 70% in Burkina Faso; 60% in Kenya, Gambia, and the Ivory Coast; and 50% in Senegal, Egypt, Guinea Bissau, and Nigeria. The mutilation often results in accumulation of menstrual blood and pelvic inflammatory disease often leading to infertility. Between 20% and 25% of infertility in Sudan has been attributed to female genital mutilation. The practice of FGM has existed for centuries, and some claim it originated in the Nile Valley during the Pharaonic era. On the other hand, Muslim countries like Iraq, Syria, and Tunisia do not practice FGM. The London Black Women's Health Action Project set up an educational network to prevent mutilations and to dispel the myth of religion about FGM. FORWARD convened the First Study Conference on Genital Mutilation of Girls in Europe in 1992 and deemed FGM a form of child abuse. Local campaigns in Africa, Asia, and the Arab world educate against FGM. The Inter-Africa Committee on Traditional Practices Affecting the Health of Women and Children, based in Addis Ababa, Ethiopia, has offices in more than 20 African nations to sensitize the public about the harmful effects of FGM. In Nigeria, the National Association of Nigerian Nurses and Midwives presents plays in the local markets about the complications of FGM.

Health sector involvement in the management of female genital mutilation/cutting in 30 countries.

PubMed

Johansen, R Elise B; Ziyada, Mai Mahgoub; Shell-Duncan, Bettina; Kaplan, Adriana Marcusàn; Leye, Els

2018-04-04

For the last decades, the international community has emphasised the importance of a multisectoral approach to tackle female genital mutilation (FGM/C). While considerable improvement concerning legislations and community involvement is reported, little is known about the involvement of the health sector. A mixed methods approach was employed to map the involvement of the health sector in the management of FGM/C both in countries where FGM/C is a traditional practice (countries of origin), and countries where FGM/C is practiced mainly by migrant populations (countries of migration). Data was collected in 2016 using a pilot-tested questionnaire from 30 countries (11 countries of origin and 19 countries of migration). In 2017, interviews were conducted to check for data accuracy and to request relevant explanations. Qualitative data was used to elucidate the quantitative data. A total of 24 countries had a policy on FGM/C, of which 19 had assigned coordination bodies and 20 had partially or fully implemented the plans. Nevertheless, allocation of funding and incorporation of monitoring and evaluation systems was lacking in 11 and 13 of these countries respectively. The level of the health sectors' involvement varied considerably across and within countries. Systematic training of healthcare providers (HCP) was more prevalent in countries of origin, whereas involvement of HCP in the prevention of FGM/C was more prevalent in countries of migration. Most countries reported to forbid HCP from conducting FGM/C on both minors and adults, but not consistently forbidding re-infibulation. Availability of healthcare services for girls and women with FGM/C related complications also varied between countries dependent on the type of services. Deinfibulation was available in almost all countries, while clitoral reconstruction and psychological and sexual counselling were available predominantly in countries of migration and then in less than half the countries. Finally, systematic recording of FGM/C in medical records was completely lacking in countries of origin and very limited in countries of migration. Substantial progress has been made in the involvement of the health sector in both the treatment and prevention of FGM/C. Still, there are several areas in need for improvement, particularly monitoring and evaluation.

Management of female genital mutilation in Djibouti: the Peltier General hospital experience.

PubMed

Collinet, P; Stien, L; Vinatier, D; Leroy, J L

2002-11-01

Female genital mutilation (FGM) is still performed on 98% of Djiboutian women. Infibulation (FGM type 3) is the most widely used method of FGM in Djibouti. Even though this operation is mutilating, illegal and sometimes results in death, it is still practiced at approximately the same rate as in the past. Mass immigration of African women to Europe, Canada, Australia and the United States in the past decade has brought the problems of FGM to these countries. Female genital mutilation is a problem unfamiliar to most Western obstetrician-gynecologists. A tight infibulation can be a high risk for the mother and fetus if not handled by a skilled operator. It can lead to an unnecessary cesarean section as a result of the fear of handling infibulated women. Therefore, Western physicians need to be informed. The aim of this article was to share our experience of FGM. It will focus on FGM in Djibouti, its types, epidemiology and health consequences. It will present the management of obstetric and gynecologic complications and discuss medico-legal and health service measures to combat these dangerous and unnecessary practices

Preparation of Functionally Graded Materials (FGMs) Using Coal Fly Ash and NiCr-Based Alloy Powder by Spark Plasma Sintering (SPS)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kaneko, Gen-yo; Kitagawa, Hiroyuki; Hasezaki, Kazuhiro

2008-02-15

Functionally Graded Materials (FGMs) were prepared by spark plasma sintering (SPS) using coal fly ash and NiCr alloy powder. The coal fly ash was produced by the Misumi Coal Thermal Power Station (Chugoku Electric Power Co., Inc.), with 80 wt% nickel and 20 wt% chromium (Fukuda Metal Foil and Powder Co., Ltd.) used as source materials. The sintering temperature in the graphite die was 1000 deg. C. X-ray diffraction patterns of the sintered coal fly ash materials indicated that mullite (3Al{sub 2}O{sub 3}{center_dot}2SiO{sub 2}) and silica (SiO{sub 2}) phases were predominant. Direct joining of coal fly ash and NiCr causesmore » fracture at the interface. This is due to the mismatch in the thermal expansion coefficients (CTE). A crack in the FGM was observed between the two layers with a CTE difference of over 4.86x10{sup -6} K{sup -1}, while a crack in the FGM was difficult to detect when the CTE difference was less than 2.77x10{sup -6} K{sup -1}.« less

Sexual Anatomy and Function in Women With and Without Genital Mutilation: A Cross-Sectional Study.

PubMed

Abdulcadir, Jasmine; Botsikas, Diomidis; Bolmont, Mylène; Bilancioni, Aline; Djema, Dahila Amal; Bianchi Demicheli, Francesco; Yaron, Michal; Petignat, Patrick

2016-02-01

Female genital mutilation (FGM), the partial or total removal of the external genitalia for non-medical reasons, can affect female sexuality. However, only few studies are available, and these have significant methodologic limitations. To understand the impact of FGM on the anatomy of the clitoris and bulbs using magnetic resonance imaging and on sexuality using psychometric instruments and to study whether differences in anatomy after FGM correlate with differences in sexual function, desire, and body image. A cross-sectional study on sexual function and sexual anatomy was performed in women with and without FGM. Fifteen women with FGM involving cutting of the clitoris and 15 uncut women as a control group matched by age and parity were prospectively recruited. Participants underwent pelvic magnetic resonance imaging with vaginal opacification by ultrasound gel and completed validated questionnaires on desire (Sexual Desire Inventory), body image (Questionnaire d'Image Corporelle [Body Image Satisfaction Scale]), and sexual function (Female Sexual Function Index). Primary outcomes were clitoral and bulbar measurements on magnetic resonance images. Secondary outcomes were sexual function, desire, and body image scores. Women with FGM did not have significantly decreased clitoral glans width and body length but did have significantly smaller volume of the clitoris plus bulbs. They scored significantly lower on sexual function and desire than women without FGM. They did not score lower on Female Sexual Function Index sub-scores for orgasm, desire, and satisfaction and on the Questionnaire d'Image Corporelle but did report significantly more dyspareunia. A larger total volume of clitoris and bulbs did not correlate with higher Female Sexual Function Index and Sexual Desire Inventory scores in women with FGM compared with uncut women who had larger total volume that correlated with higher scores. Women with FGM have sexual erectile tissues for sexual arousal, orgasm, and pleasure. Women with sexual dysfunction should be appropriately counseled and treated. Copyright © 2016 International Society for Sexual Medicine. Published by Elsevier Inc. All rights reserved.

Health complications of female genital mutilation in Sierra Leone

PubMed Central

Bjälkander, Owolabi; Bangura, Laurel; Leigh, Bailah; Berggren, Vanja; Bergström, Staffan; Almroth, Lars

2012-01-01

Sierra Leone has one of the highest rates of female genital mutilation (FGM) in the world, and yet little is known about the health consequences of the practice. Purpose To explore whether and what kind of FGM-related health complications girls and women in Sierra Leone experience, and to elucidate their health care-seeking behaviors. Patients and methods A feasibility study was conducted to test and refine questionnaires and methods used for this study. Thereafter, a cross-section of girls and women (n = 258) attending antenatal care and Well Women Clinics in Bo Town, Bo District, in the southern region and in Makeni Town, Bombali District, in the northern region of Sierra Leone were randomly selected. Participants answered interview-administrated pretested structured questionnaires with open- ended-questions, administrated by trained female personnel. Results All respondents had undergone FGM, most between 10 and 14 years of age. Complications were reported by 218 respondents (84.5%), the most common ones being excessive bleeding, delay in or incomplete healing, and tenderness. Fever was significantly more often reported by girls who had undergone FGM before 10 years of age compared with those who had undergone the procedure later. Out of those who reported complications, 187 (85.8%) sought treatment, with 89 of them visiting a traditional healer, 75 a Sowei (traditional circumciser), and 16 a health professional. Conclusion The high prevalence rate of FGM and the proportion of medical complications show that FGM is a matter for public health concern in Sierra Leone. Girls who undergo FGM before 10 years of age seem to be more vulnerable to serious complications than those who are older at the time of FGM. It is important that health care personnel are aware of, and look for possible complications from FGM, and encourage girls and women to seek medical care for their problems. PMID:22870046

Prevalence and predictors of female genital mutilation among infants in a semi urban community in northern Nigeria.

PubMed

Ashimi, Adewale O; Amole, Taiwo G; Iliyasu, Zubairu

2015-12-01

To determine the prevalence, predictors, of female genital mutilation (FGM) among infants and ascertain if their mothers knew what was done to them in Birnin Kudu northern Nigeria. Cross sectional study which utilised a pretested interviewer administered semi-structured questionnaire to assess occurrence of FGM with physical examination of the infants. Logistic regression analysis was used to assess the relative effect of determinants, after adjusting for other predictor variables. Of the 450 infants, 215(47.8%) (95% Confidence Interval [CI]: 43.1%-52.5%) had experienced one form of FGM. The ages at genital mutilation ranged from 1 to 50 days with a median of 4 days and interquartile range of 7 days. Maternal occupation, education and religion and type of facility accessed were significantly associated with occurrence of FGM in infants (p ≤ 0.05). After controlling for confounders, having a mother without formal education [AOR = 6.39 and 95% CI = 3.99-10.23] (p = 0.001) and one who was employed [Adjusted odds ratio (AOR) = 2.89 and 95% CI = 1.66-5.03] (p = 0.001) increased the likelihood of infant FGM remarkably while utilising tertiary institution for health care reduced the risk by about half [AOR = 0.49 and 95% CI = 0.26-0.92] (p = 0.03). Of the 215 infants that had undergone FGM, there was correlation between the reported and the observed forms of FGM in 16 (7.4%) of the cases. The prevalence of FGM is high with mothers' educational status, type of health facility utilised and occupational status being predictors of FGM among infants in Birnin Kudu. Majority of the mothers are not aware of what was done. Strategies aimed at discouraging this dangerous practice in the community should include female education, involvement of the men as husbands, fathers, traditional and religious leaders. Copyright © 2015 Elsevier B.V. All rights reserved.

Epidemiology, Regional Characteristics, Knowledge, and Attitude Toward Female Genital Mutilation/Cutting in Southern Iran.

PubMed

Dehghankhalili, Maryam; Fallahi, Soghra; Mahmudi, Forugh; Ghaffarpasand, Fariborz; Shahrzad, Mohammad Esmaeil; Taghavi, Mohsen; Fereydooni Asl, Marjan

2015-07-01

Female genital mutilation/cutting (FGM/C), also known as female circumcision, is an ancient traditional procedure that involves partial or total removal of the female external genitalia for nonmedical reasons. Although it is well described in African and some Arabic countries, data from Iran are scarce. To describe the epidemiology, regional characteristics, knowledge, and attitude toward FGM/C in Southern Iran. This cross-sectional study was conducted during a 36-month period from 2010 to 2013 in Hormozgan, a southern province of Iran near the Persian Gulf. We included 780 women in six major rural areas of the province who referred to healthcare centers for vaccination, midwifery, or family planning services. All participants underwent complete pelvic examination to determine the type of FGM. The questionnaire consisted of several sections such as demographic and baseline characteristics, and two self-report sections addressing the knowledge and attitude toward FGM/C and its complications. Baseline sociodemographic characteristics including age, educational level, marital status, religion, and nationality were the independent variables. Among the participants, 535 (68.5%) had undergone FGM/C. FGM/C was associated with higher age (P = 0.002), Afghan nationality (P = 0.003), Sunni Islam as religion (P = 0.019), illiteracy (P < 0.001), and family history of FGM/C in mother (P < 0.001), sister (P < 0.001), and grandmother (P < 0.001). Ancient traditions in the area (57.1%) were mentioned as the most important factor leading to FMG/C. Urinary tract infection was the most common reported complication (60.4%). FGM/C is a common practice in rural areas of Southern Iran. It is associated with increased age, illiteracy, Sunni Islam religion, Afghan nationality, and positive family history. Lack of knowledge toward FGM/C is the main cause of its high prevalence and continuation in the area. © 2015 International Society for Sexual Medicine.

Effect of female genital mutilation/cutting on sexual functions.

PubMed

Biglu, Mohammad-Hossein; Farnam, Alireza; Abotalebi, Parvaneh; Biglu, Sahar; Ghavami, Mostafa

2016-12-01

Female Genital Mutilation/Cutting (FGM/C) or female circumcision is the procedure of eliminating some or all parts of the external female genitalia. FGM/C is carried out by traditional circumcisers. They usually use cutting tools like a blade or straight-razor. Although FGM/C is well described in the African continent and some Arabic countries, data from Iran are scarce. The major objective of this current study was to investigate the effects of FGM/C on the female sexual function of married women compared to the non-circumcised women in the Kurdistan province of Iran. A case-control study was conducted in a sample of 280 married women (140 circumcised-women and 140 non-circumcised-women) who referred to the healthcare centers for vaccination, midwifery, or family planning services. Participants were requested to complete the Persian-translated version of the Female Sexual Function Index. The total score of the FSFI and its individual domains. Of the circumcised women, 51.4% reported circumcision procedures before the age of 3 years. Religion motivation (53.6%) was mentioned as the most important factor for the family leading to FGM/C. Almost all operations were performed by traditional circumcisers. Non-circumcised women had significantly higher Persian-FSFI total score (25.3 ± 4.34) compared to the circumcised women (17.9 ± 5.39). Sexual function in women with FGM/C is adversely altered. In Kurdistan province women, FGM/C is associated with reduction of scores of Persian-FSFI on all domain scores. Education in general and informing the people that FGM/C is not a religious Hadith certainly would have a great impact on the suffering of the women from FGM/C as well as the level of "desire, arousal, lubrication, orgasm, satisfaction, and pain in the sexual function of women". Copyright © 2016 Elsevier B.V. All rights reserved.

The role of men in abandonment of female genital mutilation: a systematic review.

PubMed

Varol, Nesrin; Turkmani, Sabera; Black, Kirsten; Hall, John; Dawson, Angela

2015-10-08

Men in their roles as fathers, husbands, community and religious leaders may play a pivotal part in the continuation of female genital mutilation (FGM). However, the research on their views of FGM and their potential role in its abandonment are not well described. We undertook a systematic review of all publications between 2004 and 2014 that explored men's attitudes, beliefs, and behaviours in regards to FGM, as well as their ideas about FGM prevention and abandonment. We included twenty peer-reviewed articles from 15 countries in the analysis. Analysis revealed ambiguity of men's wishes in regards to the continuation of FGM. Many men wished to abandon this practice because of the physical and psychosexual complications to both women and men. Social obligation and the silent culture between the sexes were posited as major obstacles for change. Support for abandonment was influenced by notions of social obligation, religion, education, ethnicity, urban living, migration, and understanding of the negative sequelae of FGM. The strongest influence was education. The level of education of men was one of the most important indicators for men's support for abandonment of FGM. Social obligation and the lack of dialogue between men and women were two key issues that men acknowledged as barriers to abandonment. Advocacy by men and collaboration between men and women's health and community programs may be important steps forward in the abandonment process.

Injured bodies, damaged lives: experiences and narratives of Kenyan women with obstetric fistula and Female Genital Mutilation/Cutting.

PubMed

Mwanri, Lillian; Gatwiri, Glory Joy

2017-03-14

It is well acknowledged that Female Genital Mutilation/Cutting (FGM/C/C) leads to medical, psychological and sociocultural sequels. Over 200 million cases of FGM/C exist globally, and in Kenya alone, a total of 12,418,000 (28%) of women have undergone FGM/C, making the practice not only a significant national, but also a global health catastrophe. FGM/C is rooted in patriarchal and traditional cultures as a communal experience signifying a transition from girlhood to womanhood. The conversations surrounding FGM/C have been complicated by the involvement of women themselves in perpetuating the practice. A qualitative inquiry employing face-to-face, one-on-one, in-depth semi-structured interviews was used in a study that included 30 women living with obstetric fistulas in Kenya. Using the Social Network Framework and a feminist analysis we present stories of Kenyan women who had developed obstetric fistulas following prolonged and obstructed childbirth. Of the 30 participants, three women reported that health care workers informed them that FGM/C was one of the contributing factors to their prolonged and obstructed childbirth. They reported serious obstetric complications including: the development of obstetric fistulas, lowered libido, poor quality of life and maternal and child health outcomes, including death. Fistula and subsequent loss of bodily functionalities such as uncontrollable leakage of body wastes, was reported by the women to result in rejection by spouses, families, friends and communities. Rejection further led to depression, loss of work, increased sense of apathy, lowered self-esteem and image, as well as loss of identity and communal sociocultural cohesion. FGM/C is practised in traditional, patriarchal communities across Africa. Although the practice aims to bind community members and to celebrate a rite of passage; it may lead to harmful health and social consequences. Some women with fistula report their fistula was caused by FGM/C. Concerted efforts which embrace feminist understandings of society, as well as multi-sectoral, multidisciplinary and community development approaches need to be employed to address FGM/C, and to possibly reduce cases of obstetric fistulas in Kenya and beyond. Both government and non-government organisations need to be involved in making legislative, gender sensitive policies that protect women from FGM/C. In addition, the policy makers need to be in the front line to improve the lives of women who endured the consequences of FGM/C.

Prevalence of female genital mutilation among female infants in Kano, Northern Nigeria.

PubMed

Garba, I D; Muhammed, Z; Abubakar, I S; Yakasai, I A

2012-08-01

To determine the prevalence and type of female genital mutilation (FGM) among female infants, reasons and attitude of the mothers to the practice. A cross sectional descriptive study. Tertiary centre in Kano Northern Nigeria. A Pretested questionnaire was administered for mothers of female infants presenting for routine immunization in Aminu Kano Teaching Hospital (AKTH). A total of 250 questionnaires were administered, but only 200 were properly filled and this was used for the analysis. Prevalence and type of FGM, reason for and attitude of mothers towards FGM. Twenty-six infants had FGM during the period of study, giving a prevalence rate of 13 %. The mean age at cutting was 8 days ± 7.3. The commonest type of FGM was type I accounting for 96.2 % of the cases. Tradition/culture was the commonest reason for mutilation accounting for 73.1 %, other reasons included; religious in 11.5 %, hygienic in 11.5 % and to preserve virginity in 3.8 %. Traditional barbers were the commonest operators in 80.8 % of cases, followed by the nurse/midwife in 15.4 % of cases. The fathers were the main decision makers in 46.2 %, followed by both parents in 26.9 % and grandparents in 15.4 % of the cases. 84 % of mothers were not in support of the practice. Thirteen percent of the clients would circumcise all their daughters. Forty-eight percent of the clients were of the opinion that FGM cause harm to the victims. Four percent of those whose daughters were yet to be circumcised will do so later. Female genital cutting is still practiced in our environment. Educational enlightenment is fundamental in changing public opinion as well as in offering reasonable alternative to FGM. Campaign against the practice of FGM should be encouraged to eradicate its practice.

Medicalized Female Genital Mutilation/Cutting: Contentious Practices and Persistent Debates.

PubMed

Kimani, Samuel; Shell-Duncan, Bettina

2018-01-01

Female genital cutting/mutilation (FGM/C) performed by health care professionals (medicalization) and reduced severity of cutting have been advanced as strategies for minimizing health risks, sparking acrimonious ongoing debates. This study summarizes key debates and critically assesses supporting evidence. While medicalization is concentrated in Africa, health professionals worldwide have faced requests to perform FGM/C. Whether medicalization is hindering the decline of FGM/C is unclear. Factors motivating medicalization include, but are not limited to, safety concerns. Involvement of health professionals in advocacy to end FGM/C can address both the supply and demand side of medicalization, but raises ethical concerns regarding dual loyalty. Ongoing debates need to address competing rights claims. Polarizing debates have brought little resolution. We call for a focus on common goals of protecting the health and welfare of girls living in communities where FGM/C is upheld and encourage more informed and open dialog.

Female genital mutilation: a urology focus.

PubMed

Clarke, Elinor

2016-10-13

Female genital mutilation (FGM) is a collective term for the deliberate alteration, removal and cutting of the female genitalia. It has no known health benefits and can have negative physical and psychological consequences. The number of women and girls in the UK that are affected by FGM is unknown. Recent NHS data suggested that FGM has been evident (declared or observed) in women who have accessed health care; however, there are gaps in knowledge and a limited evidence base on the health consequences of FGM. This article explores the urological complications experienced by women who have undergone this practice, and the effects this can have on their health and wellbeing.

Egyptian government broadens ban on female genital mutilation.

PubMed

1996-01-01

An estimated 70-90% of girls in Egypt are subjected to female genital mutilation (FGM) before reaching puberty. Many Egyptians believe the practice to be ordained by Islam. Whether this is true, however, remains an issue of debate among Muslim scholars. Some Egyptian Christians also secure FGM for their girls. Egyptian law prohibits anyone without medical training from performing FGM, and any physician or health worker who causes permanent damage to a girl may face 3-10 years of hard labor. However, the law is frequently ignored, especially in rural areas, where village barbers and midwives perform the operations. In October 1995, Egyptian state hospitals were banned from performing FGM. Egypt has since broadened its ban to bar all health care workers in both state-run hospitals and private clinics from performing the procedure. No health care worker affiliated with the Ministry of Health is therefore allowed to perform FGM. Almost all Egyptian doctors are affiliated with the Ministry. While this recent move by the Health Minister is laudable, it remains to be seen whether he can enforce it. The secretary-general of the Egyptian Organization for Human Rights has urged parliament to enact legislation criminalizing FGM.

Compressive evaluation of homogeneous and graded epoxy-glass particulate composites.

PubMed

Seaglar, J; Rousseau, C-E

2015-04-01

The propagation of stress waves in epoxy-glass particulate composites and graded materials was studied experimentally. Materials tested in this study consisted of an epoxy matrix with various concentrations of spherical glass particles having a mean diameter of 42μm. Plate impact experiments were performed using a gas gun. Embedded within the specimens were manganin stress gauges used to record propagating compressive longitudinal stress waves through the material. High strain rate experiments using a Split Hopkinson Pressure Bar (SHPB) apparatus were also performed to evaluate the dynamic strength of the specimens, while quasi-static compression tests were undertaken to characterize their quasi-static behavior. Ultrasonic wave speed measurements were carried-out in order to obtain additional material properties and characterize the gradation in functionally graded materials (FGM). It was found that low volume fractions of particles are detrimental to the performance of the material under impact loading, while concentrations in the range of about 30 to 45% by volume exhibit characteristics of higher degrees of scattering. This suggests that materials in this latter range would be more effective in the thwarting of destructive shock waves than the homogeneous matrix material. Impact testing of FGM specimens suggests that impact loading on the stiff (high volume fraction) face results in much higher levels of scattering. Therefore, such materials would be effective for use in light weight armor or as shielding materials due to their effective attenuation of mechanical impulses. Copyright © 2015 Elsevier B.V. All rights reserved.

A description of female genital mutilation and force-feeding practices in Mauritania: implications for the protection of child rights and health.

PubMed

Ouldzeidoune, Nacerdine; Keating, Joseph; Bertrand, Jane; Rice, Janet

2013-01-01

To establish the prevalence of female genital mutilation (FGM) and force feeding (gavage) practices among children in Mauritania; to investigate factors related to FGM and gavage practices and attitude in Mauritania; and to explore implications related to the protection of children's rights and welfare. Data from the Mauritania 2000-2001 DHS were used in this analysis. Data were collected from men and women about their attitude toward the continuation of FGM and gavage; women only were asked if they ever experienced one of these practices. Chi-square statistics were used to investigate differences in attitude and practice of FGM and gavage by demographic characteristics. Binary logistic regression was used to identify socio-demographic factors related to FGM and gavage outcomes. The overall prevalence of FGM was 77% but varied depending on ethnicity. The majority of both female and male respondents favored the continuation of the practice (64% and 70%, respectively). Almost a quarter (23%) of women reported being force fed as a child and 32% of women and 29% of men approved the continuation of the practice. Gavage is almost exclusively practiced among Arabs. The practice of both FGM and gavage is ongoing, although the prevalence and attitude towards both appears to vary as a function of ethnicity, wealth, education, marital status, and age. Contextually relevant intervention and enforcement strategies are needed to challenge these cultural norms and protect the rights and welfare of children in Mauritania.

Female genital mutilation: prevalence, perceptions and effect on women’s health in Kersa district of Ethiopia

PubMed Central

Yirga, Wondimu Shanko; Kassa, Nega Assefa; Gebremichael, Mengistu Welday; Aro, Arja R

2012-01-01

Background Female genital mutilation (FGM) is nontherapeutic surgical modification of the female genitalia. It is an ancient tradition in large parts of Africa, including Ethiopia, especially in the eastern part of the country. This study aimed to identify the prevalence, perceptions, perpetuators, reasons for conducting FGM, and factors associated with this practice with regard to women’s health. Methods Community-based cross-sectional house-to-house interviews were conducted during 2008 among 858 females of reproductive age (15–49 years), in Kersa district, East Hararge, Oromia region, Ethiopia. Proportions and Chi-square tests were used to describe the data and logistic regression was used to describe statistical associations. Statistical significance was set at P < 0.05. Results FGM was reported to be known by 327 (38.5%) of the interviewees. The majority (n = 249, 76.1%) reported that local healers were the main performers of FGM, and 258 (78.9%) respondents stated that the clitoris was the part removed during circumcision. The main reason for the practice of FGM was reduction of female sexual hyperactivity (reported by 198 women [60.3%]). Circumcision of daughters was reported by 288 (88.1%) respondents, and this showed a statistically significant association with the Christian religion (P = 0.003), illiteracy (P = 0.01), and Amhara ethnicity (P = 0.012). The majority of the respondents (792, 92.3%) were themselves circumcised and 68.8% did not know of any health-related problems associated with FGM. Conclusion In spite of FGM being a common practice in the study area, only one third of the respondents stated that they knew about it. Local healers were the main performers of FGM. Some of the women knew about the negative reproductive health effects of FGM and some had also experienced these themselves. However, only a few had tried to stop the practice and the majority had taken no steps to do so. This may be attributable to the fear of becoming alienated from the cultural system and fear of isolation. PMID:22371659

Dispelling the myths and beliefs toward female genital cutting of woman: assessing general outpatient services at a tertiary health institution in Enugu state, Nigeria.

PubMed

Ekwueme, O C; Ezegwui, H U; Ezeoke, U

2010-03-01

The practice of female genital mutilation (FGM) has continued because it is deeply entrenched in tradition and culture especially in developing countries where the victims are often its strongest proponents. This study aimed at using accurate information to dispel the traditional myths and beliefs about FGM among woman. Using a before and after intervention evaluation research design, interviewer administered questionnaires were administered to a sample of 100 women drawn by systematic sampling from the General Outpatient Department of University of Nigeria Teaching Hospital. Information's on their knowledge, attitude and behaviour towards FGM were elicited pre-and-post intervention. Pre-intervention, knowledge of the respondents on the true meaning of FGM was 54% and that of the 6 complications enlisted on average was 22.2%. Seventy (70.0%) believed that FCM is good and should be continued based mainly on culture and tradition (85.7%). Among the 29(29.0%) respondents against FGM, 26(89.7%) and 24(82.8%) said it increases risk of HIV/AIDS and pregnancy complications respectively. Respondents displayed a high negative and stigmatizing attitude toward the uncircumcised women. Seventy-four (74.0%) said they are promiscuous. Additionally, 49% said they are shameful, 14% cursed/outcast while 66% would not recommend them for marriage. Post-intervention, 85% of the respondents now understood full meaning of FGM and 71.3% on the average knew the complications. While only 11% now support FGM, 83% were against the practice. The stigmatizing attitudes held against uncircumcised women decreased significantly from baseline to post-intervention as follows: promiscuous 74% to 22%, shameful 49% to 12%, outcast/cursed 14% to 2%, and not good for marriage from 66% to 19%. The differences in the baseline and post-intervention data on knowledge, beliefs and attitudes of the respondents toward FGM were statistically significant (p < 0.001). Educational intervention programme has been successful used to impact knowledge, change beliefs and negative attitudes of women toward FGM.

Research gaps in the care of women with female genital mutilation: an analysis.

PubMed

Abdulcadir, J; Rodriguez, M I; Say, L

2015-02-01

Female genital mutilation (FGM) includes procedures involving the partial or total removal of the external female genitals for non-therapeutic reasons. They can have negative psychosexual and health consequences that need specific care. In this paper, we review some key knowledge gaps in the clinical care of women with FGM, focusing on obstetric outcomes, surgical interventions (defibulation and clitoral reconstruction), and the skills and training of healthcare professionals involved in the prevention and management of FGM. We identify research priorities to improve the evidence necessary to establish guidelines for the best multidisciplinary care, communication, and prevention, and to improve health-promotion measures for women with FGM. © 2014 Royal College of Obstetricians and Gynaecologists.

Reliability assessment of different plate theories for elastic wave propagation analysis in functionally graded plates.

PubMed

Mehrkash, Milad; Azhari, Mojtaba; Mirdamadi, Hamid Reza

2014-01-01

The importance of elastic wave propagation problem in plates arises from the application of ultrasonic elastic waves in non-destructive evaluation of plate-like structures. However, precise study and analysis of acoustic guided waves especially in non-homogeneous waveguides such as functionally graded plates are so complicated that exact elastodynamic methods are rarely employed in practical applications. Thus, the simple approximate plate theories have attracted much interest for the calculation of wave fields in FGM plates. Therefore, in the current research, the classical plate theory (CPT), first-order shear deformation theory (FSDT) and third-order shear deformation theory (TSDT) are used to obtain the transient responses of flexural waves in FGM plates subjected to transverse impulsive loadings. Moreover, comparing the results with those based on a well recognized hybrid numerical method (HNM), we examine the accuracy of the plate theories for several plates of various thicknesses under excitations of different frequencies. The material properties of the plate are assumed to vary across the plate thickness according to a simple power-law distribution in terms of volume fractions of constituents. In all analyses, spatial Fourier transform together with modal analysis are applied to compute displacement responses of the plates. A comparison of the results demonstrates the reliability ranges of the approximate plate theories for elastic wave propagation analysis in FGM plates. Furthermore, based on various examples, it is shown that whenever the plate theories are used within the appropriate ranges of plate thickness and frequency content, solution process in wave number-time domain based on modal analysis approach is not only sufficient but also efficient for finding the transient waveforms in FGM plates. Copyright © 2013 Elsevier B.V. All rights reserved.

Membranes for periodontal regeneration: From commercially available to spatially designed and functionally graded materials

NASA Astrophysics Data System (ADS)

Bottino, Marco Cicero

The aging of the global population will lead to a considerable increase in the number of surgical and restorative procedures related to oral rehabilitation or periodontal regeneration. Periodontitis is one of the most aggressive pathologies that concern the integrity of the periodontal system that can lead to the destruction of the periodontium. Guided tissue and guided bone regeneration (GTR/GBR) have been used for the repair and regeneration of periodontal tissues by utilizing an occlusive membrane. The goal of this dissertation is to advance the knowledge in the area of periodontal regeneration by investigating the properties of a commercially available freeze-dried collagen-based graft (AlloDermRTM) and by designing/fabricating a functionally graded membrane (FGM) via multilayer electrospinning. The effects of different rehydration times and of a simultaneous rehydration/crosslinking procedure on the biomechanical properties and matrix stability of the commercially available membrane were investigated. The results revealed that there are significant changes on the biomechanical properties of the graft as rehydration time increases. Moreover, it was demonstrated that the simultaneous rehydration/crosslinking protocol has a synergistic effect in terms of enhancing biomechanical properties. A FGM consisting of a core-layer (CL) and two functional surface-layers (SL) was fabricated via sequential electrospinning. Hydroxyapatite nanoparticles (n-HAp) were incorporated to enhance bone formation (SL facing bone defect), and metronidazole benzoate (MET) was added to prevent bacterial colonization (SL facing the epithelial tissue). Degradation studies performed on both the CL and the FGM confirmed that the design holds promise in terms of providing the required mechanical stability to avoid membrane collapse and, therefore, enhance bone regeneration. Finally, it was demonstrated that MET incorporation into the SL that would face epithelial tissue is effective in fighting periodontopathogens in an in vitro model. Further studies are necessary to evaluate the effectiveness of this FGM on new bone formation in bone defects and to provide a quantitative evaluation in terms of the in vivo antibacterial potential of the FGM. Keywords: Collagen-based Grafts, Periodontal Regeneration, Electrospinning, Graded-Structure, Periodontitis, Metronidazole.

The Applicability of Behaviour Change in Intervention Programmes Targeted at Ending Female Genital Mutilation in the EU: Integrating Social Cognitive and Community Level Approaches

PubMed Central

Brown, Katherine; Barrett, Hazel

2013-01-01

With increased migration, female genital mutilation (FGM) also referred to as female circumcision or female genital cutting is no longer restricted to Africa, the Middle East, and Asia. The European Parliament estimates that up to half a million women living in the EU have been subjected to FGM, with a further 180,000 at risk. Aware of the limited success of campaigns addressing FGM, the World Health Organization recommended a behavioural change approach be implemented in order to end FGM. To date, however, little progress has been made in adopting a behaviour change approach in strategies aimed at ending FGM. Based on research undertaken as part of the EU's Daphne III programme, which researched FGM intervention programmes linked to African communities in the EU (REPLACE), this paper argues that behaviour change has not been implemented due to a lack of understanding relating to the application of the two broad categories of behaviour change approach: individualistic decision-theoretic and community-change game-theoretic approaches, and how they may be integrated to aid our understanding and the development of future intervention strategies. We therefore discuss how these can be integrated and implemented using community-based participatory action research methods with affected communities. PMID:23983698

A Description of Female Genital Mutilation and Force-Feeding Practices in Mauritania: Implications for the Protection of Child Rights and Health

PubMed Central

Ouldzeidoune, Nacerdine; Keating, Joseph; Bertrand, Jane; Rice, Janet

2013-01-01

Objectives To establish the prevalence of female genital mutilation (FGM) and force feeding (gavage) practices among children in Mauritania; to investigate factors related to FGM and gavage practices and attitude in Mauritania; and to explore implications related to the protection of children’s rights and welfare. Methods Data from the Mauritania 2000–2001 DHS were used in this analysis. Data were collected from men and women about their attitude toward the continuation of FGM and gavage; women only were asked if they ever experienced one of these practices. Chi-square statistics were used to investigate differences in attitude and practice of FGM and gavage by demographic characteristics. Binary logistic regression was used to identify socio-demographic factors related to FGM and gavage outcomes. Findings The overall prevalence of FGM was 77% but varied depending on ethnicity. The majority of both female and male respondents favored the continuation of the practice (64% and 70%, respectively). Almost a quarter (23%) of women reported being force fed as a child and 32% of women and 29% of men approved the continuation of the practice. Gavage is almost exclusively practiced among Arabs. Conclusion The practice of both FGM and gavage is ongoing, although the prevalence and attitude towards both appears to vary as a function of ethnicity, wealth, education, marital status, and age. Contextually relevant intervention and enforcement strategies are needed to challenge these cultural norms and protect the rights and welfare of children in Mauritania. PMID:23593257

Clinical indications for cesarean delivery among women living with female genital mutilation.

PubMed

Rodriguez, Maria I; Say, Lale; Abdulcadir, Jasmine; Hindin, Michelle J

2017-10-01

To compare primary indications for cesarean delivery among patients with different female genital mutilation (FGM) status. The present secondary analysis included data from women who underwent trial of labor resulting in cesarean delivery at 28 obstetric centers in six African countries between November 1, 2001, and March 31, 2003. Associations between cesarean delivery indications and FGM status were assessed using descriptive statistics and multivariable multinomial logistic regression. Data from 1659 women (480 patients with no type of FGM and 1179 patients with FGM [any type]) were included; cesarean delivery indications were collapsed into five categories (fetal indications, maternal factors, stage 1 arrest, stage 2 arrest, and other). The incidence of a clear medical indication for cesarean delivery did not differ between the groups (P=0.320). Among patients without a clear indication for cesarean delivery, women with FGM were more likely to have undergone cesarean delivery for maternal factors (adjusted relative risk ratio [aRRR] 3.92, 95% confidence interval [CI] 1.3-11.71), stage 1 arrest (aRRR 7.74, 95% CI 1.33-45.07), stage 2 arrest (aRRR 6.63, 95% CI 3.74-11.73), or other factors (aRRR 2.41, 95% CI 1.04-5.60) rather than fetal factors compared with women who had no type of FGM. Among women with unclear medical indications, FGM was associated with cesarean delivery being performed for maternal factors or arrest disorders. © 2017 World Health Organization; licensed by John Wiley & Sons Ltd on behalf of International Federation of Gynecology and Obstetrics.

Coping and chronic psychosocial consequences of female genital mutilation in The Netherlands.

PubMed

Vloeberghs, Erick; van der Kwaak, Anke; Knipscheer, Jeroen; van den Muijsenbergh, Maria

2012-01-01

The study presented in this article explored psychosocial and relational problems of African immigrant women in The Netherlands who underwent female genital mutilation/cutting (FGM/C), the causes they attribute to these problems--in particular, their opinions about the relationship between these problems and their circumcision--and the way they cope with these health complaints. This mixed-methods study used standardised questionnaires as well as in-depth interviews among a purposive sample of 66 women who had migrated from Somalia, Sudan, Eritrea, Ethiopia or Sierra Leone to The Netherlands. Data were collected by ethnically similar female interviewers; interviews were coded and analysed by two independent researchers. One in six respondents suffered from post-traumatic stress disorder (PTSD), and one-third reported symptoms related to depression or anxiety. The negative feelings caused by FGM/C became more prominent during childbirth or when suffering from physical problems. Migration to the Netherlands led to a shift in how women perceive FGM, making them more aware of the negative consequences of FGM. Many women felt ashamed to be examined by a physician and avoided visiting doctors who did not conceal their astonishment about the FGM. FGM/C had a lifelong impact on the majority of the women participating in the study, causing chronic mental and psychosocial problems. Migration made women who underwent FGM/C more aware of their condition. Three types of women could be distinguished according to their coping style: the adaptives, the disempowered and the traumatised. Health care providers should become more aware of their problems and more sensitive in addressing them.

Design of phononic band gaps in functionally graded piezocomposite materials by using topology optimization

NASA Astrophysics Data System (ADS)

Vatanabe, Sandro L.; Silva, Emílio C. N.

2011-04-01

One of the properties of composite materials is the possibility of having phononic band gaps, within which sound and vibrations at certain frequencies do not propagate. These materials are called Phononic Crystals (PCs). PCs with large band gaps are of great interest for many applications, such as transducers, elastic/ acoustic filters, noise control, and vibration shields. Most of previous works concentrates on PCs made of elastic isotropic materials; however, band gaps can be enlarged by using non-isotropic materials, such as piezoelectric materials. Since the main property of PCs is the presence of band gaps, one possible way to design structures which have a desired band gap is through Topology Optimization Method (TOM). TOM is a computational technique that determines the layout of a material such that a prescribed objective is maximized. Functionally Graded Materials (FGM) are composite materials whose properties vary gradually and continuously along a specific direction within the domain of the material. One of the advantages of applying the FGM concept to TOM is that it is not necessary a discrete 0-1 result, once the material gradation is part of the solution. Therefore, the interpretation step becomes easier and the dispersion diagram obtained from the optimization is not significantly modified. In this work, the main objective is to optimize the position and width of piezocomposite materials band gaps. Finite element analysis is implemented with Bloch-Floquet theory to solve the dynamic behavior of two-dimensional functionally graded unit cells. The results demonstrate that phononic band gaps can be designed by using this methodology.

Conservation outside protected areas and the effect of human-dominated landscapes on stress hormones in Savannah elephants.

PubMed

Ahlering, M A; Maldonado, J E; Eggert, L S; Fleischer, R C; Western, D; Brown, J L

2013-06-01

Biodiversity conservation strategies are increasingly focused on regions outside national protected areas, where animals face numerous anthropogenic threats and must coexist with human settlements, livestock, and agriculture. The effects of these potential threats are not always clear, but they could have profound implications for population viability. We used savannah elephants (Loxodonta africana) as a case study to assess the physiological stress associated with living in a human-livestock-dominated landscape. We collected samples over two 3-month periods in 2007 and 2008. We used fecal DNA to identify 96 individual elephants in a community conservation area (CCA) and measured fecal glucocorticoid metabolite (FGM) concentrations as a proxy for stress. The CCA is community Maasai land managed for livestock and wildlife. We compared the FGM concentrations from the CCA to FGM concentrations of 40 elephants in Amboseli National Park and 32 elephants in the Maasai Mara National Reserve, where human settlements and intense livestock grazing were absent. In the CCA, we found no significant individual differences in FGM concentrations among the elephants in 2007 (p = 0.312) or 2008 (p = 0.412) and no difference between years (p = 0.616). The elephants in the CCA had similar FGM concentrations to the Maasai Mara population, but Amboseli elephants had significantly lower FGM concentrations than those in either Maasai Mara or the CCA (Tukey pairwise test, p < 0.001), due primarily to females excreting significantly lower FGM relative to males (p = 0.025). In the CCA, there was no relation among female group size, average pairwise group relatedness, and average group FGM concentration. We found no clear evidence of chronic stress in elephants living on CCA communal land, which is encouraging for conservation strategies promoting the protection of animals living outside protected areas. Conservation Biology © 2013 Society for Conservation Biology No claim to original US government works.

Attitude toward female genital mutilation among Somali and Harari people, Eastern Ethiopia

PubMed Central

Abathun, Asresash Demissie; Sundby, Johanne; Gele, Abdi A

2016-01-01

Background Female genital mutilation (FGM) is a worldwide problem, and it is practiced by many communities in Africa and Asia as well as immigrants from those areas. This practice results in short- and long-term health consequences on women’s health. Like many other developing countries, FGM is widely practiced in Ethiopia, especially among Somali and Harari ethnic groups. Despite intensive campaigns against FGM in Ethiopia, since 2011, it has been practiced in the aforementioned communities. There is no recent information as to whether these campaigns have an impact on the attitude and practice of the community regarding FGM. This qualitative research was aimed at exploring the attitudes of Somali and Harari people between 18 and 65 years toward FGM. Methods A purposive sampling technique was used to recruit 64 (32 in each region) participants. Data were collected from October to December 2015 in Somali and Harari Regions. Results The findings showed that there was a strong support for the continuation of the practice among female discussants in Somali region, whereas male discussants from the same region and the majority of the participants from Harari region had a positive attitude toward the discontinuation of the practice. Marriageability was the major reason for practicing FGM in Somali region, whereas making girls calm, sexually inactive, and faithful for their husbands were mentioned in Harari region. Although young men in both the regions prefer to marry uncircumcised girls, the study showed that there are some differences in the attitude toward the FGM practice between the people in the two regions. Conclusion The findings show that there is an attitudinal difference between the people in the two regions, which calls for behavioral change communication using women-centered approach and culturally appropriate strategies. As young people in both the regions had the intention to marry uncircumcised girls, there has to be a strong advocacy and multisectoral collaboration to stop FGM in both the regions. PMID:27785105

Pleasure and orgasm in women with Female Genital Mutilation/Cutting (FGM/C).

PubMed

Catania, Lucrezia; Abdulcadir, Omar; Puppo, Vincenzo; Verde, Jole Baldaro; Abdulcadir, Jasmine; Abdulcadir, Dalmar

2007-11-01

Female genital mutilation/cutting (FGM/C) violates human rights. FGM/C women's sexuality is not well known and often it is neglected by gynecologists, urologists, and sexologists. In mutilated/cut women, some fundamental structures for orgasm have not been excised. The aim of this report is to describe and analyze the results of four investigations on sexual functioning in different groups of cut women. semistructured interviews and the Female Sexual Function Index (FSFI). 137 adult women affected by different types of FGM/C; 58 young FGM/C ladies living in the West; 57 infibulated women; 15 infibulated women after the operation of defibulation. The group of 137 women, affected by different types of FGM/C, reported orgasm in almost 86%, always 69.23%; 58 mutilated young women reported orgasm in 91.43%, always 8.57%; after defibulation 14 out of 15 infibulated women reported orgasm; the group of 57 infibulated women investigated with the FSFI questionnaire showed significant differences between group of study and an equivalent group of control in desire, arousal, orgasm, and satisfaction with mean scores higher in the group of mutilated women. No significant differences were observed between the two groups in lubrication and pain. Embryology, anatomy, and physiology of female erectile organs are neglected in specialist textbooks. In infibulated women, some erectile structures fundamental for orgasm have not been excised. Cultural influence can change the perception of pleasure, as well as social acceptance. Every woman has the right to have sexual health and to feel sexual pleasure for full psychophysical well-being of the person. In accordance with other research, the present study reports that FGM/C women can also have the possibility of reaching an orgasm. Therefore, FGM/C women with sexual dysfunctions can and must be cured; they have the right to have an appropriate sexual therapy.

Thermoelastic Damping in FGM Nano-Electromechanical System in Axial Vibration Based on Eringen Nonlocal Theory

NASA Astrophysics Data System (ADS)

Rahimi, Z.; Rashahmadi, S.

2017-11-01

The thermo-elastic damping is a dominant source of internal damping in micro-electromechanical systems (MEMS) and nano-electromechanical systems (NEMS). The internal damping cannot neither be controlled nor minimized unless either mechanical or geometrical properties are changed. Therefore, a novel FGMNEM system with a controllable thermo-elastic damping of axial vibration based on Eringen nonlocal theory is considered. The effects of different parameter like the gradient index, nonlocal parameter, length of nanobeam and ambient temperature on the thermo-elastic damping quality factor are presented. It is shown that the thermo-elastic damping can be controlled by changing different parameter.

Female Genital Mutilation Reconstruction: A Preliminary Report.

PubMed

Chang, Catherine S; Low, David W; Percec, Ivona

2017-09-01

Female genital mutilation (FGM) is internationally recognized as a violation of human rights. Though rarely discussed, FGM is prevalent, affecting hundreds of millions of females worldwide. We believe that is important for plastic surgeons to be informed and prepared to address the surgical and emotional needs of these women. We present our experience on treatment of women subjected to FGM. Three consecutive patients were treated by our clitoral restoration procedure. The procedure involves conscious sedation and involves wide release of scar tissue around the labia majora and clitoris. Labial flaps are elevated and secured down to the periosteum and the clitoris is allowed to remucosalize. Three females with grade II mutilation were treated. The average age was 32.3-years-old and the average follow up was 305 days. All patients self-reported improved sexual function and decreased embarrassment with their partners. And all recommended the treatment to other women subjected to FGM. FGM is a violation of the basic rights of women and children. Plastic surgeons can help these women restore their physical and psychological sense of well-being by providing effective reconstructive options. Our goal is to raise awareness of this problem and describe a simple yet effective treatment for women that have been subject to FGM. 5. © 2017 The American Society for Aesthetic Plastic Surgery, Inc. Reprints and permission: journals.permissions@oup.com

Cognitive behavioral therapy for post-traumatic stress disorder, depression, or anxiety disorders in women and girls living with female genital mutilation: A systematic review.

PubMed

Adelufosi, Adegoke; Edet, Bassey; Arikpo, Dachi; Aquaisua, Ememobong; Meremikwu, Martin M

2017-02-01

Female genital mutilation (FGM) is associated with psychological consequences such as post-traumatic stress disorder (PSTD), depression, and anxiety disorders. Cognitive behavioral therapy (CBT), an empirically supported form of psychotherapy, may be an effective treatment for these psychological sequelae of FGM. To assess the effectiveness of CBT among individuals living with any type of FGM and diagnosed to have PTSD, depression, or anxiety disorders. CENTRAL, Medline, African Index Medicus, SCOPUS, PILOTS, POPLINE, PsycINFO, WHOLIS, LILACS, ERIC, NYAM Library, CINAHL, Web of Science were searched from inception up to August 10, 2015. Both randomized and nonrandomized studies comparing the efficacy of CBT to other forms of interventions for PTSD, depression, or anxiety disorders in individuals with FGM, were systematically reviewed. We did not identify any studies with eligible design that addressed the objective of the review. There are no included studies. Future studies need to look beyond establishing the prevalence and correlates of FGM to conducting well-designed, randomized controlled studies or well-designed interventional observational studies for the management of the psychological consequences of women and girls living with FGM. CRD42015024458. © 2017 International Federation of Gynecology and Obstetrics. The World Health Organization retains copyright and all other rights in the manuscript of this article as submitted for publication.

Providing information to improve body image and care-seeking behavior of women and girls living with female genital mutilation: A systematic review and meta-analysis.

PubMed

Esu, Ekpereonne; Okoye, Ifeyinwa; Arikpo, Iwara; Ejemot-Nwadiaro, Regina; Meremikwu, Martin M

2017-02-01

Female genital mutilation (FGM) has become recognized worldwide as an extreme form of violation of the human rights of girls and women. Strategies have been employed to curb the practice. To conduct a systematic review of randomized and nonrandomized studies of the effects of providing educational interventions on the body image and care-seeking behavior of girls and women living with FGM with the view to ending the practice. CENTRAL, MEDLINE, and other databases were searched up to August 10, 2015 without any language restrictions. Studies that provided education to women and/or girls living with any type of FGM or residing in countries where FGM is predominantly practiced were included. Two authors independently screened and collected data. We summarized dichotomous outcomes using odds ratios and evidence was assessed using the GRADE system (Grading of Recommendations Assessment, Development, and Evaluation). Educational interventions resulted in fewer women recommending FGM for their daughters and also reduced the incidence of FGM cases among daughters of women who received the educational interventions. These findings need to be validated with large randomized trials. 42015024637. © 2017 International Federation of Gynecology and Obstetrics. The World Health Organization retains copyright and all other rights in the manuscript of this article as submitted for publication.

Health information interventions for female genital mutilation.

PubMed

Smith, Helen; Stein, Karin

2017-02-01

Providing information and education to women and girls living with female genital mutilation (FGM) could be an important influence on their healthcare-seeking behavior. Healthcare providers also need adequate knowledge and skills to provide good quality care to this population. Recent WHO guidelines on managing health complications from FGM contain best practice statements for health education and information interventions for women and providers. This qualitative evidence synthesis summarizes the values and preferences of girls and women living with FGM, and healthcare providers, together with other evidence on the context and conditions of these interventions. The synthesis highlights that healthcare providers lack skills and training to manage women, and women are concerned about the lack of discussion about FGM with providers. There is a need for more training for providers, and further research to understand how health information interventions may be perceived or experienced by women living with FGM in different contexts. © 2017 International Federation of Gynecology and Obstetrics. The World Health Organization retains copyright and all other rights in the manuscript of this article as submitted for publication.

Supportive psychotherapy or client education alongside surgical procedures to correct complications of female genital mutilation: A systematic review.

PubMed

Abayomi, Olukayode; Chibuzor, Moriam T; Okusanya, Babasola O; Esu, Ekpereonne; Odey, Edward; Meremikwu, Martin M

2017-02-01

Supportive psychotherapy, in individual or group settings, may help improve surgical outcomes for women and girls living with female genital mutilation (FGM). To assess whether supportive psychotherapy given alongside surgical procedures to correct complications of FGM improves clinical outcomes. We searched major databases including CENTRAL, Medline, African Index Medicus, SCOPUS, PsycINFO, and others. There were no language restrictions. We checked the reference lists of retrieved studies for additional reports of relevant studies. We included studies of girls and women living with any type of FGM who received supportive psychotherapy or client education sessions alongside any surgical procedure to correct health complications from FGM. Two team members independently screened studies for eligibility. There were no eligible studies identified. There is no direct evidence for the benefits or harms of supportive psychotherapy alongside surgical procedures for women and girls living with FGM. Research evidence is urgently needed to guide clinical practice. 42015024639. © 2017 International Federation of Gynecology and Obstetrics. The World Health Organization retains copyright and all other rights in the manuscript of this article as submitted for publication.

Female Genital Mutilation Is a Violation of Reproductive Rights of Women: Implications for Health Workers.

PubMed

Jungari, Suresh Banayya

2016-02-01

Female genital mutilation (FGM) comprises all procedures that involve partial or total removal of the external female genitalia or other injury to the female genital organs for nonmedical reasons. This coercive practice is still prevalent in many parts of the world, in both developed and developing countries. However, FGM is more prevalent in African countries and some Asian countries. In this study, an attempt has been made to understand the prevalence and practice of FGM worldwide and its adverse effects on women's reproductive health. To fulfill the study objectives, the author collected evidence from various studies conducted by international agencies. Many studies found that FGM has no health benefits; is mostly carried out on girls before they reach the age of 15 years; can cause severe bleeding, infections, psychological illness, and infertility; and, most important, can have serious consequences during childbirth. The practice is mainly governed by the traditions and cultures of the communities without having any scientific or medical benefit. In conclusion, FGM is a practice that violates the human and reproductive rights of women.

Protecting girls and women from harmful practices affecting their health: Are we making progress?

PubMed

Cottingham, Jane; Kismodi, Eszter

2009-08-01

Since female genital mutilation (FGM) was first recognized internationally in 1958, it has now become widely accepted and anchored in international law that FGM is a violation of girls' and women's human rights. Declines in the practice, however, are slow overall, and continued work for its elimination requires action and investment at many levels. Where the practice has diminished, community action has been widespread and sustained. Governments, who are ultimately responsible for the eradication of FGM, must take many measures to outlaw the practice and protect girls' and women's rights, through legislation, policy, education, and resource allocation. Among the other key actors, health care professionals have a particularly important role in treating women and in preventing FGM by actively opposing any medicalization of the practice.

Female Genital Mutilation

MedlinePlus

... of being rejected by the community, are strong motivations to perpetuate the practice. In some communities, FGM ... of being rejected by the community, are strong motivations to perpetuate the practice. In some communities, FGM ...

Female genital mutilation: when a cultural practice generates clinical and ethical dilemmas.

PubMed

Gibeau, A M

1998-01-01

Female genital mutilation (FGM) is of growing concern to health care providers in the United States and Canada as more women from countries where the procedure is practiced emigrate to North America. An introduction to the demographics of FGM, including prevalence rates, is a necessary antecedent for understanding the cultural rationales for this widespread practice. Considering the health consequences of this practice promotes questions about legal and ethical aspects of care as North Americans approach FGM from their own individual cultural frameworks.

Female Genital Mutilation: perceptions of healthcare professionals and the perspective of the migrant families

PubMed Central

2010-01-01

Background Female Genital Mutilation (FGM) is a traditional practice which is harmful to health and is profoundly rooted in many Sub-Saharan African countries. It is estimated that between 100 and 140 million women around the world have been victims of some form of FGM and that each year 3 million girls are at risk of being submitted to these practices. As a consequence of the migratory phenomena, the problems associated with FGM have extended to the Western countries receiving the immigrants. The practice of FGM has repercussions on the physical, psychic, sexual and reproductive health of women, severely deteriorating their current and future quality of life. Primary healthcare professionals are in a privileged position to detect and prevent these situations of risk which will be increasingly more present in Spain. Methods/Design The objective of the study is to describe the knowledge, attitudes and practices of the primary healthcare professionals, working in 25 health care centres in Barcelona and Girona regions, regarding FGM, as well as to investigate the perception of this subject among the migrant communities from countries with strong roots in these practices. A transversal descriptive study will be performed with a questionnaire to primary healthcare professionals and migrant healthcare users. Using a questionnaire specifically designed for this study, we will evaluate the knowledge, attitudes and skills of the healthcare professionals to approach this problem. In a sub-study, performed with a similar methodology but with the participation of cultural mediators, the perceptions of the migrant families in relation to their position and expectancies in view of the result of preventive interventions will be determined. Variables related to the socio-demographic aspects, knowledge of FGM (types, cultural origin, geographic distribution and ethnicity), evaluation of attitudes and beliefs towards FGM and previous contact or experience with cases or risk situations will be obtained. Discussion Knowledge of these harmful practices and a preventive approach from a transcultural perspective may represent a positive intervention model for integrative care of immigrants, respecting their values and culture while also being effective in eliminating the physical and psychic consequences of FGM. PMID:20388216

Knowledge, attitudes and practices of female genital mutilation/cutting among health care professionals in The Gambia: a multiethnic study.

PubMed

Kaplan, Adriana; Hechavarría, Suiberto; Bernal, Mariola; Bonhoure, Isabelle

2013-09-16

Female genital mutilation/cutting (FGM/C) is a harmful traditional practice with severe consequences for the health and well-being of girls and women. Health care professionals (HCPs) are therefore expected to be aware of how to identify and manage these consequences in order to ensure that those affected by the practice receive quality health care. Moreover, their integration and legitimacy within the communities allow them to play a key role in the prevention of the practice. Nevertheless, the perception of HCPs on FGM/C has been barely explored in African contexts. This study seeks to contribute to this field of knowledge by examining the knowledge, attitudes, and practices regarding FGM/C among HCPs working in rural settings in The Gambia. A cross-sectional descriptive study was designed through a quantitative methodology, following a multiethnic approach. A pre-tested questionnaire with open and closed-ended questions was created. Forty medical students from the Community-based Medical Programme were trained to administer the questionnaire, face to face, at village health facilities in rural areas of The Gambia. A final sample of 468 HCPs included all nurse cadres and midwives. A significant proportion of Gambian HCPs working in rural areas embraced the continuation of FGM/C (42.5%), intended to subject their own daughters to it (47.2%), and reported having already performed it during their medical practice (7.6%). However, their knowledge, attitudes, and practices were shaped by sex and ethnic identity. Women showed less approval for continuation of FGM/C and higher endorsement of the proposed strategies to prevent it than men. However, it was among ethnic groups that differences were more substantial. HCPs belonging to traditionally practicing groups were more favourable to the perpetuation and medicalisation of FGM/C, suggesting that ethnicity prevails over professional identity. These findings demonstrate an urgent need to build HCP's capacities for FGM/C-related complications, through strategies adapted to their specific characteristics in terms of sex and ethnicity. A culturally and gender sensitive training programme might contribute to social change, promoting the abandonment of FGM/C, avoiding medicalisation, and ensuring accurate management of its health consequences.

A systematic review of doctors' experiences and needs to support the care of women with female genital mutilation.

PubMed

Dawson, Angela; Homer, Caroline S E; Turkmani, Sabera; Black, Kirsten; Varol, Nesrin

2015-10-01

Female genital mutilation (FGM) involves partial or complete removal of the external female genitalia or other injury for non-therapeutic reasons. Little is known about the knowledge and skills of doctors who care for affected women and their practice in relation to FGM. To examine the FGM experiences and educational needs of doctors. A structured search of five bibliographic databases was undertaken to identify peer-reviewed research literature published in English between 2004 and 2014 using the keywords "female genital mutilation," "medical," "doctors," "education," and "training." Observational, quasi-experimental, and non-experimental descriptive studies were suitable for inclusion. A narrative synthesis of the study findings was undertaken and themes were identified. Ten papers were included in the review, three of which were from low-income countries. The analysis identified three themes: knowledge and attitudes, FGM-related medical practices, and education and training. There is a need for improved education and training to build knowledge and skills, and to change attitudes concerning the medicalization of FGM and reinfibulation. Copyright © 2015 International Federation of Gynecology and Obstetrics. Published by Elsevier Ireland Ltd. All rights reserved.

Female genital mutilation/cutting in Africa.

PubMed

Odukogbe, Akin-Tunde A; Afolabi, Bosede B; Bello, Oluwasomidoyin O; Adeyanju, Ayodeji S

2017-04-01

Female genital mutilation/cutting (FGM/C) is a traditional practice in which the external female genitalia is partially or totally incised or excised for a non-therapeutic reason, usually without the consent of the individual. FGM/C is common in Africa with varying prevalence in different countries, though the incidence is reducing because it is considered a human rights issue with tremendous advocacy for its elimination by mainly nongovernmental organizations. It is mainly underreported in many countries in Africa especially where it has been declared illegal. FGM/C is often performed by a nonmedical practitioner with the aim of fulfilling religious or cultural rites and sometimes for economic benefits with the resultant acute, intermediate and late complications. It is sometimes performed by medical practitioners when it is speciously believed that its medicalization reduces the complications associated with the practice. The sensitivity of FGM/C is amplified when compared to male circumcision and voluntary alterations of the female external genitalia like piercing and tattooing as similar practices. The magnitude of the physical and psychosocial consequences of FGM/C outweighs the presumed benefits of the procedures highlighting the need for improvement of the multiple preventive measures by all the stakeholders and in all the sectors.

Female genital mutilation/cutting in Africa

PubMed Central

Afolabi, Bosede B.; Bello, Oluwasomidoyin O.; Adeyanju, Ayodeji S.

2017-01-01

Female genital mutilation/cutting (FGM/C) is a traditional practice in which the external female genitalia is partially or totally incised or excised for a non-therapeutic reason, usually without the consent of the individual. FGM/C is common in Africa with varying prevalence in different countries, though the incidence is reducing because it is considered a human rights issue with tremendous advocacy for its elimination by mainly nongovernmental organizations. It is mainly underreported in many countries in Africa especially where it has been declared illegal. FGM/C is often performed by a nonmedical practitioner with the aim of fulfilling religious or cultural rites and sometimes for economic benefits with the resultant acute, intermediate and late complications. It is sometimes performed by medical practitioners when it is speciously believed that its medicalization reduces the complications associated with the practice. The sensitivity of FGM/C is amplified when compared to male circumcision and voluntary alterations of the female external genitalia like piercing and tattooing as similar practices. The magnitude of the physical and psychosocial consequences of FGM/C outweighs the presumed benefits of the procedures highlighting the need for improvement of the multiple preventive measures by all the stakeholders and in all the sectors. PMID:28540220

Maternal Behavior and Physiological Stress Levels in Wild Chimpanzees (Pan troglodytes schweinfurthii).

PubMed

Stanton, Margaret A; Heintz, Matthew R; Lonsdorf, Elizabeth V; Santymire, Rachel M; Lipende, Iddi; Murray, Carson M

2015-06-01

Individual differences in maternal behavior toward, and investment in, offspring can have lasting consequences, particularly among primate taxa characterized by prolonged periods of development over which mothers can exert substantial influence. Given the role of the neuroendocrine system in the expression of behavior, researchers are increasingly interested in understanding the hormonal correlates of maternal behavior. Here, we examined the relationship between maternal behavior and physiological stress levels, as quantified by fecal glucocorticoid metabolite (FGM) concentrations, in lactating chimpanzees, Pan troglodytes schweinfurthii , at Gombe National Park, Tanzania. After accounting for temporal variation in FGM concentrations, we found that mothers interacted socially (groomed and played) with and nursed their infants more on days when FGM concentrations were elevated compared to days when FGM concentrations were within the range expected given the time of year. However, the proportion of time mothers and infants spent in contact did not differ based on FGM concentrations. These results generally agree with the suggestion that elevated GC concentrations are related to maternal motivation and responsivity to infant cues and are the first evidence of a hormonal correlate of maternal behavior in a wild great ape.

Female genital mutilation/cutting: changes and trends in knowledge, attitudes, and practices among health care professionals in The Gambia

PubMed Central

Kaplan Marcusán, Adriana; Riba Singla, Laura; Laye, Mass; Secka, Dodou M; Utzet, Mireia; Le Charles, Marie-Alix

2016-01-01

Background Female genital mutilation/cutting (FGM/C) is a harmful traditional practice that affects two out of three girls in The Gambia, seriously threatening their life and well-being with severe health consequences. By tracking the reference values established in former research conducted between 2009 and 2011, the objectives of this study are to explore trends and to measure and assess changes in knowledge, attitudes, and practices regarding FGM/C among health care professionals (HCPs) in The Gambia. Methods A cross-sectional descriptive study was designed to collect and analyze data from an overall stratified sample consisting of 1,288 HCPs including health professionals and students throughout the six regions of The Gambia. Data were collected by the implementation of a self-administered written knowledge, attitudes, and practices questionnaire between 2012 and 2014. Results The results of this study showed that 76.4% of HCPs are eager to abandon FGM/C, and 71.6% of them regard it as a harmful practice with negative consequences on life and health. HCPs reported more knowledge and favorable attitudes towards FGM/C abandonment, being better able to identify the practice, more aware of its health complications, and more concerned in their essential role as social agents of change. However, 25.4% of HCPs still embraced the continuation of the practice, 24.4% expressed intention of subjecting their own daughters to it, and 10.5% declared to have performed it within their professional praxis. Conclusion Findings confirm progress in knowledge and attitudes regarding FGM/C among HCPs, who are better skilled to understand and manage the consequences. Nevertheless, discrepancies between information, intention, and behavior unveil resistance in practice and proves that FGM/C medicalization is increasing. Thus, there is an urgent need to support HCPs in the integration of FGM/C preventive interventions within the public health system, to address arguments favoring medicalization, and to use data to design appropriate strategies. PMID:27110140

Violence against women.

PubMed

Nelson, T

1996-01-01

This essay opens its discussion of violence against women by referring to the 1994 television broadcast of a 10-year-old Egyptian girl undergoing female genital mutilation (FGM) without benefit of infection control measures or anesthesia at the hands of a local barber. After presenting a brief description of FGM, its various justifications, and its impacts on its victims, the official Egyptian policy is described as ambiguous, and the broadcast is shown to have caused influential religious leaders and medical personnel to defend FGM and, thus, led to postponement of a bill to outlaw FGM. The next section of the essay shows that Egypt's response to FGM reflects the international debate on all forms of violence against women emerging from and reinforcing the social relationships that give men power over women. These forms of violence include domestic violence in almost all societies; the dowry-related, bride-burning homicides that claim 5000-12,000 lives each year in India; son preference that leads to abortion of female fetuses and female infanticide; and crimes such as rape, sexual abuse, and forced prostitution. The essay continues with a look at the costs of violence hidden in the damage to women that increases health care costs substantially and reduces economic productivity. Violence towards women, which occurs throughout the world and can prevent women from participating in public life or from controlling their fertility, is a male tool to inhibit women from gaining autonomy outside the home. The essay concludes that victims of violence are beginning to break the silence that surrounded these deeds and are seeking legislative protection. Laws may not result in real-life changes, but the movement to eliminate FGM may prove to be the first success in women's efforts to achieve human rights. An example is the important precedent being set in the US by a woman seeking asylum to avoid facing an arranged marriage and FGM in her native Togo.

Effects of female genital cutting on physical health outcomes: a systematic review and meta-analysis

PubMed Central

Berg, Rigmor C; Underland, Vigdis; Odgaard-Jensen, Jan; Fretheim, Atle; Vist, Gunn E

2014-01-01

Objective Worldwide, an estimated 125 million girls and women live with female genital mutilation/cutting (FGM/C). We aimed to systematically review the evidence for physical health risks associated with FGM/C. Design We searched 15 databases to identify studies (up to January 2012). Selection criteria were empirical studies reporting physical health outcomes from FGM/C, affecting females with any type of FGM/C, irrespective of ethnicity, nationality and age. Two review authors independently screened titles and abstracts, applied eligibility criteria, assessed methodological study quality and extracted full-text data. To derive overall risk estimates, we combined data from included studies using the Mantel-Haenszel method for unadjusted dichotomous data and the generic inverse-variance method for adjusted data. Outcomes that were sufficiently similar across studies and reasonably resistant to biases were aggregated in meta-analyses. We applied the instrument Grading of Recommendations Assessment, Development and Evaluation to assess the extent to which we have confidence in the effect estimates. Results Our search returned 5109 results, of which 185 studies (3.17 million women) satisfied the inclusion criteria. The risks of systematic and random errors were variable and we focused on key outcomes from the 57 studies with the best available evidence. The most common immediate complications were excessive bleeding, urine retention and genital tissue swelling. The most valid and statistically significant associations for the physical health sequelae of FGM/C were seen on urinary tract infections (unadjusted RR=3.01), bacterial vaginosis (adjusted OR (AOR)=1.68), dyspareunia (RR=1.53), prolonged labour (AOR=1.49), caesarean section (AOR=1.60), and difficult delivery (AOR=1.88). Conclusions While the precise estimation of the frequency and risk of immediate, gynaecological, sexual and obstetric complications is not possible, the results weigh against the continuation of FGM/C and support the diagnosis and management of girls and women suffering the physical risks of FGM/C. Trial registration number This study is registered with PROSPERO, number CRD42012003321. PMID:25416059

Female genital mutilation: the role of medical professional organizations.

PubMed

Bazi, Tony

2017-04-01

Female genital mutilation (FGM) refers to alteration of the external genitalia of girls without medical benefit. It is estimated by United Nations agencies that 200 million living girls and women have been subjected to different forms of FGM worldwide. Despite the criminalization of the procedure in the vast majority of countries where it is practiced, the decline in the incidence of this ritual is far from satisfactory. Immediate and long-term ill effects are well documented. Most publications of relevance originate from countries outside the map of FGM. In addition, there are major gaps in research related to this issue, considering the magnitude of the problem. International medical organizations and societies should assume their responsibility by providing a platform to professionals engaged in the prevention and treatment of the consequences of FGM, especially those living in the communities where the practice is endemic.

Female genital mutilation in the Sudan: survey of the attitude of Khartoum university students towards this practice.

PubMed

Herieka, E; Dhar, J

2003-06-01

Female genital mutilation (FGM) or female circumcision is the removal of variable amounts of tissue from the female external genitalia. It is practised all over the world on very young girls. This study was conducted in Sudan where FGM is a criminal offence and not a religious dictate. We assessed the knowledge, attitudes, and perceptions of this practice among Khartoum university students and compared the differences between male and female student responses. An anonymised detailed questionnaire was distributed among the university students. In addition to the participant's age, marital status, course studying, details regarding their attitude, knowledge of the practice of FGM, and their own experiences were collected. Of the 500 questionnaires distributed, 414 (82.8%) were returned from 192 (46%) females and 222 (54%) males. 109 (56.8%) of the female respondents were themselves circumcised.18.8% of the male students and 9.4% of the female students thought FGM was recommended by their religion. Only 90 (46.9%) female students compared with 133 (59.9%) male students thought FGM was illegal. Though 16 (8.3%) female respondents thought FGM would increase their chances of marriage, the majority, 166 (74.8%), of the male students would prefer a non-circumcised female. This study shows that 109 (56.8%) female university students who responded were circumcised. Confusing religious messages and ambiguous laws seem to be responsible for the continuation of this practice. The study highlights the partnership that needs to be established between religious leaders and educationalists to end this medieval practice.

Maternal effects on offspring stress physiology in wild chimpanzees.

PubMed

Murray, Carson M; Stanton, Margaret A; Wellens, Kaitlin R; Santymire, Rachel M; Heintz, Matthew R; Lonsdorf, Elizabeth V

2018-01-01

Early life experiences are known to influence hypothalamic-pituitary-adrenal (HPA) axis development, which can impact health outcomes through the individual's ability to mount appropriate physiological reactions to stressors. In primates, these early experiences are most often mediated through the mother and can include the physiological environment experienced during gestation. Here, we investigate stress physiology of dependent offspring in wild chimpanzees for the first time and examine whether differences in maternal stress physiology are related to differences in offspring stress physiology. Specifically, we explore the relationship between maternal rank and maternal fecal glucocorticoid metabolite (FGM) concentration during pregnancy and early lactation (first 6 months post-partum) and examine whether differences based on maternal rank are associated with dependent offspring FGM concentrations. We found that low-ranking females exhibited significantly higher FGM concentrations during pregnancy than during the first 6 months of lactation. Furthermore, during pregnancy, low-ranking females experienced significantly higher FGM concentrations than high-ranking females. As for dependent offspring, we found that male offspring of low-ranking mothers experienced stronger decreases in FGM concentrations as they aged compared to males with high-ranking mothers or their dependent female counterparts. Together, these results suggest that maternal rank and FGM concentrations experienced during gestation are related to offspring stress physiology and that this relationship is particularly pronounced in males compared to females. Importantly, this study provides the first evidence for maternal effects on the development of offspring HPA function in wild chimpanzees, which likely relates to subsequent health and fitness outcomes. Am. J. Primatol. 80:e22525, 2018. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Gender equality and human rights approaches to female genital mutilation: a review of international human rights norms and standards.

PubMed

Khosla, Rajat; Banerjee, Joya; Chou, Doris; Say, Lale; Fried, Susana T

2017-05-12

Two hundred million girls and women in the world are estimated to have undergone female genital mutilation (FGM), and another 15 million girls are at risk of experiencing it by 2020 in high prevalence countries (UNICEF, 2016. Female genital mutilation/cutting: a global concern. 2016). Despite decades of concerted efforts to eradicate or abandon the practice, and the increased need for clear guidance on the treatment and care of women who have undergone FGM, present efforts have not yet been able to effectively curb the number of women and girls subjected to this practice (UNICEF. Female genital mutilation/cutting: a statistical overview and exploration of the dynamics of change. 2013), nor are they sufficient to respond to health needs of millions of women and girls living with FGM. International efforts to address FGM have thus far focused primarily on preventing the practice, with less attention to treating associated health complications, caring for survivors, and engaging health care providers as key stakeholders. Recognizing this imperative, WHO developed guidelines on management of health complications of FGM. In this paper, based on foundational research for the development of WHO's guidelines, we situate the practice of FGM as a rights violation in the context of international and national policy and efforts, and explore the role of health providers in upholding health-related human rights of women at girls who are survivors, or who are at risk. Findings are based on a literature review of relevant international human rights treaties and UN Treaty Monitoring Bodies.

Effects of management strategies on glucocorticoids and behavior in Indian rhinoceros (Rhinoceros unicornis): translocation and operant conditioning.

PubMed

Capiro, Jonnie M; Stoops, Monica A; Freeman, Elizabeth W; Clawson, Dave; Schook, Mandi W

2014-01-01

The ex situ Indian rhino population experienced a decrease in genetic diversity indicating that the breeding program could possibly benefit from novel reproductive management strategies to ensure population sustainability. We sought to determine how management tools used for reproductive management, specifically translocation and operant conditioning, impact physiological and behavioral measures of welfare in Indian rhinos. First, an adrenocorticotropic hormone challenge performed in an adult male resulted in a 38-fold increase in urinary and a 3.5-fold increase in fecal glucocorticoid metabolites (FGM). Mean and peak FGM differed among three females, but all demonstrated elevated (P < 0.0001) concentrations for variable durations after translocation that lasted up to 9 weeks. Lastly, behavioral and adrenal responses of two females to operant conditioning to stand during transrectal ultrasound exams were monitored and rhinos differed in their mean and peak FGM concentrations. However, FGM were not different before versus during training or on pasture versus in the barn. One female exhibited more stereotypic behavior during training in the barn than on pasture (P < 0.05); although, stereotypies (1.73% of time) were relatively uncommon overall. In summary, individual variation exists in FGM both at baseline levels and in response to a stressor. In addition, while a transient rise in glucocorticoid activity post-translocation indicated that Indian rhinos have a physiological response to changes in their environment, minor alterations in daily routines using operant conditioning only resulted in minimal changes in behaviors and FGM. © 2014 Wiley Periodicals Inc.

Female Genital Cutting

MedlinePlus

... in which FGM/C is regularly practiced. Recent research shows that these efforts may be working. In some regions, education is changing attitudes and influencing a family's choice to have FGM/C performed. For example, in Egypt, 96% of women 45 to 49 ...

Knowledge, attitudes and practices of female genital mutilation/cutting among health care professionals in The Gambia: a multiethnic study

PubMed Central

2013-01-01

Background Female genital mutilation/cutting (FGM/C) is a harmful traditional practice with severe consequences for the health and well-being of girls and women. Health care professionals (HCPs) are therefore expected to be aware of how to identify and manage these consequences in order to ensure that those affected by the practice receive quality health care. Moreover, their integration and legitimacy within the communities allow them to play a key role in the prevention of the practice. Nevertheless, the perception of HCPs on FGM/C has been barely explored in African contexts. This study seeks to contribute to this field of knowledge by examining the knowledge, attitudes, and practices regarding FGM/C among HCPs working in rural settings in The Gambia. Methods A cross-sectional descriptive study was designed through a quantitative methodology, following a multiethnic approach. A pre-tested questionnaire with open and closed-ended questions was created. Forty medical students from the Community-based Medical Programme were trained to administer the questionnaire, face to face, at village health facilities in rural areas of The Gambia. A final sample of 468 HCPs included all nurse cadres and midwives. Results A significant proportion of Gambian HCPs working in rural areas embraced the continuation of FGM/C (42.5%), intended to subject their own daughters to it (47.2%), and reported having already performed it during their medical practice (7.6%). However, their knowledge, attitudes, and practices were shaped by sex and ethnic identity. Women showed less approval for continuation of FGM/C and higher endorsement of the proposed strategies to prevent it than men. However, it was among ethnic groups that differences were more substantial. HCPs belonging to traditionally practicing groups were more favourable to the perpetuation and medicalisation of FGM/C, suggesting that ethnicity prevails over professional identity. Conclusions These findings demonstrate an urgent need to build HCP’s capacities for FGM/C-related complications, through strategies adapted to their specific characteristics in terms of sex and ethnicity. A culturally and gender sensitive training programme might contribute to social change, promoting the abandonment of FGM/C, avoiding medicalisation, and ensuring accurate management of its health consequences. PMID:24040762

Fabrication and mechanical properties of Al2O3/SiC/ZrO2 functionally graded material by electrophoretic deposition.

PubMed

Askari, E; Mehrali, M; Metselaar, I H S C; Kadri, N A; Rahman, Md M

2012-08-01

This study describes the synthesis of Al(2)O(3)/SiC/ZrO(2) functionally graded material (FGM) in bio-implants (artificial joints) by electrophoretic deposition (EPD). A suitable suspension that was based on 2-butanone was applied for the EPD of Al(2)O(3)/SiC/ZrO(2), and a pressureless sintering process was applied as a presintering. Hot isostatic pressing (HIP) was used to densify the deposit, with beneficial mechanical properties after 2 h at 1800 °C in Ar atmosphere. The maximum hardness in the outer layer (90 vol.% Al(2)O(3)+10 vol.% SiC) and maximum fracture toughness in the core layer (75 vol.% Al(2)O(3)+10 vol.% SiC + 15 vol.% ZrO(2)) composite were 20.8±0.3 GPa and 8±0.1 MPa m(1/2), respectively. The results, when compared with results from Al(2)O(3)/ZrO(2) FGM, showed that SiC increased the compressive stresses in the outer layers, while the inner layers were under a residual tensile stress. Copyright © 2012 Elsevier Ltd. All rights reserved.

Educating about female genital mutilation.

PubMed

Holmes, Victoria; Farrington, Rebecca; Mulongo, Peggy

2017-01-01

Female genital mutilation (FGM) is illegal in the UK but nevertheless practised in some immigrant communities. Effective educational approaches are required to inform policy and to direct resources, often in the voluntary sector. The opinions in this article arise from discussions with professionals and members of FGM-practising communities. We highlight the importance of sharing experiences and expertise across health and social care professionals as well as working in partnership with culturally sensitive Non-Governmental Organisations. Enlisting the support of men and religious leaders is crucial to breaking down barriers in male-dominated communities and dispelling myths about FGM being a 'requirement' of faith.

Fisher's geometric model predicts the effects of random mutations when tested in the wild.

PubMed

Stearns, Frank W; Fenster, Charles B

2016-02-01

Fisher's geometric model of adaptation (FGM) has been the conceptual foundation for studies investigating the genetic basis of adaptation since the onset of the neo Darwinian synthesis. FGM describes adaptation as the movement of a genotype toward a fitness optimum due to beneficial mutations. To date, one prediction of FGM, the probability of improvement is related to the distance from the optimum, has only been tested in microorganisms under laboratory conditions. There is reason to believe that results might differ under natural conditions where more mutations likely affect fitness, and where environmental variance may obscure the expected pattern. We chemically induced mutations into a set of 19 Arabidopsis thaliana accessions from across the native range of A. thaliana and planted them alongside the premutated founder lines in two habitats in the mid-Atlantic region of the United States under field conditions. We show that FGM is able to predict the outcome of a set of random induced mutations on fitness in a set of A. thaliana accessions grown in the wild: mutations are more likely to be beneficial in relatively less fit genotypes. This finding suggests that FGM is an accurate approximation of the process of adaptation under more realistic ecological conditions. © 2016 The Author(s). Evolution © 2016 The Society for the Study of Evolution.

[Male perceptions of sequelae associated with female genital mutilation].

PubMed

Jiménez-Ruiz, Ismael; Almansa Martínez, Pilar; Pastor Bravo, María Del Mar

2016-01-01

To explore men's knowledge of the negative consequences of female genital mutilation (FGM) to women's health in countries where this practice is performed. A qualitative methodology was used with an ethnomethodological approach. Both individual and group semi-structured interviews concerning FGM were conducted with 25 men, selected by triple sampling. A study presentation letter was provided to participants, together with an informed consent declaration. Permission was also procured to record the interviews in audio format. Data analysis was performed using the Atlas Ti7 software. Those participants against FGM are aware of the range of complications this practice can cause, being able to identify physical, obstetric, psychological, sexuality and social consequences in women subjected to FGM. However, those men who are in favour display a general ignorance of the problems resulting from this practice. Participants from countries where FGM is performed who are against this practice are more aware of the negative consequences than those who claim to be in favour. The design of awareness-raising programmes and other tools to combat female genital mutilation must highlight the implications for women's and girls' health, and include family-targeted campaigns which involve men in the process of eradicating this practice. Copyright © 2016 SESPAS. Published by Elsevier Espana. All rights reserved.

Crossing borders: Discussing the evidence relating to the mental health needs of women exposed to female genital mutilation

PubMed Central

Mulongo, Peggy; McAndrew, Sue; Hollins Martin, Caroline

2014-01-01

The terms ‘Female Circumcision’ (FC), ‘FG Cutting’ (FGC) and ‘FG Mutilation’ (FGM) refer to procedures involving the partial or total removal of the external female genitalia for non-medical reasons. In practicing countries, FGC/FC is more widely used, as it is believed to be inoffensive, providing more impartial ways of discussing the practice. Positive beliefs about FC/FGC include virginity, marriage prospects, family reputation, or passage to adulthood. Regardless of terminology, the practice exists in at least 28 African counties, and a few Asian and Middle Eastern countries. In Western society, FGM is considered a breach of human rights, being outlawed in a number of countries. With immigration trends, FGC is now prominent in Western society among practicing communities. While the past decade has seen an increase in studies and recommendations for health-care support related to the physical health consequences of FGM, little is known about the psychological impact and its management. For many girls and women, FGC is a traumatic practice, transforming it to FGM and affecting their mental health. This discussion paper focuses on evidence relating to the mental health consequences of FGM, therapeutic interventions, and the mental health nurse's role in addressing the needs of this group of women. PMID:24548699

The ongoing violence against women: Female Genital Mutilation/Cutting.

PubMed

Muteshi, Jacinta K; Miller, Suellen; Belizán, José M

2016-04-18

Female Genital Mutilation/Cutting (FGM/C) comprises different practices involving cutting, pricking, removing and sometimes sewing up external female genitalia for non-medical reasons. The practice of FGM/C is highly concentrated in a band of African countries from the Atlantic coast to the Horn of Africa, in areas of the Middle East such as Iraq and Yemen, and in some countries in Asia like Indonesia. Girls exposed to FGM/C are at risk of immediate physical consequences such as severe pain, bleeding, and shock, difficulty in passing urine and faeces, and sepsis. Long-term consequences can include chronic pain and infections. FGM/C is a deeply entrenched social norm, perpetrated by families for a variety of reasons, but the results are harmful. FGM/C is a human rights issue that affects girls and women worldwide. The practice is decreasing, due to intensive advocacy activities of international, national, and grassroots agencies. An adolescent girl today is about a third less likely to be cut than 30 years ago. However, the rates of abandonment are not high enough, and change is not happening as rapidly as necessary. Multiple interventions have been implemented, but the evidence base on what works is lacking. We in reproductive health must work harder to find strategies to help communities and families abandon these harmful practices.

Between Moral Relativism and Moral Hypocrisy: Reframing the Debate on "FGM".

PubMed

Earp, Brian D

2016-06-01

The spectrum of practices termed "Female Genital Mutilation" (or FGM) by the World Health Organization is sometimes held up as a counterexample to moral relativism. Those who advance this line of thought suggest the practices are so harmful in terms of their physical and emotional consequences, as well as so problematic in terms of their sexist or oppressive implications, that they provide sufficient, rational grounds for the assertion of a universal moral claim--namely, that all forms of FGM are wrong, regardless of the cultural context. However, others point to cultural bias and moral double standards on the part of those who espouse this argument, and have begun to question the received interpretation of the relevant empirical data on FGM as well. In this article I assess the merits of these competing perspectives. I argue that each of them involves valid moral concerns that should be taken seriously in order to move the discussion forward. In doing so, I draw on the biomedical "enhancement" literature in order to develop a novel ethical framework for evaluating FGM (and related interventions--such as female genital "cosmetic" surgery and nontherapeutic male circumcision) that takes into account the genuine harms that are at stake in these procedures, but which does not suffer from being based on cultural or moral double standards.

Reasons for and Experiences With Surgical Interventions for Female Genital Mutilation/Cutting (FGM/C): A Systematic Review.

PubMed

Berg, Rigmor C; Taraldsen, Sølvi; Said, Maryan A; Sørbye, Ingvil Krarup; Vangen, Siri

2017-08-01

Because female genital mutilation/cutting (FGM/C) leads to changes in normal genital anatomy and functionality, women are increasingly seeking surgical interventions for their FGM/C-related concerns. To conduct a systematic review of empirical quantitative and qualitative research on interventions for women with FGM/C-related complications. We conducted systematic searches up to May 2016 in 16 databases to obtain references from different disciplines. We accepted all study designs consisting of girls and women who had been subjected to FGM/C and that examined a reparative intervention for a FGM/C-related concern. We screened the titles, abstracts, and full texts of retrieved records for relevance. Then, we assessed the methodologic quality of the included studies and extracted and synthesized the study data. All outcomes were included. Of 3,726 retrieved references, 71 studies including 7,291 women were eligible for inclusion. We identified three different types of surgical intervention: defibulation or surgical separation of fused labia, excision of a cyst with or without some form of reconstruction, and clitoral or clitoral-labial reconstruction. Reasons for seeking surgical interventions consisted of functional complaints, sexual aspirations, esthetic aspirations, and identity recovery. The most common reasons for defibulation were a desire for improved sexual pleasure, vaginal appearance, and functioning. For cyst excision, cystic swelling was the main reason for seeking excision; for reconstruction, the main reason was to recover identity. Data on women's experiences with a surgical intervention are sparse, but we found that women reported easier births after defibulation. Our findings also suggested that most women were satisfied with defibulation (overall satisfaction = 50-100%), typically because of improvements in their sexual lives. Conversely, the results suggested that defibulation had low social acceptance and that the procedure created distress in some women who disliked the new appearance of their genitalia. Most women were satisfied with clitoral reconstruction, but approximately one third were dissatisfied with or perceived a worsening in the esthetic look. The information health care professionals give to women who seek surgical interventions for FGM/C should detail the intervention options available and what women can realistically expect from such interventions. The systematic review was conducted in accordance with guidelines, but there is a slight possibility that studies were missed. There are some data on women's motivations for surgery for FGM/C-related concerns, but little is known about whether women are satisfied with the surgery, and experiences appear mixed. Berg RC, Taraldsen S, Said MA, et al. Reasons for and Experiences With Surgical Interventions for Female Genital Mutilation/Cutting (FGM/C): A Systematic Review. J Sex Med 2017;14:977-990. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

Effectiveness of health education as an intervention designed to prevent female genital mutilation/cutting (FGM/C): a systematic review.

PubMed

Waigwa, Susan; Doos, Lucy; Bradbury-Jones, Caroline; Taylor, Julie

2018-04-12

Female Genital Mutilation/Cutting (FGM/C) is a harmful practice that violates the human rights of women and girls. Despite global efforts to restrict the practice, there have been few reports on major positive changes to the problem. Health education interventions have been successful in preventing various health conditions and promoting service use. They have also been regarded as promising interventions for preventing FGM/C. The objective of this systematic review is to synthesise findings of studies about effectiveness of health education as an intervention to prevent FGM/C. The electronic databases searched were MEDLINE, EMBASE, Cochrane library, Web of Science, Psych INFO, CINAHL and ASSIA. Our search included papers published in the English language without date limits. Study quality was assessed using the Mixed Methods Appraisal Tool (MMAT). A predesigned data recording form was used to extract data from the included studies which were summarised by comparing similar themes. Twelve out of 359 individual studies met our inclusion criteria. Seven studies were quantitative, three were qualitative and two used mixed methods. Six studies tested before and after the interventions, four studies assessed the effectiveness of previous interventions used by different research teams and two studies endorsed the intervention. Four main factors emerged and were associated with facilitating or hindering the effectiveness of health education interventions: sociodemographic factors; socioeconomic factors; traditions and beliefs; and intervention strategy, structure and delivery. It is vital to target factors associated with facilitating or hindering the effectiveness of health education for FGM/C. This increases the possibility of effective, collective change in behaviour and attitude which leads to the sustainable prevention of FGM/C and ultimately the improved reproductive health and well-being of individuals and communities.

Thirty-year trends in the prevalence and severity of female genital mutilation: a comparison of 22 countries

PubMed Central

Heymann, Jody

2017-01-01

Introduction Female genital mutilation (FGM) harms women’s health and well-being and is widely considered a violation of human rights. The United Nations has called for elimination of the practice by 2030. Methods We used household survey data to measure trends in the prevalence of FGM in 22 countries. We also examined trends in the severity of the practice by measuring changes in the prevalence of flesh removal, infibulation and symbolic ‘nicking’ of the genitals. We evaluated the extent to which measurement error may have influenced our estimates by observing the consistency of reports for the same birth cohorts over successive survey waves. Results The prevalence of all types of FGM fell in 17 of 22 countries we examined. The vast majority of women who undergo FGM have flesh removed from their genitals, likely corresponding to the partial or total removal of the clitoris and labia. Infibulation is still practised throughout much of sub-Saharan Africa. Its prevalence has declined in most countries, but in Chad, Mali and Sierra Leone the prevalence has increased by 2–8 percentage points over 30 years. Symbolic nicking of the genitals is relatively rare but becoming more common in Burkina Faso, Chad, Guinea and Mali. Conclusion FGM is becoming less common over time, but it remains a pervasive practice in some countries: more than half of women in 7 of the 22 countries we examined still experience FGM. The severity of the procedures has not changed substantially over time. Rigorous evaluation of interventions aimed at eliminating or reducing the harms associated with the practice is needed. PMID:29225952

Direct laser metal deposition of WC/Co/Cr powder by means of the functionally graded materials strategy

NASA Astrophysics Data System (ADS)

Angelastro, A.; Campanelli, S. L.

2017-12-01

One of the many applications of direct laser metal deposition (DLMD) is the realization of multilayer thick coatings having particular mechanical characteristics, such as high hardness. The objective of this work was to obtain a thick, very hard and wear resistant coating, containing a high percentage of tungsten carbide (WC), on an AISI 304 stainless steel substrate. In order to achieve this result, a tungsten carbide-cobalt-chrome (WC/Co/Cr) powder was processed by the DLMD method. WC/Co/Cr is a composite widely used as a wear-resistant material for cutting tools, molds, coatings and other severe applications. Because of its high hardness, poor ductility and low thermal expansion coefficient, depositing this material directly on the stainless steel substrate is very difficult. In order to overcome this problem, the strategy of functionally graded materials (FGM) was used. Colmonoy 227-F nickel alloy was chosen for this purpose in order to generate a mixture with the WC/Co/Cr powder. Four different materials were deposited, layer by layer, by mixing Colmonoy 227-F with an increasing amount of WC/Co/Cr powders, until obtaining a thick surface coating with a maximum amount of WC of 77.4 wt%. For each powder mixture, a mathematical model was applied to calculate optimal values of translation speed and overlap percentages. A metallographic examination was performed in order to detect macro- and micro-structures of the different materials. Finally, Vickers micro-hardness was measured at various locations along the transverse section to appreciate the gradual increase of the FGM hardness, starting from the substrate and culminating at the top surface of the last deposited material.

Controversial issues: female genital mutilation.

PubMed

Richards, D

2000-01-01

As immigrant women from African countries enter the U.S., Canada, Australia, and Western Europe, western health care providers are beginning to see patients affected by the cultural practice of Female Genital Mutilation (FGM). Unfamiliar with the practice, either medically or culturally, these providers are turning to medical librarians for information. Complicating the issue are the strong negative feelings most western health care workers have about FGM, which appears to them to be both barbaric and cruel. These feelings may conflict strongly with those of their immigrant patients, who regard the practice as normal and desirable. Both medical and cultural information are needed for the professional to provide treatment of medical conditions, while also establishing a good relationship with the FGM affected patient. This article identifies and describes the most important refereed journal article databases, available now over the Internet, providing both medical and cultural information on FGM, and the most useful Web sites for health professionals, librarians, and interested laypersons who need information about this difficult multicultural issue.

Dismantling the man-made myths upholding female genital mutilation.

PubMed

Jiménez Ruiz, Ismael; Almansa Martínez, Pilar; Alcón Belchí, Carolina

2017-05-01

Female genital mutilation (FGM) is internationally considered an affront to human rights and an act of violence against women and young girls. Furthermore, it hierarchizes and perpetuates inequality and denies women and girls the right to physical and psychosexual integrity. The aim of this study is to detect the weak points and false premises underlying male justification of FGM and to present demythologization as a health education tool. We used a qualitative methodology with an ethonursing focus via semistructured individual and group interviews in 25 men associated with FGM. Our results found that nine myths and their mythologization are presented through the masculine voices of those associated with this tradition. These myths are used as justification by men and women in order to uphold the practice of FGM. Demythologization as a nursing intervention based on reorienting or restructuring models of cultural care allows us to work against the false premises making up the myths which act to protect this tradition.

The effect of consignment to broodmare sales on physiological stress measured by faecal glucocorticoid metabolites in pregnant Thoroughbred mares.

PubMed

Schulman, Martin; Becker, Annet; Ganswindt, Stefanie; Guthrie, Alan; Stout, Tom; Ganswindt, Andre

2014-01-17

Validation of a method for the minimally-invasive measurement of physiological stress will help understanding of risk factors that may contribute to stress-associated events including recrudescence of Equid herpesvirus (EHV), which is anecdotally associated with sales consignment of pregnant Thoroughbred mares. In this study we compared two similar groups of late-gestation Thoroughbred broodmares on the same farm: a consigned Sales group (N = 8) and a non-consigned Control group (N = 6). The Sales mares were separated from their paddock companions and grouped prior to their preparation for, transport to, and return from the sales venue. Both groups were monitored by sampling at regular intervals from 5 days prior to until 14 days after the sales date (D0) to measure physiological stress in terms of changes in faecal glucocorticoid metabolite (FGM) concentrations, and for event-related viral recrudescence via daily body temperature measurements and periodic nasal swabs for PCR analysis for EHV-1 and -4 DNA. In both groups, FGM levels increased post-sales before returning to pre-sales levels. Specifically, FGM concentrations in the Sales mares were significantly higher on D + 3 and D + 10 than on D-4 and D-3 (F = 12.03, P < 0.0001, Post hoc: P = 0.0003-0.0008) and in the Control group FGM concentrations were higher on D + 10 than D-4 (F = 5.52, P = 0.004, Post hoc: P = 0.005). Interestingly, mean FGM levels in Control mares were significantly higher at 4 of the 5 sampling points (t = 5.64-2.25, p = 0.0001-0.044). Only one (Sales) mare showed PCR evidence of EHV-1 shedding. Using FGM to measure physiological stress was supported by the increases observed in all mares after Sales consignment, including those not consigned to the sale. Monitoring FGM levels therefore represents an appropriate, minimally-invasive method for future studies to assess the contribution of physiological stress to EHV recrudescence in horses transported to sales or equestrian events.

Prevalence of female genital mutilation and its effect on women's health in Bale zone, Ethiopia: a cross-sectional study.

PubMed

Bogale, Daniel; Markos, Desalegn; Kaso, Muhammedawel

2014-10-16

Females' genital mutilation (FGM) is one of the harmful traditional practices affecting the health of women and children. It has a long-term physiological, sexual and psychological effect on women. It remains still a serious problem for large proportion of women in most sub-Saharan Africa countries including Ethiopia. A community based cross sectional study design which is supplemented by qualitative method was conducted in 2014. A total of 634 reproductive age women were involved in the quantitative part of the study. The respondents were drawn from five randomly selected districts of Bale zone. The total sample was allocated proportionally to each district based on the number of reproductive age women it has. Purposive sampling method was used for qualitative study. Then, data were collected using pre-tested and structured questionnaire. The collected data were analyzed by SPSS for windows version 16.0. Multiple logistic regressions were carried out to examine the existence of relationship between FGM and selected determinant factors. Variables significant in the bivariate analysis were then entered into a multiple logistic regression analysis. In this study, 486 (78.5%) of women had undergone some form of FGM with 75% lower and 82% upper confidence interval. To get married, to get social acceptance, to safeguard virginity, to suppress sexual desire and religious recommendations were the main reasons of FGM. The reported immediate complications were excessive bleeding at the time of the procedure, infection, urine retention and swelling of genital organ. Muslim women and women from rural areas were significantly more likely to have undergone the procedure. In addition to these, compared to women 15-20 years old older women were more likely to report themselves having undergone FGM. Although younger women, those from urban residence and some religions are less likely to have had FGM it is still extremely common in this zone. Deep cultural issues and strongly personally held beliefs which are not simple to predict or quantify are likely to be involved in the perpetuation of FGM. Efforts to eradicate the practice should incorporate a human rights approach rather than rely solely on the damaging health consequences.

Non-invasive monitoring of adrenocortical activity in captive African Penguin (Spheniscus demersus) by measuring faecal glucocorticoid metabolites.

PubMed

Ozella, L; Anfossi, L; Di Nardo, F; Pessani, D

2015-12-01

Measurement of faecal glucocorticoid metabolites (FGMs) has become a useful and widely-accepted method for the non-invasive evaluation of stress in vertebrates. In this study we assessed the adrenocortical activity of five captive African Penguins (Spheniscus demersus) by means of FGM evaluation following a biological stressor, i.e. capture and immobilization. In addition, we detected individual differences in secretion of FGMs during a stage of the normal biological cycle of penguins, namely the breeding period, without any external or induced causes of stress. Our results showed that FGM concentrations peaked 5.5-8h after the induced stress in all birds, and significantly decreased within 30 h. As predictable, the highest peak of FGMs (6591 ng/g) was reached by the youngest penguin, which was at its first experience with the stressor. This peak was 1.8-2.7-fold higher compared to those of the other animals habituated to the stimulus. For the breeding period, our results revealed that the increase in FGMs compared to ordinary levels, and the peaks of FGMs, varied widely depending on the age and mainly on the reproductive state of the animal. The bird which showed the lowest peak (2518 ng/g) was an old male that was not in a reproductive state at the time of the study. Higher FGM increases and peaks were reached by the two birds which were brooding (male: 5552%, 96,631 ng/g; female: 1438%, 22,846 ng/g) and by the youngest bird (1582%, 39,700 ng/g). The impact of the reproductive state on FGM levels was unexpected compared to that produced by the induced stress. The EIA used in this study to measure FGM levels proved to be a reliable tool for assessing individual and biologically-relevant changes in FGM concentrations in African Penguin. Moreover, this method allowed detection of physiological stress during the breeding period, and identification of individual differences in relation to the reproductive status. The increase in FGM levels as a response to capture and immobilization suggests that the measured metabolites are appropriate indicators of adrenal activity in these birds. Copyright © 2015 Elsevier Inc. All rights reserved.

The effect of consignment to broodmare Sales on physiological stress measured by faecal glucocorticoid metabolites in pregnant Thoroughbred mares

PubMed Central

2014-01-01

Background Validation of a method for the minimally-invasive measurement of physiological stress will help understanding of risk factors that may contribute to stress-associated events including recrudescence of Equid herpesvirus (EHV), which is anecdotally associated with sales consignment of pregnant Thoroughbred mares. In this study we compared two similar groups of late-gestation Thoroughbred broodmares on the same farm: a consigned Sales group (N = 8) and a non-consigned Control group (N = 6). The Sales mares were separated from their paddock companions and grouped prior to their preparation for, transport to, and return from the sales venue. Both groups were monitored by sampling at regular intervals from 5 days prior to until 14 days after the sales date (D0) to measure physiological stress in terms of changes in faecal glucocorticoid metabolite (FGM) concentrations, and for event-related viral recrudescence via daily body temperature measurements and periodic nasal swabs for PCR analysis for EHV-1 and -4 DNA. Results In both groups, FGM levels increased post-sales before returning to pre-sales levels. Specifically, FGM concentrations in the Sales mares were significantly higher on D + 3 and D + 10 than on D-4 and D-3 (F = 12.03, P < 0.0001, Post hoc: P = 0.0003 – 0.0008) and in the Control group FGM concentrations were higher on D + 10 than D-4 (F = 5.52, P = 0.004, Post hoc: P = 0.005). Interestingly, mean FGM levels in Control mares were significantly higher at 4 of the 5 sampling points (t = 5.64 – 2.25, p = 0.0001 – 0.044). Only one (Sales) mare showed PCR evidence of EHV-1 shedding. Conclusions Using FGM to measure physiological stress was supported by the increases observed in all mares after Sales consignment, including those not consigned to the sale. Monitoring FGM levels therefore represents an appropriate, minimally-invasive method for future studies to assess the contribution of physiological stress to EHV recrudescence in horses transported to sales or equestrian events. PMID:24433380

Blue phase-change recording at high data densities and data rates

NASA Astrophysics Data System (ADS)

Dekker, Martijn K.; Pfeffer, Nicola; Kuijper, Maarten; Ubbens, Igolt P.; Coene, Wim M. J.; Meinders, E. R.; Borg, Herman J.

2000-09-01

For the DVR system with the use of a blue laser diode (wavelength 405 nm) we developed (12 cm) discs with a total capacity of 22.4 GB. The land/groove track pitch is 0.30 micrometers and the channel bit length is 87 nm. The DVR system uses a d equals 1 code. These phase change discs can be recorded at continuous angular velocity at a maximum of 50 Mbps user data rate (including all format and ECC overhead) and meet the system specifications. Fast growth determined phase change materials (FGM) are used for the active layer. In order to apply these FGM discs at small track pitch special attention has been paid to the issue of thermal cross-write. Finally routes towards higher capacities such as advanced bit detection schemes and the use of a smaller track pitch are considered. These show the feasibility in the near future of at least 26.0 GB on a disc for the DVR system with a blue laser diode.

A computational fluid–structure interaction model to predict the biomechanical properties of the artificial functionally graded aorta

PubMed Central

Khosravi, Arezoo; Bani, Milad Salimi; Bahreinizade, Hossein; Karimi, Alireza

2016-01-01

In the present study, three layers of the ascending aorta in respect to the time and space at various blood pressures have been simulated. Two well-known commercial finite element (FE) software have used to be able to provide a range of reliable numerical results while independent on the software type. The radial displacement compared with the time as well as the peripheral stress and von Mises stress of the aorta have calculated. The aorta model was validated using the differential quadrature method (DQM) solution and, then, in order to design functionally graded materials (FGMs) with different heterogeneous indexes for the artificial vessel, two different materials have been employed. Fluid–structure interaction (FSI) simulation has been carried out on the FGM and a natural vessel of the human body. The heterogeneous index defines the variation of the length in a function. The blood pressure was considered to be a function of both the time and location. Finally, the response characteristics of functionally graded biomaterials (FGBMs) models with different values of heterogeneous material parameters were determined and compared with the behaviour of a natural vessel. The results showed a very good agreement between the numerical findings of the FGM materials and that of the natural vessel. The findings of the present study may have implications not only to understand the performance of different FGMs in bearing the stress and deformation in comparison with the natural human vessels, but also to provide information for the biomaterials expert to be able to select a suitable material as an implant for the aorta. PMID:27836981

Evidence to inform education, training and supportive work environments for midwives involved in the care of women with female genital mutilation: a review of global experience.

PubMed

Dawson, Angela; Turkmani, Sabera; Fray, Shairon; Nanayakkara, Susie; Varol, Nesrin; Homer, Caroline

2015-01-01

to identify how midwives in low and middle income countries (LMIC) and high income countries (HIC) care for women with female genital mutilation (FGM), their perceived challenges and what professional development and workplace strategies might better support midwives to provide appropriate quality care. an integrative review involving a narrative synthesis of the literature was undertaken to include peer reviewed research literature published between 2004 and 2014. 10 papers were included in the review, two from LMIC and eight from HIC. A lack of technical knowledge and limited cultural competency was identified, as well as socio-cultural challenges in the abandonment process of the practice, particularly in LMIC settings. Training in the area of FGM was limited. One study reported the outcomes of an education initiative that was found to be beneficial. professional education and training, a working environment supported by guidelines and responsive policy and community education, are necessary to enable midwives to improve the care of women with FGM and advocate against the practice. improved opportunities for midwives to learn about FGM and receive advice and support, alongside opportunities for collaborative practice in contexts that enable the effective reporting of FGM to authorities, may be beneficial and require further investigation. Copyright © 2014 Elsevier Ltd. All rights reserved.

Surgical and nonsurgical interventions for vulvar and clitoral pain in girls and women living with female genital mutilation: A systematic review.

PubMed

Ezebialu, Ifeanyichukwu; Okafo, Obiamaka; Oringanje, Chukwudi; Ogbonna, Udoezuo; Udoh, Ekong; Odey, Friday; Meremikwu, Martin M

2017-02-01

Vulvar and clitoral pain are known complications of female genital mutilation (FGM). Several interventions have been used to treat these conditions. This review focuses on surgical and nonsurgical interventions to improve vulvar and clitoral pain in women living with FGM. To evaluate the impact of nonsurgical and surgical interventions for alleviating vulvar and clitoral pain in women living with any type of FGM and to assess the associated adverse events. The search included the following major databases: Cochrane Central Register for Controlled Trials (CENTRAL), MEDLINE, Scopus, Web of Science, and ClinicalTrials.gov. These were searched from inception until August 10, 2015 without any language restrictions. Study designs included randomized controlled trials, cluster randomized trials, nonrandomized trials, cohort studies, case-control studies, controlled before-and-after studies, historical control studies, and interrupted time series with reported data comparing outcomes among women with FGM who were treated for clitoral or vulvar pain with either surgical or nonsurgical interventions. Two team members independently screened studies for eligibility. No studies were included. Limited information exists on management of vulvar and clitoral pain in women living with FGM. This constitutes an important area for further research. CRD42015024521. © 2017 International Federation of Gynecology and Obstetrics.The World Health Organization retains copyright and all other rights in the manuscript of this article as submitted for publication.

Female sexual dysfunction in female genital mutilation.

PubMed

Elneil, Sohier

2016-01-01

Female genital mutilation (FGM), otherwise known as female genital cutting (FGC), is currently very topical and has become a significant global political issue. The impact of FGM on the lives of women and girls is enormous, as it often affects both their psychology and physical being. Among the complications that are often under-reported and not always acknowledged is female sexual dysfunction (FSD). FSD presents with a complex of symptoms including lack of libido, arousability and orgasm. This often occurs in tandem with chronic urogenital pain and anatomical disruption due to perineal scarring.To treat FSD in FGM each woman needs specifically directed holistic care, geared to her individual case. This may include psychological support, physiotherapy and, on occasion, reconstructive surgery. In many cases the situation is complicated by symptoms of chronic pelvic pain, which can make treatment increasingly difficult as this issue needs a defined multidisciplinary approach for its effective management in its own right. The problems suffered by women with FGM are wholly preventable, as the practice need not happen. The current global momentum to address the social, cultural, economic and medical issues of FGM is being supported by communities, governments, non-governmental agencies (NGOs) and healthcare providers. It is only by working together that the practice can be abolished and women and girls may be free from this practice and its associated consequences. © The Author(s) 2016.

Microsatellite Digital Magnetometer SMILE - Present State and Future Trends

NASA Astrophysics Data System (ADS)

Belyayev, Serhiy; Ivchenko, Nickolay

2010-05-01

The fluxgate magnetometers (FGM) are probably the most widespread instruments used onboard spacecrafts for both scientific and service purposes. The recent trend to decrease the weight and size of the spacecrafts requires creating as small as possible but enough sensitive FGM. A joint Swedish-Ukrainian team made the development of such a magnetometer and as the result the Small Magnetometer In Low mass Experiment (SMILE) - a digital fluxgate microsatellite magnetometer - was created [1]. Majority of electronic units of this FGM were combined in a digital integrated circuit - a Field Programmable Gate Array (FPGA). The FPGA provides full processing (determined by a digital correlation algorithm) of amplified and digitized fluxgate sensor output signals and provides both FGM output data and feedback signals. Such digital design makes the instrument very flexible, reduces power consumption and opens possibilities for customization of the operation modes. It allows miniaturizing the electronic unit and, together with the smallest in the world low noise three-component fluxgate sensor with the side dimension of 20 mm and weight about 20 grams only, the small but enough sensitive space qualified FGM is created. SMILE magnetometer was successfully flown onboard the NASA Cascades-2 sounding rocket, and is to fly in the LAPLander package onboard the ESA REXUS-8 student sounding rocket [2]. Unfortunately, such a design of electronic circuit does not allow us to realize all possibilities of the miniature sensor. The separate tests of the sensor with highest-class analog electronics showed that its noise level may be reduced to as low value as 10…15 picoTesla at 1 Hz. Also the use of volume compensation in the sensor provides high geometrical stability of the axes and improved performance compared to component compensated sensors. The measured parameters appear to be comparable or even better than these of best stationary FGM and, if realized in small enough volume and weight, such a sensitive but small FGM could be a good candidate for planned Lunar missions where the weight is the major restriction factor. This stimulated further research in the direction of the analysis and elimination of noise sources of digital design, as well as of the optimization of FGM electronic circuit structure. The description of the obtained results of the electronic unit upgrade and recent FGM model tests are given and future improvement directions are discussed. These works are partially supported by NSAU contract No. 1499. References: 1. Åke Forslund, Serhiy Belyayev, Nickolay Ivchenko, Göran Olsson, Terry Edberg and Andriy Marusenkov, Miniaturized digital fluxgate magnetometer for small spacecraft applications 2008 Meas. Sci. Technol. 19 2. T. Sundberg, N. Ivchenko, D. Borglund, P. Ahlen, M. Gustavsson, C. Jonsson, J. Juhlen, O. Neunet, J. Sandstrom, E. Sund, M. Wartelski, C. Westlund, L. Xin, Small Recoverable Payload for Deployable Sounding Rocket Experiments. ESA Special Publication SP671

Mothers' Perceptions of Female Genital Mutilation

ERIC Educational Resources Information Center

Ahanonu, E. L.; Victor, O.

2014-01-01

The practice of female genital mutilation (FGM) is widespread in Nigeria. This study was conducted to assess the perceptions of FGM among mothers at a primary healthcare centre in Lagos, Nigeria. A convenience sample of 95 mothers completed the pre-tested, semi-structured questionnaires. Data analysis was carried out using descriptive statistics…

Functionally Graded Materials by Laser Metal Deposition (PREPRINT)

DTIC Science & Technology

2010-03-01

composition of Fe-82 wt% V (powder-1) and Inconel - 625 (powder-2) powders are listed in Table 1. The substrate materials used for the experiment were cold...like laser power, travel speed and powder feed rate is yet to be determined to obtain a successful FGM. Inconel - 625 deposits showed macro-cracks...Composition (wt%) Powder-1: Fe-82 wt% V V (82), Al (0.68), Si (0.9), C (0.07), S (0.01), P (0.02), Fe (18) Powder-2: Inconel - 625 Ni (58), Cr (20-23

An initial investigation of the long-term trends in the fluxgate magnetometer (FGM) calibration parameters on the four Cluster spacecraft

NASA Astrophysics Data System (ADS)

Alconcel, L. N. S.; Fox, P.; Brown, P.; Oddy, T. M.; Lucek, E. L.; Carr, C. M.

2014-07-01

Over the course of more than 10 years in operation, the calibration parameters of the outboard fluxgate magnetometer (FGM) sensors on the four Cluster spacecraft are shown to be remarkably stable. The parameters are refined on the ground during the rigorous FGM calibration process performed for the Cluster Active Archive (CAA). Fluctuations in some parameters show some correlation with trends in the sensor temperature (orbit position). The parameters, particularly the offsets, of the spacecraft 1 (C1) sensor have undergone more long-term drift than those of the other spacecraft (C2, C3 and C4) sensors. Some potentially anomalous calibration parameters have been identified and will require further investigation in future. However, the observed long-term stability demonstrated in this initial study gives confidence in the accuracy of the Cluster magnetic field data. For the most sensitive ranges of the FGM instrument, the offset drift is typically 0.2 nT per year in each sensor on C1 and negligible on C2, C3 and C4.

An initial investigation of the long-term trends in the fluxgate magnetometer (FGM) calibration parameters on the four Cluster spacecraft

NASA Astrophysics Data System (ADS)

Alconcel, L. N. S.; Fox, P.; Brown, P.; Oddy, T. M.; Lucek, E. L.; Carr, C. M.

2014-01-01

Over the course of more than ten years in operation, the calibration parameters of the outboard fluxgate magnetometer (FGM) sensors on the four Cluster spacecraft are shown to be remarkably stable. The parameters are refined on the ground during the rigorous FGM calibration process performed for the Cluster Active Archive (CAA). Fluctuations in some parameters show some correlation with trends in the sensor temperature (orbit position). The parameters, particularly the offsets, of the Spacecraft1 (C1) sensor have undergone more long-term drift than those of the other spacecraft (C2, C3 and C4) sensors. Some potentially anomalous calibration parameters have been identified and will require further investigation in future. However, the observed long-term stability demonstrated in this initial study gives confidence in the relative accuracy of the Cluster magnetic field data. For the most sensitive ranges of the FGM instrument, the offset drift is typically 0.2 nT yr-1 in each sensor on C1 and negligible on C2, C3 and C4.

Improved porous silicon (P-Si) microarray based PSA (prostate specific antigen) immunoassay by optimized surface density of the capture antibody

PubMed Central

Lee, SangWook; Kim, Soyoun; Malm, Johan; Jeong, Ok Chan; Lilja, Hans; Laurell, Thomas

2014-01-01

Enriching the surface density of immobilized capture antibodies enhances the detection signal of antibody sandwich microarrays. In this study, we improved the detection sensitivity of our previously developed P-Si (porous silicon) antibody microarray by optimizing concentrations of the capturing antibody. We investigated immunoassays using a P-Si microarray at three different capture antibody (PSA - prostate specific antigen) concentrations, analyzing the influence of the antibody density on the assay detection sensitivity. The LOD (limit of detection) for PSA was 2.5ngmL−1, 80pgmL−1, and 800fgmL−1 when arraying the PSA antibody, H117 at the concentration 15µgmL−1, 35µgmL−1 and 154µgmL−1, respectively. We further investigated PSA spiked into human female serum in the range of 800fgmL−1 to 500ngmL−1. The microarray showed a LOD of 800fgmL−1 and a dynamic range of 800 fgmL−1 to 80ngmL−1 in serum spiked samples. PMID:24016590

Reconstructive surgery for female genital mutilation starts sexual functioning in Sudanese woman: a case report.

PubMed

Fazari, Atif B E; Berg, Rigmor C; Mohammed, Wafaa A; Gailii, Enas B; Elmusharaf, Khalifa

2013-11-01

Female genital mutilation (FGM) involves the partial or complete removal of the external female genitalia and/or other injury to the female genital organs whether for cultural or other nontherapeutic reasons. The study aims to describe the method of and findings from reconstructive surgery for FGM victims. We present a case of a 24-year-old Sudanese female, who had undergone ritual FGM type III as a young girl. She had suffered from a large, vulval mass for the last 6 years and came to the clinic because of apareunia. We performed mass excision and reconstructive surgery of the mutilated genital tissue. The giant mass was successfully removed. Remaining genital tissues were approximated and sutured, with hemostasis assured for the reconstructed organs on each side. Reconstructive surgery for women who suffer sexual consequences from FGM is feasible, with a high degree of client acceptance and satisfaction. It restores some of women's natural genital anatomy, and offers the potential for improved female sexuality. © 2013 International Society for Sexual Medicine.

Determination of Flux-Gate Magnetometer Spin Axis Offsets with the Electron Drift Instrument

NASA Astrophysics Data System (ADS)

Plaschke, Ferdinand; Nakamura, Rumi; Giner, Lukas; Teubenbacher, Robert; Chutter, Mark; Leinweber, Hannes K.; Magnes, Werner

2014-05-01

Spin-stabilization of spacecraft enormously supports the in-flight calibration of onboard flux-gate magnetometers (FGMs): eight out of twelve calibration parameters can be determined by minimization of spin tone and harmonics in the calibrated magnetic field measurements. From the remaining four parameters, the spin axis offset is usually obtained by analyzing observations of Alfvénic fluctuations in the solar wind. If solar wind measurements are unavailable, other methods for spin axis offset determination need to be used. We present two alternative methods that are based on the comparison of FGM and electron drift instrument (EDI) data: (1) EDI measures the gyration periods of instrument-emitted electrons in the ambient magnetic field. They are inversely proportional to the magnetic field strength. Differences between FGM and EDI measured field strengths can be attributed to inaccuracies in spin axis offset, if the other calibration parameters are accurately known. (2) For EDI electrons to return to the spacecraft, they have to be sent out in perpendicular direction to the ambient magnetic field. Minimization of the variance of electron beam directions with respect to the FGM-determined magnetic field direction also yields an estimate of the spin axis offset. Prior to spin axis offset determination, systematic inaccuracies in EDI gyration period measurements and in the transformation of EDI beam directions into the FGM spin-aligned reference coordinate system have to be corrected. We show how this can be done by FGM/EDI data comparison, as well.

FEMALE GENITAL MUTILATION: ARE WE WINNING?

PubMed

Makinde, O N; Elusiyan, J B E; Adeyemi, A B; Taiwo, O T

2012-06-01

For more than 25 years, efforts have been geared towards curtailing the practice of female genital mutilation (FGM) in countries like Nigeria. This study was designed to see if all these efforts have made any impact in reducing the prevalence of FGM appreciably in the south-West of Nigeria. To determine the prevalence of female genital mutilation and profiling the trends of FGM affected patients. A prospective study based on direct observation of the external genitalia by health-care workers . Five hundred and sixty five females less than 15 years of age. The children emergency and gynaecological wards of the Obafemi Awolowo University Teaching Hospitals Complex, Ile-Ife, Nigeria from 1st of January to December 31s 2007. Forty one point nine percent of the patients examined had female genital mutilation, 93.2% of these had the procedure before attaining the age of one year. Type 2 FGM predominated (58.22%). The procedure was performed predominantly (64.6%) by traditional birth attendants. The decision to have the procedure done was influenced in 78% of cases by mothers and grandmothers. In 35.4% of cases, there were immediate and short term complications. Demands of tradition predominated (59.1%) as the most important reason for the practice of female genital mutilation. The practice of FGM appears to be still highly prevalent and resistant to change probably due to deep rooted socio-cultural factors. Strategies such as public education campaigns highlighting its negative impact on health and disregard for human rights should be evolved.

GOJJAM ZONE, WESTERN AMHARA, ETHIOPIA.

PubMed

Andualem, Mulusew

2016-07-01

Female genital mutilation is one of the harmful traditional practices among women and girls. More than 130 million girls and women live today who have undergone female genital mutilation. In Ethiopia, a high prevalence (74.3% national and 68.5% in Amhara region) has been reported. This study was aimed to identify determinant factors of female genital mutilation practices in East Gojjam Zone, Western Amhara, Ethiopia community based cross sectional study was conducted among 730 women aged 15-49 years and having children < 5 years old in September, 2014. Data were collected using a pretested interviewer administered questionnaire. Descriptive statistics were used to describe study objectives, and bivariate and multivariate analysis to identify determinant factors to female genital mutilation. 718 women and 805 daughters participated in the study. FGM prevalence was 689 (96%) and 403 (49%) among women and daughters< 5 years of age, respectively. Type1 and type 2 FGMs were common and daughters <1 years of age exhibited 91% female genital mutilation. Daughters' age, parent education level, residence, women circumcision history, culture, health education, frequent health extension workers follow up and participation in anti FGM interventions were risk factors to female genital mutilation practice. Female genital mutilation practices continues to be a major problem to women and daughter <5 years of age in the study area. A number of factors were associated with FGM practices including daughters’ age, parent education level, residence, health education, culture, mothers circumcision history, frequent health extensions workers follow up and participation in anti FGM interventions were determinants to higher FGM practices.

Crossing borders: discussing the evidence relating to the mental health needs of women exposed to female genital mutilation.

PubMed

Mulongo, Peggy; McAndrew, Sue; Hollins Martin, Caroline

2014-08-01

The terms 'Female Circumcision' (FC), 'FG Cutting' (FGC) and 'FG Mutilation' (FGM) refer to procedures involving the partial or total removal of the external female genitalia for non-medical reasons. In practicing countries, FGC/FC is more widely used, as it is believed to be inoffensive, providing more impartial ways of discussing the practice. Positive beliefs about FC/FGC include virginity, marriage prospects, family reputation, or passage to adulthood. Regardless of terminology, the practice exists in at least 28 African counties, and a few Asian and Middle Eastern countries. In Western society, FGM is considered a breach of human rights, being outlawed in a number of countries. With immigration trends, FGC is now prominent in Western society among practicing communities. While the past decade has seen an increase in studies and recommendations for health-care support related to the physical health consequences of FGM, little is known about the psychological impact and its management. For many girls and women, FGC is a traumatic practice, transforming it to FGM and affecting their mental health. This discussion paper focuses on evidence relating to the mental health consequences of FGM, therapeutic interventions, and the mental health nurse's role in addressing the needs of this group of women. © 2014 The Authors. International Journal of Mental Health Nursing published by Wiley Publishing Asia Pty Ltd on behalf of Australian College of Mental Health Nurses Inc.

Awareness and predictors of female genital mutilation/cutting among young health advocates

PubMed Central

Abolfotouh, Sherif M; Ebrahim, Ahmed Z; Abolfotouh, Mostafa A

2015-01-01

The act of female genital mutilation/cutting (FGM/C) is considered internationally as a violent act against girls and women and a violation of their human rights. This study sought to assess the awareness and predictors of FGM/C in young Egyptian health advocates. A cross-sectional study of 600 medical students from a total of 2,500 members of the International Federation of Medical Students’ Associations (IFMSA)-Egypt, across all Egyptian medical schools, was conducted using a previously validated online Google survey. The overall prevalence of circumcision was 14.7/100 female students, with a significantly higher prevalence in students from rural areas (25%) than in non-rural areas (10.8%, P=0.001), and in those residing in Upper (southern) Egypt (20.6%) than in Lower (northern) Egypt (8.7%, P=0.003). The students’ mean percentage score for knowledge about the negative health consequences of FGM/C was 53.50±29.07, reflecting a modest level of knowledge; only 30.5% had a good level of knowledge. The mean percentage score for the overall attitude toward discontinuation of the practice of FGM/C was 76.29±17.93, reflecting a neutral attitude; 58.7% had a favorable attitude/norms toward discontinuation of the practice. Of circumcised students, approximately one-half (46.8%) were unwilling to have their daughters circumcised, and 60% reported no harm from being circumcised. After controlling for confounders, a negative attitude toward FGM/C was significantly (P<0.001 in all cases) associated with male sex, residency in Upper Egypt, rural origin, previous circumcision, and the preclinical medical phase of education. The low level of knowledge among even future health professions in our study suggests that communication, rather than passive learning, is needed to convey the potentially negative consequences of FGM/C and to drive a change in attitude toward discontinuation of this harmful practice. PMID:25759602

Chemical, Physiochemical, and Microstructural Properties, and Probiotic Survivability of Fermented Goat Milk Using Polymerized Whey Protein and Starter Culture Kefir Mild 01.

PubMed

Wang, Hao; Wang, Cuina; Wang, Mu; Guo, Mingruo

2017-11-01

A set-type fermented goat milk (FGM) using polymerized whey protein (PWP) as main thickening agent and Kefir Mild 01 as starter culture was developed. The FGM with PWP (0.3%, w/v) and pectin (0.2%, w/v) had low syneresis (5.44 ± 0.92%), desirable viscosity (952.86 ± 61.52 mPa⋅s), and hardness (112.57 ± 3.23 g), which were comparable to a fermented cow milk. Sensory evaluation data showed that the FGM with PWP and pectin had higher scores of both flavor (4.41 ± 0.39) and taste (3.72 ± 0.34) than the sample without PWP. Chemical composition of both fermented goat and cow milk were analyzed. The protein content of goat and cow milk samples were 3.50% ± 0.12% and 3.28% ± 0.09% (w/w), respectively. Lactobacillus acidophilus population in both FGM samples remained above 10 6 CFU/g during the 1st 4-wk storage. There was a slight but no significant (P > 0.05) decrease in pH and TA during storage. Scanning electron microscopy micrographs displayed a compact and homogeneous protein network of the FGM with PWP and pectin. Polymerized whey protein may be a novel protein-based thickening agent for formulation of a set-type FGM with starter culture Kefir Mild 01. Fermented goat milk is an increasingly popular dairy product in the world. However, it is difficult to make set type fermented goat milk due to the smaller size and lower content of casein micelles in goat milk. A fermented goat milk with PWP (0.3%, w/v) and pectin (0.2%, w/v) was successfully developed in this study. The product fermented by Kefir Mild 01 starter culture had a similar taste with Kefir but no yeast or alcoholic exists. The new product would be a promising food in the market. © 2017 Institute of Food Technologists®.

Setting up a clinic to assess children and young people for female genital mutilation.

PubMed

Hodes, Deborah; Creighton, Sarah M

2017-02-01

It is now mandatory for health, social care professionals and teachers to report to the police all under-18s where female genital mutilation (FGM) has been disclosed by the child or where physical signs of FGM are seen. Such referrals are likely to result in a request for medical examination. New multiagency statutory guidance sets out instructions for physical examination but provides no details how services should be set-up. This review gives practical guidance learnt from the first year of the UK's only dedicated children's FGM service. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

Forest genetic monitoring: an overview of concepts and definitions.

PubMed

Fussi, Barbara; Westergren, Marjana; Aravanopoulos, Filippos; Baier, Roland; Kavaliauskas, Darius; Finzgar, Domen; Alizoti, Paraskevi; Bozic, Gregor; Avramidou, Evangelia; Konnert, Monika; Kraigher, Hojka

2016-08-01

Safeguarding sustainability of forest ecosystems with their habitat variability and all their functions is of highest priority. Therefore, the long-term adaptability of forest ecosystems to a changing environment must be secured, e.g., through sustainable forest management. High adaptability is based on biological variation starting at the genetic level. Thus, the ultimate goal of the Convention on Biological Diversity (CBD) to halt the ongoing erosion of biological variation is of utmost importance for forest ecosystem functioning and sustainability. Monitoring of biological diversity over time is needed to detect changes that threaten these biological resources. Genetic variation, as an integral part of biological diversity, needs special attention, and its monitoring can ensure its effective conservation. We compare forest genetic monitoring to other biodiversity monitoring concepts. Forest genetic monitoring (FGM) enables early detection of potentially harmful changes of forest adaptability before these appear at higher biodiversity levels (e.g., species or ecosystem diversity) and can improve the sustainability of applied forest management practices and direct further research. Theoretical genetic monitoring concepts developed up to now need to be evaluated before being implemented on a national and international scale. This article provides an overview of FGM concepts and definitions, discusses their advantages and disadvantages, and provides a flow chart of the steps needed for the optimization and implementation of FGM. FGM is an important module of biodiversity monitoring, and we define an effective FGM scheme as consisting of an assessment of a forest population's capacity to survive, reproduce, and persist under rapid environmental changes on a long-term scale.

Foveolar gastric metaplasia of the duodenum: a frequent, so far neglected type of duodenal polyp.

PubMed

Sarbia, M; Sauer, G; Karimi, D; Berndt, R

2014-04-01

Foveolar gastric metaplasia of the duodenum (FGM) is considered as imperfect mucosal healing in the context of H. pylori gastritis and intake of NSAIDs or ASS.  Typical endoscopic findings are redness of the mucosa, erosion/ulcer and loss of mucosal folds. During diagnostic histological examinations we observed a frequent so far not described association of FGM with endoscopically observed duodenal polyps. The archives of two institutes of pathology with high gastroenterological workload (approximately 100 000 patients per year) were investigated for an association between "duodenal polyp" and "foveolar gastric metaplasia". In Institute 1, of 481 duodenal polyps 41 % were classified as FGM, 9 % as adenoma and 2 % as heterotopic gastric mucosa. In 48 % no histological correlate was present. In Institute 2, 217 cases of FGM were diagnosed. Of these, in 69 cases the endoscopic finding was "polyp" (32 %). In the other cases, the endoscopic findings were mucosal defect (18 %), redness/inflammation (16 %), suspicion for gastric heterotopia (5 %) and scar (3 %). In 26 % of cases no pathologic endoscopic finding was reported. Both groups of patients with FGM showed a similar distribution of age ranges (24 - 83 years and 16 - 88 years), median age (62 years and 61 years, respectively) and a dominance of male sex (both 1.5:1). In conclusion, foveolar gastric metaplasia is a frequent, so far neglected correlate of endoscopically detected duodenal polyps. © Georg Thieme Verlag KG Stuttgart · New York.

A multidisciplinary approach to clitoral reconstruction after female genital mutilation: the crucial role of counselling.

PubMed

De Schrijver, Lotte; Leye, Els; Merckx, Mireille

2016-08-01

Female genital mutilation (FGM) is becoming more widely seen in the West, due to immigration and population movement. Health services are being confronted with the need to provide care for women with FGM. One of the more recent trends is the provision of clitoral reconstruction. It remains unclear, however, what constitutes good practice with regard to this type of surgery. Based on a keynote presentation about reconstructive clitoral surgery, we briefly discuss the possible consequences of FGM and the findings from recent publications on clitoral reconstruction. Recognising individual differences in women, we suggest a multidisciplinary counselling model to provide appropriate care for women requesting clitoral reconstruction. The literature shows that FGM influences physical, mental and sexual health. Clitoral reconstructive surgery can lead to an increase in sexual satisfaction and orgasm in some, but not all, women. A multidisciplinary approach would enable a more satisfactory and individually tailored approach to care. The multidisciplinary team should consist of a midwife, a gynaecological surgeon, a psychologist-psychotherapist, a sexologist and a social worker. Comprehensive health counselling should be the common thread in this model of care. Our proposed care pathway starts with taking a thorough history, followed by medical, psychological and sexological consultations. Women with FGM requesting clitoral reconstruction might primarily be looking to improve their sexual life, to recover their identity and to reduce pain. Surgery may not always be the right answer. Thorough counselling that includes medical, psychological and sexual advice is therefore necessary as part of a multidisciplinary approach.

Addressing female genital mutilation in Europe: a scoping review of approaches to participation, prevention, protection, and provision of services.

PubMed

Baillot, Helen; Murray, Nina; Connelly, Elaine; Howard, Natasha

2018-02-08

Public and policy attention to female genital mutilation (FGM) in diaspora communities has increased in Europe, but research remains limited and misinformation abounds. As a first step to addressing these issues, this study explored FGM prevention and response interventions in Europe, using a scoping literature review and key informant interviews. A scoping study design was selected, using Arksey and O'Malley's six-stage scoping framework to review identified sources. Key informant interviews were used to inform and add depth to literature findings. Findings were summarised thematically, guided by the Scottish Government's '4Ps' framework for tackling violence against women (i.e. participation, prevention, protection, providing services). Seventy literature sources, of 1095 screened, plus 16 individual and 3 group interview sources were included. Several countries have developed promising interventions supporting FGM resistance and recovery. However, gaps remain including community participation, professional knowledge and linkages, and evaluation of approaches. This scoping review is an initial attempt to describe available primary evidence on European initiatives responding to FGM. Further research is required to determine whether interventions are effective, while policy and practice development must be shaped and driven by the experiences, needs, and views of affected communities.

Female genital mutilation in Djibouti.

PubMed

Martinelli, M; Ollé-Goig, J E

2012-12-01

The practice of female genital mutilation (we will use the latest definition adopted by WHO/UNFP: female genital mutilation/cutting or FGM/C) is still widespread in 28 African countries. The World Health Organisation (WHO) estimates that more than two million females undergo some form of genital mutilation every year. Its negative health impact and its ethical and human rights aspects have been discussed and attempts to eliminate it have been the objectives of several meetings promoted by national and international organisations thanks to an increased awareness related to FGM/C in those countries practicing it and also, maybe due to the number of Africans migrating to industrialized countries. We review the present situation in Djibouti, a small country in the Horn of Africa, where 98 % of the female population has suffered different forms of FGM/C.

Crime in Nigeria: An Exploratory Analysis

DTIC Science & Technology

2012-11-02

and actual practice of Female Genital Mutilation and Cutting (FGM/C), early marriage, a substantial age gap between spouses (usually an older husband...prevention among 15-24 years-old, 2007 FGM: occurrence of Female Genital Mutilation /Cutting among daughters 15-49 yr old, 2007 Gender Parity... genital mutilation /cutting among 15-49 year old adults, 2007 AIDS Knowledge: Percentage with "comprehensive knowledge" of HIV/AIDS

What are the experiences of seeking, receiving and providing FGM-related healthcare? Perspectives of health professionals and women/girls who have undergone FGM: protocol for a systematic review of qualitative evidence.

PubMed

Evans, Catrin; Tweheyo, Ritah; McGarry, Julie; Eldridge, Jeanette; McCormick, Carol; Nkoyo, Valentine; Higginbottom, Gina Marie Awoko

2017-12-14

Female genital mutilation (FGM) is an issue of global concern. High levels of migration mean that healthcare systems in higher-income western countries are increasingly being challenged to respond to the care needs of affected communities. Research has identified significant challenges in the provision of, and access to, FGM-related healthcare. There is a lack of confidence and competence among health professionals in providing appropriate care, suggesting an urgent need for evidence-based service development in this area. This study will involve two systematic reviews of qualitative evidence to explore the experiences, needs, barriers and facilitators to seeking and providing FGM-related healthcare in high-income (Organisation for Economic Cooperation and Development) countries, from the perspectives of: (1) women and girls who have undergone FGM and (2) health professionals. Twelve databases including MEDLINE, EMBASE, PsycINFO, ASSIA, Web of Science, ERIC, CINAHL, and POPLINE will be searched with no limits on publication year. Relevant grey literature will be identified from digital sources and professional networks.Two reviewers will independently screen, select and critically appraise the studies. Study quality will be assessed using the Joanna Briggs Institute Qualitative Assessment and Review Instrument appraisal tool. Findings will be extracted into NVivo software. Synthesis will involve inductive thematic analysis, including in-depth reading, line by line coding of the findings, development of descriptive themes and re-coding to higher level analytical themes. Confidence in the review findings will be assessed using the CERQual approach. Findings will be integrated into a comprehensive set of recommendations for research, policy and practice. The syntheses will be reported as per the Enhancing Transparency in Reporting the Synthesis of Qualitative Research (ENTREQ) statement. Two reviews will be published in peer-reviewed journals and an integrated report disseminated at stakeholder engagement events. CRD42015030001: 2015 and CRD42015030004: 2015. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Hepatitis B birth dose vaccination rates among children in Beijing: A comparison of local residents and first and second generation migrants

PubMed Central

Chen, Ruohan; Li, Youwei; Wangen, Knut Reidar; Nicholas, Stephen; Maitland, Elizabeth; Wang, Jian

2016-01-01

ABSTRACT Providing hepatitis B vaccine to all neonates within 24 hours of birth (Timely Birth Dose, TBD) is the key preventative measure to control perinatal hepatitis B virus infection. Previous Chinese studies of TBD only differentiated between migrant and non-migrant (local-born generation-LG) children. Our study is the first to stratify migrants in Beijing into first generation migrants (FGM) and second generation migrants (SGM). Based on a questionnaire survey of 2682 people in 3 Beijing villages, we identified 283 children aged 0–15 years, from 246 households, who were eligible for a TBD. Multinomial logistic regression and statistical analyses were used to examine factors explaining TBD rates for LG, FGM and SGM children. Surprisingly, the TBD for LG Beijing children was not significantly different from migrant children. But after stratifying migrant children into FGM and SGM, revealed significant TBD differences were revealed across LG, FGM and SGM according to domicile (p-value < 0.001, OR = 3.24), first vaccination covered by government policy (p-value < 0.05, OR = 3.24), mother's knowledge of hepatitis B (p-value < 0.05, OR = 1.01) and the government's HBV policy environment (p-value < 0.05, OR = 2.338). Birthplace (p-value = 0.002, OR = 6.21) and better policy environments (p-value = 0.01, OR = 2.80) were associated with higher TBD rate for LG and SGM children. Compared with FGM children, SGM had a significantly poorer TBD rate (Fisher exact test of chi-square = 0.013). We identified SGM as a special risk group; proposed Hukou reform to improve SGM TBD; and called for Beijing health authorities to match TBD rates in other provinces, especially by improving practices by health authorities and knowledge of parents. PMID:27043864

Hepatitis B birth dose vaccination rates among children in Beijing: A comparison of local residents and first and second generation migrants.

PubMed

Chen, Ruohan; Li, Youwei; Wangen, Knut Reidar; Nicholas, Stephen; Maitland, Elizabeth; Wang, Jian

2016-05-03

Providing hepatitis B vaccine to all neonates within 24 hours of birth (Timely Birth Dose, TBD) is the key preventative measure to control perinatal hepatitis B virus infection. Previous Chinese studies of TBD only differentiated between migrant and non-migrant (local-born generation-LG) children. Our study is the first to stratify migrants in Beijing into first generation migrants (FGM) and second generation migrants (SGM). Based on a questionnaire survey of 2682 people in 3 Beijing villages, we identified 283 children aged 0-15 years, from 246 households, who were eligible for a TBD. Multinomial logistic regression and statistical analyses were used to examine factors explaining TBD rates for LG, FGM and SGM children. Surprisingly, the TBD for LG Beijing children was not significantly different from migrant children. But after stratifying migrant children into FGM and SGM, revealed significant TBD differences were revealed across LG, FGM and SGM according to domicile (p-value < 0.001, OR = 3.24), first vaccination covered by government policy (p-value < 0.05, OR = 3.24), mother's knowledge of hepatitis B (p-value < 0.05, OR = 1.01) and the government's HBV policy environment (p-value < 0.05, OR = 2.338). Birthplace (p-value = 0.002, OR = 6.21) and better policy environments (p-value = 0.01, OR = 2.80) were associated with higher TBD rate for LG and SGM children. Compared with FGM children, SGM had a significantly poorer TBD rate (Fisher exact test of chi-square = 0.013). We identified SGM as a special risk group; proposed Hukou reform to improve SGM TBD; and called for Beijing health authorities to match TBD rates in other provinces, especially by improving practices by health authorities and knowledge of parents.

Development of an event-specific hydrolysis probe quantitative real-time polymerase chain reaction assay for Embrapa 5.1 genetically modified common bean (Phaseolus vulgaris).

PubMed

Treml, Diana; Venturelli, Gustavo L; Brod, Fábio C A; Faria, Josias C; Arisi, Ana C M

2014-12-10

A genetically modified (GM) common bean event, namely Embrapa 5.1, resistant to the bean golden mosaic virus (BGMV), was approved for commercialization in Brazil. Brazilian regulation for genetically modified organism (GMO) labeling requires that any food containing more than 1% GMO be labeled. The event-specific polymerase chain reaction (PCR) method has been the primary trend for GMO identification and quantitation because of its high specificity based on the flanking sequence. This work reports the development of an event-specific assay, named FGM, for Embrapa 5.1 detection and quantitation by use of SYBR Green or hydrolysis probe. The FGM assay specificity was tested for Embrapa 2.3 event (a noncommercial GM common bean also resistant to BGMV), 46 non-GM common bean varieties, and other crop species including maize, GM maize, soybean, and GM soybean. The FGM assay showed high specificity to detect the Embrapa 5.1 event. Standard curves for the FGM assay presented a mean efficiency of 95% and a limit of detection (LOD) of 100 genome copies in the presence of background DNA. The primers and probe developed are suitable for the detection and quantitation of Embrapa 5.1.

Environmental enrichment affects adrenocortical stress responses in the endangered black-footed ferret

USGS Publications Warehouse

Poessel, S.A.; Biggins, D.E.; Santymire, R.M.; Livieri, T.M.; Crooks, K.R.; Angeloni, L.

2011-01-01

Potential stressors of wildlife living in captivity, such as artificial living conditions and frequent human contact, may lead to a higher occurrence of disease and reduced reproductive function. One successful method used by wildlife managers to improve general well-being is the provision of environmental enrichment, which is the practice of providing animals under managed care with environmental stimuli. The black-footed ferret (Mustela nigripes) is a highly-endangered carnivore species that was rescued from extinction by removal of the last remaining individuals from the wild to begin an ex situ breeding program. Our goal was to examine the effect of environmental enrichment on adrenocortical activity in ferrets by monitoring fecal glucocorticoid metabolites (FGM). Results demonstrated that enrichment lowered FGM in juvenile male ferrets, while increasing it in adult females; enrichment had no effect on FGM in juvenile females and adult males. These results correspond with our findings that juvenile males interacted more with the enrichment items than did adult females. However, we did not detect an impact of FGM on the incidence of disease or on the ability of ferrets to become reproductive during the following breeding season. We conclude that an environmental enrichment program could benefit captive juvenile male ferrets by reducing adrenocortical activity. ?? 2011 Elsevier Inc.

Deinfibulation for treating urologic complications of type III female genital mutilation: A systematic review.

PubMed

Effa, Emmanuel; Ojo, Olumuyiwa; Ihesie, Austin; Meremikwu, Martin M

2017-02-01

Women and girls who have undergone type III female genital mutilation (FGM) may suffer urologic complications such as recurrent urinary tract infections, obstruction, stones, and incontinence. To assess the effectiveness of deinfibulation for preventing and treating urologic complications in women and girls living with FGM. The following major databases were searched from inception to August 2015: Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, SCOPUS, Web of Science, and ClinicalTrials.gov without language restrictions. Randomized controlled studies (RCTs) or observational studies with controls were considered. We screened the results of the search independently for potentially relevant studies and applied inclusion and exclusion criteria for the full texts of the relevant studies. No RCTs were found. We found three case reports and a retrospective case review, all of which were excluded. There is no evidence on the use of deinfibulation to improve urologic complications among women with type III FGM. Current clinical practice may be informed by anecdotal evidence from case reports. Appropriate RCTs and observational studies with comparison groups in countries where FGM is common are needed. PROSPERO registration: CRD42015024901. © 2017 International Federation of Gynecology and Obstetrics. The World Health Organization retains copyright and all other rights in the manuscript of this article as submitted for publication.

The timing of female genital mutilation and the role of contralateral palpal insertions in the spider Cyclosa argenteoalba.

PubMed

Nakata, Kensuke

2017-11-01

Some male spiders exhibit female genital mutilation behaviour (FGM) by removing the female genital appendage (scape) to control the mating frequency of females. Female spiders have two, i.e. right and left, genital openings connected with separate spermathecae into which males transfer sperm successively using one pedipalp (secondary genitalia) at a time. Thus, males must complete at least two palpal insertions to fill both spermathecae, before FGM. The present study examined whether (i) scape removal is only associated with the second palpal insertion (one-action hypothesis) or (ii) two contralateral palpal insertions facilitate FGM, with each insertion cutting the basal part of the scape halfway (two-actions hypothesis). Experiments in which females were replaced after a male had made the first insertion did not support the one-action hypothesis, because scapes remained intact after the newly introduced virgin females received their first palpal insertion, which was the second insertion by the males. In comparison, mating experiments using two half-eunuchs (i.e. one of the palps of each male had been manually removed, forcing them to fill female spermatheca on one side only) supported the two-actions hypothesis. FGM was more frequent in females that received two contralateral palpal insertions than in females that received ipsilateral insertions.

The timing of female genital mutilation and the role of contralateral palpal insertions in the spider Cyclosa argenteoalba

PubMed Central

2017-01-01

Some male spiders exhibit female genital mutilation behaviour (FGM) by removing the female genital appendage (scape) to control the mating frequency of females. Female spiders have two, i.e. right and left, genital openings connected with separate spermathecae into which males transfer sperm successively using one pedipalp (secondary genitalia) at a time. Thus, males must complete at least two palpal insertions to fill both spermathecae, before FGM. The present study examined whether (i) scape removal is only associated with the second palpal insertion (one-action hypothesis) or (ii) two contralateral palpal insertions facilitate FGM, with each insertion cutting the basal part of the scape halfway (two-actions hypothesis). Experiments in which females were replaced after a male had made the first insertion did not support the one-action hypothesis, because scapes remained intact after the newly introduced virgin females received their first palpal insertion, which was the second insertion by the males. In comparison, mating experiments using two half-eunuchs (i.e. one of the palps of each male had been manually removed, forcing them to fill female spermatheca on one side only) supported the two-actions hypothesis. FGM was more frequent in females that received two contralateral palpal insertions than in females that received ipsilateral insertions. PMID:29291078

Behavioural and faecal glucocorticoid metabolite responses of single caging in six cats over 30 days

PubMed Central

Ellis, J. J.; Protopapadaki, V.; Stryhn, H.; Spears, J.; Cockram, M. S.

2014-01-01

Objectives The aim was to characterize the behaviour and faecal glucocorticoid metabolite (FGM) responses of six cats (Felis catus) to single caging for 30 days. Design In this observational study, changes in outcome measures were monitored with habituation to caging. Continuous focal observations of the activity, location in the cage, and posture were conducted from video recordings for one 24-hour period/week/cat. Cat-Stress-Scores were recorded daily. All faecal samples were collected for analysis of FGM. Results The percentage time spent eating increased, while percentage time spent grooming decreased, from week 1 to week 2. Cat-Stress-Score declined significantly from week 1 to week 2. FGM concentrations were significantly greater in week 1 than in week 5. A posthabituation time budget of the behaviour of the cats in the single cages showed that inactivity dominated the time budget and the cats were located on the shelf almost half of the time. Conclusions Results suggests that a shelf was a resource of value to the cats, and that its inclusion in enclosure design is important. Quantitative and qualitative behavioural data indicated that there was an initial stress response to caging that stabilised after the first week, while FGM concentration took longer to stabilise. PMID:26392880

Environmental enrichment affects adrenocortical stress responses in the endangered black-footed ferret.

PubMed

Poessel, Sharon A; Biggins, Dean E; Santymire, Rachel M; Livieri, Travis M; Crooks, Kevin R; Angeloni, Lisa

2011-07-01

Potential stressors of wildlife living in captivity, such as artificial living conditions and frequent human contact, may lead to a higher occurrence of disease and reduced reproductive function. One successful method used by wildlife managers to improve general well-being is the provision of environmental enrichment, which is the practice of providing animals under managed care with environmental stimuli. The black-footed ferret (Mustela nigripes) is a highly-endangered carnivore species that was rescued from extinction by removal of the last remaining individuals from the wild to begin an ex situ breeding program. Our goal was to examine the effect of environmental enrichment on adrenocortical activity in ferrets by monitoring fecal glucocorticoid metabolites (FGM). Results demonstrated that enrichment lowered FGM in juvenile male ferrets, while increasing it in adult females; enrichment had no effect on FGM in juvenile females and adult males. These results correspond with our findings that juvenile males interacted more with the enrichment items than did adult females. However, we did not detect an impact of FGM on the incidence of disease or on the ability of ferrets to become reproductive during the following breeding season. We conclude that an environmental enrichment program could benefit captive juvenile male ferrets by reducing adrenocortical activity. Copyright © 2011 Elsevier Inc. All rights reserved.

Finite Element Analysis of Functionally Graded Material to Reduce Crazing in Transparent Armor

DTIC Science & Technology

2015-09-01

Constraints 3 Results 4 Tensile Pressure (psi) 4 Conclusions and Path Forward 5 References 7 Distribution List 9 FIGURES 1 Pressure plot 1 2 3D...Digimat unit cell and 2D plane strain model for ABAQUS 2 3 Control and FGM models 3 4 Boundary conditions 4 5 Pressure results (time = 23.47 µs) 4...6 Pressure results 1 5 7 Pressure results 2 5 UNCLASSIFIED Approved for public release; distribution is unlimited. 1 INTRODUCTION

FGM (Functionally Graded Material) Thermal Barrier Coatings for Hypersonic Structures - Design and Thermal Structural Analysis

DTIC Science & Technology

2007-06-29

than others. It was found that TZ-3Y-E, which is a partially stabilised zirconia powder , was particularly suitable. The percentage of ceramic powder...layered coatings The current ceramic powder that was being used was a fully stabilised zirconia powder TZ-0Y. However a readily available powder...TZ-3Y-E, partially stabilised zirconia powder , was available and utilised. These tests consisted of a combination of 3, 4 and 5 layers. In the

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lherbier, Louis, W.; Novotnak, David, J.; Herling, Darrell, R.

Hot forming processes such as forging, die casting and glass forming require tooling that is subjected to high temperatures during the manufacturing of components. Current tooling is adversely affected by prolonged exposure at high temperatures. Initial studies were conducted to determine the root cause of tool failures in a number of applications. Results show that tool failures vary and depend on the operating environment under which they are used. Major root cause failures include (1) thermal softening, (2) fatigue and (3) tool erosion, all of which are affected by process boundary conditions such as lubrication, cooling, process speed, etc. Whilemore » thermal management is a key to addressing tooling failures, it was clear that new tooling materials with superior high temperature strength could provide improved manufacturing efficiencies. These efficiencies are based on the use of functionally graded materials (FGM), a new subset of hybrid tools with customizable properties that can be fabricated using advanced powder metallurgy manufacturing technologies. Modeling studies of the various hot forming processes helped identify the effect of key variables such as stress, temperature and cooling rate and aid in the selection of tooling materials for specific applications. To address the problem of high temperature strength, several advanced powder metallurgy nickel and cobalt based alloys were selected for evaluation. These materials were manufactured into tooling using two relatively new consolidation processes. One process involved laser powder deposition (LPD) and the second involved a solid state dynamic powder consolidation (SSDPC) process. These processes made possible functionally graded materials (FGM) that resulted in shaped tooling that was monolithic, bi-metallic or substrate coated. Manufacturing of tooling with these processes was determined to be robust and consistent for a variety of materials. Prototype and production testing of FGM tooling showed the benefits of the nickel and cobalt based powder metallurgy alloys in a number of applications evaluated. Improvements in tool life ranged from three (3) to twenty (20) or more times than currently used tooling. Improvements were most dramatic where tool softening and deformation were the major cause of tool failures in hot/warm forging applications. Significant improvement was also noted in erosion of aluminum die casting tooling. Cost and energy savings can be realized as a result of increased tooling life, increased productivity and a reduction in scrap because of improved dimensional controls. Although LPD and SSDPC tooling usually have higher acquisition costs, net tooling costs per component produced drops dramatically with superior tool performance. Less energy is used to manufacture the tooling because fewer tools are required and less recycling of used tools are needed for the hot forming process. Energy is saved during the component manufacturing cycle because more parts can be produced in shorter periods of time. Energy is also saved by minimizing heating furnace idling time because of less downtime for tooling changes.« less

The surface crack problem for a functionally graded coating bonded to a homogeneous layer

NASA Astrophysics Data System (ADS)

Kasmalkar, Maheendra B.

In the continuing search for materials which can withstand the grueling requirements of modern day applications, Functionally Graded Materials (FGMs) seem to be a promising alternative to conventional materials. These nonhomogeneous materials offer better interfacial properties by improving bond strength and reducing thermal mismatch. Before putting these materials into application, an important step in the design of FGMs is the stress analysis and fracture characterization. The fracture performance of FGM coatings on homogeneous substrates is the focus of this study. In this study, various internal and surface crack configurations in the coating and the substrate are subjected to mechanical and thermal loads. The analysis is linear elastic. The thermo-mechanical properties of the FGM coating are assumed to vary exponentially with the spatial coordinate. The equilibrium equations are solved using integral transforms. The resulting singular integral equations are solved using numerical integration. The results of interest for this mode I formulation are the stress intensity factors and the crack opening displacements. The effects of the nonhomogeneity parameter and various dimensionless length parameters are studied. One of the most important outcomes of this study is the theoretical proof that "kink" in material property at the interface does not introduce any singularity. In the numerical results it is observed that generally the stress intensity factors tend to increase with material nonhomogeneity. Also, it is observed that the substrate thickness tends to suppress cracking in the coating. In pure thermal loading, the surface cracks may either be arrested or there might be crack closure. The stress intensity factors from different loadings can be added up to obtain the resultant stress intensity factor for multiple loading. Results in this study have wide-ranging applications. They can be applied to thermal barrier coatings on turbine components, combustion chambers, parts of the airframe for the "Space Plane", soil mechanics, bone fractures and many more applications where the material is macroscopically nonhomogeneous. Thus this study solves a basic problem common to a variety of applications in diverse fields.

Antepartum or intrapartum deinfibulation for childbirth in women with type III female genital mutilation: A systematic review and meta-analysis.

PubMed

Esu, Ekpereonne; Udo, Atim; Okusanya, Babasola O; Agamse, David; Meremikwu, Martin M

2017-02-01

There remains no consensus on the best timing of deinfibulation in women with type III female genital mutilation (FGM). To conduct a systematic review of the effects of antepartum or intrapartum deinfibulation on childbirth outcomes in women with type III FGM. The following major databases were searched: Cochrane Central Register for Controlled Trials (CENTRAL), MEDLINE, Scopus, Web of Science, and ClinicalTrials.gov, from inception until August 2015 without any language restrictions. Studies of pregnant women or girls with type III FGM who were deinfibulated antepartum or intrapartum were included. Two team members independently screened and collected data. Quality of evidence was assessed using GRADE. Summary odds ratios and proportions were calculated when possible. There is no evidence of a significant difference between antepartum and intrapartum deinfibulation for obstetric outcomes such as duration of labor, perineal lacerations, episiotomies, postpartum hemorrhage, and cesarean deliveries. Outcomes in women living with type III FGM and those who have undergone deinfibulation were not statistically different; however, trends show a benefit for deinfibulation. All studies were underpowered to detect statistical differences. Larger studies are required to have full confidence in these findings. CRD42015024464. © 2017 International Federation of Gynecology and Obstetrics. The World Health Organization retains copyright and all other rights in the manuscript of this article as submitted for publication.

Providing information about the consequences of female genital mutilation to healthcare providers caring for women and girls living with female genital mutilation: A systematic review.

PubMed

Oringanje, Chioma M; Okoro, Anthony; Nwankwo, Ogonna N; Meremikwu, Martin M

2017-02-01

The persistence of female genital mutilation (FGM) in some countries, despite an overall decline in the prevalence of the practice, calls for improvement in the capacity of healthcare workers and institutions to provide optimal care for this population. To determine the impact of providing information on FGM and its consequences to healthcare providers on their attitudes toward FGM, and quality of care and patient satisfaction. The following major databases were searched from inception to August 2015: Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, SCOPUS, Web of Science, and ClinicalTrials.gov, without language restrictions. Controlled studies were included based on use of objective measures. Two team members independently screened and collected data. Relative risks and proportions were calculated and evidence assessed using the GRADE (Grade of Recommendation, Assessment, Development and Evaluation) approach. One study was identified. Based on this study there was no evidence to suggest change in healthcare provider outcomes after the intervention. Despite a comprehensive search, only one study of low methodological quality was included. This precludes a definitive conclusion regarding the impact of providing information on FGM to healthcare providers. More research is needed. CRD42015024570. © 2017 International Federation of Gynecology and Obstetrics. The World Health Organization retains copyright and all other rights in the manuscript of this article as submitted for publication.

Sexual counselling for treating or preventing sexual dysfunction in women living with female genital mutilation: A systematic review.

PubMed

Okomo, Uduak; Ogugbue, Miriam; Inyang, Elizabeth; Meremikwu, Martin M

2017-02-01

Female sexual dysfunction is the persistent or recurring decrease in sexual desire or arousal, the difficulty or inability to achieve an orgasm, and/or the feeling of pain during sexual intercourse. Impaired sexual function can occur with all types of female genital mutilation (FGM) owing to the structural changes, pain, or traumatic memories associated with the procedure. To conduct a systematic review of randomized and nonrandomized studies into the effects of sexual counseling with or without genital lubricants on the sexual function of women living with FGM. Cochrane Central Register of Controlled Trials, MEDLINE, African Index Medicus, SCOPUS, LILACS, CINAHL, ClinicalTrials.gov, Pan African Clinical Trials Registry, and other databases were searched to August 2015. The reference lists of retrieved studies were checked for reports of additional studies, and lead authors contacted for additional data. Studies of girls and women living with any type of FGM who received counselling interventions for sexual dysfunction were included. No relevant studies that addressed the objective of the review were identified. Despite a comprehensive search, the authors could not find evidence of the effects of sexual counseling on the sexual function of women living with FGM. Studies assessing this intervention are needed. CRD42015024593. © 2017 International Federation of Gynecology and Obstetrics. The World Health Organization retains copyright and all other rights in the manuscript of this article as submitted for publication.

Primates Living Outside Protected Habitats Are More Stressed: The Case of Black Howler Monkeys in the Yucatán Peninsula

PubMed Central

Rangel-Negrín, Ariadna; Coyohua-Fuentes, Alejandro; Chavira, Roberto; Canales-Espinosa, Domingo; Dias, Pedro Américo D.

2014-01-01

The non-invasive monitoring of glucocorticoid hormones allows for the assessment of the physiological effects of anthropogenic disturbances on wildlife. Variation in glucocorticoid levels of the same species between protected and unprotect areas seldom has been measured, and the available evidence suggests that this relationship may depend on species-specific habitat requirements and biology. In the present study we focused on black howler monkeys (Alouatta pigra), a canopy-dwelling primate species, as a case study to evaluate the physiological consequences of living in unprotected areas, and relate them with intragroup competition and competition with extragroup individuals. From February 2006 to September 2007 we collected 371 fecal samples from 21 adults belonging to five groups (two from protected and three from unprotected areas) in Campeche, Mexico. We recorded agonistic interactions within groups and encounters with other groups (1,200 h of behavioral observations), and determined fecal glucocorticoid metabolite (FGM) concentrations with radioimmunoassays. We used linear mixed models and Akaike's information criterion to choose the best model explaining variation in FGM concentrations between protected and unprotected areas calculated from five categorical variables: habitat type (protected vs. unprotected), participation in agonistic interactions, intergroup encounters, sex and female reproductive state, and season. The best model included habitat type, the interaction between habitat type and agonism, and the interaction between habitat type and season. FGM concentrations were higher in unprotected habitats, particularly when individuals were involved in agonistic interactions; seasonal variation in FGM concentrations was only detected in protected habitats. High FGM concentrations in black howler monkeys living in unprotected habitats are associated with increased within-group food competition and probably associated with exposure to anthropogenic stressors and overall food scarcity. Because persistent high GC levels can be detrimental to health and fitness, populations living in disturbed unprotected areas may not be viable in the long-term. PMID:25375243

Primates living outside protected habitats are more stressed: the case of black howler monkeys in the Yucatán Peninsula.

PubMed

Rangel-Negrín, Ariadna; Coyohua-Fuentes, Alejandro; Chavira, Roberto; Canales-Espinosa, Domingo; Dias, Pedro Américo D

2014-01-01

The non-invasive monitoring of glucocorticoid hormones allows for the assessment of the physiological effects of anthropogenic disturbances on wildlife. Variation in glucocorticoid levels of the same species between protected and unprotect areas seldom has been measured, and the available evidence suggests that this relationship may depend on species-specific habitat requirements and biology. In the present study we focused on black howler monkeys (Alouatta pigra), a canopy-dwelling primate species, as a case study to evaluate the physiological consequences of living in unprotected areas, and relate them with intragroup competition and competition with extragroup individuals. From February 2006 to September 2007 we collected 371 fecal samples from 21 adults belonging to five groups (two from protected and three from unprotected areas) in Campeche, Mexico. We recorded agonistic interactions within groups and encounters with other groups (1,200 h of behavioral observations), and determined fecal glucocorticoid metabolite (FGM) concentrations with radioimmunoassays. We used linear mixed models and Akaike's information criterion to choose the best model explaining variation in FGM concentrations between protected and unprotected areas calculated from five categorical variables: habitat type (protected vs. unprotected), participation in agonistic interactions, intergroup encounters, sex and female reproductive state, and season. The best model included habitat type, the interaction between habitat type and agonism, and the interaction between habitat type and season. FGM concentrations were higher in unprotected habitats, particularly when individuals were involved in agonistic interactions; seasonal variation in FGM concentrations was only detected in protected habitats. High FGM concentrations in black howler monkeys living in unprotected habitats are associated with increased within-group food competition and probably associated with exposure to anthropogenic stressors and overall food scarcity. Because persistent high GC levels can be detrimental to health and fitness, populations living in disturbed unprotected areas may not be viable in the long-term.

Using the Female Sexual Function Index (FSFI) to evaluate sexual function in women with genital mutilation undergoing surgical reconstruction: a pilot prospective study.

PubMed

Vital, Mathilde; de Visme, Sophie; Hanf, Matthieu; Philippe, Henri-Jean; Winer, Norbert; Wylomanski, Sophie

2016-07-01

Few prospective studies have evaluated sexual function in women with female genital mutilation by cutting (FGM/C) before and after clitoral reconstructive surgery, and none used a validated questionnaire. A validated questionnaire, the Female Sexual Function Index (FSFI) was used for the first time, to assess the impact of reconstructive surgery on sexual function in women with female genital mutilation/cutting (FGM/C) before and after clitoral reconstructive surgery. Women with FGM/C consulting at the Nantes University Hospital for clitoral reconstruction between 2013 and 2014 were prospectively included. All patients completed a questionnaire at inclusion, describing their social, demographic, and FGM/C characteristics. They were also asked to complete the FSFI as well as a questionnaire about clitoral sensations, symptoms of depression or anxiety, and self-esteem before and 3 and 6 months after the surgery. Paired Wilcoxon and McNemar tests were used to compare data. Of the 12 women included, 9 (75%) had type II mutilations. Results showed a global sexual dysfunction (median FSFI summary score=17) before surgery. Clitoral sensations were absent in 8 women (67%). Six months after surgery, all FSFI dimensions except lubrication had improved significantly (median FSFI summary score=29, P=0.009). Ten women had clitoral sensations, and 11 (92%) were satisfied with their surgery. This study shows that 6 months after clitoral reconstructive surgery, women reported a multidimensional positive improvement in their sexual function. The FSFI is a promising tool for routine standardized assessment of the sexual function of women with FGM/C for determining appropriate management and assessing it. Larger studies with validated questionnaires assessing self-esteem, depression, and body image are also needed to develop an integrative approach and to provide evidence-based recommendations about management of these women. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Management of painful clitoral neuroma after female genital mutilation/cutting.

PubMed

Abdulcadir, Jasmine; Tille, Jean-Christophe; Petignat, Patrick

2017-02-08

Traumatic neuromas are the result of regenerative disorganized proliferation of the proximal portion of lesioned nerves. They can exist in any anatomical site and are responsible for neuropathic pain. Post-traumatic neuromas of the clitoris have been described as an uncommon consequence of female genital mutilation/cutting (FGM/C). FGM/C involves partial or total removal of the female genital organs for non-therapeutic reasons. It can involve cutting of the clitoris and can cause psychological, sexual, and physical complications. We aimed to evaluate the symptoms and management of women presenting with a clitoral neuroma after female genital mutilation/cutting (FGM/C). We identified women who attended our specialized clinic for women with FGM/C who were diagnosed with a traumatic neuroma of the clitoris between April 1, 2010 and June 30, 2016. We reviewed their medical files and collected socio-demographic, clinical, surgical, and histopathological information. Seven women were diagnosed with clitoral neuroma. Six attended our clinic to undergo clitoral reconstruction, and three of these suffered from clitoral pain. The peri-clitoral fibrosis was removed during clitoral reconstruction, which revealed neuroma of the clitoris in all six subjects. Pain was ameliorated after surgery. The seventh woman presented with a visible and palpable painful clitoral mass diagnosed as a neuroma. Excision of the mass ameliorated the pain. Sexual function improved in five women. One was not sexually active, and one had not yet resumed sex. Post-traumatic clitoral neuroma can be a consequence of FGM/C. It can cause clitoral pain or be asymptomatic. In the case of pain symptoms, effective treatment is neuroma surgical excision, which can be performed during clitoral reconstruction. Surgery should be considered as part of multidisciplinary care. The efficacy of neuroma excision alone or during clitoral reconstruction to treat clitoral pain should be further assessed among symptomatic women.

NiCo2S4 nanorod embedded rGO sheets as electrodes for supercapacitor

NASA Astrophysics Data System (ADS)

Sarkar, Aatreyee; Bera, Supriya; Chakraborty, Amit Kumar

2018-04-01

We report the synthesis of a hybrid nanostructure based on NiCo2S4 and reduced graphene oxide (rGO) following a facile hydrothermal method. X-ray diffraction (XRD), and electron microscopy (FESEM and HRTEM) analyses showed rod-like NiCo2S4 nanostructures embedded in rGO sheets. The electrochemical analysis of the synthesized nanohybrid using cyclic voltammetry (CV) and galvanostatic charge discharge (GCD) revealed specific capacitance of 410 F/gm indicating its suitability as a good electrode material for supercapacitor.

One-dimensional array of gold nanoparticles fabricated using biotemplate and its application to fine FET

NASA Astrophysics Data System (ADS)

Ban, Takahiko; Uenuma, Mutsunori; Migita, Shinji; Okamoto, Naofumi; Ishikawa, Yasuaki; Uraoka, Yukiharu; Yamashita, Ichiro; Yamamoto, Shin-ichi

2018-06-01

By synthesizing AuS nanoparticles (NPs) with spherical shell protein (ferritin) and using a V-groove, a one-dimensional array of NPs was formed at the bottom of the V-groove. It has been reported that AuS NPs are converted to Au NPs by UV/ozone treatment. Floating gate memory (FGM) was fabricated by applying this one-dimensional array to V-grooved junctionless (JL) FETs, V-grooved nin-like-type FETs, and pip-like-type FETs, which are fine FETs. In JL-FETs, it is considered that conversion occurred because of good charge storage efficiency, and operation in the opposite direction to normal FGM operation was seen. In the nin-like and pip-like types devices, the same operation as in conventional FGM was shown, and the width of the memory window was about the same size as when one electron entered one NP. The one-dimensional arrangement of the metal NPs used in this study is considered to be applicable to various fields of nanotechnology.

Management of type III female genital mutilation in Birmingham, UK: a retrospective audit.

PubMed

Paliwal, Priya; Ali, Sarah; Bradshaw, Sally; Hughes, Alison; Jolly, Kate

2014-03-01

to audit clinical management of women with type III female genital mutilation (FGM) according to local guidelines. Secondary objectives were to describe the population that uses the service and compare obstetric outcomes of intrapartum deinfibulation and antenatal deinfibulation. retrospective audit. a hospital midwifery-led FGM specialist service in Birmingham, UK. 253 women with type III FGM who gave birth between January 2008 and December 2009 METHODS: retrospective case analysis using patient records. proportion of women managed according to locally agreed criteria for the management of FGM; obstetric outcomes including perineal tears, episiotomy rates, estimated blood loss, infant APGAR scores and indications for caesarean section. 91 (36%) women booked into antenatal care after 16 weeks gestation. Only 26 (10.3%) were managed fully according to guidelines. The area with poorest performance was child protection, where the presence of normal genitalia was documented in only 52 (38.8%) of medical notes following birth of a female infant. The majority of women (214, 84.6%) had been deinfibulated in a previous pregnancy. Of the 39 infibulated at booking, only 9 (23.1%) were deinfibulated antenatally, the rest opted for intrapartum deinfibulation. Women who had intrapartum deinfibulation had a higher average blood loss and more tears than those deinfibulated antenatally, although this was not statistically significant. alternative systems should be considered to improve documentation of child protection related information. Further research is needed to confirm or refute the adverse findings among those that delayed deinfibulation. Copyright © 2013 Elsevier Ltd. All rights reserved.

Analytical Model for Thermal Elastoplastic Stresses of Functionally Graded Materials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhai, P. C.; Chen, G.; Liu, L. S.

2008-02-15

A modification analytical model is presented for the thermal elastoplastic stresses of functionally graded materials subjected to thermal loading. The presented model follows the analytical scheme presented by Y. L. Shen and S. Suresh [6]. In the present model, the functionally graded materials are considered as multilayered materials. Each layer consists of metal and ceramic with different volume fraction. The ceramic layer and the FGM interlayers are considered as elastic brittle materials. The metal layer is considered as elastic-perfectly plastic ductile materials. Closed-form solutions for different characteristic temperature for thermal loading are presented as a function of the structure geometriesmore » and the thermomechanical properties of the materials. A main advance of the present model is that the possibility of the initial and spread of plasticity from the two sides of the ductile layers taken into account. Comparing the analytical results with the results from the finite element analysis, the thermal stresses and deformation from the present model are in good agreement with the numerical ones.« less

Magnetospheric Multiscale Mission Examination of Stress Balance in FTE-Type Flux Ropes at the Earth's Magnetopause

NASA Astrophysics Data System (ADS)

Akhavan-Tafti, M.; Slavin, J. A.; Le, G.; Eastwood, J. P.; Strangeway, R. J.; Russell, C. T.; Nakamura, R.; Baumjohann, W.; Torbert, R. B.; Giles, B. L.; Gershman, D. J.; Burch, J. L.

2016-12-01

Determining the magnetic field structure, electric currents, and plasma distribution within flux transfer event (FTE)-type flux ropes is critical to the understanding of their origin, evolution, and dynamics. We analyze FTEs observed by the Magnetospheric Multiscale (MMS) mission in the vicinity of the sub-solar magnetopause, i.e. 12 ± 22.5' Local Time and XGSM > 7 RE. High-resolution data from the Fluxgate Magnetometer (FGM) and Fast Plasma Investigation (FPI) are used to determine and compare the extent to which large (> 1 RE) and small (ion scale) diameter FTEs are force-free, i.e. J×B=0, or non-force-free, i.e. J×B= gradP. Three independent methods are used: i) current density parallel and perpendicular to the magnetic field derived from the plasma measurements or magnetic field using the curlometer technique; ii) direct measurement of the plasma pressure gradient by FPI; and iii) fitting magnetic field to force-free (J=αB) flux rope models. Our initial results indicate that the plasma content of the ion-scale FTEs often exceeds that of larger FTEs. This results in higher plasma pressure gradients inside smaller FTEs and a magnetic field that is less force-free than the larger flux ropes.

Qualitative evaluation of the Saleema campaign to eliminate female genital mutilation and cutting in Sudan.

PubMed

Johnson, Andrea C; Douglas Evans, W; Barrett, Nicole; Badri, Howida; Abdalla, Tamador; Donahue, Cody

2018-02-17

Female genital mutilation and cutting (FGM/C, herein FGM) is a widespread and harmful practice. The Government developed a national campaign in Sudan, called Saleema, to change social norms discouraging FGM. Saleema translates to being "whole", healthy in body and mind, unharmed, intact, pristine, and untouched, in a God-given condition. An interim evaluation was conducted using focus groups among Sudanese adults. The primary aim was to explore perceptions of the Saleema poster exemplars and to assess if the desired themes were being communicated. Secondary aims were to understand more about participants' information sources, values, and suggestions for the campaign broadly. The Saleema campaign evaluation included four focus groups from each of the 18 states in Sudan (72 total). Participants were presented with three poster stimuli from the Saleema campaign and asked about the content and their reactions. Themes were coded inductively by concepts that arose through content in the transcripts. Codes were also reviewed in conjunction with themes from the broader Saleema evaluation framework. Participants reported the most common source of information or admiration was from local leaders who are responsive to a community, media-based outlets, and discussions among community members. Participants held high value for education, community solidarity, and/or religious devotion. Participants had positive opinions of Saleema and responded positively to the branding elements in the posters and the campaign as a whole. The most common suggestion was continued awareness. Advocacy, training, and posters were suggested to highlight the harms of FGM through leaders or in community settings. Individuals suggested that these activities target older women and individuals in rural villages. There was also a burgeoning theme of targeting youth for support of the campaign. The results of this focus group analysis demonstrate support for future Saleema campaign efforts promoting awareness and community engagement. The campaign could capitalize on partnerships with young people and those who are respected in the community (e.g., religious leaders) or continue promoting common values aligning with the support of education and community solidarity. Continuing campaign efforts have promise to decrease the harms of FGM in Sudan.

Functional genomic mRNA profiling of a large cancer data base demonstrates mesothelin overexpression in a broad range of tumor types.

PubMed

Lamberts, Laetitia E; de Groot, Derk Jan A; Bense, Rico D; de Vries, Elisabeth G E; Fehrmann, Rudolf S N

2015-09-29

The membrane bound glycoprotein mesothelin (MSLN) is a highly specific tumor marker, which is currently exploited as target for drugs. There are only limited data available on MSLN expression by human tumors. Therefore we determined overexpression of MSLN across different tumor types with Functional Genomic mRNA (FGM) profiling of a large cancer database. Results were compared with data in articles reporting immunohistochemical (IHC) MSLN tumor expression. FGM profiling is a technique that allows prediction of biologically relevant overexpression of proteins from a robust data set of mRNA microarrays. This technique was used in a database comprising 19,746 tumors to identify for 41 tumor types the percentage of samples with an overexpression of MSLN compared to a normal background. A literature search was performed to compare the FGM profiling data with studies reporting IHC MSLN tumor expression. FGM profiling showed MSLN overexpression in gastrointestinal (12-36%) and gynecological tumors (20-66%), non-small cell lung cancer (21%) and synovial sarcomas (30%). The overexpression found in thyroid cancers (5%) and renal cell cancers (10%) was not yet reported with IHC analyses. We observed that MSLN amplification rate within esophageal cancer depends on the histotype (31% for adenocarcinomas versus 3% for squamous-cell carcinomas). Subset analysis in breast cancer showed MSLN amplification rates of 28% in triple-negative breast cancer (TNBC) and 33% in basal-like breast cancer. Further subtype analysis of TNBCs showed the highest amplification rate (42%) in the basal-like 1 subtype and the lowest amplification rate (9%) in the luminal androgen receptor subtype.

I knew how it feels but couldn't save my daughter; testimony of an Ethiopian mother on female genital mutilation/cutting.

PubMed

Adinew, Yohannes Mehretie; Mekete, Beza Tamirat

2017-12-01

World Health Organization defines female genital mutilation/cutting as all procedures that involve partial or total removal of the external female genitalia, or other injury to the female genital organs for non-medical reasons. The practice is common in Ethiopia, especially among Somali (99%) ethnic groups. Even though FGM/C is labeled illegal practice according to the revised 2005 Penal Code of the country, the practice is still responsible for misery of many girls in Ethiopia. This personal testimony is presented using woman's own words. Data were collected through in-depth interview with a woman at Gursum health center, Somali regional state, eastern Ethiopia on June 19/2016. The interview was conducted in a private environment and original names were changed to overcome ethical concerns. Informed written consent was obtained from the participant prior to data collection. The interview was audio-taped using a digital voice recorder, later transcribed and translated verbatim from the local language, Amharic to English. The study participant described a range of experiences she had during her own and her daughter's circumcision. Three themes emerged from the woman's description: womanhood, social pressure and stigmatization of uncircumcised women and uncertain future. Even though the national prevalence may show a decline, FGM/C is still practiced underground. Thus, anti-FGM/C interventions shall take in to account elders influence and incorporate a human rights approach rather than relying merely on the dire health consequences. Further exploration of the determinants of FGM/C on a wider scale is recommended.

Mothers' factors associated with female genital mutilation in daughters in the Iraqi Kurdistan Region.

PubMed

Shabila, Nazar P

2017-03-01

An important proactive factor for the continuation of female genital mutilation (FGM) is tradition and customs inherited in the family from mothers to daughters. Therefore, the aim of this study was to determine mothers' factors associated with the occurrence of FGM among their daughters. The datasets from the Iraq Multiple Indicator Cluster Survey 2011, on 5,184 women aged 15 to 49 years having at least one daughter, was used. Multivariate analysis based on a binary logistic regression model was applied. Mothers' age (adjusted odds ratio [aOR] = 8.18 at ages 25-34 years, aOR = 22.64 at ages 35-44 years, and aOR = 29.78 at ages 45-49 years, compared to the age group 15-24 years), educational level (aOR = 0.52 for primary education, aOR = 0.26 for secondary education, and aOR = 0.03 for higher education compared to uneducated), employment status (aOR = 0.55 for women having office work compared with unemployed), FGM status (aOR = 27.44 for circumcised mothers compared to uncircumcised), the governorate of residence (aOR = 18.73 for Suleimaniya and aOR = 33.23 for Erbil compared with Dohuk), and the wealth index of the household (aOR = 0.55 for richest group compared to the poorest) were significantly associated with the occurrence of FGM in daughters. Strategies aimed at preventing this harmful practice in the Iraqi Kurdistan Region should include female education and empowerment.

Using fecal hormonal and behavioral analyses to evaluate the introduction of two sable antelope at Lincoln Park Zoo.

PubMed

Loeding, Erin; Thomas, Jeanette; Bernier, Dave; Santymire, Rachel

2011-01-01

Introductions of sable antelope (Hippotragus niger) can be difficult due to the potential ensuing aggression compounded by their large horns. The goal was to use hormonal assays and behavioral analyses to evaluate the success of an introduction of 2 adult females at Lincoln Park Zoo. The objectives were to (a) document behavioral and hormonal changes in 2 female sable antelope during the introduction, (b) compare fecal glucocorticoid metabolites (FGM) in each individual during the introduction stages, (c) measure fecal androgen metabolites (FAM) during introduction and compare with dominance rank and observed aggression, and (d) monitor estrous cycle synchronization. Results demonstrate that FGM were higher before than during and after the introduction. Behavioral observations indicated limited aggression between females, although the keeper survey results revealed that the new female was more dominant and had higher mean FGM and FAM than the resident. Both sable antelope were reproductively active throughout the year. Results indicate that fecal hormone analysis can provide zoo management with valuable information to minimize the risk of aggression, injury, and stress during introductions of nonhuman animals.

Psychological and counselling interventions for female genital mutilation.

PubMed

Smith, Helen; Stein, Karin

2017-02-01

Women and girls living with female genital mutilation (FGM) are more likely to experience psychological problems than women without FGM. As well as psychological support, this population may need additional care when seeking surgical interventions to correct complications of FGM. Recent WHO guidelines recommend cognitive behavioral therapy for women and girls experiencing anxiety disorders, depression, or post-traumatic stress disorder. The guidelines also suggest that preoperative counselling for deinfibulation, and psychological support alongside surgical interventions, can help women manage the physiological and psychological changes following surgery. This synthesis summarizes evidence on women's values and preferences, and the context and conditions that may be required to provide psychological and counselling interventions. Understanding women's views, their own ways of coping, as well social and cultural factors that influence women's mental well-being, may help identify the types of interventions this population needs at different times and stages of their lives. © 2017 International Federation of Gynecology and Obstetrics. The World Health Organization retains copyright and all other rights in the manuscript of this article as submitted for publication.

Addressing Female Genital Mutilation/Cutting (FGM/C) in the Era of Clitoral Reconstruction: Plastic Surgery.

PubMed

Sigurjonsson, Hannes; Jordal, Malin

2018-01-01

The aim of this review is to give an overview of the recent evidence on clitoral reconstruction and other relevant reconstructive plastic surgery measures after female genital mutilation/cutting (FGM/C). Recent publications present refinements and modifications of the surgical technique of clitoral reconstruction along with reconstruction of the labia majora and clitoral hood. Novel approaches with reposition of the clitoral nerve, anchoring of the labia majora, fat grafting, and full thickness mucosa grafts have been introduced. The current evidence on outcomes of clitoral reconstruction shows potential benefits. However, there is a risk of postoperative complications and a negative outcome. Experts in the field advocate for a multidisciplinary approach including psychosexual counseling and health education with or without subsequent clitoral reconstructive surgery. The evolution of reconstructive treatment for women with FGM/C is expanding, however at a slow rate. The scarcity of evidence on clitoral reconstruction halters availability of clinical guidelines and consensus regarding best practice. Clitoral reconstruction should be provided by multidisciplinary referral centers in a research setting with long-term follow-up on outcomes of postoperative morbidity and possible benefits.

Seasonal and spatial distributions of atmospheric polychlorinated naphthalenes in Shanghai, China.

PubMed

Die, Qingqi; Nie, Zhiqiang; Fang, Yanyan; Yang, Yufei; Gao, Xingbao; Tian, Yajun; He, Jie; Liu, Feng; Huang, Qifei; Tian, Shulei

2016-02-01

Air samples were collected in Shanghai during summer and winter 2013, and the gas and particulate concentrations of polychlorinated naphthalenes (PCNs) were measured. All 75 congeners were quantified and the corresponding toxic equivalents (TEQs) were calculated. PCN concentrations were higher in summer than winter, at 8.22-102 pg/m(3) (average of 61.3 pg/m(3)) in summer and 16.5-61.1 pg/m(3) (average of 37.7 pg/m(3)) in winter. Their seasonal TEQ values were in contrast, at 1.35-7.31 fg/m(3) (average of 3.84 fg/m(3)) in summer and 4.08-23.3 fg/m(3) (average of 8.80 fg/m(3)) in winter, because of the seasonal change in congener profiles. Tri-CNs were the predominant homologs in both the summer and winter samples. However, the major congeners in summer were PCNs containing less chlorine, but these decreased over winter. Air mass back trajectories suggested that wind direction over various sites was similar in the summer and winter seasons, yet there were clear seasonal variations in atmospheric PCN concentrations. Ratios of several characteristic congeners were calculated and the results indicated that the ratios varied only to a limited extent with PCN emissions profile from industrial thermal sources, but varied strongly with profiles of technical PCN and PCN contaminants in polychlorinated biphenyl mixtures. The results of principal component analysis suggest that local industrial thermal emissions (thermal processes containing waste incineration and secondary metal smelting processes) still play a considerable role in influencing the atmospheric PCNs in Shanghai. Copyright © 2015 Elsevier Ltd. All rights reserved.

Mechanical and physical behavior of newly developed functionally graded materials and composites of stainless steel 316L with calcium silicate and hydroxyapatite.

PubMed

Ataollahi Oshkour, Azim; Pramanik, Sumit; Mehrali, Mehdi; Yau, Yat Huang; Tarlochan, Faris; Abu Osman, Noor Azuan

2015-09-01

This study aimed to investigate the structural, physical and mechanical behavior of composites and functionally graded materials (FGMs) made of stainless steel (SS-316L)/hydroxyapatite (HA) and SS-316L/calcium silicate (CS) employing powder metallurgical solid state sintering. The structural analysis using X-ray diffraction showed that the sintering at high temperature led to the reaction between compounds of the SS-316L and HA, while SS-316L and CS remained intact during the sintering process in composites of SS-316L/CS. A dimensional expansion was found in the composites made of 40 and 50 wt% HA. The minimum shrinkage was emerged in 50 wt% CS composite, while the maximum shrinkage was revealed in samples with pure SS-316L, HA and CS. Compressive mechanical properties of SS-316L/HA decreased sharply with increasing of HA content up to 20 wt% and gradually with CS content up to 50 wt% for SS-316L/CS composites. The mechanical properties of the FGM of SS-316L/HA dropped with increase in temperature, while it was improved for the FGM of SS-316L/CS with temperature enhancement. It has been found that the FGMs emerged a better compressive mechanical properties compared to both the composite systems. Therefore, the SS-316L/CS composites and their FGMs have superior compressive mechanical properties to the SS-316L/HA composites and their FGMs and also the newly developed FGMs of SS-316L/CS with improved mechanical and enhanced gradation in physical and structural properties can potentially be utilized in the components with load-bearing application. Copyright © 2015 Elsevier Ltd. All rights reserved.

Design, Manufacturing and Characterization of Functionally Graded Flextensional Piezoelectric Actuators

NASA Astrophysics Data System (ADS)

Amigo, R. C. R.; Vatanabe, S. L.; Silva, E. C. N.

2013-03-01

Previous works have been shown several advantages in using Functionally Graded Materials (FGMs) for the performance of flextensional devices, such as reduction of stress concentrations and gains in reliability. In this work, the FGM concept is explored in the design of graded devices by using the Topology Optimization Method (TOM), in order to determine optimal topologies and gradations of the coupled structures of piezoactuators. The graded pieces are manufactured by using the Spark Plasma Sintering (SPS) technique and are bonded to piezoelectric ceramics. The graded actuators are then tested by using a modular vibrometer system for measuring output displacements, in order to validate the numerical simulations. The technological path developed here represents the initial step toward the manufacturing of an integral piezoelectric device, constituted by piezoelectric and non-piezoelectric materials without bonding layers.

Using PEACE Data from the four CLUSTER Spacecraft to Measure Compressibility, Vorticity, and the Taylor Microscale in the Magnetosheath and Plasma Sheet

NASA Technical Reports Server (NTRS)

Goldstein, Melvyn L.; Parks, George; Gurgiolo, C.; Fazakerley, Andrew N.

2008-01-01

We present determinations of compressibility and vorticity in the magnetosheath and plasma sheet using moments from the four PEACE thermal electron instruments on CLUSTER. The methodology used assumes a linear variation of the moments throughout the volume defined by the four satellites, which allows spatially independent estimates of the divergence, curl, and gradient. Once the vorticity has been computed, it is possible to estimate directly the Taylor microscale. We have shown previously that the technique works well in the solar wind. Because the background flow speed in the magnetosheath and plasma sheet is usually less than the Alfven speed, the Taylor frozen-in-flow approximation cannot be used. Consequently, this four spacecraft approach is the only viable method for obtaining the wave number properties of the ambient fluctuations. Our results using electron velocity moments will be compared with previous work using magnetometer data from the FGM experiment on Cluster.

Urinary and genital tract obstruction as a complication of female genital mutilation: case report and literature review.

PubMed

Okwudili, Obi Anselm; Chukwudi, Onoh Robinson

2012-01-01

Female genital mutilation (FGM) is the partial or total removal of the female external genitalia or other deliberate injury to the female genital organs, either for cultural or non-therapeutic reasons. This barbaric act is accompanied by a variety of complications ranging from hemorrhage, fracture, infective complications, gynetresia, with its attendant sexual and obstetric difficulties, and death. A 23-year-old girl, with urinary and genital tract obstruction following female genital mutilation(infibulation) is presented. She was managed by elective defibulation, with a satisfactory outcome. Robust health education strategies are needed for the eradication of FGM.

Urinary and Genital Tract Obstruction as a Complication of Female Genital Mutilation: Case Report and Literature Review

PubMed Central

Okwudili, Obi Anselm; Chukwudi, Onoh Robinson

2012-01-01

Female genital mutilation (FGM) is the partial or total removal of the female external genitalia or other deliberate injury to the female genital organs, either for cultural or non-therapeutic reasons. This barbaric act is accompanied by a variety of complications ranging from hemorrhage, fracture, infective complications, gynetresia, with its attendant sexual and obstetric difficulties, and death. A 23-year-old girl, with urinary and genital tract obstruction following female genital mutilation(infibulation) is presented. She was managed by elective defibulation, with a satisfactory outcome. Robust health education strategies are needed for the eradication of FGM. PMID:23066470

Flux-gate magnetometer spin axis offset calibration using the electron drift instrument

NASA Astrophysics Data System (ADS)

Plaschke, Ferdinand; Nakamura, Rumi; Leinweber, Hannes K.; Chutter, Mark; Vaith, Hans; Baumjohann, Wolfgang; Steller, Manfred; Magnes, Werner

2014-10-01

Spin-stabilization of spacecraft immensely supports the in-flight calibration of on-board flux-gate magnetometers (FGMs). From 12 calibration parameters in total, 8 can be easily obtained by spectral analysis. From the remaining 4, the spin axis offset is known to be particularly variable. It is usually determined by analysis of Alfvénic fluctuations that are embedded in the solar wind. In the absence of solar wind observations, the spin axis offset may be obtained by comparison of FGM and electron drift instrument (EDI) measurements. The aim of our study is to develop methods that are readily usable for routine FGM spin axis offset calibration with EDI. This paper represents a major step forward in this direction. We improve an existing method to determine FGM spin axis offsets from EDI time-of-flight measurements by providing it with a comprehensive error analysis. In addition, we introduce a new, complementary method that uses EDI beam direction data instead of time-of-flight data. Using Cluster data, we show that both methods yield similarly accurate results, which are comparable yet more stable than those from a commonly used solar wind-based method.

Female genital mutilation as sexual disability: perceptions of women and their spouses in Akure, Ondo State, Nigeria.

PubMed

Owojuyigbe, Michael; Bolorunduro, Miracle-Eunice; Busari, Dauda

2017-05-01

Disability encompasses the limitations on an individual's basic physical activities, and the consequent social oppressions such individual faces in society. In this regard, the limitation on the use of some parts of the genitals in a patriarchal system is considered a form of disability. This paper describes the perceptions of and the coping mechanisms employed by affected couples dealing with the consequences of female genital mutilation (FGM) as a form of sexual disability. Cultural Libertarianism was employed as a theoretical framework. The paper presents the results of a descriptive cross-sectional study conducted in Akure, Ondo State, Nigeria, with 10 male and 12 female respondents purposively selected through a snowball sampling for in-depth interviews. The findings present the justifications provided for the practice of FGM, and victims' perceptions of how it affects their sexual relations. Furthermore, it highlights coping strategies employed by affected women and their spouses. The study shows that the disabling consequence of FGM is largely sexual in nature, leading to traumatic experiences and negative beliefs about sex, and requiring a myriad of coping strategies employed by the disabled women, and their spouses, which may have its own implications for marital and sexual bliss.

Female Genital Mutilation in Sudan.

PubMed

Elduma, Adel Hussein

2018-02-15

Female genital mutilation or female circumcision (FGM) is a serious health problem in Sudan. This procedure is harmful to women and causes many complications during pregnancy and childbirth. This study aims to determine the female genital mutilation (FGM) and its associated factors in Sudan. Data from Sudan Multiple Indicator Cluster Survey (MICS - UNICEF) was used in this research. The survey was carried out in 2014 and included women aged between 14 - 49 years. A logistic regression model was used to find an association between dependent and independent variables. Total numbers of 21947 women were included in the survey and out of the 6249 (28.5 %) from urban and 15698 (71.5%) from rural areas. The prevalence of female circumcision was 89%. Women who had circumcised daughters were 32.1 %. The highest prevalence of FGM was reported from South Kordofan state with 7.8%, and lowest was in Red Sea state (7.6%). A significant association was observed between circumcised women and their marital status, daughter circumcision, and the level of education. The practice of female genital mutilation is spread all over the country. Poor women with low level of education are at high risk for this phenomenon. More efforts have to be provided to end this dangerous practice.

A systematic review of the evidence on clitoral reconstruction after female genital mutilation/cutting.

PubMed

Abdulcadir, Jasmine; Rodriguez, Maria I; Say, Lale

2015-05-01

Clitoral reconstruction is a new surgical technique for women who have undergone female genital mutilation/cutting (FGM/C). To review evidence on the safety and efficacy of clitoral reconstruction. PubMed and Cochrane databases were searched for articles published in any language from database inception until May 2014. Search terms related to FGM/C and clitoral reconstruction were used in various combinations. Studies of any design that reported on safety or clinical outcomes (e.g. appearance, pain, sexual response, or patient satisfaction) associated with clitoral reconstruction after FGM/C were included. Evidence was summarized and systematically assessed via a standard data abstraction form. Four of 269 identified articles were included. They were fair to poor in quality. Summary measures could not be computed owing to heterogeneity. The studies reported on immediate surgical complications, clitoral appearance, dyspareunia or chronic pain, and clitoral function postoperatively via non-standardized scales. Women who request clitoral reconstruction should be informed about the scarcity of evidence available. Additional research is needed on the safety and efficacy of the procedure to identify both long-term outcomes and which women might benefit. Copyright © 2015 International Federation of Gynecology and Obstetrics. Published by Elsevier Ireland Ltd. All rights reserved.

Pollution level and distribution of PCDD/PCDF congeners between vapor phase and particulate phase in winter air of Dalian, China.

PubMed

Wang, Wei; Qin, Songtao; Song, Yu; Xu, Qian; Ni, Yuwen; Chen, Jiping; Zhang, Xueping; Mu, Jim; Zhu, Xiuhua

2011-06-01

In December 2009, ambient air was sampled with active high-volume air samplers at two sites: on the roof of the No. l building of Dalian Jiaotong University and on the roof of the building of Dalian Meteorological Observatory. The concentrations and the congeners between vapor phase and particulate phase of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in the air were measured. Sample analysis results showed that the concentrations of PCDD/Fs in particulate phase was higher than that in gaseous phase. The ratio of PCDD to PCDF in gaseous phase and particulate phase was lower than 0.4 in all samples. The total I-TEQ value in gaseous phase and particulate phase was 5.5 and 453.8 fg/m(3) at Dalian Jiaotong University, 16.6 and 462.1 fg/m(3) at Dalian Meteorological Observatory, respectively. The I-TEQ value of Dalian atmosphere was 5.5-462.1 fg/m(3) which was lower than international standard, the atmospheric quality in Dalian is better. Copyright © 2011 The Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.

The modern trends in space electromagnetic instrumentation

NASA Astrophysics Data System (ADS)

Korepanov, V.

The future trends of the experimental plasma physical development in outer space demands more and more exact and sophisticated scientific instrumentation. Moreover, the situation is complicated by constant reducing of financial support of scientific research, even in leading countries. This resulted in the development of mini, micro and nanosatellites with low price and short preparation time. Consequently, it provoked the creation of new generation of scientific instruments with reduced weight and power consumption but increased level of metrological parameters. The recent state of the development of electromagnetic (EM) sensors for microsatellites is reported. The set of EM sensors produced at LCISR includes following devices. Flux-gate magnetometers (FGM). The reduction of new of satellite versions FGM weight as well as power consumption was achieved not only due to the use of new electronic components but also because the development of new operation modes. To this the scientific and technological study allowed to decrease FGM noise and now typical figure is about 10 picotesla rms at 1 Hz and the record one is below 1 picotesla. Also because of satellite weight reduction the possibility was studied to use FGM only for satellite attitude control. The magnetic orientation and stabilization system was developed and new FGM for orientation was created. It uses industrial components and special measures are taken to increase its reliability. Search-coil magnetometers (SCM). The super-light version of SCM was created as the result of intensive scientific and technological research. These new SCMs can have about six decades operational frequency band noise with upper limit ~ 1 MHz and noise level of few femtotesla with total weight about 75 grams. Electric probes (EP). The study of operation condition of EP immersed in space plasma allowed to find the possibilities to decrease the EP weight conserving the same noise factor. Two types of EP operating from DC and from 0,1 Hz are created and successfully tested. Wave probe (WP). The WP is another kind of instrument which combines in one sensor three independent sensors: SCM, EP and split Langmuir probe. Such a combination allowed to create a principally new instru ment U wave probe. The developed theory confirms that WP can directly measure vector components in space plasma. All these space sensors are described and their experimentally obtained parameters are presented. This work was partially supported by INTAS grant 2000-465.

Female genital mutilation: a systematic review of research on its economic and social impacts across four decades.

PubMed

Mpinga, Emmanuel Kabengele; Macias, Aurélie; Hasselgard-Rowe, Jennifer; Kandala, Ngianga-Bakwin; Félicien, Tshimungu Kandolo; Verloo, Henk; Bukonda, Ngoyi K Zacharie; Chastonay, Philippe

2016-01-01

Global efforts to end female genital mutilation (FGM) have intensified in recent decades because of the rising awareness that such a practice is an act of extreme violence against women and girls. Articles on FGM have been published highlighting the combined efforts of international and non-governmental organizations, governments, as well as religious and civil society groups to end the practice. However, the consequences of this research are not well known, and it seems that the socioeconomic aspects of the practice are underreported. This review aims to characterize over a 40-year period the scientific output on the consequences of FGM in African countries, the most affected region known for the high prevalence of FGM, and review data on the socioeconomic consequences of the practice. A systematic review of literature was done, looking at the following databases: PubMed, Embase, CINAHL, BDSP, Web of Science, PsycINFO, FRANCIS, Sociological Abstracts, WHOLIS, RERO, and SAPHIR. The analysis was limited to articles concerning the African continent, published in English and French, from January 1, 1972, to December 31, 2011. One hundred ninety-eight articles were reviewed. More than half of the articles were published during the last decade of the study period. The majority of papers were published in biomedical journals (64.1%). Most studies looked at Africa as a region (33.3%). Nigeria was the single country most investigated (19.2%), followed by Egypt (10.6%). Most first authors were affiliated to non-African countries (60.6%): among them 21.2% were US-based, 4% were from African institutions, and 16.2% from Nigeria.The medical and psychological consequences (51.5%) and the prevalence and ethics of the practice (34.4%) were the most frequently investigated topics. The socioeconomic consequences were addressed in a minority of the papers (14.1%): they were classified into direct economic consequences (2.5%), school attendance (1%), marriageability (2%), sexual and marital consequences (3.5%), fertility (2.5%), domestic violence (1%), and discrimination (1.5%). The publication of articles on the consequences of FGM is increasing, but there is little research on the socioeconomic consequences of the practice. More scientific data focusing on this dimension is necessary to strengthen prevention, advocacy, and intervention campaigns.

Female genital mutilation: a systematic review of research on its economic and social impacts across four decades

PubMed Central

Mpinga, Emmanuel Kabengele; Macias, Aurélie; Hasselgard-Rowe, Jennifer; Kandala, Ngianga-Bakwin; Félicien, Tshimungu Kandolo; Verloo, Henk; Bukonda, Ngoyi K. Zacharie; Chastonay, Philippe

2016-01-01

Background Global efforts to end female genital mutilation (FGM) have intensified in recent decades because of the rising awareness that such a practice is an act of extreme violence against women and girls. Articles on FGM have been published highlighting the combined efforts of international and non-governmental organizations, governments, as well as religious and civil society groups to end the practice. However, the consequences of this research are not well known, and it seems that the socioeconomic aspects of the practice are underreported. Objective This review aims to characterize over a 40-year period the scientific output on the consequences of FGM in African countries, the most affected region known for the high prevalence of FGM, and review data on the socioeconomic consequences of the practice. Design A systematic review of literature was done, looking at the following databases: PubMed, Embase, CINAHL, BDSP, Web of Science, PsycINFO, FRANCIS, Sociological Abstracts, WHOLIS, RERO, and SAPHIR. The analysis was limited to articles concerning the African continent, published in English and French, from January 1, 1972, to December 31, 2011. Results One hundred ninety-eight articles were reviewed. More than half of the articles were published during the last decade of the study period. The majority of papers were published in biomedical journals (64.1%). Most studies looked at Africa as a region (33.3%). Nigeria was the single country most investigated (19.2%), followed by Egypt (10.6%). Most first authors were affiliated to non-African countries (60.6%): among them 21.2% were US-based, 4% were from African institutions, and 16.2% from Nigeria. The medical and psychological consequences (51.5%) and the prevalence and ethics of the practice (34.4%) were the most frequently investigated topics. The socioeconomic consequences were addressed in a minority of the papers (14.1%): they were classified into direct economic consequences (2.5%), school attendance (1%), marriageability (2%), sexual and marital consequences (3.5%), fertility (2.5%), domestic violence (1%), and discrimination (1.5%). Conclusions The publication of articles on the consequences of FGM is increasing, but there is little research on the socioeconomic consequences of the practice. More scientific data focusing on this dimension is necessary to strengthen prevention, advocacy, and intervention campaigns. PMID:27707452

Stochastic Investigation of Natural Frequency for Functionally Graded Plates

NASA Astrophysics Data System (ADS)

Karsh, P. K.; Mukhopadhyay, T.; Dey, S.

2018-03-01

This paper presents the stochastic natural frequency analysis of functionally graded plates by applying artificial neural network (ANN) approach. Latin hypercube sampling is utilised to train the ANN model. The proposed algorithm for stochastic natural frequency analysis of FGM plates is validated and verified with original finite element method and Monte Carlo simulation (MCS). The combined stochastic variation of input parameters such as, elastic modulus, shear modulus, Poisson ratio, and mass density are considered. Power law is applied to distribute the material properties across the thickness. The present ANN model reduces the sample size and computationally found efficient as compared to conventional Monte Carlo simulation.

Counselling for deinfibulation among women with type III female genital mutilation: A systematic review.

PubMed

Bello, Segun; Ogugbue, Miriam; Chibuzor, Moriam; Okomo, Uduak; Meremikwu, Martin M

2017-02-01

Counselling is a routine practice done before deinfibulation in women with type III female genital mutilation (FGM). However, cultural and social pressures, in addition to maladaptation to the changes in the body post deinfibulation, cause some women to choose to be reinfibulated after being deinfibulated. To conduct a systematic review of the impact of counselling prior to deinfibulation on patient satisfaction, marital satisfaction, and rate of requests for reinfibulation among women living with type III FGM. The secondary aim was to assess the impact of male partner involvement in counselling on patient satisfaction, marital satisfaction, and rate of requests for reinfibulation. Major databases including Cochrane Central Register of Controlled Trials, Medline, SCOPUS, and ClinicalTrials.gov were searched until August 2015. Studies comparing women with type III FGM who received counselling before deinfibulation versus no counselling were included. Two team members independently screened and collected data. No eligible studies were identified. There is no evidence to conclude that counselling before deinfibulation influences patients' satisfaction with overall quality of care or rates of request for reinfibulation. CRD42015024675. © 2017 International Federation of Gynecology and Obstetrics. The World Health Organization retains copyright and all other rights in the manuscript of this article as submitted for publication.

Female Genital Mutilation in Sudan

PubMed Central

Elduma, Adel Hussein

2018-01-01

BACKGROUND: Female genital mutilation or female circumcision (FGM) is a serious health problem in Sudan. This procedure is harmful to women and causes many complications during pregnancy and childbirth. OBJECTIVE: This study aims to determine the female genital mutilation (FGM) and its associated factors in Sudan. SUBJECTS AND METHODS: Data from Sudan Multiple Indicator Cluster Survey (MICS - UNICEF) was used in this research. The survey was carried out in 2014 and included women aged between 14 – 49 years. A logistic regression model was used to find an association between dependent and independent variables. RESULT: Total numbers of 21947 women were included in the survey and out of the 6249 (28.5 %) from urban and 15698 (71.5%) from rural areas. The prevalence of female circumcision was 89%. Women who had circumcised daughters were 32.1 %. The highest prevalence of FGM was reported from South Kordofan state with 7.8%, and lowest was in Red Sea state (7.6%). A significant association was observed between circumcised women and their marital status, daughter circumcision, and the level of education. CONCLUSION: The practice of female genital mutilation is spread all over the country. Poor women with low level of education are at high risk for this phenomenon. More efforts have to be provided to end this dangerous practice. PMID:29531618

[Female genital mutilation meets Swedish health care. Female genital mutilation is one of many forms of discrimination of women in the world].

PubMed

Andersson, C

2001-05-16

About 27,000 women from countries in which female genital mutilation (FGM) is a common practice are presently living in Sweden. This means that FGM is a phenomenon that directly affects the Swedish health care system. Knowledge and understanding of the background, meaning and consequences of FGM are a prerequisite for effective prevention, proper clinical handling and supportive reception of the women. To avoid a stigmatizing reception it is also important to understand the situation of genitally mutilated women, and to become aware of the identity crisis many of them experience when they come to Sweden and lose their identity as "normal" women. It is essential to remember that female genital mutilation is one of many forms of discrimination affecting girls and women around the world. This discrimination knows no national or cultural borders and varies in expression and extent. In order to offer optimal care and reception of women who have been socialized into a gender role that is often seen as completely different from the gender role that Swedish society is said to embrace, it is of the utmost importance to first take a critical look beneath the veil of alleged gender equality of Swedish women.

Physiological Stress and Refuge Behavior by African Elephants

PubMed Central

Jachowski, David S.; Slotow, Rob; Millspaugh, Joshua J.

2012-01-01

Physiological stress responses allow individuals to adapt to changes in their status or surroundings, but chronic exposure to stressors could have detrimental effects. Increased stress hormone secretion leads to short-term escape behavior; however, no studies have assessed the potential of longer-term escape behavior, when individuals are in a chronic physiological state. Such refuge behavior is likely to take two forms, where an individual or population restricts its space use patterns spatially (spatial refuge hypothesis), or alters its use of space temporally (temporal refuge hypothesis). We tested the spatial and temporal refuge hypotheses by comparing space use patterns among three African elephant populations maintaining different fecal glucocorticoid metabolite (FGM) concentrations. In support of the spatial refuge hypothesis, the elephant population that maintained elevated FGM concentrations (iSimangaliso) used 20% less of its reserve than did an elephant population with lower FGM concentrations (Pilanesberg) in a reserve of similar size, and 43% less than elephants in the smaller Phinda reserve. We found mixed support for the temporal refuge hypothesis; home range sizes in the iSimangaliso population did not differ by day compared to nighttime, but elephants used areas within their home ranges differently between day and night. Elephants in all three reserves generally selected forest and woodland habitats over grasslands, but elephants in iSimangaliso selected exotic forest plantations over native habitat types. Our findings suggest that chronic stress is associated with restricted space use and altered habitat preferences that resemble a facultative refuge behavioral response. Elephants can maintain elevated FGM levels for ≥6 years following translocation, during which they exhibit refuge behavior that is likely a result of human disturbance and habitat conditions. Wildlife managers planning to translocate animals, or to initiate other management activities that could result in chronic stress responses, should consider the potential for, and consequences of, refuge behavior. PMID:22384079

On the formulation and assessment of flamelet-generated manifolds applied to two-phase turbulent combustion

NASA Astrophysics Data System (ADS)

Bojko, Brian T.

Accounting for the effects of finite rate chemistry in reacting flows is intractable when considering the number of species and reactions to be solved for during a large scale flow simulation. This is especially complicated when solid/liquid fuels are also considered. While modeling the reacting boundary layer with the use of finite-rate chemistry may allow for a highly accurate description of the coupling between the flame and fuel surface, it is not tractable in large scale simulations when considering detailed chemical kinetics. It is the goal of this research to investigate a Flamelet-Generated Manifold (FGM) method in order to reduce the finite rate chemistry to a lookup table cataloged by progress variables and queried during runtime. In this study, simplified unsteady 1D flames with mass blowing are considered for a solid biomass fuel where the FGM method is employed as a model reduction strategy for potential application to multidimensional calculations. Two types of FGM are considered. The first are a set of steady-state flames differentiated by their scalar dissipation rate. Results show the use of steady flames produce unacceptable errors compared to the finite-rate chemistry solution, with temperature errors in excess of 45%. To avoid these errors, a new methodology for developing an unsteady FGM (UFGM) is presented that accounts for unsteady diffusion effects and greatly reduces errors in temperature with differences that are under 10%. The FGM modeling is then extended to individual droplet combustion with the development of a Droplet Flamelet-Generated Manifold (DFGM) to account for the effects of finite-rate chemistry of individual droplets. A spherically symmetric droplet model is developed for methanol and aluminum. The inclusion of finite-rate chemistry allows the capturing of the transition from diffusion to kinetically controlled combustion as the droplet diameter decreases. The droplet model is then used to create a DFGM by successively solving the 1D flame equations at varying drop sizes, where the source terms for energy, mixture fraction, and progress variable are cataloged as a function of normalized diameter. A unique coupling of the DFGM and planar UFGM is developed and is used to account for individual and gas phase combustion processes in turbulent combustion situations, such as spray flames, particle laden blasts, etc. The DFGM for the methanol and aluminum droplets are used in mixed Eulerian and Eulerian-Lagrangian formulations of compressible multiphase flows. System level simulations are conducted and compared experimental data for a methanol spray flame and an aluminized blast studied at the Explosives Components Facility (ECF) at Sandia National Laboratories.

[Fatal female genital mutilation in a 10-year-old girl].

PubMed

Sow, A; Diagne, G; Keita, Y; Sow, O; Ndiath, A; Ouattara, A; Sarr, M-L; Sylla, A; Moreira, C

2017-10-01

Female genital mutilation (FGM) comprises all procedures involving partial or total removal of the external genitalia and/or any other procedures affecting the female genitalia, for cultural or religious reasons or for nontherapeutic purposes in general. FGM is responsible for a number of short-, medium-, and long-term complications that can engage the vital and functional prognosis, especially in African countries. We report on a case in a 10-year-old girl who underwent genital mutilation, a traditional type of total excision during the neonatal period. She was followed for urethral meatus stenosis, which then was complicated by obstructive chronic kidney failure and urinary sepsis, whose progression was fatal. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Nanoscale Graphene Disk: A Natural Functionally Graded Material-How is Fourier's Law Violated along Radius Direction of 2D Disk.

PubMed

Yang, Nuo; Hu, Shiqian; Ma, Dengke; Lu, Tingyu; Li, Baowen

2015-10-07

In this Paper, we investigate numerically and analytically the thermal conductivity of nanoscale graphene disks (NGDs), and discussed the possibility to realize functionally graded material (FGM) with only one material, NGDs. Different from previous studies on divergence/non-diffusive of thermal conductivity in nano-structures with different size, we found a novel non-homogeneous (graded) thermal conductivity along the radius direction in a single nano-disk structure. We found that, instead of a constant value, the NGD has a graded thermal conductivity along the radius direction. That is, Fourier's law of heat conduction is not valid in two dimensional graphene disk structures Moreover, we show the dependent of NGDs' thermal conductivity on radius and temperature. Our study might inspire experimentalists to develop NGD based versatile FGMs, improve understanding of the heat removal of hot spots on chips, and enhance thermoelectric energy conversion efficiency by two dimensional disk with a graded thermal conductivity.

Fabrication, Characterization and Modeling of Functionally Graded Materials

NASA Astrophysics Data System (ADS)

Lee, Po-Hua

In the past few decades, a number of theoretical and experimental studies for design, fabrication and performance analysis of solar panel systems (photovoltaic/thermal systems) have been documented. The existing literature shows that the use of solar energy provides a promising solution to alleviate the shortage of natural resources and the environmental pollution associated with electricity generation. A hybrid solar panel has been invented to integrate photovoltaic (PV) cells onto a substrate through a functionally graded material (FGM) with water tubes cast inside, through which water flow serves as both a heat sink and a solar heat collector. Due to the unique and graded material properties of FGMs, this novel design not only supplies efficient thermal harvest and electrical production, but also provides benefits such as structural integrity and material efficiency. In this work, a sedimentation method has been used to fabricate aluminum (Al) and high-density polyethylene (HDPE) FGMs. The size effect of aluminum powder on the material gradation along the depth direction is investigated. Aluminum powder or the mixture of Al and HDPE powder is thoroughly mixed and uniformly dispersed in ethanol and then subjected to sedimentation. During the sedimentation process, the concentration of Al and HDPE particles temporally and spatially changes in the depth direction due to the non-uniform motion of particles; this change further affects the effective viscosity of the suspension and thus changes the drag force of particles. A Stokes' law based model is developed to simulate the sedimentation process, demonstrate the effect of manufacturing parameters on sedimentation, and predict the graded microstructure of deposition in the depth direction. In order to improve the modeling for sedimentation behavior of particles, the Eshelby's equivalent inclusion method (EIM) is presented to determine the interaction between particles, which is not considered in a Stokes' law based model. This method is initially applied to study the case of one drop moving in a viscous fluid; the solution recovers the closed form classic solution when the drop is spherical. Moreover, this method is general and can be applied to the cases of different drop shapes and the interaction between multiple drops. The translation velocities of the drops depend on the relative position, the center-to-center distance of drops, the viscosity and size of drops. For the case of a pair of identical spherical drops, the present method using a linear approximation of the eigenstrain rate has provided a very close solution to the classic explicit solution. If a higher order of the polynomial form of the eigenstrain rate is used, one can expect a more accurate result. To meet the final goal of mass production of the aforementioned Al-HDPE FGM, a faster and more economical material manufacturing method is proposed through a vibration method. The particle segregation of larger aluminum particles embedded in the concentrated suspension of smaller high-density polyethylene is investigated under vibration with different frequencies and magnitudes. Altering experimental parameters including time and amplitude of vibration, the suspension exhibits different particle segregation patterns: uniform-like, graded and bi-layered. For material characterization, small cylinder films of Al-HDPE system FGM are obtained after the stages of dry, melt and solidification. Solar panel prototypes are fabricated and tested at different water flow rates and solar irradiation intensities. The temperature distribution in the solar panel is measured and simulated to evaluate the performance of the solar panel. Finite element simulation results are very consistent with the experimental data. The understanding of heat transfer in the hybrid solar panel prototypes gained through this study will provide a foundation for future solar panel design and optimization.

Subclassification and Clinical Management of Extraction Sockets with Labial Dentoalveolar Dehiscence Defects.

PubMed

Chu, Stephen J; Sarnachiaro, Guido O; Hochman, Mark N; Tarnow, Dennis P

2015-01-01

Immediate implant therapy involving implants placed into intact Type 1 extraction sockets has become a consistent clinical technique. The classification of Type 2 extraction sockets, where the mucosal tissues are present but there is a midfacial osseous dehiscence defect, has been described according to the extent of the buccal bone plate absence. The literature has offered different techniques in the treatment of Type 2 sockets; however, the extent of the defect has never been defined or delineated. In this article, the authors describe a subclassification of Type 2 sockets: Type 2A presents with a dehiscence defect roughly 5 mm to 6 mm from the free gingival margin (FGM) involving the coronal one-third of the labial bone plate; Type 2B presents with a dehiscence defect involving the middle one-third of the labial plate, approximately 7 mm to 9 mm from the FGM; and in Type 2C the dehiscence defect involves the apical one-third of the labial osseous plate roughly 10 mm or greater from the FGM. The authors also offer a protocol and technique employing immediate implant placement, guided bone regeneration, and bone graft containment with a custom two-piece healing abutment that can lead to consistent and satisfactory clinical outcomes in low-smile-line patients. The treatment protocol and sequence is outlined in a clinical case presentation involving a Type 2B socket.

Impact of Subgrid Scale Models and Heat Loss on Large Eddy Simulations of a Premixed Jet Burner Using Flamelet-Generated Manifolds

NASA Astrophysics Data System (ADS)

Hernandez Perez, Francisco E.; Im, Hong G.; Lee, Bok Jik; Fancello, Alessio; Donini, Andrea; van Oijen, Jeroen A.; de Goey, L. Philip H.

2017-11-01

Large eddy simulations (LES) of a turbulent premixed jet flame in a confined chamber are performed employing the flamelet-generated manifold (FGM) method for tabulation of chemical kinetics and thermochemical properties, as well as the OpenFOAM framework for computational fluid dynamics. The burner has been experimentally studied by Lammel et al. (2011) and features an off-center nozzle, feeding a preheated lean methane-air mixture with an equivalence ratio of 0.71 and mean velocity of 90 m/s, at 573 K and atmospheric pressure. Conductive heat loss is accounted for in the FGM tabulation via burner-stabilized flamelets and the subgrid-scale (SGS) turbulence-chemistry interaction is modeled via presumed filtered density functions. The impact of heat loss inclusion as well as SGS modeling for both the SGS stresses and SGS variance of progress variable on the numerical results is investigated. Comparisons of the LES results against measurements show a significant improvement in the prediction of temperature when heat losses are incorporated into FGM. While further enhancements in the LES results are accomplished by using SGS models based on transported quantities and/or dynamically computed coefficients as compared to the Smagorinsky model, heat loss inclusion is more relevant. This research was sponsored by King Abdullah University of Science and Technology (KAUST) and made use of computational resources at KAUST Supercomputing Laboratory.

Female genital mutilation and monandry in an orb-web spider

PubMed Central

2016-01-01

Monandry, in which a female has only one mating partner during the reproductive period, is established when a female spontaneously refrains from re-mating, or when a partner male interferes with the attempts of a female to mate again. In the latter case, however, females often have countermeasures against males, which may explain why polyandry is ubiquitous. Here, I demonstrate that the genital appendage, or scape, of the female orb-web spider (Cyclosa argenteoalba) is injured after her first mating, possibly by her first male partner. This female genital mutilation (FGM) permanently precludes copulation, and females appear to have no countermeasures. FGM is considered to confer a strong advantage to males in sexual conflicts over the number of female matings, and it may widely occur in spiders. PMID:26911338

Female genital mutilation and monandry in an orb-web spider.

PubMed

Nakata, Kensuke

2016-02-01

Monandry, in which a female has only one mating partner during the reproductive period, is established when a female spontaneously refrains from re-mating, or when a partner male interferes with the attempts of a female to mate again. In the latter case, however, females often have countermeasures against males, which may explain why polyandry is ubiquitous. Here, I demonstrate that the genital appendage, or scape, of the female orb-web spider (Cyclosa argenteoalba) is injured after her first mating, possibly by her first male partner. This female genital mutilation (FGM) permanently precludes copulation, and females appear to have no countermeasures. FGM is considered to confer a strong advantage to males in sexual conflicts over the number of female matings, and it may widely occur in spiders. © 2016 The Author(s).

Convection driven generation of long-range material gradients

PubMed Central

Du, Yanan; Hancock, Matthew J.; He, Jiankang; Villa-Uribe, Jose; Wang, Ben; Cropek, Donald M.; Khademhosseini, Ali

2009-01-01

Natural materials exhibit anisotropy with variations in soluble factors, cell distribution, and matrix properties. The ability to recreate the heterogeneity of the natural materials is a major challenge for investigating cell-material interactions and for developing biomimetic materials. Here we present a generic fluidic approach using convection and alternating flow to rapidly generate multi-centimeter gradients of biomolecules, polymers, beads and cells and cross-gradients of two species in a microchannel. Accompanying theoretical estimates and simulations of gradient growth provide design criteria over a range of material properties. A poly(ethyleneglycol) hydrogel gradient, a porous collagen gradient and a composite material with a hyaluronic acid/gelatin cross-gradient were generated with continuous variations in material properties and in their ability to regulate cellular response. This simple yet generic fluidic platform should prove useful for creating anisotropic biomimetic materials and high-throughput platforms for investigating cell-microenvironment interaction. PMID:20035990

Detection of equine herpesvirus-4 and physiological stress patterns in young Thoroughbreds consigned to a South African auction sale.

PubMed

Badenhorst, Marcha; Page, Patrick; Ganswindt, Andre; Laver, Peter; Guthrie, Alan; Schulman, Martin

2015-06-02

The prevalence of equine herpesvirus types-1 and -4 (EHV-1 and -4) in South African Thoroughbreds at auction sales is currently undefined. Commingling of young Thoroughbreds from various populations together with physiological stress related to their transport and confinement at a sales complex, may be associated with shedding and transmission of EHV-1 and -4. This prospective cohort study sampled 90 young Thoroughbreds consigned from eight farms, originating from three provinces representative of the South African Thoroughbred breeding demographic to a sales complex. Nasal swabs for quantitative real-time polymerase chain reaction (qPCR) assay to detect EHV-1 and -4 nucleic acid and blood samples for enzyme-linked immunosorbent assay for EHV-1 and -4 antibodies were collected from all horses on arrival and departure. Additional nasal swabs for qPCR were obtained serially from those displaying pyrexia and, or nasal discharge. Daily faecal samples were used for determination of faecal glucocorticoid metabolite (FGM) concentrations as a measurement of physiological stress and these values were modelled to determine the factors best explaining FGM variability. EHV-4 nucleic acid was detected in 14.4 % and EHV-1 from none of the animals in the study population. Most (93.3 %) and very few (1.1 %) of this population showed antibodies indicating prior exposure to EHV-4 and EHV-1 respectively. Pyrexia and nasal discharge were poor predictors for detecting EHV-4 nucleic acid. The horses' FGM concentrations increased following arrival before decreasing for most of the remaining study period including the auction process. Model averaging showed that variation in FGM concentrations was best explained by days post-arrival and transport duration. In this study population, sales consignment was associated with limited detection of EHV-4 nucleic acid in nasal secretions, with most showing prior exposure to EHV-4 and very few to EHV-1. The physiological stress response shown by most reflected the combination of stressors associated with transport and arrival and these are key areas for future investigation into management practices to enhance health and welfare of young Thoroughbreds during sales consignment.

Microfluidic Synthesis of Composite Cross-Gradient Materials for Investigating Cell–Biomaterial Interactions

PubMed Central

He, Jiankang; Du, Yanan; Guo, Yuqi; Hancock, Matthew J.; Wang, Ben; Shin, Hyeongho; Wu, Jinhui; Li, Dichen; Khademhosseini, Ali

2010-01-01

Combinatorial material synthesis is a powerful approach for creating composite material libraries for the high-throughput screening of cell–material interactions. Although current combinatorial screening platforms have been tremendously successful in identifying target (termed “hit”) materials from composite material libraries, new material synthesis approaches are needed to further optimize the concentrations and blending ratios of the component materials. Here we employed a microfluidic platform to rapidly synthesize composite materials containing cross-gradients of gelatin and chitosan for investigating cell–biomaterial interactions. The microfluidic synthesis of the cross-gradient was optimized experimentally and theoretically to produce quantitatively controllable variations in the concentrations and blending ratios of the two components. The anisotropic chemical compositions of the gelatin/chitosan cross-gradients were characterized by Fourier transform infrared spectrometry and X-ray photoelectron spectrometry. The three-dimensional (3D) porous gelatin/chitosan cross-gradient materials were shown to regulate the cellular morphology and proliferation of smooth muscle cells (SMCs) in a gradient-dependent manner. We envision that our microfluidic cross-gradient platform may accelerate the material development processes involved in a wide range of biomedical applications. PMID:20721897

Damage tolerant functionally graded materials for advanced wear and friction applications

NASA Astrophysics Data System (ADS)

Prchlik, Lubos

The research work presented in this dissertation focused on processing effects, microstructure development, characterization and performance evaluation of composite and graded coatings used for friction and wear control. The following issues were addressed. (1) Definition of prerequisites for a successful composite and graded coating formation by means of thermal spraying. (2) Improvement of characterization methods available for homogenous thermally sprayed coating and their extension to composite and graded materials. (3) Development of novel characterization methods specifically for FGMs, with a focus on through thickness property measurement by indentation and in-situ curvature techniques. (4) Design of composite materials with improved properties compared to homogenous coatings. (5) Fabrication and performance assessment of FGM with improved wear and impact damage properties. Materials. The materials studied included several material systems relevant to low friction and contact damage tolerant applications: MO-Mo2C, WC-Co cermets as materials commonly used sliding components of industrial machinery and NiCrAlY/8%-Yttria Partially Stabilized Zirconia composites as a potential solution for abradable sections of gas turbines and aircraft engines. In addition, uniform coatings such as molybdenum and Ni5%Al alloy were evaluated as model system to assess the influence of microstructure variation onto the mechanical property and wear response. Methods. The contact response of the materials was investigated through several techniques. These included methods evaluating the relevant intrinsic coating properties such as elastic modulus, residual stress, fracture toughness, scratch resistance and tests measuring the abrasion and friction-sliding behavior. Dry-sand and wet two-body abrasion testing was performed in addition to traditional ball on disc sliding tests. Among all characterization techniques the spherical indentation deserved most attention and enabled to measure elastic-plastic properties of uniform and graded structures. In-situ curvature method used for residual stress and elastic modulus measurement was extended from uniform coatings to coatings with compositional/property gradients. Properties of composite and graded materials were measured using the inverse analysis. Conclusions. The specifics of the elastic-plastic response for thermally sprayed coatings were demonstrated. These included the strain dependence of elastic modulus and damage accumulation related to unloading/reloading loop formation. The measurement of elastic-plastic characteristics of composite coatings revealed the mixing and bonding mechanisms unique for thermally sprayed materials. Microstructural and compositional factors governing the frictional vs. abrasion response of carbide-metallic composite coatings were described. The measurement of abrasion resistance and friction sliding properties demonstrated that grading of cermet and ceramic coatings by adding moderate amount of metallic alloys can enhance elastic-properties radically and have a beneficial effect onto the coating performance.

A Modified Kirchhoff plate theory for Free Vibration analysis of functionally graded material plates using meshfree method

NASA Astrophysics Data System (ADS)

Nguyen Van Do, Vuong

2018-04-01

In this paper, a modified Kirchhoff theory is presented for free vibration analyses of functionally graded material (FGM) plate based on modified radial point interpolation method (RPIM). The shear deformation effects are taken account into modified theory to ignore the locking phenomenon of thin plates. Due to the proposed refined plate theory, the number of independent unknowns reduces one variable and exists with four degrees of freedom per node. The simulated free vibration results employed by the modified RPIM are compared with the other analytical solutions to verify the effectiveness and the accuracy of the developed mesh-free method. Detail parametric studies of the proposed method are then conducted including the effectiveness of thickness ratio, boundary condition and material inhomogeneity on the sample problems of square plates. Results illustrated that the modified mesh-free RPIM can effectively predict the numerical calculation as compared to the exact solutions. The obtained numerical results are indicated that the proposed method are stable and well accurate prediction to evaluate with other published analyses.

Mechanical and Thermal Analysis of Classical Functionally Graded Coated Beam

NASA Astrophysics Data System (ADS)

Toudehdehghan, Abdolreza; Mujibur Rahman, Md.; Tarlochan, Faris

2018-03-01

The governing equation of a classical rectangular coated beam made of two layers subjected to thermal and uniformly distributed mechanical loads are derived by using the principle of virtual displacements and based on Euler-Bernoulli deformation beam theory (EBT). The aim of this paper was to analyze the static behavior of clamped-clamped thin coated beam under thermo-mechanical load using MATLAB. Two models were considered for composite coated. The first model was consisting of ceramic layer as a coated and substrate which was metal (HC model). The second model was consisting of Functionally Graded Material (FGM) as a coated layer and metal substrate (FGC model). From the result it was apparent that the superiority of the FGC composite against conventional coated composite has been demonstrated. From the analysis, the stress level throughout the thickness at the interface of the coated beam for the FGC was reduced. Yet, the deflection in return was observed to increase. Therefore, this could cater to various new engineering applications where warrant the utilization of material that has properties that are well-beyond the capabilities of the conventional or yesteryears materials.

Finite element analysis of functionally graded bone plate at femur bone fracture site

NASA Astrophysics Data System (ADS)

Satapathy, Pravat Kumar; Sahoo, Bamadev; Panda, L. N.; Das, S.

2018-03-01

This paper focuses on the analysis of fractured Femur bone with functionally graded bone plate. The Femur bone is modeled by using the data from the CT (Computerized Tomography) scan and the material properties are assigned using Mimics software. The fracture fixation plate used here is composed of Functionally Graded Material (FGM). The functionally graded bone plate is considered to be composed of different layers of homogeneous materials. Finite element method approach is adopted for analysis. The volume fraction of the material is calculated by considering its variation along the thickness direction (z) according to a power law and the effective properties of the homogeneous layers are estimated. The model developed is validated by comparing numerical results available in the literature. Static analysis has been performed for the bone plate system by considering both axial compressive load and torsional load. The investigation shows that by introducing FG bone plate instead of titanium, the stress at the fracture site increases by 63 percentage and the deformation decreases by 15 percentage, especially when torsional load is taken into consideration. The present model yields better results in comparison with the commercially available bone plates.

Nanoscale Graphene Disk: A Natural Functionally Graded Material–How is Fourier’s Law Violated along Radius Direction of 2D Disk

PubMed Central

Yang, Nuo; Hu, Shiqian; Ma, Dengke; Lu, Tingyu; Li, Baowen

2015-01-01

In this Paper, we investigate numerically and analytically the thermal conductivity of nanoscale graphene disks (NGDs), and discussed the possibility to realize functionally graded material (FGM) with only one material, NGDs. Different from previous studies on divergence/non-diffusive of thermal conductivity in nano-structures with different size, we found a novel non-homogeneous (graded) thermal conductivity along the radius direction in a single nano-disk structure. We found that, instead of a constant value, the NGD has a graded thermal conductivity along the radius direction. That is, Fourier’s law of heat conduction is not valid in two dimensional graphene disk structures Moreover, we show the dependent of NGDs’ thermal conductivity on radius and temperature. Our study might inspire experimentalists to develop NGD based versatile FGMs, improve understanding of the heat removal of hot spots on chips, and enhance thermoelectric energy conversion efficiency by two dimensional disk with a graded thermal conductivity. PMID:26443206

Surgical or medical interventions for female genital mutilation.

PubMed

Smith, Helen; Stein, Karin

2017-02-01

Deinfibulation can prevent or treat gynecological and obstetric complications in women living with type III female genital mutilation (FGM), and subsequently improve childbirth outcomes. Recently published WHO guidelines recommend use of deinfibulation in both circumstances. However, to really impact practice, evidence-based guidance needs to be matched with evidence-based implementation strategies. This qualitative evidence synthesis provides information on the factors that facilitate or act as barriers to use of deinfibulation, and the context and conditions that are necessary for implementing the procedure, including healthcare providers' knowledge and experience, the service delivery environment, as well as broader health system contexts. This information is of great value for policy makers and others considering this as an option for better clinical care of women living with FGM. © 2017 International Federation of Gynecology and Obstetrics. The World Health Organization retains copyright and all other rights in the manuscript of this article as submitted for publication.

3D Printing of Materials with Tunable Failure via Bioinspired Mechanical Gradients.

PubMed

Kokkinis, Dimitri; Bouville, Florian; Studart, André R

2018-05-01

Mechanical gradients are useful to reduce strain mismatches in heterogeneous materials and thus prevent premature failure of devices in a wide range of applications. While complex graded designs are a hallmark of biological materials, gradients in manmade materials are often limited to 1D profiles due to the lack of adequate fabrication tools. Here, a multimaterial 3D-printing platform is developed to fabricate elastomer gradients spanning three orders of magnitude in elastic modulus and used to investigate the role of various bioinspired gradient designs on the local and global mechanical behavior of synthetic materials. The digital image correlation data and finite element modeling indicate that gradients can be effectively used to manipulate the stress state and thus circumvent the weakening effect of defect-rich interfaces or program the failure behavior of heterogeneous materials. Implementing this concept in materials with bioinspired designs can potentially lead to defect-tolerant structures and to materials whose tunable failure facilitates repair of biomedical implants, stretchable electronics, or soft robotics. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Mechanical and biological properties of the micro-/nano-grain functionally graded hydroxyapatite bioceramics for bone tissue engineering.

PubMed

Zhou, Changchun; Deng, Congying; Chen, Xuening; Zhao, Xiufen; Chen, Ying; Fan, Yujiang; Zhang, Xingdong

2015-08-01

Functionally graded materials (FGM) open the promising approach for bone tissue repair. In this study, a novel functionally graded hydroxyapatite (HA) bioceramic with micrograin and nanograin structure was fabricated. Its mechanical properties were tailored by composition of micrograin and nanograin. The dynamic mechanical analysis (DMA) indicated that the graded HA ceramics had similar mechanical property compared to natural bones. Their cytocompatibility was evaluated via fluorescent microscopy and MTT colorimetric assay. The viability and proliferation of rabbit bone marrow mesenchymal stem cells (BMSCs) on ceramics indicated that this functionally graded HA ceramic had better cytocompatibility than conventional HA ceramic. This study demonstrated that functionally graded HA ceramics create suitable structures to satisfy both the mechanical and biological requirements of bone tissues. Copyright © 2015 Elsevier Ltd. All rights reserved.

Constructing a bivariate distribution function with given marginals and correlation: application to the galaxy luminosity function

NASA Astrophysics Data System (ADS)

Takeuchi, Tsutomu T.

2010-08-01

We provide an analytic method to construct a bivariate distribution function (DF) with given marginal distributions and correlation coefficient. We introduce a convenient mathematical tool, called a copula, to connect two DFs with any prescribed dependence structure. If the correlation of two variables is weak (Pearson's correlation coefficient |ρ| < 1/3), the Farlie-Gumbel-Morgenstern (FGM) copula provides an intuitive and natural way to construct such a bivariate DF. When the linear correlation is stronger, the FGM copula cannot work anymore. In this case, we propose using a Gaussian copula, which connects two given marginals and is directly related to the linear correlation coefficient between two variables. Using the copulas, we construct the bivariate luminosity function (BLF) and discuss its statistical properties. We focus especially on the far-infrared-far-ulatraviolet (FUV-FIR) BLF, since these two wavelength regions are related to star-formation (SF) activity. Though both the FUV and FIR are related to SF activity, the univariate LFs have a very different functional form: the former is well described by the Schechter function whilst the latter has a much more extended power-law-like luminous end. We construct the FUV-FIR BLFs using the FGM and Gaussian copulas with different strengths of correlation, and examine their statistical properties. We then discuss some further possible applications of the BLF: the problem of a multiband flux-limited sample selection, the construction of the star-formation rate (SFR) function, and the construction of the stellar mass of galaxies (M*)-specific SFR (SFR/M*) relation. The copulas turn out to be a very useful tool to investigate all these issues, especially for including complicated selection effects.

Non-invasive assessment of adrenocortical function in captive Nile crocodiles (Crocodylus niloticus).

PubMed

Ganswindt, Stefanie B; Myburgh, Jan G; Cameron, Elissa Z; Ganswindt, Andre

2014-11-01

The occurrence of stress-inducing factors in captive crocodilians is a concern, since chronic stress can negatively affect animal health and reproduction, and hence production. Monitoring stress in wild crocodiles could also be beneficial for assessing the state of health in populations which are potentially threatened by environmental pollution. In both cases, a non-invasive approach to assess adrenocortical function as a measure of stress would be preferable, as animals are not disturbed during sample collection, and therefore sampling is feedback-free. So far, however, such a non-invasive method has not been established for any crocodilian species. As an initial step, we therefore examined the suitability of two enzyme-immunoassays, detecting faecal glucocorticoid metabolites (FGMs) with a 11β,21-diol-20-one and 5β-3α-ol-11-one structure, respectively, for monitoring stress-related physiological responses in captive Nile crocodiles (Crocodylus niloticus). An adrenocorticotropic hormone (ACTH) challenge was performed on 10 sub-adult crocodiles, resulting in an overall increase in serum corticosterone levels of 272% above the pre-injection levels 5h post-injection. Saline-treated control animals (n=8) showed an overall increase of 156% in serum corticosterone levels 5h post-administration. Faecal samples pre- and post-injection could be obtained from three of the six individually housed crocodiles, resulting in FGM concentrations 136-380% above pre-injection levels, always detected in the first sample collected post-treatment (7-15 days post-injection). FGM concentrations seem comparatively stable at ambient temperatures for up to 72 h post-defaecation. In conclusion, non-invasive hormone monitoring can be used for assessing adrenocortical function in captive Nile crocodiles based on FGM analysis. Copyright © 2014 Elsevier Inc. All rights reserved.

Female genital mutilation/cutting in Italy: an enhanced estimation for first generation migrant women based on 2016 survey data.

PubMed

Ortensi, Livia Elisa; Farina, Patrizia; Leye, Els

2018-01-12

Migration flows of women from Female Genital Mutilation/Cutting practicing countries have generated a need for data on women potentially affected by Female Genital Mutilation/Cutting. This paper presents enhanced estimates for foreign-born women and asylum seekers in Italy in 2016, with the aim of supporting resource planning and policy making, and advancing the methodological debate on estimation methods. The estimates build on the most recent methodological development in Female Genital Mutilation/Cutting direct and indirect estimation for Female Genital Mutilation/Cutting non-practicing countries. Direct estimation of prevalence was performed for 9 communities using the results of the survey FGM-Prev, held in Italy in 2016. Prevalence for communities not involved in the FGM-Prev survey was estimated using to the 'extrapolation-of-FGM/C countries prevalence data method' with corrections according to the selection hypothesis. It is estimated that 60 to 80 thousand foreign-born women aged 15 and over with Female Genital Mutilation/Cutting are present in Italy in 2016. We also estimated the presence of around 11 to 13 thousand cut women aged 15 and over among asylum seekers to Italy in 2014-2016. Due to the long established presence of female migrants from some practicing communities Female Genital Mutilation/Cutting is emerging as an issue also among women aged 60 and over from selected communities. Female Genital Mutilation/Cutting is an additional source of concern for slightly more than 60% of women seeking asylum. Reliable estimates on Female Genital Mutilation/Cutting at country level are important for evidence-based policy making and service planning. This study suggests that indirect estimations cannot fully replace direct estimations, even if corrections for migrant socioeconomic selection can be implemented to reduce the bias.

Assessing polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans in air across Latin American countries using polyurethane foam disk passive air samplers.

PubMed

Schuster, Jasmin K; Harner, Tom; Fillmann, Gilberto; Ahrens, Lutz; Altamirano, Jorgelina C; Aristizábal, Beatriz; Bastos, Wanderley; Castillo, Luisa Eugenia; Cortés, Johana; Fentanes, Oscar; Gusev, Alexey; Hernandez, Maricruz; Ibarra, Martín Villa; Lana, Nerina B; Lee, Sum Chi; Martínez, Ana Patricia; Miglioranza, Karina S B; Puerta, Andrea Padilla; Segovia, Federico; Siu, May; Tominaga, Maria Yumiko

2015-03-17

A passive air sampling network has been established to investigate polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) at Global Atmospheric Passive Sampling (GAPS) sites and six additional sites in the Group of Latin American and Caribbean Countries (GRULAC) region. The air sampling network covers background, agricultural, rural, and urban sites. Samples have been collected over four consecutive periods of 6 months, which started in January 2011 [period 1 (January to June 2011), period 2 (July to December 2011), period 3 (January to June 2012), and period 4 (July 2012 to January 2013)]. Results show that (i) the GAPS passive samplers (PUF disk type) and analytical methodology are adequate for measuring PCDD/F burdens in air and (ii) PCDD/F concentrations in air across the GRULAC region are widely variable by almost 2 orders of magnitude. The highest concentrations in air of Σ4-8PCDD/Fs were found at the urban site São Luis (Brazil, UR) (i.e., 2560 fg/m3) followed by the sites in São Paulo (Brazil, UR), Mendoza (Argentina, RU), and Sonora (Mexico, AG) with values of 1690, 1660, and 1610 fg/m3, respectively. Very low concentrations of PCDD/Fs in air were observed at the background site Tapanti (Costa Rica, BA), 10.8 fg/m3. This variability is attributed to differences in site characteristics and potential local/regional sources as well as meteorological influences. The measurements of PCDD/Fs in air agree well with model-predicted concentrations performed using the Global EMEP Multimedia Modeling System (GLEMOS) and emission scenario constructed on the basis of the UNEP Stockholm Convention inventory of dioxin and furan emissions.

Strength gradient enhances fatigue resistance of steels

NASA Astrophysics Data System (ADS)

Ma, Zhiwei; Liu, Jiabin; Wang, Gang; Wang, Hongtao; Wei, Yujie; Gao, Huajian

2016-02-01

Steels are heavily used in infrastructure and the transportation industry, and enhancing their fatigue resistance is a major challenge in materials engineering. In this study, by introducing a gradient microstructure into 304 austenitic steel, which is one of the most widely used types of stainless steel, we show that a strength gradient substantially enhances the fatigue life of the material. Pre-notched samples with negative strength gradients in front of the notch’s tip endure many more fatigue cycles than do samples with positive strength gradients during the crack initiation stage, and samples with either type of gradient perform better than do gradient-free samples with the same average yield strength. However, as a crack grows, samples with positive strength gradients exhibit better resistance to fatigue crack propagation than do samples with negative gradients or no gradient. This study demonstrates a simple and promising strategy for using gradient structures to enhance the fatigue resistance of materials and complements related studies of strength and ductility.

Strength gradient enhances fatigue resistance of steels

PubMed Central

Ma, Zhiwei; Liu, Jiabin; Wang, Gang; Wang, Hongtao; Wei, Yujie; Gao, Huajian

2016-01-01

Steels are heavily used in infrastructure and the transportation industry, and enhancing their fatigue resistance is a major challenge in materials engineering. In this study, by introducing a gradient microstructure into 304 austenitic steel, which is one of the most widely used types of stainless steel, we show that a strength gradient substantially enhances the fatigue life of the material. Pre-notched samples with negative strength gradients in front of the notch’s tip endure many more fatigue cycles than do samples with positive strength gradients during the crack initiation stage, and samples with either type of gradient perform better than do gradient-free samples with the same average yield strength. However, as a crack grows, samples with positive strength gradients exhibit better resistance to fatigue crack propagation than do samples with negative gradients or no gradient. This study demonstrates a simple and promising strategy for using gradient structures to enhance the fatigue resistance of materials and complements related studies of strength and ductility. PMID:26907708

Microstructure-property relationships and constitutive response of plastically graded case hardened steels

NASA Astrophysics Data System (ADS)

Klecka, Michael A.

Case hardened materials, popularly used in many demanding engineering applications such as bearings, gears, and wear/impact surfaces, have high surface hardness and a gradient in material properties (hardness, yield strength, etc.) as a function of depth; therefore, they behave as plastically graded materials. In the current study, two different commercially available case carburized steels along with two through hardened steels are characterized to obtain relationships among the volume fraction of subsurface carbides, indentation hardness, elastic modulus, and yield strength as a function of depth. A variety of methods including microindentation, nanoindentation, ultrasonic measurements, compression testing, rule of mixtures, and upper and lower bound models are used to determine the relationships for elastic modulus and compare the experimental results with model predictions. In addition, the morphology, composition, and properties of the carbide particles are also determined. The gradient in hardness with depth in graded materials is commonly determined using microindentation on the cross-section of the material which contains the gradation in microstructure or composition. In the current study, a novel method is proposed to predict the hardness gradient profile using solely surface indentations at a range of loads. The method does not require the graded material to be sectioned, and has practical utility in the surface heat-treatment industry. For a material with a decreasing gradient in hardness, higher indent loads result in a lower measured hardness due to the influence of the softer subsurface layers. A power-law model is presented which relates the measured surface indentation hardness under increasing load to the subsurface gradient in hardness. A coordinated experimental and numerical study is presented to extract the constitutive response of graded materials, utilizing relationships between hardness, plastic deformation, and strain hardening response. The average plastic strain induced by an indent is shown to be an effective measure of the representative plastic strain, which is used in order to relate hardness to yield strength in both virgin and plastically deformed materials. It is shown that the two carburized steels contain gradients in yield strength, but constant strain hardening exponent with depth. The resulting model of material behavior is used to characterize the influence of specific gradients in material properties on the surface indentation behavior under increasing indentation loads. It is also shown that the response of the material is not greatly influenced by strain hardening exponent, while a gradient in strain hardening ability only has minimal impact. Gradients in elastic properties are also shown to have negligible influence for a fixed gradient in hardness. The depth of subsurface plastic deformation is shown to increase with sharper gradients in hardness, but is not altered by gradients in elastic properties. The proposed approach is not specific to case hardened materials and can be used to determine the subsurface hardness gradient for any graded material.

Concern mounts over female genital mutilation.

PubMed

Jones, J

2000-07-29

According to estimates by the WHO, up to 140 million girls and women have undergone female genital mutilation (FGM), and each year another 2 million are thought to be at risk of it. Most girls who undergo this ritual live in Africa and to a lesser extent in Asia and the Middle East. However, there has been an increasing occurrence of genital mutilations among migrants from these countries who have settled in the US, Europe, and Australia. Although some countries prohibit the practice, evidence suggests that these laws are defied. In the UK, Baroness Ruth Rendell, the prime mover behind a cross-party parliament inquiry into FGM is convinced that some health professionals are still carrying out the operation on request. To this effect, she is advocating some prosecutions under the 1985 act. Rendell is also pressing for resources to be put into education and awareness campaigns for girls and women to have an informed choice as to whether to submit to the procedure or not.

Gradient Material Strategies for Hydrogel Optimization in Tissue Engineering Applications

PubMed Central

2018-01-01

Although a number of combinatorial/high-throughput approaches have been developed for biomaterial hydrogel optimization, a gradient sample approach is particularly well suited to identify hydrogel property thresholds that alter cellular behavior in response to interacting with the hydrogel due to reduced variation in material preparation and the ability to screen biological response over a range instead of discrete samples each containing only one condition. This review highlights recent work on cell–hydrogel interactions using a gradient material sample approach. Fabrication strategies for composition, material and mechanical property, and bioactive signaling gradient hydrogels that can be used to examine cell–hydrogel interactions will be discussed. The effects of gradients in hydrogel samples on cellular adhesion, migration, proliferation, and differentiation will then be examined, providing an assessment of the current state of the field and the potential of wider use of the gradient sample approach to accelerate our understanding of matrices on cellular behavior. PMID:29485612

Biomimetic Gradient Polymers with Enhanced Damping Capacities.

PubMed

Wang, Dong; Zhang, Huan; Guo, Jing; Cheng, Beichen; Cao, Yuan; Lu, Shengjun; Zhao, Ning; Xu, Jian

2016-04-01

Designing gradient structures, mimicking biological materials, such as pummelo peels and tendon, is a promising strategy for developing advanced materials with superior energy damping capacities. Here a facile and effective approach for fabricating polymers with composition gradients at millimeter length scale is presented. The gradient thiol-ene polymers (TEPs) are created by the use of density difference of ternary thiol-ene-ene precursors and the subsequent photo-crosslinking via thiol-ene reaction. The compositional gradients are analyzed via differential scanning calorimeter (DSC), compressive modulus testing, atomic force microscopy (AFM) indentation, and swelling measurements. In contrast to homogeneous TEPs networks, the resultant gradient polymer shows a broader effective damping temperature range combining with good mechanical properties. The present result provides an effective route toward high damping materials by the fabrication of gradient structures. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Modeling Issues and Results for Hydrogen Isotopes in NIF Materials

NASA Astrophysics Data System (ADS)

Grossman, Arthur A.; Doerner, R. P.; Luckhardt, S. C.; Seraydarian, R.; Sze, D.; Burnham, A.

1998-11-01

The TMAP4 (G. Longhurst, et al. INEL 1992) model of hydrogen isotope transport in solid materials includes a particle diffusion calculation with Fick's Law modified for Soret Effect (Thermal Diffusion or Thermomigration), coupled to heat transport calculations which are needed because of the strong temperature dependence of diffusivity. These TMAP4 calculations applied to NIF show that high temperatures approaching the melting point and strong thermal gradients of 10^6 K/cm are reached in the first micron of wall material during the SXR pulse. These strong thermal gradients can drive hydrogen isotope migration up or down the thermal gradient depending on the sign of the heat of transport (Soret coefficient) which depends on whether the material dissolves hydrogen endothermically or exothermically. Two candidates for NIF wall material-boron carbide and stainless steel are compared. Boron carbide dissolves hydrogen exothermically so it may drive Soret migration down the thermal gradient deeper into the material, although the thermal gradient is not as large and hydrogen is not as mobile as in stainless steel. Stainless steel dissolves hydrogen endothermically, with a negative Soret coefficient which can drive hydrogen up the thermal gradient and out of the wall.

Enhanced protective role in materials with gradient structural orientations: Lessons from Nature.

PubMed

Liu, Zengqian; Zhu, Yankun; Jiao, Da; Weng, Zhaoyong; Zhang, Zhefeng; Ritchie, Robert O

2016-10-15

Living organisms are adept at resisting contact deformation and damage by assembling protective surfaces with spatially varied mechanical properties, i.e., by creating functionally graded materials. Such gradients, together with multiple length-scale hierarchical structures, represent the two prime characteristics of many biological materials to be translated into engineering design. Here, we examine one design motif from a variety of biological tissues and materials where site-specific mechanical properties are generated for enhanced protection by adopting gradients in structural orientation over multiple length-scales, without manipulation of composition or microstructural dimension. Quantitative correlations are established between the structural orientations and local mechanical properties, such as stiffness, strength and fracture resistance; based on such gradients, the underlying mechanisms for the enhanced protective role of these materials are clarified. Theoretical analysis is presented and corroborated through numerical simulations of the indentation behavior of composites with distinct orientations. The design strategy of such bioinspired gradients is outlined in terms of the geometry of constituents. This study may offer a feasible approach towards generating functionally graded mechanical properties in synthetic materials for improved contact damage resistance. Living organisms are adept at resisting contact damage by assembling protective surfaces with spatially varied mechanical properties, i.e., by creating functionally-graded materials. Such gradients, together with multiple length-scale hierarchical structures, represent the prime characteristics of many biological materials. Here, we examine one design motif from a variety of biological tissues where site-specific mechanical properties are generated for enhanced protection by adopting gradients in structural orientation at multiple length-scales, without changes in composition or microstructural dimension. The design strategy of such bioinspired gradients is outlined in terms of the geometry of constituents. This study may offer a feasible approach towards generating functionally-graded mechanical properties in synthetic materials for improved damage resistance. Published by Elsevier Ltd.

High energy X-ray diffraction study of a dental ceramics–titanium functional gradient material prepared by field assisted sintering technique

DOE Office of Scientific and Technical Information (OSTI.GOV)

Witte, K., E-mail: kerstin.witte@uni-rostock.de; Bodnar, W.; Schell, N.

A functional gradient material with eleven layers composed of a dental ceramics and titanium was successfully consolidated using field assisted sintering technique in a two-step sintering process. High energy X-ray diffraction studies on the gradient were performed at High Energy Material Science beamline at Desy in Hamburg. Phase composition, crystal unit edges and lattice mismatch along the gradient were determined applying Rietveld refinement procedure. Phase analysis revealed that the main crystalline phase present in the gradient is α-Ti. Crystallinity increases stepwisely along the gradient with a decreasing increment between every next layer, following rather the weight fraction of titanium. Themore » crystal unit edge a of titanium remains approximately constant with a value of 2.9686(1) Å, while c is reduced with increasing amount of titanium. In the layer with pure titanium the crystal unit edge c is constant with a value of 4.7174(2) Å. The lattice mismatch leading to an internal stress was calculated over the whole gradient. It was found that the maximal internal stress in titanium embedded in the studied gradient is significantly smaller than its yield strength, which implies that the structure of titanium along the whole gradient is mechanically stable. - Highlights: • High energy XRD studies of dental ceramics–Ti gradient material consolidated by FAST. • Phase composition, crystallinity and lattice parameters are determined. • Crystallinity increases stepwisely along the gradient following weight fraction of Ti. • Lattice mismatch leading to internal stress is calculated over the whole gradient. • Internal stress in α-Ti embedded in the gradient is smaller than its yield strength.« less

Juno Magnetometer Observations in the Earth's Magnetosphere

NASA Astrophysics Data System (ADS)

Connerney, J. E.; Oliversen, R. J.; Espley, J. R.; MacDowall, R. J.; Schnurr, R.; Sheppard, D.; Odom, J.; Lawton, P.; Murphy, S.; Joergensen, J. L.; Joergensen, P. S.; Merayo, J. M.; Denver, T.; Bloxham, J.; Smith, E. J.; Murphy, N.

2013-12-01

The Juno spacecraft enjoyed a close encounter with Earth on October 9, 2013, en route to Jupiter Orbit Insertion (JOI) on July 5, 2016. The Earth Flyby (EFB) provided a unique opportunity for the Juno particles and fields instruments to sample mission relevant environments and exercise operations anticipated for orbital operations at Jupiter, particularly the period of intense activity around perijove. The magnetic field investigation onboard Juno is equipped with two magnetometer sensor suites, located at 10 and 12 m from the spacecraft body at the end of one of the three solar panel wings. Each contains a vector fluxgate magnetometer (FGM) sensor and a pair of co-located non-magnetic star tracker camera heads which provide accurate attitude determination for the FGM sensors. This very capable magnetic observatory sampled the Earth's magnetic field at 64 vector samples/second throughout passage through the Earth's magnetosphere. We present observations of the Earth's magnetic field and magnetosphere obtained throughout the encounter and compare these observations with those of other Earth-orbiting assets, as available, and with particles and fields observations acquired by other Juno instruments operated during EFB.

Differentially Private Frequent Subgraph Mining

PubMed Central

Xu, Shengzhi; Xiong, Li; Cheng, Xiang; Xiao, Ke

2016-01-01

Mining frequent subgraphs from a collection of input graphs is an important topic in data mining research. However, if the input graphs contain sensitive information, releasing frequent subgraphs may pose considerable threats to individual's privacy. In this paper, we study the problem of frequent subgraph mining (FGM) under the rigorous differential privacy model. We introduce a novel differentially private FGM algorithm, which is referred to as DFG. In this algorithm, we first privately identify frequent subgraphs from input graphs, and then compute the noisy support of each identified frequent subgraph. In particular, to privately identify frequent subgraphs, we present a frequent subgraph identification approach which can improve the utility of frequent subgraph identifications through candidates pruning. Moreover, to compute the noisy support of each identified frequent subgraph, we devise a lattice-based noisy support derivation approach, where a series of methods has been proposed to improve the accuracy of the noisy supports. Through formal privacy analysis, we prove that our DFG algorithm satisfies ε-differential privacy. Extensive experimental results on real datasets show that the DFG algorithm can privately find frequent subgraphs with high data utility. PMID:27616876

Ambipolar nonvolatile memory based on a quantum-dot transistor with a nanoscale floating gate

DOE Office of Scientific and Technical Information (OSTI.GOV)

Che, Yongli; Zhang, Yating, E-mail: yating@tju.edu.cn; Song, Xiaoxian

2016-07-04

Using only solution processing methods, we developed ambipolar quantum-dot (QD) transistor floating-gate memory (FGM) that uses Au nanoparticles as a floating gate. Because of the bipolarity of the active channel of PbSe QDs, the memory could easily trap holes or electrons in the floating gate by programming/erasing (P/E) operations, which could shift the threshold voltage both up and down. As a result, the memory exhibited good programmable memory characteristics: a large memory window (ΔV{sub th} ∼ 15 V) and a long retention time (>10{sup 5 }s). The magnitude of ΔV{sub th} depended on both P/E voltages and the bias voltage (V{sub DS}): ΔV{sub th}more » was a cubic function to V{sub P/E} and linearly depended on V{sub DS}. Therefore, this FGM based on a QD transistor is a promising alternative to its inorganic counterparts owing to its advantages of bipolarity, high mobility, low cost, and large-area production.« less

Physiological stress responses in wild Asian elephants Elephas maximus in a human-dominated landscape in the Western Ghats, southern India.

PubMed

Vijayakrishnan, Sreedhar; Kumar, Mavatur Ananda; Umapathy, G; Kumar, Vinod; Sinha, Anindya

2018-05-17

Increasing anthropogenic pressures on forests, especially in the tropical regions of the world, have restricted several large mammalian species such as the Asian elephant to fragmented habitats within human-dominated landscapes. In this study, we assessed the effects of an anthropogenic landscape and its associated conflict with humans on the physiological stress responses displayed by Asian elephants in the Anamalai Hills of the Western Ghats mountains in south India. We have quantified faecal glucocorticoid metabolite (FGM) concentrations in focal individual elephants within and across herds, inhabiting both anthropogenic and natural habitats, and evaluated their physiological responses to different socio-ecological situations between November 2013 and April 2014. Physiological stress responses varied significantly among the tested elephant age- and sex categories but not across different types of social organisation. Adults generally showed higher FGM concentrations, even in the absence of stressors, than did any other age category. Males also appeared to have higher stress responses than did females. Although there was no significant variation in mean stress levels between elephants on the plateau in the absence of human interactions and those in adjacent, relatively undisturbed forest habitats, FGM concentrations increased significantly for adult and subadult individuals as well as for calves following drives, during which elephants were driven off aggressively by people. Our study emphasises the general importance of understanding individual variation in physiology and behaviour within a population of a seriously threatened mammalian species, the Asian elephant, and specifically highlights the need for long-term monitoring of the stress physiology and behavioural responses of individual elephants across both human-dominated and natural landscapes. Such studies would not only provide comprehensive insights into the adaptive biology of elephants in changing ecological regimes but also aid in the development of effective management and conservation strategies for endangered populations of the species. Copyright © 2018 Elsevier Inc. All rights reserved.

Science objectives of the magnetic field experiment onboard Aditya-L1 spacecraft

NASA Astrophysics Data System (ADS)

Yadav, Vipin K.; Srivastava, Nandita; Ghosh, S. S.; Srikar, P. T.; Subhalakshmi, Krishnamoorthy

2018-01-01

The Aditya-L1 is first Indian solar mission scheduled to be placed in a halo orbit around the first Lagrangian point (L1) of Sun-Earth system in the year 2018-19. The approved scientific payloads onboard Aditya-L1 spacecraft includes a Fluxgate Digital Magnetometer (FGM) to measure the local magnetic field which is necessary to supplement the outcome of other scientific experiments onboard. The in-situ vector magnetic field data at L1 is essential for better understanding of the data provided by the particle and plasma analysis experiments, onboard Aditya-L1 mission. Also, the dynamics of Coronal Mass Ejections (CMEs) can be better understood with the help of in-situ magnetic field data at the L1 point region. This data will also serve as crucial input for the short lead-time space weather forecasting models. The proposed FGM is a dual range magnetic sensor on a 6 m long boom mounted on the Sun viewing panel deck and configured to deploy along the negative roll direction of the spacecraft. Two sets of sensors (tri-axial each) are proposed to be mounted, one at the tip of boom (6 m from the spacecraft) and other, midway (3 m from the spacecraft). The main science objective of this experiment is to measure the magnitude and nature of the interplanetary magnetic field (IMF) locally and to study the disturbed magnetic conditions and extreme solar events by detecting the CME from Sun as a transient event. The proposed secondary science objectives are to study the impact of interplanetary structures and shock solar wind interaction on geo-space environment and to detect low frequency plasma waves emanating from the solar corona at L1 point. This will provide a better understanding on how the Sun affects interplanetary space. In this paper, we shall give the main scientific objectives of the magnetic field experiment and brief technical details of the FGM onboard Aditya-1 spacecraft.

Characterization of Ovarian Steroid Patterns in Female African Lions (Panthera leo), and the Effects of Contraception on Reproductive Function

PubMed Central

Putman, Sarah B.; Brown, Janine L.; Franklin, Ashley D.; Schneider, Emily C.; Boisseau, Nicole P.; Asa, Cheryl S.; Pukazhenthi, Budhan S.

2015-01-01

Because of poor reproduction after the lifting of an 8-year breeding moratorium, a biomedical survey of female lions in U.S. zoos was initiated in 2007. Fecal estrogen (FEM), progestagen (FPM) and glucocorticoid (FGM) metabolites were analyzed in samples collected 3–4 times per wk from 28 lions at 17 facilities (0.9–13.8 yr of age) for 4 mo—3.5 yr and body weights were obtained ~monthly from 17 animals at eight facilities (0.0–3.0 yr of age). Based on FEM, estrous cycle length averaged 17.5 ± 0.4 d in duration, with estrus lasting 4.4 ± 0.2 d. All but one female exhibited waves of estrogenic activity indicative of follicular activity; however, not all females expressed estrous behaviors (73%), suggesting silent estrus was common. Female lions experienced puberty earlier than expected; waves of estrogenic activity were observed as young as 1.1 yr of age, which may be related to a faster growth rate of captive vs. wild lions. Mean gestation length was 109.5 ± 1.0 d, whereas the non-pregnant luteal phase was less than half (46.0 ± 1.2 d). Non-mating induced increases in FPM were observed in 33% of females housed without a male, consistent with spontaneous ovulation. A number of study animals had been contracepted, and the return to cyclicity after treatment withdrawal, while variable, was ~4.0 yr and longer than the 1-yr expected efficacy, especially for those implanted with Suprelorin. For FGM, there were no differences in overall, baseline or peak mean concentrations among the age groups or across seasons, nor were there any relationships between reproductive parameters and FGM concentrations. Overall, results suggest that poor reproduction in lions after the breeding moratorium was not related to altered adrenal or ovarian steroid activity, but for some females may have been a consequence of individual institutions’ management decisions. PMID:26460849

Enamel Mineral Content Changes After Bleaching With High and Low Hydrogen Peroxide Concentrations: Colorimetric Spectrophotometry and Total Reflection X-ray Fluorescence Analyses.

PubMed

Pinto, Avd; Bridi, E C; Amaral, Flb; França, Fmg; Turssi, C P; Pérez, C A; Martinez, E F; Flório, F M; Basting, R T

The purpose of this study was to evaluate the calcium (Ca) and phosphorous (P) content in enamel bleached with high and low concentrations of hydrogen peroxide (HP) using Total Reflection X-Ray Fluorescence (TXRF) and colorimetric spectrophotometry (SPEC). Forty-eight sound human third molars were used. Their roots were embedded in polystyrene resin and immersed for seven days in an artificial saliva solution. Then they were distributed into six groups to receive the bleaching treatments. The agents of high HP concentration (for in-office use) evaluated were Whiteness HP Maxx/FGM (35% HP), Whiteness HP Blue/FGM (35% HP, 2% calcium gluconate), Pola Office+/SDI (37.5% HP, 5% potassium nitrate), and Opalescence Boost/Ultradent (38% HP, 1.1% ion fluoride, 3% potassium nitrate); these agents were applied to enamel in three sessions. The agents of low HP concentration (for home use) evaluated were Pola Day/SDI (9.5% HP) and White Class 10%/FGM (10% HP, potassium nitrate, calcium, fluoride), and these agents were applied for 14 days. Enamel microbiopsies were evaluated by TXRF and SPEC analysis before the bleaching treatment (baseline), during the treatment, and 14 days after the end of the treatment. For TXRF, the Kruskal-Wallis test showed that Ca and P were not influenced by agent (p>0.05). For SPEC, Pola Office+, Opalescence Boost, Pola Day, and White Class 10% caused a decrease of Ca over time; there was a significant decrease of P over time to Pola Office+ and White Class 10%. The Spearman test showed no correlation between the Ca (p=0.987; r 2 =-0.020) and P (p=0.728, r 2 =0.038) obtained by SPEC and TXRF. For TXRF and SPEC, changes in Ca and P during bleaching occurred independently of the HP concentration used.

Characterization of Ovarian Steroid Patterns in Female African Lions (Panthera leo), and the Effects of Contraception on Reproductive Function.

PubMed

Putman, Sarah B; Brown, Janine L; Franklin, Ashley D; Schneider, Emily C; Boisseau, Nicole P; Asa, Cheryl S; Pukazhenthi, Budhan S

2015-01-01

Because of poor reproduction after the lifting of an 8-year breeding moratorium, a biomedical survey of female lions in U.S. zoos was initiated in 2007. Fecal estrogen (FEM), progestagen (FPM) and glucocorticoid (FGM) metabolites were analyzed in samples collected 3-4 times per wk from 28 lions at 17 facilities (0.9-13.8 yr of age) for 4 mo-3.5 yr and body weights were obtained ~monthly from 17 animals at eight facilities (0.0-3.0 yr of age). Based on FEM, estrous cycle length averaged 17.5 ± 0.4 d in duration, with estrus lasting 4.4 ± 0.2 d. All but one female exhibited waves of estrogenic activity indicative of follicular activity; however, not all females expressed estrous behaviors (73%), suggesting silent estrus was common. Female lions experienced puberty earlier than expected; waves of estrogenic activity were observed as young as 1.1 yr of age, which may be related to a faster growth rate of captive vs. wild lions. Mean gestation length was 109.5 ± 1.0 d, whereas the non-pregnant luteal phase was less than half (46.0 ± 1.2 d). Non-mating induced increases in FPM were observed in 33% of females housed without a male, consistent with spontaneous ovulation. A number of study animals had been contracepted, and the return to cyclicity after treatment withdrawal, while variable, was ~4.0 yr and longer than the 1-yr expected efficacy, especially for those implanted with Suprelorin. For FGM, there were no differences in overall, baseline or peak mean concentrations among the age groups or across seasons, nor were there any relationships between reproductive parameters and FGM concentrations. Overall, results suggest that poor reproduction in lions after the breeding moratorium was not related to altered adrenal or ovarian steroid activity, but for some females may have been a consequence of individual institutions' management decisions.

Protein gradient films of fibroin and gelatine.

PubMed

Claussen, Kai U; Lintz, Eileen S; Giesa, Reiner; Schmidt, Hans-Werner; Scheibel, Thomas

2013-10-01

Gradients are a natural design principle in biological systems that are used to diminish stress concentration where materials of differing mechanical properties connect. An interesting example of a natural gradient material is byssus, which anchors mussels to rocks and other hard substrata. Building upon previous work with synthetic polymers and inspired by byssal threads, protein gradient films are cast using glycerine-plasticized gelatine and fibroin exhibiting a highly reproducible and smooth mechanical gradient, which encompasses a large range of modulus from 160 to 550 MPa. The reproducible production of biocompatible gradient films represents a first step towards medical applications. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Fabrication of microscale materials with programmable composition gradients.

PubMed

Laval, Cédric; Bouchaudy, Anne; Salmon, Jean-Baptiste

2016-04-07

We present an original microfluidic technique coupling pervaporation and the use of Quake valves to fabricate microscale materials (∼10 × 100 μm(2) × 1 cm) with composition gradients along their longest dimension. Our device exploits pervaporation of water through a thin poly(dimethylsiloxane) (PDMS) membrane to continuously pump solutions (or dispersions) contained in different reservoirs connected to a microfluidic channel. This pervaporation-induced flow concentrates solutes (or particles) at the tip of the channel up to the formation of a dense material. The latter invades the channel as it is constantly enriched by an incoming flux of solutes/particles. Upstream Quake valves are used to select which reservoir is connected to the pervaporation channel and thus which solution (or dispersion) enriches the material during its growth. The microfluidic configuration of the pervaporation process is used to impose controlled growth along the channel thus enabling one to program spatial composition gradients using appropriate actuations of the valves. We demonstrate the possibilities offered by our technique through the fabrication of dense assemblies of nanoparticles and polymer composites with programmed gradients of fluorescent dyes. We also address the key issue of the spatial resolution of our gradients and we show that well-defined spatial modulations down to ≈50 μm can be obtained within colloidal materials, whereas gradients within polymer materials are resolved on length scales down to ≈1 mm due to molecular diffusion.

Children in Africa: Key Statistics on Child Survival, Protection and Development

ERIC Educational Resources Information Center

UNICEF, 2014

2014-01-01

This report presents key statistics relating to: (1) child malnutrition in Africa; (2) HIV/AIDS and Malaria in Africa; (3) child marriage, birth registration and Female Genital Mutilation/Cutting (FGM/C); (4) education in Africa; (5) child mortality in Africa; (6) Drinking water and sanitation in Africa; and (7) maternal health in Africa.…

[RNA polymerase II and pre-mRNA splicing factors in diplotene oocyte nuclei of the giant African gastropod Achatina fulica].

PubMed

Stepanova, I S; Bogoliubov, D S

2003-01-01

The nuclear distribution of pre-mRNA splicing factors (snRNPs and SR-protein SC35) and unphosphorylated from of RNA polymerase II (Pol II) was studied using fluorescent and immunoelectron cytochemistry in diplotene oocytes of the gastropod Achatina fulica. Association of Pol II and splicing factors with oocyte nuclear structures was analysed. The antibodies against splicing factors and Pol II were shown to label perichromatin fibrils at the periphery of condensed chromatin blocks as well as those in interchromatin regions of nucleoplasm. The revealed character of distribution of snRNPs, SC35 protein, and Pol II, together with the decondensed chromatin and absence of karyosphere, enable us to suggest that oocyte chromosomes maintain their transcriptional activity at the diplotene stage of oogenesis. In A. fulica oocytes, sparse nuclear bodies (NBs) of a complex morphological structure were revealed. These NBs contain snRNPs rather than SC35 protein. NBs are associated with a fibrogranular material (FGM), which contains SC35 protein. No snRNPs were revealed in this material. Homology of A. fulica oocyte nuclear structures to Cajal bodies and interchromatin granule clusters is discussed.

An analytical solution for transient flow of Bingham viscoplastic materials in rock fractures

USGS Publications Warehouse

Amadei, B.; Savage, W.Z.

2001-01-01

We present below an analytical solution to model the one-dimensional transient flow of a Bingham viscoplastic material in a fracture with parallel walls (smooth or rough) that is subjected to an applied pressure gradient. The solution models the acceleration and the deceleration of the material as the pressure gradient changes with time. Two cases are considered: A pressure gradient applied over a finite time interval and an applied pressure gradient that is constant over time. The solution is expressed in dimensionless form and can therefore be used for a wide range of Bingham viscoplastic materials. The solution is also capable of capturing the transition that takes place in a fracture between viscoplastic flow and rigid plug flow. Also, it shows the development of a rigid central layer in fractures, the extent of which depends on the fluid properties (viscosity and yield stress), the magnitude of the pressure gradient, and the fracture aperture and surface roughness. Finally, it is shown that when a pressure gradient is applied and kept constant, the solution for the fracture flow rate converges over time to a steady-state solution that can be defined as a modified cubic law. In this case, the fracture transmissivity is found to be a non-linear function of the head gradient. This solution provides a tool for a better understanding of the flow of Bingham materials in rock fractures, interfaces, and cracks. ?? 2001 Elsevier Science Ltd. All rights reserved.

Plasma pressure distribution at the geocentric distances smaller than 15 Re and the structure of magnetospheric current systems

NASA Astrophysics Data System (ADS)

Kirpichev, Igor; Antonova, Elizaveta

We analyzed the characteristics of the plasma region surrounding the Earth at the geocentric distances between 6 and 15 Re using the data of THEMIS mission. To calculate plasma pressure including ion and electron contributions we have used the particle spectra measured by ESA and SST instruments. The magnetic field was obtained from the FGM magnetometer data. We take into account the daytime compression of the magnetic field lines and the shift of the minimal value of the magnetic field to higher latitudes. The obtained averaged distributions of plasma pressure, of pressure anisotropy, and of magnetic field near the equatorial plane showed the presence of a ring-shaped structure surrounding the Earth at the geocentric distances till the dayside magnetopause near noon. Plasma pressure gradients in the analyzed region have mainly earthward direction which means the existence of westward directed transverse currents. We obtain the values of such current densities and integral currents along field lines during quite geomagnetic conditions suggesting the validity of the condition of the magnetostatic equilibrium. We show that transverse currents in the high latitude magnetosphere have the ring-like structure forming the high latitude continuation of the ordinary ring current. The obtained data base is used for the creation of the model of the pressure distribution during different IMF and solar wind conditions.

Plasmasphere-Ring Current-Radiation Belts Interactions: Review of 16 Years of Cluster Observations

NASA Astrophysics Data System (ADS)

Dandouras, I. S.

2016-12-01

The Cluster mission is based on four identical spacecraft launched in 2000 on similar elliptical polar orbits with an initial perigee at about 4 RE and an apogee at 19.6 RE. This allows Cluster to cross the outer plasmasphere, the ring current region and the radiation belts, from south to north, during every perigee pass and to obtain their latitudinal profile following almost the same flux tube. Due to various perturbations the perigee geocentric distance decreased during 2007-2010 to about 2 RE, whereas actually it is again up to about 5 RE, allowing in this way to study, during the mission, the inner magnetosphere populations and their interactions at a wide range of L-shells and under different solar activity conditions. The CIS experiment, on board these spacecraft, provides the ion distribution functions from 1 eV (plasmasphere populations) up to 40 keV (ring current), whereas the MeV penetrating particles allow to monitor the position and dynamics of the radiation belts. The FGM experiment on board these four spacecraft allowed for the first time an instantaneous calculation of the magnetic field gradients and thus a direct measurement of the local current density using the curlometer technique. Earlier and more recent results, based on Cluster data acquired during the passes in inner magnetosphere, will be reviewed and analysed.

Material and shape perception based on two types of intensity gradient information

PubMed Central

Nishida, Shin'ya

2018-01-01

Visual estimation of the material and shape of an object from a single image includes a hard ill-posed computational problem. However, in our daily life we feel we can estimate both reasonably well. The neural computation underlying this ability remains poorly understood. Here we propose that the human visual system uses different aspects of object images to separately estimate the contributions of the material and shape. Specifically, material perception relies mainly on the intensity gradient magnitude information, while shape perception relies mainly on the intensity gradient order information. A clue to this hypothesis was provided by the observation that luminance-histogram manipulation, which changes luminance gradient magnitudes but not the luminance-order map, effectively alters the material appearance but not the shape of an object. In agreement with this observation, we found that the simulated physical material changes do not significantly affect the intensity order information. A series of psychophysical experiments further indicate that human surface shape perception is robust against intensity manipulations provided they do not disturb the intensity order information. In addition, we show that the two types of gradient information can be utilized for the discrimination of albedo changes from highlights. These findings suggest that the visual system relies on these diagnostic image features to estimate physical properties in a distal world. PMID:29702644

Time Prediction Models for Echinococcosis Based on Gray System Theory and Epidemic Dynamics.

PubMed

Zhang, Liping; Wang, Li; Zheng, Yanling; Wang, Kai; Zhang, Xueliang; Zheng, Yujian

2017-03-04

Echinococcosis, which can seriously harm human health and animal husbandry production, has become an endemic in the Xinjiang Uygur Autonomous Region of China. In order to explore an effective human Echinococcosis forecasting model in Xinjiang, three grey models, namely, the traditional grey GM(1,1) model, the Grey-Periodic Extensional Combinatorial Model (PECGM(1,1)), and the Modified Grey Model using Fourier Series (FGM(1,1)), in addition to a multiplicative seasonal ARIMA(1,0,1)(1,1,0)₄ model, are applied in this study for short-term predictions. The accuracy of the different grey models is also investigated. The simulation results show that the FGM(1,1) model has a higher performance ability, not only for model fitting, but also for forecasting. Furthermore, considering the stability and the modeling precision in the long run, a dynamic epidemic prediction model based on the transmission mechanism of Echinococcosis is also established for long-term predictions. Results demonstrate that the dynamic epidemic prediction model is capable of identifying the future tendency. The number of human Echinococcosis cases will increase steadily over the next 25 years, reaching a peak of about 1250 cases, before eventually witnessing a slow decline, until it finally ends.

Prioritizing and synthesizing evidence to improve the health care of girls and women living with female genital mutilation: An overview of the process.

PubMed

Stein, Karin; Hindin, Michelle J; Chou, Doris; Say, Lale

2017-02-01

Female genital mutilation (FGM) constitutes a harmful traditional practice that can have a profound impact on the health and well-being of girls and women who undergo the procedure. In recent years, due to international migration, healthcare providers worldwide are increasingly confronted with the need to provide adequate health care to this population. Recognizing this situation the WHO recently developed the first evidence-based guidelines on the management of health complications from FGM. To inform the guideline recommendations, an expert-driven, two-step process was conducted. The first step consisted of developing and ranking a list of priority research questions for the evidence retrieval. The second step involved conducting a series of systematic reviews and qualitative data syntheses. In the present paper, we first provide the methodology used in the development and ranking of the research questions (step 1) and then detail the common methodology for each of the systematic reviews and qualitative evidence syntheses (step 2). © 2017 International Federation of Gynecology and Obstetrics. The World Health Organization retains copyright and all other rights in the manuscript of this article as submitted for publication.

Field-gradient partitioning for fracture and frictional contact in the material point method: Field-gradient partitioning for fracture and frictional contact in the material point method [Fracture and frictional contact in material point method using damage-field gradients for velocity-field partitioning

DOE Office of Scientific and Technical Information (OSTI.GOV)

Homel, Michael A.; Herbold, Eric B.

Contact and fracture in the material point method require grid-scale enrichment or partitioning of material into distinct velocity fields to allow for displacement or velocity discontinuities at a material interface. We present a new method which a kernel-based damage field is constructed from the particle data. The gradient of this field is used to dynamically repartition the material into contact pairs at each node. Our approach avoids the need to construct and evolve explicit cracks or contact surfaces and is therefore well suited to problems involving complex 3-D fracture with crack branching and coalescence. A straightforward extension of this approachmore » permits frictional ‘self-contact’ between surfaces that are initially part of a single velocity field, enabling more accurate simulation of granular flow, porous compaction, fragmentation, and comminution of brittle materials. Finally, numerical simulations of self contact and dynamic crack propagation are presented to demonstrate the accuracy of the approach.« less

Field-gradient partitioning for fracture and frictional contact in the material point method: Field-gradient partitioning for fracture and frictional contact in the material point method [Fracture and frictional contact in material point method using damage-field gradients for velocity-field partitioning

DOE PAGES

Homel, Michael A.; Herbold, Eric B.

2016-08-15

Contact and fracture in the material point method require grid-scale enrichment or partitioning of material into distinct velocity fields to allow for displacement or velocity discontinuities at a material interface. We present a new method which a kernel-based damage field is constructed from the particle data. The gradient of this field is used to dynamically repartition the material into contact pairs at each node. Our approach avoids the need to construct and evolve explicit cracks or contact surfaces and is therefore well suited to problems involving complex 3-D fracture with crack branching and coalescence. A straightforward extension of this approachmore » permits frictional ‘self-contact’ between surfaces that are initially part of a single velocity field, enabling more accurate simulation of granular flow, porous compaction, fragmentation, and comminution of brittle materials. Finally, numerical simulations of self contact and dynamic crack propagation are presented to demonstrate the accuracy of the approach.« less

Comparison of a triaxial fluxgate magnetometer and Toftness sensometer for body surface EMF measurement.

PubMed

Zhang, John; Toftness, Dave; Snyder, Brian; Nosco, Dennis; Balcavage, Walter; Nindl, Gabi

2004-12-01

The use of magnetic fields to treat disease has intrigued mankind since the time of the ancient Greeks. More recently it has been shown that electromagnetic field (EMF) treatment aids bone healing, and repetitive transcranial magnetic stimulation (rTMS) appears to be beneficial in treating schizophrenia and depression. Since external EMFs influence internal body processes, we hypothesized that measurement of body surface EMFs might be used to detect disease states and direct the course of subsequent therapy. However, measurement of minute body surface EMFs requires use of a sensitive and well documented magnetometer. In this study we evaluated the sensitivity and frequency response of a fluxgate magnetometer with a triaxial probe for use in detecting body surface EMF and we compared the magnetometer readings with a signal from a Toftness Sensometer, operated by an experienced clinician, in the laboratory and in a clinical setting. A Peavy Audio Amplifier and variable power output Telulex signal generator were used to develop 50 microT EMFs in a three coil Merritt coil system. A calibrated magnetometer was used to set a 60 Hz 50 microT field in the coil and an ammeter was used to measure the current required to develop the 50 microT field. At frequencies other than 60 Hz, the field strength was maintained at 50 microT by adjusting the Telulex signal output to keep the current constant. The field generated was monitored using a 10 turn coil connected to an oscilloscope. The oscilloscope reading indicated that the field strength was the same at all frequencies tested. To determine if there was a correspondence between the signals detected by a fluxgate magnetometer (FGM1) and the Toftness Sensometer both devices were placed in the Merritt coil and readings were recorded from the FGM1 and compared with the ability of a highly experienced Toftness operator to detect the 50 microT field. Subsequently, in a clinical setting, FGM1 readings made by an FGM1 technician and Sensometer readings were made by 4 Toftness Sensometer operators, having various degrees of experience with this device. Each examiner obtained instrument readings from 5 different volunteers in separate chiropractic adjusting rooms. Additionally, one of the Toftness Sensometers was equipped with an integrated fluxgate magnetometer (FGM2) and this magnetometer was used to obtain a second set of EMF readings in the clinical setting. The triaxial fluxgate magnetometer was determined to be moderately responsive to changes in magnetic field frequency below 10 Hz. At frequencies above 10 Hz the readings corresponded to that of the ambient static geofield. The practitioner operating the Toftness Sensometer was unable to detect magnetic fields at high frequencies (above 10 Hz) even at very high EMFs. The fluxgate magnetometer was shown to be essentially a DC/static magnetic field detector and like all such devices it has a limited frequency range with some low level of sensitivity at very low field frequencies. The interexaminer reliability of four Toftness practitioners using the Sensometer on 5 patients showed low to moderate correlation. The fluxgate magnetometer although highly sensitive to static (DC) EMFs has only limited sensitivity to EMFs in the range of 1 to 10 Hz and is very insensitive to frequencies above 10 Hz. In laboratory comparisons of the Sensometer and the fluxgate magnetometer there was an occasional correspondence between the two instruments in detecting magnetic fields within the Merritt coil but these occasions were not reproducible. In the clinical studies there was low to moderate agreement between the clinicians using the Sensometer to diagnosing spinal conditions and there was little if any agreement between the Sensometer and the fluxgate magnetometer in detecting EMFs emanating from the volunteers body surface.

Comparison of a triaxial fluxgate magnetometer and Toftness sensometer for body surface EMF measurement

PubMed Central

Zhang, John; Toftness, Dave; Snyder, Brian; Nosco, Dennis; Balcavage, Walter; Nindl, Gabi

2004-01-01

Introduction The use of magnetic fields to treat disease has intrigued mankind since the time of the ancient Greeks. More recently it has been shown that electromagnetic field (EMF) treatment aids bone healing, and repetitive transcranial magnetic stimulation (rTMS) appears to be beneficial in treating schizophrenia and depression. Since external EMFs influence internal body processes, we hypothesized that measurement of body surface EMFs might be used to detect disease states and direct the course of subsequent therapy. However, measurement of minute body surface EMFs requires use of a sensitive and well documented magnetometer. In this study we evaluated the sensitivity and frequency response of a fluxgate magnetometer with a triaxial probe for use in detecting body surface EMF and we compared the magnetometer readings with a signal from a Toftness Sensometer, operated by an experienced clinician, in the laboratory and in a clinical setting. Methods A Peavy Audio Amplifier and variable power output Telulex signal generator were used to develop 50 μT EMFs in a three coil Merritt coil system. A calibrated magnetometer was used to set a 60 Hz 50 μT field in the coil and an ammeter was used to measure the current required to develop the 50 μT field. At frequencies other than 60 Hz, the field strength was maintained at 50 μT by adjusting the Telulex signal output to keep the current constant. The field generated was monitored using a 10 turn coil connected to an oscilloscope. The oscilloscope reading indicated that the field strength was the same at all frequencies tested. To determine if there was a correspondence between the signals detected by a fluxgate magnetometer (FGM1) and the Toftness Sensometer both devices were placed in the Merritt coil and readings were recorded from the FGM1 and compared with the ability of a highly experienced Toftness operator to detect the 50 μT field. Subsequently, in a clinical setting, FGM1 readings made by an FGM1 technician and Sensometer readings were made by 4 Toftness Sensometer operators, having various degrees of experience with this device. Each examiner obtained instrument readings from 5 different volunteers in separate chiropractic adjusting rooms. Additionally, one of the Toftness Sensometers was equipped with an integrated fluxgate magnetometer (FGM2) and this magnetometer was used to obtain a second set of EMF readings in the clinical setting. Results The triaxial fluxgate magnetometer was determined to be moderately responsive to changes in magnetic field frequency below 10 Hz. At frequencies above 10 Hz the readings corresponded to that of the ambient static geofield. The practitioner operating the Toftness Sensometer was unable to detect magnetic fields at high frequencies (above 10 Hz) even at very high EMFs. The fluxgate magnetometer was shown to be essentially a DC/static magnetic field detector and like all such devices it has a limited frequency range with some low level of sensitivity at very low field frequencies. The interexaminer reliability of four Toftness practitioners using the Sensometer on 5 patients showed low to moderate correlation. Conclusions The fluxgate magnetometer although highly sensitive to static (DC) EMFs has only limited sensitivity to EMFs in the range of 1 to 10 Hz and is very insensitive to frequencies above 10 Hz. In laboratory comparisons of the Sensometer and the fluxgate magnetometer there was an occasional correspondence between the two instruments in detecting magnetic fields within the Merritt coil but these occasions were not reproducible. In the clinical studies there was low to moderate agreement between the clinicians using the Sensometer to diagnosing spinal conditions and there was little if any agreement between the Sensometer and the fluxgate magnetometer in detecting EMFs emanating from the volunteers body surface. PMID:17549105

Gradient isolator for flow field of fuel cell assembly

DOEpatents

Ernst, W.D.

1999-06-15

Isolator(s) include isolating material and optionally gasketing material strategically positioned within a fuel cell assembly. The isolating material is disposed between a solid electrolyte and a metal flow field plate. Reactant fluid carried by flow field plate channel(s) forms a generally transverse electrochemical gradient. The isolator(s) serve to isolate electrochemically a portion of the flow field plate, for example, transversely outward from the channel(s), from the electrochemical gradient. Further, the isolator(s) serve to protect a portion of the solid electrolyte from metallic ions. 4 figs.

Gradient isolator for flow field of fuel cell assembly

DOEpatents

Ernst, William D.

1999-01-01

Isolator(s) include isolating material and optionally gasketing material strategically positioned within a fuel cell assembly. The isolating material is disposed between a solid electrolyte and a metal flow field plate. Reactant fluid carried by flow field plate channel(s) forms a generally transverse electrochemical gradient. The isolator(s) serve to isolate electrochemically a portion of the flow field plate, for example, transversely outward from the channel(s), from the electrochemical gradient. Further, the isolator(s) serve to protect a portion of the solid electrolyte from metallic ions.

Observation of Enhanced Hole Extraction in Br Concentration Gradient Perovskite Materials.

PubMed

Kim, Min-Cheol; Kim, Byeong Jo; Son, Dae-Yong; Park, Nam-Gyu; Jung, Hyun Suk; Choi, Mansoo

2016-09-14

Enhancing hole extraction inside the perovskite layer is the key factor for boosting photovoltaic performance. Realization of halide concentration gradient perovskite materials has been expected to exhibit rapid hole extraction due to the precise bandgap tuning. Moreover, a formation of Br-rich region on the tri-iodide perovskite layer is expected to enhance moisture stability without a loss of current density. However, conventional synthetic techniques of perovskite materials such as the solution process have not achieved the realization of halide concentration gradient perovskite materials. In this report, we demonstrate the fabrication of Br concentration gradient mixed halide perovskite materials using a novel and facile halide conversion method based on vaporized hydrobromic acid. Accelerated hole extraction and enhanced lifetime due to Br gradient was verified by observing photoluminescence properties. Through the combination of secondary ion mass spectroscopy and transmission electron microscopy with energy-dispersive X-ray spectroscopy analysis, the diffusion behavior of Br ions in perovskite materials was investigated. The Br-gradient was found to be eventually converted into a homogeneous mixed halide layer after undergoing an intermixing process. Br-substituted perovskite solar cells exhibited a power conversion efficiency of 18.94% due to an increase in open circuit voltage from 1.08 to 1.11 V and an advance in fill-factor from 0.71 to 0.74. Long-term stability was also dramatically enhanced after the conversion process, i.e., the power conversion efficiency of the post-treated device has remained over 97% of the initial value under high humid conditions (40-90%) without any encapsulation for 4 weeks.

Tanzania: Background and Current Conditions

DTIC Science & Technology

2010-12-08

movement of refugees. Societal violence against women and persons with albinism and women persisted. Female genital mutilation (FGM), especially of...Zanzibar /islands over 99% Muslim Literacy: Male, 77.5%; Female , 66.2% (2003) Under-5 Mortality: 165 deaths/1,000 live births HIV/AIDS adult...infection rate: 6.2% (2007) Life Expectancy, years at birth: Male, 50.5 Female , 53.5 (2009 est.) Sources: CIA World Factbook 2010. Tanzania

Tanzania: Background and Current Conditions

DTIC Science & Technology

2010-07-23

persons with albinism and women persisted. Female genital mutilation (FGM), especially of young girls, continued to be practiced. Trafficking in...35%; Zanzibar /islands over 99% Muslim Literacy: Male, 77.5%; Female , 66.2% (2003) Under-5 Mortality: 165 deaths/1,000 live births HIV/AIDS adult...infection rate: 6.2% (2007) Life Expectancy, years at birth: Male, 50.5 Female , 53.5 (2009 est.) Sources: CIA World Factbook 2010. Tanzania

Egypt: Background and U.S. Relations

DTIC Science & Technology

2006-06-14

genital mutilation (FGM) remained a serious problem due to widespread cultural acceptance, despite the government’s attempts to eliminate the practice... female ) Unemployment Rate: 15%-20% (est.) External Debt: (as % of GDP) $33 billion 37.8% Source: U.S. Central Intelligence Agency World Factbook 2005. CRS...group’s members have been detained. In May 2005, female Kefaya activists accused Egyptian police officers of sexually assaulting female protesters

The nearly neutral and selection theories of molecular evolution under the fisher geometrical framework: substitution rate, population size, and complexity.

PubMed

Razeto-Barry, Pablo; Díaz, Javier; Vásquez, Rodrigo A

2012-06-01

The general theories of molecular evolution depend on relatively arbitrary assumptions about the relative distribution and rate of advantageous, deleterious, neutral, and nearly neutral mutations. The Fisher geometrical model (FGM) has been used to make distributions of mutations biologically interpretable. We explored an FGM-based molecular model to represent molecular evolutionary processes typically studied by nearly neutral and selection models, but in which distributions and relative rates of mutations with different selection coefficients are a consequence of biologically interpretable parameters, such as the average size of the phenotypic effect of mutations and the number of traits (complexity) of organisms. A variant of the FGM-based model that we called the static regime (SR) represents evolution as a nearly neutral process in which substitution rates are determined by a dynamic substitution process in which the population's phenotype remains around a suboptimum equilibrium fitness produced by a balance between slightly deleterious and slightly advantageous compensatory substitutions. As in previous nearly neutral models, the SR predicts a negative relationship between molecular evolutionary rate and population size; however, SR does not have the unrealistic properties of previous nearly neutral models such as the narrow window of selection strengths in which they work. In addition, the SR suggests that compensatory mutations cannot explain the high rate of fixations driven by positive selection currently found in DNA sequences, contrary to what has been previously suggested. We also developed a generalization of SR in which the optimum phenotype can change stochastically due to environmental or physiological shifts, which we called the variable regime (VR). VR models evolution as an interplay between adaptive processes and nearly neutral steady-state processes. When strong environmental fluctuations are incorporated, the process becomes a selection model in which evolutionary rate does not depend on population size, but is critically dependent on the complexity of organisms and mutation size. For SR as well as VR we found that key parameters of molecular evolution are linked by biological factors, and we showed that they cannot be fixed independently by arbitrary criteria, as has usually been assumed in previous molecular evolutionary models.

The Nearly Neutral and Selection Theories of Molecular Evolution Under the Fisher Geometrical Framework: Substitution Rate, Population Size, and Complexity

PubMed Central

Razeto-Barry, Pablo; Díaz, Javier; Vásquez, Rodrigo A.

2012-01-01

The general theories of molecular evolution depend on relatively arbitrary assumptions about the relative distribution and rate of advantageous, deleterious, neutral, and nearly neutral mutations. The Fisher geometrical model (FGM) has been used to make distributions of mutations biologically interpretable. We explored an FGM-based molecular model to represent molecular evolutionary processes typically studied by nearly neutral and selection models, but in which distributions and relative rates of mutations with different selection coefficients are a consequence of biologically interpretable parameters, such as the average size of the phenotypic effect of mutations and the number of traits (complexity) of organisms. A variant of the FGM-based model that we called the static regime (SR) represents evolution as a nearly neutral process in which substitution rates are determined by a dynamic substitution process in which the population’s phenotype remains around a suboptimum equilibrium fitness produced by a balance between slightly deleterious and slightly advantageous compensatory substitutions. As in previous nearly neutral models, the SR predicts a negative relationship between molecular evolutionary rate and population size; however, SR does not have the unrealistic properties of previous nearly neutral models such as the narrow window of selection strengths in which they work. In addition, the SR suggests that compensatory mutations cannot explain the high rate of fixations driven by positive selection currently found in DNA sequences, contrary to what has been previously suggested. We also developed a generalization of SR in which the optimum phenotype can change stochastically due to environmental or physiological shifts, which we called the variable regime (VR). VR models evolution as an interplay between adaptive processes and nearly neutral steady-state processes. When strong environmental fluctuations are incorporated, the process becomes a selection model in which evolutionary rate does not depend on population size, but is critically dependent on the complexity of organisms and mutation size. For SR as well as VR we found that key parameters of molecular evolution are linked by biological factors, and we showed that they cannot be fixed independently by arbitrary criteria, as has usually been assumed in previous molecular evolutionary models. PMID:22426879

Robotic Tactile Sensors Fabricated from a Monolithic Silicon Integrated Circuit and a Piezoelectric Polyvinylidene Fluoride Thin Film

DTIC Science & Technology

1991-12-01

gradient will be presented. -Finally, a brief discussion of various piezoelectric materials will be presented, including Rochelle salt, quartz, barium...consideringr a microscopic-level dipole arrangement. The strain induced by ain external force or a tempem at ure gradient changes hie orientation of the...pyroelectric materials, an externally applied temperature gradient can be related to the resulting polarization by a l)yroelectric * constant.1 p (130

Fabrication and microstructures of functional gradient SiBCN–Nb composite by hot pressing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sun, Min, E-mail: lcxsunmin@163.com; Fu, Ruoyu; Chen, Jun

2016-04-15

A functional gradient material with five layers composed of SiBCN ceramic and niobium (Nb) was prepared successfully by hot pressing. The phase composition, morphology features and microstructures were investigated in each layer of the gradient material. The Nb-containing compounds involving NbC, Nb{sub 6}C{sub 5}, Nb{sub 4}C{sub 3}, Nb{sub 5}Si{sub 3} and NbN increase with the volume fraction of Nb increasing in the sub-layer. They are randomly scattered (≤ 25 vol.% Nb), then strip-like, and finally distribute continuously (≥ 75 vol.% Nb). The size of BN(C) and SiC grains in Nb-containing layers is larger than in 100% SiBCN layer due tomore » the loss of the capsule-like structures. No distinct interfaces form in the transition regions indicating the gradual changes in phase composition and microstructures. - Highlights: • A functional gradient SiBCN–Nb material was prepared successfully by hot pressing. • Phase composition, morphology features and microstructures were investigated. • Thermodynamic calculation was used to aid in the phase analysis. • No distinct interfaces form typical of the functional gradient material.« less

High-gradient permanent magnet apparatus and its use in particle collection

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cheng, Mengdawn; Ludtka, Gerard Michael; Avens, Larry R.

A high-gradient permanent magnet apparatus for capturing paramagnetic particles, the apparatus comprising: (i) at least two permanent magnets positioned with like poles facing each other; (ii) a ferromagnetic spacer separating the like poles; and (iii) a magnetizable porous filling material in close proximity to the at least two permanent magnets. Also described is a method for capturing paramagnetic particles in which a gas or liquid sample containing the paramagnetic particles is contacted with the high-gradient permanent magnet apparatus described above; wherein, during the contacting step, the gas or liquid sample contacts the magnetizable porous filling material of the high-gradient permanentmore » magnet apparatus, and at least a portion of the paramagnetic particles in the gas or liquid sample is captured on the magnetizable porous filling material.« less

Effect of the laser heat treatment on the formation of the gradient structures in alloys based on Fe - Cr - Ni system

NASA Astrophysics Data System (ADS)

Andreev, A. O.; Bykovskiy, D. P.; Osintsev, A. V.; Petrovskiy, V. N.; Ryashko, I. I.; Blinova, E. N.; Libman, M. A.; Glezer, A. M.

2017-12-01

The possibility of producing gradient materials, i.e. materials with pre-set distribution of areas having fundamentally different physical and mechanical characteristics, with the help of laser heat treatment was investigated. Using as an example austenitic-martensitic alloys of iron-chromium-nickel, subjected to cold plastic deformation led to formation of martensite, we show that using laser at the temperature higher than the temperature of reverse martensite transformation leads to the formation of areas of high-strength austenite having predetermined form inside the martensite matrix. Influence of austenite areas geometry on mechanical properties of gradient material was studied.

Low-Resolution Screening of Early Stage Acquisition Simulation Scenario Development Decisions

DTIC Science & Technology

2012-12-01

6 seconds) incorporating reload times and assumptions. Phit for min range is assumed to be 100% (excepting FGM- 148, which was estimated for a...User Interface HTN Hierarchical Task Network MCCDC Marine Corps Combat Development Command Phit Probability to hit the intended target Pkill...well beyond the scope of this study. 5. Weapon Capabilities Translation COMBATXXI develops situation probabilities to hit ( Phit ) and probabilities to

Computational Study of a Functionally Graded Ceramic-Metallic Armor

DTIC Science & Technology

2006-12-15

UNCLAS –Dist. A - Approved for public release Computational Study of a Functionally Graded Ceramic-Metallic Armor Douglas W. Templeton1, Tara J...efficiency of a postulated FGM ceramic-metallic armor system composed of aluminum nitride (AlN) and aluminum. The study had two primary...2006 2. REPORT TYPE N/ A 3. DATES COVERED - 4. TITLE AND SUBTITLE Computational Study of a Functionally Graded Ceramic-Metallic Armor 5a

Texture Segregation Causes Early Figure Enhancement and Later Ground Suppression in Areas V1 and V4 of Visual Cortex

PubMed Central

Poort, Jasper; Self, Matthew W.; van Vugt, Bram; Malkki, Hemi; Roelfsema, Pieter R.

2016-01-01

Segregation of images into figures and background is fundamental for visual perception. Cortical neurons respond more strongly to figural image elements than to background elements, but the mechanisms of figure–ground modulation (FGM) are only partially understood. It is unclear whether FGM in early and mid-level visual cortex is caused by an enhanced response to the figure, a suppressed response to the background, or both. We studied neuronal activity in areas V1 and V4 in monkeys performing a texture segregation task. We compared texture-defined figures with homogeneous textures and found an early enhancement of the figure representation, and a later suppression of the background. Across neurons, the strength of figure enhancement was independent of the strength of background suppression. We also examined activity in the different V1 layers. Both figure enhancement and ground suppression were strongest in superficial and deep layers and weaker in layer 4. The current–source density profiles suggested that figure enhancement was caused by stronger synaptic inputs in feedback-recipient layers 1, 2, and 5 and ground suppression by weaker inputs in these layers, suggesting an important role for feedback connections from higher level areas. These results provide new insights into the mechanisms for figure–ground organization. PMID:27522074

A method for combining search coil and fluxgate magnetometer data to reveal finer structures in reconnection physics

NASA Astrophysics Data System (ADS)

Argall, M. R.; Caide, A.; Chen, L.; Torbert, R. B.

2012-12-01

Magnetometers have been used to measure terrestrial and extraterrestrial magnetic fields in space exploration ever since Sputnik 3. Modern space missions, such as Cluster, RBSP, and MMS incorporate both search coil magnetometers (SCMs) and fluxgate magnetometers (FGMs) in their instrument suites: FGMs work well at low frequencies while SCMs perform better at high frequencies. In analyzing the noise floor of these instruments, a cross-over region is apparent around 0.3-1.5Hz. The satellite separation of MMS and average speeds of field convection and plasma flows at the subsolar magnetopause make this a crucial range for the upcoming MMS mission. The method presented here combines the signals from SCM and FGM by taking a weighted average of both in this frequency range in order to draw out key features, such as narrow current sheet structures, that would otherwise not be visible. The technique is applied to burst mode Cluster data for reported magnetopause and magnetotail reconnection events to demonstrate the power of the combined data. This technique is also applied to data from the the EMFISIS instrument on the RBSP mission. The authors acknowledge and thank the FGM and STAFF team for the use of their data from the CLUSTER Active Archive.

Time Prediction Models for Echinococcosis Based on Gray System Theory and Epidemic Dynamics

PubMed Central

Zhang, Liping; Wang, Li; Zheng, Yanling; Wang, Kai; Zhang, Xueliang; Zheng, Yujian

2017-01-01

Echinococcosis, which can seriously harm human health and animal husbandry production, has become an endemic in the Xinjiang Uygur Autonomous Region of China. In order to explore an effective human Echinococcosis forecasting model in Xinjiang, three grey models, namely, the traditional grey GM(1,1) model, the Grey-Periodic Extensional Combinatorial Model (PECGM(1,1)), and the Modified Grey Model using Fourier Series (FGM(1,1)), in addition to a multiplicative seasonal ARIMA(1,0,1)(1,1,0)4 model, are applied in this study for short-term predictions. The accuracy of the different grey models is also investigated. The simulation results show that the FGM(1,1) model has a higher performance ability, not only for model fitting, but also for forecasting. Furthermore, considering the stability and the modeling precision in the long run, a dynamic epidemic prediction model based on the transmission mechanism of Echinococcosis is also established for long-term predictions. Results demonstrate that the dynamic epidemic prediction model is capable of identifying the future tendency. The number of human Echinococcosis cases will increase steadily over the next 25 years, reaching a peak of about 1250 cases, before eventually witnessing a slow decline, until it finally ends. PMID:28273856

Expression profiles of antimicrobial peptides in the genital tract of women using progesterone intrauterine devices versus combined oral contraceptives.

PubMed

Introini, Andrea; Kaldensjö, Tove; Hirbod, Taha; Röhl, Maria; Tjernlund, Annelie; Andersson, Sonia; Broliden, Kristina

2014-11-01

Sex hormones can influence the immune defenses of the female genital tract (FGT) and its susceptibility to infections. Here we investigated the effect of different hormonal contraceptives on the production of antimicrobial peptides (AMPs) in different compartments of the female genital mucosa (FGM), secretions and tissue. Cervicovaginal secretions (CVS) and ectocervical tissue samples obtained from women using progesterone intrauterine devices (pIUD) (n = 23) and combined oral contraceptives (COC) (n = 23) were analyzed for the expression and in situ localization of HNP1-3, BD-2, LL-37, SLPI and trappin-2 by ELISA, real-time PCR and immunohistochemistry. Women using COC had significantly lower mRNA levels of BD-2 and trappin-2 in ectocervical tissue than pIUD users. The two groups showed no differences in CVS concentration, as well as similar in situ expression patterns in ectocervical tissue, of all five AMPs. The use of hormonal contraceptives influences AMP expression differently in genital secretions compared to ectocervical tissue. This suggests that the impact of sex hormones on local immune defenses varies in different compartments of the FGM, and likely in different locations across the FGT. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

A high-sensitivity electrochemical aptasensor of carcinoembryonic antigen based on graphene quantum dots-ionic liquid-nafion nanomatrix and DNAzyme-assisted signal amplification strategy.

PubMed

Huang, Jing-Yi; Zhao, Lang; Lei, Wan; Wen, Wei; Wang, Yi-Jia; Bao, Ting; Xiong, Hua-Yu; Zhang, Xiu-Hua; Wang, Sheng-Fu

2018-01-15

In this work, we have developed an electrochemical aptasensor for high-sensitivity determination of carcinoembryonic antigen (CEA) based on lead ion (Pb 2+ )-dependent DNAzyme-assisted signal amplification and graphene quantum dot-ionic liquid-nafion (GQDs-IL-NF) composite film. We designed hairpin DNA containing CEA-specific aptamers and DNAzyme chains. In the presence of CEA, hairpin DNA recognized the target and performed a DNAzyme-assisted signal amplification reaction to yield a large number of single-stranded DNA. The GQDs-IL-NF composite film was immobilized on the glassy carbon electrode for the interaction with single-stranded DNA through noncovalent π-π stacking interaction. Therefore, the methylene blue-labeled substrate DNA (MB-substrate) was fixed on the electrode and exhibited an initial electrochemical signal. Under optimal conditions, the response current change was proportional to the concentration of CEA, demonstrating a wide linear range from 0.5fgmL -1 to 0.5ngmL -1 , with a low detection limit of 0.34fgmL -1 . Furthermore, the proposed aptasensor was successfully applied in determining CEA in serum samples, showing its superior prospects in clinical diagnosis. Copyright © 2017 Elsevier B.V. All rights reserved.

Gradient Plasticity Model and its Implementation into MARMOT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Barker, Erin I.; Li, Dongsheng; Zbib, Hussein M.

2013-08-01

The influence of strain gradient on deformation behavior of nuclear structural materials, such as boby centered cubic (bcc) iron alloys has been investigated. We have developed and implemented a dislocation based strain gradient crystal plasticity material model. A mesoscale crystal plasticity model for inelastic deformation of metallic material, bcc steel, has been developed and implemented numerically. Continuum Dislocation Dynamics (CDD) with a novel constitutive law based on dislocation density evolution mechanisms was developed to investigate the deformation behaviors of single crystals, as well as polycrystalline materials by coupling CDD and crystal plasticity (CP). The dislocation density evolution law in thismore » model is mechanism-based, with parameters measured from experiments or simulated with lower-length scale models, not an empirical law with parameters back-fitted from the flow curves.« less

Translucency and masking ability of various composite resins at different thicknesses.

PubMed

Darabi, Farideh; Radafshar, Golpar; Tavangar, Maryam; Davaloo, Reza; Khosravian, Aref; Mirfarhadi, Nastaran

2014-09-01

Optical properties of the composite resins, concerning their translucency and thickness, are affected by discolored tooth structure or inherent darkness of the oral cavity. This study aimed to compare the translucency parameter (TP) of five different composite resins in different thicknesses and to evaluate their masking ability in black backgrounds. Five brands of composite resins; Gradia (GC) and Crystalline (Confi-dental) in opaque A2 (OA2), Vit-l-escence (Ultradent) in opaque snow (OS), Herculite XRV (Kerr) and Opallis (FGM) in dentin A2 (DA2) shades were selected to enroll the study. Color coordinates of each composite were determined at 0.5, 1, and 1.5 mm thicknesses on a white backing, the backing of material itself and a black backing were calculated by using a spectrophotometer to evaluate the translucency parameter (TP) of the study materials. The masking ability was also calculated from the specimens on the material itself and on black backing. The values under 2 were estimated as imperceptible. One-way ANOVA, T-test and Tukey HSD were employed for statistical analysis. The masking ability values, recorded for the 1.5 mm-thick specimens, were in the range of imperceptible except for the Herculite. There was no difference in TP values of the materials at 1.5 mm thickness. Opaque snow shade of Vit-l-escence and opaque A2 shade of Gradia showed lower TP values in comparison with the other 1 and 0.5 mm-thick materials and this difference was statistically significant (p< 0.05). In relatively thin thicknesses (≤1mm), these opaque/dentin shade composite resins could not mask the black background color.

Efficient Reformulation of the Thermoelastic Higher-order Theory for Fgms

NASA Technical Reports Server (NTRS)

Bansal, Yogesh; Pindera, Marek-Jerzy; Arnold, Steven M. (Technical Monitor)

2002-01-01

Functionally graded materials (FGMs) are characterized by spatially variable microstructures which are introduced to satisfy given performance requirements. The microstructural gradation gives rise to continuously or discretely changing material properties which complicate FGM analysis. Various techniques have been developed during the past several decades for analyzing traditional composites and many of these have been adapted for the analysis of FGMs. Most of the available techniques use the so-called uncoupled approach in order to analyze graded structures. These techniques ignore the effect of microstructural gradation by employing specific spatial material property variations that are either assumed or obtained by local homogenization. The higher-order theory for functionally graded materials (HOTFGM) is a coupled approach developed by Aboudi et al. (1999) which takes the effect of microstructural gradation into consideration and does not ignore the local-global interaction of the spatially variable inclusion phase(s). Despite its demonstrated utility, however, the original formulation of the higher-order theory is computationally intensive. Herein, an efficient reformulation of the original higher-order theory for two-dimensional elastic problems is developed and validated. The use of the local-global conductivity and local-global stiffness matrix approach is made in order to reduce the number of equations involved. In this approach, surface-averaged quantities are the primary variables which replace volume-averaged quantities employed in the original formulation. The reformulation decreases the size of the global conductivity and stiffness matrices by approximately sixty percent. Various thermal, mechanical, and combined thermomechanical problems are analyzed in order to validate the accuracy of the reformulated theory through comparison with analytical and finite-element solutions. The presented results illustrate the efficiency of the reformulation and its advantages in analyzing functionally graded materials.

User's Manual and Final Report for Hot-SMAC GUI Development

NASA Technical Reports Server (NTRS)

Yarrington, Phil

2001-01-01

A new software package called Higher Order Theory-Structural/Micro Analysis Code (HOT-SMAC) has been developed as an effective alternative to the finite element approach for Functionally Graded Material (FGM) modeling. HOT-SMAC is a self-contained package including pre- and post-processing through an intuitive graphical user interface, along with the well-established Higher Order Theory for Functionally Graded Materials (HOTFGM) thermomechanical analysis engine. This document represents a Getting Started/User's Manual for HOT-SMAC and a final report for its development. First, the features of the software are presented in a simple step-by-step example where a HOT-SMAC model representing a functionally graded material is created, mechanical and thermal boundary conditions are applied, the model is analyzed and results are reviewed. In a second step-by-step example, a HOT-SMAC model of an actively cooled metallic channel with ceramic thermal barrier coating is built and analyzed. HOT-SMAC results from this model are compared to recently published results (NASA/TM-2001-210702) for two grid densities. Finally, a prototype integration of HOTSMAC with the commercially available HyperSizer(R) structural analysis and sizing software is presented. In this integration, local strain results from HyperSizer's structural analysis are fed to a detailed HOT-SMAC model of the flange-to-facesheet bond region of a stiffened panel. HOT-SMAC is then used to determine the peak shear and peel (normal) stresses between the facesheet and bonded flange of the panel and determine the "free edge" effects.

Lateral Temperature-Gradient Method for High-Throughput Characterization of Material Processing by Millisecond Laser Annealing.

PubMed

Bell, Robert T; Jacobs, Alan G; Sorg, Victoria C; Jung, Byungki; Hill, Megan O; Treml, Benjamin E; Thompson, Michael O

2016-09-12

A high-throughput method for characterizing the temperature dependence of material properties following microsecond to millisecond thermal annealing, exploiting the temperature gradients created by a lateral gradient laser spike anneal (lgLSA), is presented. Laser scans generate spatial thermal gradients of up to 5 °C/μm with peak temperatures ranging from ambient to in excess of 1400 °C, limited only by laser power and materials thermal limits. Discrete spatial property measurements across the temperature gradient are then equivalent to independent measurements after varying temperature anneals. Accurate temperature calibrations, essential to quantitative analysis, are critical and methods for both peak temperature and spatial/temporal temperature profile characterization are presented. These include absolute temperature calibrations based on melting and thermal decomposition, and time-resolved profiles measured using platinum thermistors. A variety of spatially resolved measurement probes, ranging from point-like continuous profiling to large area sampling, are discussed. Examples from annealing of III-V semiconductors, CdSe quantum dots, low-κ dielectrics, and block copolymers are included to demonstrate the flexibility, high throughput, and precision of this technique.

Representing Matrix Cracks Through Decomposition of the Deformation Gradient Tensor in Continuum Damage Mechanics Methods

NASA Technical Reports Server (NTRS)

Leone, Frank A., Jr.

2015-01-01

A method is presented to represent the large-deformation kinematics of intraply matrix cracks and delaminations in continuum damage mechanics (CDM) constitutive material models. The method involves the additive decomposition of the deformation gradient tensor into 'crack' and 'bulk material' components. The response of the intact bulk material is represented by a reduced deformation gradient tensor, and the opening of an embedded cohesive interface is represented by a normalized cohesive displacement-jump vector. The rotation of the embedded interface is tracked as the material deforms and as the crack opens. The distribution of the total local deformation between the bulk material and the cohesive interface components is determined by minimizing the difference between the cohesive stress and the bulk material stress projected onto the cohesive interface. The improvements to the accuracy of CDM models that incorporate the presented method over existing approaches are demonstrated for a single element subjected to simple shear deformation and for a finite element model of a unidirectional open-hole tension specimen. The material model is implemented as a VUMAT user subroutine for the Abaqus/Explicit finite element software. The presented deformation gradient decomposition method reduces the artificial load transfer across matrix cracks subjected to large shearing deformations, and avoids the spurious secondary failure modes that often occur in analyses based on conventional progressive damage models.

Separation of cells from the rat anterior pituitary gland

NASA Technical Reports Server (NTRS)

Hymer, Wesley C.; Hatfield, J. Michael

1983-01-01

Various techniques for separating the hormone-producing cell types from the rat anterior pituitary gland are examined. The purity, viability, and responsiveness of the separated cells depend on the physiological state of the donor, the tissue dissociation procedures, the staining technique used for identification of cell type, and the cell separation technique. The chamber-gradient setup and operation, the characteristics of the gradient materials, and the separated cell analysis of velocity sedimentation techniques (in particular Staput and Celsep) are described. Consideration is given to the various types of materials used in density gradient centrifugation and the operation of a gradient generating device. The use of electrophoresis to separate rat pituitary cells is discussed.

Spatial gradient tuning in metamaterials

NASA Astrophysics Data System (ADS)

Driscoll, Tom; Goldflam, Michael; Jokerst, Nan; Basov, Dimitri; Smith, David

2011-03-01

Gradient Index (GRIN) metamaterials have been used to create devices inspired by, but often surpassing the potential of, conventional GRIN optics. The unit-cell nature of metamaterials presents the opportunity to exert much greater control over spatial gradients than is possible in natural materials. This is true not only during the design phase but also offers the potential for real-time reconfiguration of the metamaterial gradient. This ability fits nicely into the picture of transformation-optics, in which spatial gradients can enable an impressive suite of innovative devices. We discuss methods to exert control over metamaterial response, focusing on our recent demonstrations using Vanadium Dioxide. We give special attention to role of memristance and mem-capacitance observed in Vanadium Dioxide, which simplify the demands of stimuli and addressing, as well as intersecting metamaterials with the field of memory-materials.

Designing optimal nanofocusing with a gradient hyperlens

NASA Astrophysics Data System (ADS)

Shen, Lian; Prokopeva, Ludmila J.; Chen, Hongsheng; Kildishev, Alexander V.

2017-11-01

We report the design of a high-throughput gradient hyperbolic lenslet built with real-life materials and capable of focusing a beam into a deep sub-wavelength spot of λ/23. This efficient design is achieved through high-order transformation optics and circular effective-medium theory (CEMT), which are used to engineer the radially varying anisotropic artificial material based on the thin alternating cylindrical metal and dielectric layers. The radial gradient of the effective anisotropic optical constants allows for matching the impedances at the input and output interfaces, drastically improving the throughput of the lenslet. However, it is the use of the zeroth-order CEMT that enables the practical realization of a gradient hyperlens with realistic materials. To illustrate the importance of using the CEMT versus the conventional planar effective-medium theory (PEMT) for cylindrical anisotropic systems, such as our hyperlens, both the CEMT and PEMT are adopted to design gradient hyperlenses with the same materials and order of elemental layers. The CEMT- and PEMT-based designs show similar performance if the number of metal-dielectric binary layers is sufficiently large (9+ pairs) and if the layers are sufficiently thin. However, for the manufacturable lenses with realistic numbers of layers (e.g. five pairs) and thicknesses, the performance of the CEMT design continues to be practical, whereas the PEMT-based design stops working altogether. The accurate design of transformation optics-based layered cylindrical devices enabled by CEMT allow for a new class of robustly manufacturable nanophotonic systems, even with relatively thick layers of real-life materials.

A review of gradient stiffness hydrogels used in tissue engineering and regenerative medicine.

PubMed

Xia, Tingting; Liu, Wanqian; Yang, Li

2017-06-01

Substrate stiffness is known to impact characteristics including cell differentiation, proliferation, migration and apoptosis. Hydrogels are polymeric materials distinguished by high water content and diverse physical properties. Gradient stiffness hydrogels are designed by the need to develop biologically friendly materials as extracellular matrix (ECM) alternatives to replace the separated and narrow-ranged hydrogel substrates. Important new discoveries in cell behaviors have been realized with model gradient stiffness hydrogel systems from the two-dimensional (2D) to three-dimensional (3D) scale. Basic and clinical applications for gradient stiffness hydrogels in tissue engineering and regenerative medicine continue to drive the development of stiffness and structure varied hydrogels. Given the importance of gradient stiffness hydrogels in basic research and biomedical applications, there is a clear need for systems for gradient stiffness hydrogel design strategies and their applications. This review will highlight past work in the field of gradient stiffness hydrogels fabrication methods, mechanical property test, applications as well as areas for future study. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 1799-1812, 2017. © 2017 Wiley Periodicals, Inc.

Engineering Ferroic and Multiferroic Materials for Active Cooling Applications

DTIC Science & Technology

2014-02-11

large strain gradients (>105 m-1) – nearly 5-6 orders of magnitude larger than what can be achieved in bulk-versions of materials. These large strain...larger than what can be achieved in bulk-versions of materials. These large strain gradients gave rise to unexpected crystal and domain structure...parameters that are more favorable for generating a compressively strained variety of the Zr-rich phases. In this case, akin to what has been

Designing gradient coils with reduced hot spot temperatures.

PubMed

While, Peter T; Forbes, Larry K; Crozier, Stuart

2010-03-01

Gradient coil temperature is an important concern in the design and construction of MRI scanners. Closely spaced gradient coil windings cause temperature hot spots within the system as a result of Ohmic heating associated with large current being driven through resistive material, and can strongly affect the performance of the coils. In this paper, a model is presented for predicting the spatial temperature distribution of a gradient coil, including the location and extent of temperature hot spots. Subsequently, a method is described for designing gradient coils with improved temperature distributions and reduced hot spot temperatures. Maximum temperature represents a non-linear constraint and a relaxed fixed point iteration routine is proposed to adjust coil windings iteratively to minimise this coil feature. Several examples are considered that assume different thermal material properties and cooling mechanisms for the gradient system. Coil winding solutions are obtained for all cases considered that display a considerable drop in hot spot temperature (>20%) when compared to standard minimum power gradient coils with equivalent gradient homogeneity, efficiency and inductance. The method is semi-analytical in nature and can be adapted easily to consider other non-linear constraints in the design of gradient coils or similar systems. Crown Copyright (c) 2009. Published by Elsevier Inc. All rights reserved.

Edge remap for solids

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kamm, James R.; Love, Edward; Robinson, Allen C.

We review the edge element formulation for describing the kinematics of hyperelastic solids. This approach is used to frame the problem of remapping the inverse deformation gradient for Arbitrary Lagrangian-Eulerian (ALE) simulations of solid dynamics. For hyperelastic materials, the stress state is completely determined by the deformation gradient, so remapping this quantity effectively updates the stress state of the material. A method, inspired by the constrained transport remap in electromagnetics, is reviewed, according to which the zero-curl constraint on the inverse deformation gradient is implicitly satisfied. Open issues related to the accuracy of this approach are identified. An optimization-based approachmore » is implemented to enforce positivity of the determinant of the deformation gradient. The efficacy of this approach is illustrated with numerical examples.« less

Polychromatic microdiffraction characterization of defect gradients in severely deformed materials.

PubMed

Barabash, Rozaliya I; Ice, Gene E; Liu, Wenjun; Barabash, Oleg M

2009-01-01

This paper analyzes local lattice rotations introduced in severely deformed polycrystalline titanium by friction stir welding. Nondestructive three-dimensional (3D) spatially resolved polychromatic X-ray microdiffraction, is used to resolve the local crystal structure of the restructured surface from neighboring local structures in the sample material. The measurements reveal strong gradients of strain and geometrically necessary dislocations near the surface and illustrate the potential of polychromatic microdiffraction for the study of deformation in complex materials systems.

Chromatic Properties of Index of Refraction Gradients in Glass.

NASA Astrophysics Data System (ADS)

Ryan-Howard, Danette Patrice

The chromatic properties of index of refraction gradients have been predicted theoretically and verified experimentally. The use of these materials in the design of color corrected optical systems has been investigated and confirmed by the evaluation of two fabricated lenses. A model for the chromatic properties of gradient index materials has been developed. The index of refraction is calculated based on the composition of the material. Since the index of refraction and the conventional Abbe number change as a function of the composition of the glass, a gradient Abbe number and a partial dispersion are defined. Analysis of combinations of ion exchange pairs and glasses result in a wide range of gradient Abbe numbers and partial dispersions. These ranges can be further extended by using glasses which contain more than one exchange ion or by using mixed salt baths. The chromatic properties were measured with a multiple wavelength A.C. interferometer. The gradient Abbe numbers and partial dispersions for a number of samples were calculated. Evaluation of the samples showed that the index and dispersion data correlated well with that predicted by the model. Thin lens formulae for the paraxial axial color and secondary spectrum of a radial gradient singlet with curves were examined. The design of a single element 10x microscope objective verified the applicability of these formulae. The design of a two element 40x microscope objective showed that a six element diffraction limited 40x objective can be replaced with a two element system composed of one homogeneous lens and one gradient lens without sacrificing either monochromatic performance or color correction. A previously fabricated axial gradient collimator and a fabricated Wood element were evaluated. Correlation of the directly measured quantities, paraxial axial color, secondary spectrum and spherochromatism with the values predicted by the model verified that the predicted superior performance of gradient-index lenses can be obtained.

Methods and apparatus for moving and separating materials exhibiting different physical properties

DOEpatents

Peterson, Stephen C.; Brimhall, Owen D.; McLaughlin, Thomas J.; Baker, Charles D.; Sparks, Sam L.

1991-01-01

Methods and apparatus for controlling the movement of materials having different physical properties when one of the materials is a fluid. The invention does not rely on flocculation, sedimentation, centrifugation, the buoyancy of the materials, or any other gravity dependent characteristic, in order to achieve its desired results. The methods of the present invention provide that a first acoustic wave is propagated through a vessel containing the materials. A second acoustic wave, at a frequency different than the first acoustic wave, is also propagated through the vessel so that the two acoustic waves are superimposed upon each other. The superimposition of the two waves creates a beat frequency wave. The beat frequency wave comprises pressure gradients dividing regions of maximum and minimum pressure. The pressure gradients and the regions of maximum and minimum pressure move through space and time at a group velocity. The moving pressure gradients and regions of maximum and minimum pressure act upon the materials so as to move one of the materials towards a predetermined location in the vessel. The present invention provides that the materials may be controllably moved toward a location, aggregated at a particular location, or physically separated from each other.

Evading the strength–ductility trade-off dilemma in steel through gradient hierarchical nanotwins

PubMed Central

Wei, Yujie; Li, Yongqiang; Zhu, Lianchun; Liu, Yao; Lei, Xianqi; Wang, Gang; Wu, Yanxin; Mi, Zhenli; Liu, Jiabin; Wang, Hongtao; Gao, Huajian

2014-01-01

The strength–ductility trade-off has been a long-standing dilemma in materials science. This has limited the potential of many structural materials, steels in particular. Here we report a way of enhancing the strength of twinning-induced plasticity steel at no ductility trade-off. After applying torsion to cylindrical twinning-induced plasticity steel samples to generate a gradient nanotwinned structure along the radial direction, we find that the yielding strength of the material can be doubled at no reduction in ductility. It is shown that this evasion of strength–ductility trade-off is due to the formation of a gradient hierarchical nanotwinned structure during pre-torsion and subsequent tensile deformation. A series of finite element simulations based on crystal plasticity are performed to understand why the gradient twin structure can cause strengthening and ductility retention, and how sequential torsion and tension lead to the observed hierarchical nanotwinned structure through activation of different twinning systems. PMID:24686581

Texture Segregation Causes Early Figure Enhancement and Later Ground Suppression in Areas V1 and V4 of Visual Cortex.

PubMed

Poort, Jasper; Self, Matthew W; van Vugt, Bram; Malkki, Hemi; Roelfsema, Pieter R

2016-10-01

Segregation of images into figures and background is fundamental for visual perception. Cortical neurons respond more strongly to figural image elements than to background elements, but the mechanisms of figure-ground modulation (FGM) are only partially understood. It is unclear whether FGM in early and mid-level visual cortex is caused by an enhanced response to the figure, a suppressed response to the background, or both.We studied neuronal activity in areas V1 and V4 in monkeys performing a texture segregation task. We compared texture-defined figures with homogeneous textures and found an early enhancement of the figure representation, and a later suppression of the background. Across neurons, the strength of figure enhancement was independent of the strength of background suppression.We also examined activity in the different V1 layers. Both figure enhancement and ground suppression were strongest in superficial and deep layers and weaker in layer 4. The current-source density profiles suggested that figure enhancement was caused by stronger synaptic inputs in feedback-recipient layers 1, 2, and 5 and ground suppression by weaker inputs in these layers, suggesting an important role for feedback connections from higher level areas. These results provide new insights into the mechanisms for figure-ground organization. © The Author 2016. Published by Oxford University Press.

Microstructure and Properties of Thermally Sprayed Functionally Graded Coatings for Polymeric Substrates

NASA Technical Reports Server (NTRS)

Ivosevic, M.; Knight, R.; Kalidindi, S. R.; Palmese, G. R.; Sutter, J. K.

2003-01-01

The use of polymer matrix composites (PMCs) in the gas flow path of advanced turbine engines offers significant benefits for aircraft engine performance but their useful lifetime is limited by their poor erosion resistance. High velocity oxy-fuel (HVOF) sprayed polymer/cermet functionally graded (FGM) coatings are being investigated as a method to address this technology gap by providing erosion and oxidation protection to polymer matrix composites. The FGM coating structures are based on a polyimide matrix filled with varying volume fractions of WC-Co. The graded coating architecture was produced using a combination of internal and external feedstock injection, via two computer-controlled powder feeders and controlled substrate preheating. Porosity, coating thickness and volume fraction of the WC-Co filler retained in the coatings were determined using standard metallographic techniques and computer image analysis. The pull-off strength (often referred to as the adhesive strength) of the coatings was evaluated according to the ASTM D 4541 standard test method, which measured the greatest normal tensile force that the coating could withstand. Adhesive/cohesive strengths were determined for three different types of coating structures and compared based on the maximum indicated load and the surface area loaded. The nature and locus of the fractures were characterized according to the percent of adhesive and/or cohesive failure, and the tested interfaces and layers involved were analyzed by Scanning Electron Microscopy.

US EPA's National Dioxin Air Monitoring Network: Analytical ...

EPA Pesticide Factsheets

The U.S. EPA has established a National Dioxin Air Monitoring Network (NDAMN) to determine the temporal and geographical variability of atmospheric chlorinated dibenzo-p-dioxins (CDDs), furans (CDFs), and coplanar polychlorinated biphenyls (PCBs) at rural and non-impacted locations throughout the United States. Currently operating at 32 sampling stations, NDAMN has three primary purposes: (1) to determine the atmospheric levels and occurrences of dioxin-like compounds in rural and agricultural areas where livestock, poultry, and animal feed crops are grown; (2) to provide measurements of atmospheric levels in different geographic regions of the U.S.; and (3) to provide information regarding the long-range transport of dioxin-like compounds in air over the U.S. Designed in 1997, NDAMN has been implemented in phases, with the first phase consisting of 9 monitoring stations and is achieving congener-specific detection lmits of 0.1 fg/m3 for 2,3,7,8-TCDD and 10 fg/m3 for OCDD. With respect to coplanar PCBs, the detection limits are generally higher due to the presence of background levels in the air during the preparation and processing of the samples. Achieving these extremely low levels of detection present a host of analytical issues. Among these issues are the methods used to establish ultra-trace detection limits, measures to ensure against and monitor for breakthrough of native analytes when sampling large volumes of air, and procedures for handling and e

Impacts of visitor number on Kangaroos housed in free-range exhibits.

PubMed

Sherwen, Sally L; Hemsworth, Paul H; Butler, Kym L; Fanson, Kerry V; Magrath, Michael J L

2015-01-01

Free range exhibits are becoming increasingly popular in zoos as a means to enhance interaction between visitors and animals. However very little research exists on the impacts of visitors on animal behaviour and stress in free range exhibits. We investigated the effects of visitor number on the behaviour and stress physiology of Kangaroo Island (KI) Kangaroos, Macropus fuliginosus fuliginosus, and Red Kangaroos, Macropus rufus, housed in two free range exhibits in Australian zoos. Behavioural observations were conducted on individual kangaroos at each site using instantaneous scan sampling to record activity (e.g., vigilance, foraging, resting) and distance from the visitor pathway. Individually identifiable faecal samples were collected at the end of each study day and analysed for faecal glucocorticoid metabolite (FGM) concentration. When visitor number increased, both KI Kangaroos and Red Kangaroos increased the time spent engaged in visitor-directed vigilance and KI Kangaroos also increased the time spent engaged in locomotion and decreased the time spent resting. There was no effect of visitor number on the distance kangaroos positioned themselves from the visitor pathway or FGM concentration in either species. While there are limitations in interpreting these results in terms of fear of visitors, there was no evidence of adverse effects animal welfare in these study groups based on avoidance behaviour or stress physiology under the range of visitor numbers that we studied. © 2015 Wiley Periodicals, Inc.

High-Thermal- and Air-Stability Cathode Material with Concentration-Gradient Buffer for Li-Ion Batteries.

PubMed

Shi, Ji-Lei; Qi, Ran; Zhang, Xu-Dong; Wang, Peng-Fei; Fu, Wei-Gui; Yin, Ya-Xia; Xu, Jian; Wan, Li-Jun; Guo, Yu-Guo

2017-12-13

Delivery of high capacity with high thermal and air stability is a great challenge in the development of Ni-rich layered cathodes for commercialized Li-ion batteries (LIBs). Herein we present a surface concentration-gradient spherical particle with varying elemental composition from the outer end LiNi 1/3 Co 1/3 Mn 1/3 O 2 (NCM) to the inner end LiNi 0.8 Co 0.15 Al 0.05 O 2 (NCA). This cathode material with the merit of NCM concentration-gradient protective buffer and the inner NCA core shows high capacity retention of 99.8% after 200 cycles at 0.5 C. Furthermore, this cathode material exhibits much improved thermal and air stability compared with bare NCA. These results provide new insights into the structural design of high-performance cathodes with high energy density, long life span, and storage stability materials for LIBs in the future.

A low-cost gradient system for high-performance liquid chromatography. Quantitation of complex pharmaceutical raw materials.

PubMed

Erni, F; Frei, R W

1976-09-29

A device is described that makes use of an eight-port motor valve to generate step gradients on the low-pressure side of a piston pump with a low dead volume. Such a gradient device with an automatic control unit, which also permits repetition of previous steps, can be built for about half the cost of a gradient system with two pumps. Applications of this gradient unit to the separation of complex mixtures of glycosides and alkaloids are discussed and compared with separations systems using two high-pressure pumps. The gradients that are used on reversed-phase material with solvent mixtures of water and completely miscible organic solvents are suitable for quantitative routine control of pharmaceutical products. The reproducibility of retention data is excellent over several months and, with the use of loop injectors, major components can be determined quantitatively with a reproducibility of better than 2% (relative standard deviation). The step gradient selector valve can also be used as an introduction system for very large sample volumes. Up to 11 can be injected and samples with concentrations of less than 1 ppb can be determined with good reproducibilities.

Test Method for the Fatigue Life of Layered TiB/Ti Functionally Graded Beams Subjected to Fully Reversed Bending

NASA Astrophysics Data System (ADS)

Byrd, Larry; Rickerd, Greg; Wyen, Travis; Cooley, Glenn; Quast, Jeff

2008-02-01

Sonic fatigue of aircraft is characterized by fully reversed bending of components subjected to acoustic excitation. This problem is compounded in high temperature environments because solutions for acoustics which tend to result in stiff structures make thermal problems worse. Conversely solutions to the thermal problem which allow expansion often fail in the presence of high acoustic levels. Errors in fatigue life prediction in the combined environment often range from a factor of 4 to 10. This results in either heavy, overly stiff structure or premature failure. This work will test the hypothesis that the fatigue life of a layered functionally graded material (FGM) will be dominated by the failure of the stiffest outer layer. This is based on the observation that for isotropic materials the life is approximately 90% crack initiation and only 10% crack growth before failure. Four sets of cantilever specimens will be tested using an electro-mechanical shaker for base excitation. The excitation will be narrow band random around the fundamental frequency. Two sets of specimens are of uniform composition consisting of 85%TiB/Ti and two are graded specimens consisting of layers that vary from commercially pure titanium to 85%TiB/Ti. Strain vs number of cycles to failure curves will be generated with both constant amplitude sine and narrow band random around the fundamental frequency excitation. The results will be examined to compare life of the uniform material to the functionally graded material. Also to be studied will be the use of Miner's rule to predict the fatigue life of the randomly excited specimens.

The Transition from Stiff to Compliant Materials in Squid Beaks

PubMed Central

Miserez, Ali; Schneberk, Todd; Sun, Chengjun; Zok, Frank W.; Waite, J. Herbert

2009-01-01

The beak of the Humboldt squid Dosidicus gigas represents one of the hardest and stiffest wholly organic materials known. As it is deeply embedded within the soft buccal envelope, the manner in which impact forces are transmitted between beak and envelope is a matter of considerable scientific interest. Here, we show that the hydrated beak exhibits a large stiffness gradient, spanning two orders of magnitude from the tip to the base. This gradient is correlated with a chemical gradient involving mixtures of chitin, water, and His-rich proteins that contain 3,4-dihydroxyphenyl-l-alanine (dopa) and undergo extensive stabilization by histidyl-dopa cross-link formation. These findings may serve as a foundation for identifying design principles for attaching mechanically mismatched materials in engineering and biological applications. PMID:18369144

The transition from stiff to compliant materials in squid beaks.

PubMed

Miserez, Ali; Schneberk, Todd; Sun, Chengjun; Zok, Frank W; Waite, J Herbert

2008-03-28

The beak of the Humboldt squid Dosidicus gigas represents one of the hardest and stiffest wholly organic materials known. As it is deeply embedded within the soft buccal envelope, the manner in which impact forces are transmitted between beak and envelope is a matter of considerable scientific interest. Here, we show that the hydrated beak exhibits a large stiffness gradient, spanning two orders of magnitude from the tip to the base. This gradient is correlated with a chemical gradient involving mixtures of chitin, water, and His-rich proteins that contain 3,4-dihydroxyphenyl-L-alanine (dopa) and undergo extensive stabilization by histidyl-dopa cross-link formation. These findings may serve as a foundation for identifying design principles for attaching mechanically mismatched materials in engineering and biological applications.

The Transition from Stiff to Compliant Materials in Squid Beaks

NASA Astrophysics Data System (ADS)

Miserez, Ali; Schneberk, Todd; Sun, Chengjun; Zok, Frank W.; Waite, J. Herbert

2008-03-01

The beak of the Humboldt squid Dosidicus gigas represents one of the hardest and stiffest wholly organic materials known. As it is deeply embedded within the soft buccal envelope, the manner in which impact forces are transmitted between beak and envelope is a matter of considerable scientific interest. Here, we show that the hydrated beak exhibits a large stiffness gradient, spanning two orders of magnitude from the tip to the base. This gradient is correlated with a chemical gradient involving mixtures of chitin, water, and His-rich proteins that contain 3,4-dihydroxyphenyl-L-alanine (dopa) and undergo extensive stabilization by histidyl-dopa cross-link formation. These findings may serve as a foundation for identifying design principles for attaching mechanically mismatched materials in engineering and biological applications.

Superconducting thermoelectric generator

DOEpatents

Metzger, J.D.; El-Genk, M.S.

1998-05-05

An apparatus and method for producing electricity from heat is disclosed. The present invention is a thermoelectric generator that uses materials with substantially no electrical resistance, often called superconductors, to efficiently convert heat into electrical energy without resistive losses. Preferably, an array of superconducting elements is encased within a second material with a high thermal conductivity. The second material is preferably a semiconductor. Alternatively, the superconducting material can be doped on a base semiconducting material, or the superconducting material and the semiconducting material can exist as alternating, interleaved layers of waferlike materials. A temperature gradient imposed across the boundary of the two materials establishes an electrical potential related to the magnitude of the temperature gradient. The superconducting material carries the resulting electrical current at zero resistivity, thereby eliminating resistive losses. The elimination of resistive losses significantly increases the conversion efficiency of the thermoelectric device. 4 figs.

Superconducting thermoelectric generator

DOEpatents

Metzger, J.D.; El-Genk, M.S.

1996-01-01

An apparatus and method for producing electricity from heat. The present invention is a thermoelectric generator that uses materials with substantially no electrical resistance, often called superconductors, to efficiently convert heat into electrical energy without resistive losses. Preferably, an array of superconducting elements is encased within a second material with a high thermal conductivity. The second material is preferably a semiconductor. Alternatively, the superconducting material can be doped on a base semiconducting material, or the superconducting material and the semiconducting material can exist as alternating, interleaved layers of waferlike materials. A temperature gradient imposed across the boundary of the two materials establishes an electrical potential related to the magnitude of the temperature gradient. The superconducting material carries the resulting electrical current at zero resistivity, thereby eliminating resistive losses. The elimination of resistive losses significantly increases the conversion efficiency of the thermoelectric device.

Superconducting thermoelectric generator

DOEpatents

Metzger, John D.; El-Genk, Mohamed S.

1998-01-01

An apparatus and method for producing electricity from heat. The present invention is a thermoelectric generator that uses materials with substantially no electrical resistance, often called superconductors, to efficiently convert heat into electrical energy without resistive losses. Preferably, an array of superconducting elements is encased within a second material with a high thermal conductivity. The second material is preferably a semiconductor. Alternatively, the superconducting material can be doped on a base semiconducting material, or the superconducting material and the semiconducting material can exist as alternating, interleaved layers of waferlike materials. A temperature gradient imposed across the boundary of the two materials establishes an electrical potential related to the magnitude of the temperature gradient. The superconducting material carries the resulting electrical current at zero resistivity, thereby eliminating resistive losses. The elimination of resistive losses significantly increases the conversion efficiency of the thermoelectric device.

Methods and apparatus for moving and separating materials exhibiting different physical properties

DOEpatents

Peterson, Stephen C.; Brimhall, Owen D.; McLaughlin, Thomas J.; Baker, Charles D.; Sparks, Sam L.

1988-01-01

Methods and apparatus for controlling the movement of materials having different physical properties when one of the materials is a fluid. The invention does not rely on flocculation, sedimentation, centrifugation, the buoyancy of the materials, or any other gravity dependent characteristic, in order to achieve its desired results. The methods of the present invention provide that a first acoustic wave is progpagated through a vessel containing the materials. A second acoustic wave, at a frequency different than the first acoustic wave, is also propagated through the vessel so that the two acoustic waves are superimposed upon each other. The superimposition of the two waves creates a beat frequency wave. The beat frequency wave comprises pressure gradients dividing regions of maximum and minimum pressure. The pressure gradients and the regions of maximum and minimum pressure move through space and time at a group velocity. The moving pressure gradients and regions of maximum and minimum pressure act upon the marterials so as to move one of the materials towards a predetermined location in the vessel. The present invention provides that the materials may be controllably moved toward a location, aggreated at a particular location, or physically separated from each other.

Usage of Nest Materials by House Sparrow (Passer domesticus) Along an Urban to Rural Gradient in Coimbatore, India.

PubMed

Radhamany, Dhanya; Das, Karumampoyil Sakthidas Anoop; Azeez, Parappurath Abdul; Wen, Longying; Sreekala, Leelambika Krishnan

2016-08-01

The house sparrow (Passer domesticus) is a widely distributed bird species found throughout the world. Being a species which has close association with humans, they chiefly nest on man-made structures. Here we describe the materials used by the house sparrow for making nests along an urban to rural gradient. For the current study, we selected the Coimbatore to Anaikatty road (State Highway-164), a 27 km inter-state highway, which traverses along an urban core to rural outstretch of Coimbatore. Of the 30 nests observed, 15 nests were from the rural, 8 were from the suburban, and 7 were from the urban areas. The nests had two distinct layers, specifically the structural layer and the inner lining. In the current study, we identified 11 plant species, 2 types of animal matter, and 6 types of anthropogenic matter, including plastic pieces and fine rope. The amount of anthropogenic materials in the nest formation varied along the gradients. The usage of anthropogenic materials was high in urban areas (p<0.05) whereas it did not differ at the sub-urban regions (p>0.05). A gradual decrease in the usage of plant matter towards the urban area was noticed (p<0.05). This study explicitly documents the links between nest material usage along an urban to rural gradient, in a human associated bird.

A nonlocal strain gradient model for dynamic deformation of orthotropic viscoelastic graphene sheets under time harmonic thermal load

NASA Astrophysics Data System (ADS)

Radwan, Ahmed F.; Sobhy, Mohammed

2018-06-01

This work presents a nonlocal strain gradient theory for the dynamic deformation response of a single-layered graphene sheet (SLGS) on a viscoelastic foundation and subjected to a time harmonic thermal load for various boundary conditions. Material of graphene sheets is presumed to be orthotropic and viscoelastic. The viscoelastic foundation is modeled as Kelvin-Voigt's pattern. Based on the two-unknown plate theory, the motion equations are obtained from the dynamic version of the virtual work principle. The nonlocal strain gradient theory is established from Eringen nonlocal and strain gradient theories, therefore, it contains two material scale parameters, which are nonlocal parameter and gradient coefficient. These scale parameters have two different effects on the graphene sheets. The obtained deflection is compared with that predicted in the literature. Additional numerical examples are introduced to illustrate the influences of the two length scale coefficients and other parameters on the dynamic deformation of the viscoelastic graphene sheets.

Thermal rectification in thin films driven by gradient grain microstructure

NASA Astrophysics Data System (ADS)

Cheng, Zhe; Foley, Brian M.; Bougher, Thomas; Yates, Luke; Cola, Baratunde A.; Graham, Samuel

2018-03-01

As one of the basic components of phononics, thermal rectifiers transmit heat current asymmetrically similar to electronic rectifiers in microelectronics. Heat can be conducted through them easily in one direction while being blocked in the other direction. In this work, we report a thermal rectifier that is driven by the gradient grain structure and the inherent gradient in thermal properties as found in these materials. To demonstrate their thermal rectification properties, we build a spectral thermal conductivity model with complete phonon dispersion relationships using the thermophysical properties of chemical vapor deposited (CVD) diamond films which possess gradient grain microstructures. To explain the observed significant thermal rectification, the temperature and thermal conductivity distribution are studied. Additionally, the effects of temperature bias and film thickness are discussed, which shed light on tuning the thermal rectification based on the gradient microstructures. Our results show that the columnar grain microstructure makes CVD materials unique candidates for mesoscale thermal rectifiers without a sharp temperature change.

Minimum maximum temperature gradient coil design.

PubMed

While, Peter T; Poole, Michael S; Forbes, Larry K; Crozier, Stuart

2013-08-01

Ohmic heating is a serious problem in gradient coil operation. A method is presented for redesigning cylindrical gradient coils to operate at minimum peak temperature, while maintaining field homogeneity and coil performance. To generate these minimaxT coil windings, an existing analytic method for simulating the spatial temperature distribution of single layer gradient coils is combined with a minimax optimization routine based on sequential quadratic programming. Simulations are provided for symmetric and asymmetric gradient coils that show considerable improvements in reducing maximum temperature over existing methods. The winding patterns of the minimaxT coils were found to be heavily dependent on the assumed thermal material properties and generally display an interesting "fish-eye" spreading of windings in the dense regions of the coil. Small prototype coils were constructed and tested for experimental validation and these demonstrate that with a reasonable estimate of material properties, thermal performance can be improved considerably with negligible change to the field error or standard figures of merit. © 2012 Wiley Periodicals, Inc.

Finite element analysis of gradient z-coil induced eddy currents in a permanent MRI magnet.

PubMed

Li, Xia; Xia, Ling; Chen, Wufan; Liu, Feng; Crozier, Stuart; Xie, Dexin

2011-01-01

In permanent magnetic resonance imaging (MRI) systems, pulsed gradient fields induce strong eddy currents in the conducting structures of the magnet body. The gradient field for image encoding is perturbed by these eddy currents leading to MR image distortions. This paper presents a comprehensive finite element (FE) analysis of the eddy current generation in the magnet conductors. In the proposed FE model, the hysteretic characteristics of ferromagnetic materials are considered and a scalar Preisach hysteresis model is employed. The developed FE model was applied to study gradient z-coil induced eddy currents in a 0.5 T permanent MRI device. The simulation results demonstrate that the approach could be effectively used to investigate eddy current problems involving ferromagnetic materials. With the knowledge gained from this eddy current model, our next step is to design a passive magnet structure and active gradient coils to reduce the eddy current effects. Copyright © 2010 Elsevier Inc. All rights reserved.

Acoustic beam control in biomimetic projector via velocity gradient

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gao, Xiaowei; Dong, Erqian; Song, Zhongchang

A biomimetic projector (BioP) based on computerized tomography of pygmy sperm whale's biosonar system has been designed using gradient-index (GRIN) material. The directivity of this BioP device was investigated as function of frequency and the velocity gradient of the GRIN material. A strong beam control over a broad bandwidth at the subwavelength scale has been achieved. Compared with a bare subwavelength source, the main lobe pressure of the BioP is about five times as high and the angular resolution is one order of magnitude better. Our results indicate that this BioP has excellent application potential in miniaturized underwater sonars.

Acoustic beam control in biomimetic projector via velocity gradient

NASA Astrophysics Data System (ADS)

Gao, Xiaowei; Zhang, Yu; Cao, Wenwu; Dong, Erqian; Song, Zhongchang; Li, Songhai; Tang, Liguo; Zhang, Sai

2016-07-01

A biomimetic projector (BioP) based on computerized tomography of pygmy sperm whale's biosonar system has been designed using gradient-index (GRIN) material. The directivity of this BioP device was investigated as function of frequency and the velocity gradient of the GRIN material. A strong beam control over a broad bandwidth at the subwavelength scale has been achieved. Compared with a bare subwavelength source, the main lobe pressure of the BioP is about five times as high and the angular resolution is one order of magnitude better. Our results indicate that this BioP has excellent application potential in miniaturized underwater sonars.

A new method of determining moisture gradient in wood

Treesearch

Zhiyong Cai

2008-01-01

Moisture gradient in wood and wood composites is one of most important factors that affects both physical stability and mechanical performance. This paper describes a method for measuring moisture gradient in lumber and engineering wood composites as it varies across material thickness. This innovative method employs a collimated radiation beam (x rays or [gamma] rays...

A new leakage measurement method for damaged seal material

NASA Astrophysics Data System (ADS)

Wang, Shen; Yao, Xue Feng; Yang, Heng; Yuan, Li; Dong, Yi Feng

2018-07-01

In this paper, a new leakage measurement method based on the temperature field and temperature gradient field is proposed for detecting the leakage location and measuring the leakage rate in damaged seal material. First, a heat transfer leakage model is established, which can calculate the leakage rate based on the temperature gradient field near the damaged zone. Second, a finite element model of an infinite plate with a damaged zone is built to calculate the leakage rate, which fits the simulated leakage rate well. Finally, specimens in a tubular rubber seal with different damage shapes are used to conduct the leakage experiment, validating the correctness of this new measurement principle for the leakage rate and the leakage position. The results indicate the feasibility of the leakage measurement method for damaged seal material based on the temperature gradient field from infrared thermography.

Mechanisms of high-gradient microwave breakdown on metal surfaces in high power microwave source

NASA Astrophysics Data System (ADS)

Xie, Jialing; Chen, Changhua; Chang, Chao; Wu, Cheng; Huo, Yankun

2017-12-01

A breakdown cavity was designed to study the high-gradient microwave breakdown on a metal surface. The breakdown cavity can be distinguished into an electron emission boundary and a bombardment boundary as there is an evident difference in amplitude of the electric field between the two planes in the cavity. Breakdown tracks on the cavity were studied with an electron scanning microscope. The tracks on the electron emission boundary with the higher electric field were eroded; a component analysis indicates that these tracks contain an emission boundary material. On the bombardment boundary with a lower electric field, two kinds of tracks exist: an erosion track containing a bombardment boundary material and a sputtered track containing an emission boundary material. From these tracks, the mechanisms of high-gradient microwave breakdown on a metal surface have been analyzed.

Temperature and diet effects on omnivorous fish performance: Implications for the latitudinal diversity gradient in herbivorous fishes

USGS Publications Warehouse

Behrens, M.D.; Lafferty, K.D.

2007-01-01

Herbivorous fishes show a clear latitudinal diversity gradient, making up a larger proportion of the fish species in a community in tropical waters than in temperate waters. One proposed mechanism that could drive this gradient is a physiological constraint due to temperature. One prediction based on this mechanism is that if herbivorous fishes could shift their diet to animal material, they would be better able to grow, survive, and reproduce in cold waters. We tested this prediction on the omnivore Girella nigricans under different temperature and diet regimes using RNA-DNA ratios as an indicator of performance. Fish had increased performance (100%) at low temperatures (12??C) when their diet was supplemented with animal material. In contrast, at higher temperatures (17, 22, and 27??C) fish showed no differences between diets. This indicates that omnivorous fishes could increase their performance at low temperatures by consuming more animal matter. This study supports the hypothesis that a relative increase in the nutritional value of plant material at warmer temperatures could drive the latitudinal diversity gradient in herbivorous fishes. ?? 2007 NRC.

Suppression/Reversal of Natural Convection by Exploiting the Temperature/Composition Dependence of Magnetic Susceptibility

NASA Technical Reports Server (NTRS)

Seybert, C. D.; Evans, J. W.; Leslie, F.; Jones, W. K., Jr.

2000-01-01

Natural convection, driven by temperature-or concentration gradients or both, is an inherent phenomenon during solidification of materials on Earth. This convection has practical consequences (e.g effecting macrosegregation) but also renders difficult the scientific examination of diffusive/conductive phenomena during solidification. It is possible to halt, or even reverse, natural convection by exploiting the variation (with temperature, for example) of the susceptibility of a material. If the material is placed in a vertical magnetic field gradient, a buoyancy force of magnetic origin arises and, at a critical field gradient, can balance the normal buoyancy forces to halt convection. At higher field gradients the convection can be reversed. The effect has been demonstrated in experiments at Marshall Space Flight Center where flow was measured by PIV in MnCl2 solution in a superconducting magnet. In auxiliary experiments the field in the magnet and the properties of the solution were measured. Computations of the natural convection, its halting and reversal, using the commercial software FLUENT were in good agreement with the measurements.

Stress analysis in cylindrical composition-gradient electrodes of lithium-ion battery

NASA Astrophysics Data System (ADS)

Zhong, Yaotian; Liu, Yulan; Wang, B.

2017-07-01

In recent years, the composition-gradient electrode material has been verified to be one of the most promising materials in lithium-ion battery. To investigate diffusion-induced stresses (DIS) generated in a cylindrical composition-gradient electrode, the finite deformation theory and the stress-induced diffusion hypothesis are adopted to establish the constitutive equations. Compared with stress distributions in a homogeneous electrode, the increasing forms of Young's modulus E(R) and partial molar volume Ω(R) from the electrode center to the surface along the radial direction drastically increase the maximal magnitudes of hoop and axial stresses, while both of the decreasing forms are able to make the stress fields smaller and flatter. Also, it is found that the slope of -1 for E(R) with that of -0.5 for Ω(R) is a preferable strategy to prevent the inhomogeneous electrode from cracking, while for the sake of protecting the electrode from compression failure, the optimal slope for inhomogeneous E(R) and the preferential one for Ω(R) are both -0.5. The results provide a theoretical guidance for the design of composition-gradient electrode materials.

Material Gradients in Oxygen System Components Improve Safety

NASA Technical Reports Server (NTRS)

Forsyth, Bradley S.

2011-01-01

Oxygen system components fabricated by Laser Engineered Net Shaping (TradeMark) (LENS(TradeMark)) could result in improved safety and performance. LENS(TradeMark) is a near-net shape manufacturing process fusing powdered materials injected into a laser beam. Parts can be fabricated with a variety of elemental metals, alloys, and nonmetallic materials without the use of a mold. The LENS(TradeMark) process allows the injected materials to be varied throughout a single workpiece. Hence, surfaces exposed to oxygen could be constructed of an oxygen-compatible material while the remainder of the part could be one chosen for strength or reduced weight. Unlike conventional coating applications, a compositional gradient would exist between the two materials, so no abrupt material boundary exists. Without an interface between dissimilar materials, there is less tendency for chipping or cracking associated with thermal-expansion mismatches.

Anisotropic failure and size effects in periodic honeycomb materials: A gradient-elasticity approach

NASA Astrophysics Data System (ADS)

Réthoré, Julien; Dang, Thi Bach Tuyet; Kaltenbrunner, Christine

2017-02-01

This paper proposes a fracture mechanics model for the analysis of crack propagation in periodic honeycomb materials. The model is based on gradient-elasticity which enables us to account for the effect of the material structure at the macroscopic scale. For simulating the propagation of cracks along an arbitrary path, the numerical implementation is elaborated based on an extended finite element method with the required level of continuity. The two main features captured by the model are directionality and size effect. The numerical predictions are consistent with experimental results on honeycomb materials but also with results reported in the literature for microstructurally short cracks in metals.

Study of the possibility of growing germanium single crystals under low temperature gradients

NASA Astrophysics Data System (ADS)

Moskovskih, V. A.; Kasimkin, P. V.; Shlegel, V. N.; Vasiliev, Y. V.; Gridchin, V. A.; Podkopaev, O. I.; Zhdankov, V. N.

2014-03-01

The possibility of growing germanium single crystals under low temperature gradients in order to produce a dislocation-free material has been studied. Germanium crystals with a dislocation density of about 100-200 cm-2 have been grown in a system with a weight control of crystal growth at maximum axial gradients of about 1.5 K/cm.

A Novel Microcharacterization Technique in the Measurement of Strain and Orientation Gradient in Advanced Materials

NASA Technical Reports Server (NTRS)

Garmestai, H.; Harris, K.; Lourenco, L.

1997-01-01

Representation of morphology and evolution of the microstructure during processing and their relation to properties requires proper experimental techniques. Residual strains, lattice distortion, and texture (micro-texture) at the interface and the matrix of a layered structure or a functionally gradient material and their variation are among parameters important in materials characterization but hard to measure with present experimental techniques. Current techniques available to measure changes in interred material parameters (residual stress, micro-texture, microplasticity) produce results which are either qualitative or unreliable. This problem becomes even more complicated in the case of a temperature variation. These parameters affect many of the mechanical properties of advanced materials including stress-strain relation, ductility, creep, and fatigue. A review of some novel experimental techniques using recent advances in electron microscopy is presented here to measure internal stress, (micro)texture, interracial strength and (sub)grain formation and realignment. Two of these techniques are combined in the chamber of an Environmental Scanning Electron Microscope to measure strain and orientation gradients in advanced materials. These techniques which include Backscattered Kikuchi Diffractometry (BKD) and Microscopic Strain Field Analysis are used to characterize metallic and intermetallic matrix composites and superplastic materials. These techniques are compared with the more conventional x-ray diffraction and indentation techniques.

Methods for Fabricating Gradient Alloy Articles with Multi-Functional Properties

NASA Technical Reports Server (NTRS)

Hofmann, Douglas C. (Inventor); Suh, Eric J. (Inventor); Borgonia, John Paul C. (Inventor); Dillon, Robert P. (Inventor); Mulder, Jerry L. (Inventor); Gardner, Paul B. (Inventor)

2015-01-01

Systems and methods for fabricating multi-functional articles comprised of additively formed gradient materials are provided. The fabrication of multi-functional articles using the additive deposition of gradient alloys represents a paradigm shift from the traditional way that metal alloys and metal/metal alloy parts are fabricated. Since a gradient alloy that transitions from one metal to a different metal cannot be fabricated through any conventional metallurgy techniques, the technique presents many applications. Moreover, the embodiments described identify a broad range of properties and applications.

CLUSTER STAFF search coils magnetometer calibration - comparisons with FGM

NASA Astrophysics Data System (ADS)

Robert, P.; Cornilleau-Wehrlin, N.; Piberne, R.; de Conchy, Y.; Lacombe, C.; Bouzid, V.; Grison, B.; Alison, D.; Canu, P.

2013-12-01

The main part of Cluster Spatio Temporal Analysis of Field Fluctuations (STAFF) experiment consists of triaxial search coils allowing the measurements of the three magnetic components of the waves from 0.1 Hz up to 4 kHz. Two sets of data are produced, one by a module to filter and transmit the corresponding waveform up to either 10 or 180 Hz (STAFF-SC) and the second by an onboard Spectrum Analyser (STAFF-SA) to compute the elements of the spectral matrix for five components of the waves, 3 × B and 2 × E (from EFW experiment) in the frequency range 8 Hz to 4 kHz. In order to understand the way the output signal of the search coils are calibrated, the transfer functions of the different parts of the instrument are described as well as the way to transform telemetry data into physical units, across various coordinate systems from the spinning sensors to a fixed and known frame. The instrument sensitivity is discussed. Cross-calibration inside STAFF (SC and SA) is presented. Results of cross-calibration between the STAFF search coils and the Cluster Flux Gate Magnetometer (FGM) data are discussed. It is shown that these cross-calibrations lead to an agreement between both data sets at low frequency within a 2% error. By means of statistics done over 10 yr, it is shown that the functionalities and characteristics of both instruments have not changed during this period.

CLUSTER-STAFF search coil magnetometer calibration - comparisons with FGM

NASA Astrophysics Data System (ADS)

Robert, P.; Cornilleau-Wehrlin, N.; Piberne, R.; de Conchy, Y.; Lacombe, C.; Bouzid, V.; Grison, B.; Alison, D.; Canu, P.

2014-09-01

The main part of the Cluster Spatio-Temporal Analysis of Field Fluctuations (STAFF) experiment consists of triaxial search coils allowing the measurements of the three magnetic components of the waves from 0.1 Hz up to 4 kHz. Two sets of data are produced, one by a module to filter and transmit the corresponding waveform up to either 10 or 180 Hz (STAFF-SC), and the second by the onboard Spectrum Analyser (STAFF-SA) to compute the elements of the spectral matrix for five components of the waves, 3 × B and 2 × E (from the EFW experiment), in the frequency range 8 Hz to 4 kHz. In order to understand the way the output signals of the search coils are calibrated, the transfer functions of the different parts of the instrument are described as well as the way to transform telemetry data into physical units across various coordinate systems from the spinning sensors to a fixed and known frame. The instrument sensitivity is discussed. Cross-calibration inside STAFF (SC and SA) is presented. Results of cross-calibration between the STAFF search coils and the Cluster Fluxgate Magnetometer (FGM) data are discussed. It is shown that these cross-calibrations lead to an agreement between both data sets at low frequency within a 2% error. By means of statistics done over 10 yr, it is shown that the functionalities and characteristics of both instruments have not changed during this period.

Features of highly structured equatorial plasma irregularities deduced from CHAMP observations

NASA Astrophysics Data System (ADS)

Xiong, C.; Lühr, H.; Ma, S. Y.; Stolle, C.; Fejer, B. G.

2012-08-01

In this study five years of CHAMP (Challenging Mini-satellite Payload) fluxgate magnetometer (FGM) data is used to investigate the characteristics of Equatorial Plasma Bubbles (EPBs). We filtered the FGM data by using band-passes with four different cut-off periods to get the EPBs with different maximum spatial scale sizes in the meridional plane ranging from 76-608 km. Associated with the EPB observations at about 400 km, the typical altitude of CHAMP during the year 2000-2005, we also investigate the post-sunset equatorial vertical plasma drift data from ROCSAT-1 (Republic of China Satellite 1). Since the height of the F-layer is highly correlated with the vertical plasma drift and solar flux, we sorted the ROCSAT-1 data into different groups by F10.7. From the integrated vertical drift we have estimated the post-sunset uplift of the ionosphere. By comparing the properties of EPB occurrence for different scale sizes with the global distribution of plasma vertical uplift, we have found that EPBs reaching higher altitudes are more structured than those which are sampled by CHAMP near the top side of the depleted fluxtube. Such a result is in accord with 3-D model simulations (Aveiro and Hysell, 2010). Small-scale EPB structures are observed by CHAMP when the irregularities reach apex heights of 800 km and more. Such events are encountered primarily in the Brazilian sector during the months around November, when the post-sunset vertical plasma drift is high.

The modern trends in space electromagnetic instrumentation

NASA Astrophysics Data System (ADS)

Korepanov, V. E.

The future trends of the experimental plasma physics development in outer space demand more and more exact and sophisticated scientific instrumentation. Moreover, the situation is complicated by constant reduction of financial support of scientific research, even in leading countries. This resulted in the development of mini; micro and nanosatellites with low price and short preparation time. Consequently, it provoked the creation of new generation of scientific instruments with reduced weight and power consumption but increased level of metrological parameters. The recent state of the development of electromagnetic (EM) sensors for microsatellites is reported. For flux-gate magnetometers (FGM) the reduction of weight as well as power consumption was achieved not only due to the use of new electronic components but also because of the new operation mode development. The scientific and technological study allowed to decrease FGM noise and now the typical noise figure is about 10 picotesla rms at 1 Hz and the record one is below 1 picotesla. The super-light version of search-coil magnetometers (SCM) was created as the result of intensive research. These new SCMs can have about six decades of operational frequency band with upper limit ˜ 1 MHz and noise level of few femtotesla with total weight about 75 grams, including electronics. A new instrument.- wave probe (WP) - which combines three independent sensors in one body - SCM, split Langmuir probe and electric potential sensor - was created. The developed theory confirms that WP can directly measure the wave vector components in space plasmas.

Infiltration of chitin by protein coacervates defines the squid beak mechanical gradient.

PubMed

Tan, YerPeng; Hoon, Shawn; Guerette, Paul A; Wei, Wei; Ghadban, Ali; Hao, Cai; Miserez, Ali; Waite, J Herbert

2015-07-01

The beak of the jumbo squid Dosidicus gigas is a fascinating example of how seamlessly nature builds with mechanically mismatched materials. A 200-fold stiffness gradient begins in the hydrated chitin of the soft beak base and gradually increases to maximum stiffness in the dehydrated distal rostrum. Here, we combined RNA-Seq and proteomics to show that the beak contains two protein families. One family consists of chitin-binding proteins (DgCBPs) that physically join chitin chains, whereas the other family comprises highly modular histidine-rich proteins (DgHBPs). We propose that DgHBPs play multiple key roles during beak bioprocessing, first by forming concentrated coacervate solutions that diffuse into the DgCBP-chitin scaffold, and second by inducing crosslinking via an abundant GHG sequence motif. These processes generate spatially controlled desolvation, resulting in the impressive biomechanical gradient. Our findings provide novel molecular-scale strategies for designing functional gradient materials.

The notion of a plastic material spin in atomistic simulations

NASA Astrophysics Data System (ADS)

Dickel, D.; Tenev, T. G.; Gullett, P.; Horstemeyer, M. F.

2016-12-01

A kinematic algorithm is proposed to extend existing constructions of strain tensors from atomistic data to decouple elastic and plastic contributions to the strain. Elastic and plastic deformation and ultimately the plastic spin, useful quantities in continuum mechanics and finite element simulations, are computed from the full, discrete deformation gradient and an algorithm for the local elastic deformation gradient. This elastic deformation gradient algorithm identifies a crystal type using bond angle analysis (Ackland and Jones 2006 Phys. Rev. B 73 054104) and further exploits the relationship between bond angles to determine the local deformation from an ideal crystal lattice. Full definitions of plastic deformation follow directly using a multiplicative decomposition of the deformation gradient. The results of molecular dynamics simulations of copper in simple shear and torsion are presented to demonstrate the ability of these new discrete measures to describe plastic material spin in atomistic simulation and to compare them with continuum theory.

NASA-UVa light aerospace alloy and structures technology program

NASA Technical Reports Server (NTRS)

Gangloff, Richard P.; Haviland, John K.; Herakovich, Carl T.; Pilkey, Walter D.; Pindera, Marek-Jerzy; Scully, John R.; Stoner, Glenn E.; Swanson, Robert E.; Thornton, Earl A.; Wawner, Franklin E., Jr.

1991-01-01

The general objective of the NASA-UVa Light Aerospace Alloy and Structures Technology Program was to conduct research on the performance of next generation, light weight aerospace alloys, composites, and associated thermal gradient structures. The following research areas were actively investigated: (1) mechanical and environmental degradation mechanisms in advanced light metals and composites; (2) aerospace materials science; (3) mechanics of materials and composites for aerospace structures; and (4) thermal gradient structures.

Coupling of order parameters, chirality, and interfacial structures in multiferroic materials.

PubMed

Conti, Sergio; Müller, Stefan; Poliakovsky, Arkady; Salje, Ekhard K H

2011-04-13

We study optimal interfacial structures in multiferroic materials with a biquadratic coupling between two order parameters. We discover a new duality relation between the strong coupling and the weak coupling regime for the case of isotropic gradient terms. We analyze the phase diagram depending on the coupling constant and anisotropy of the gradient term, and show that in a certain regime the secondary order parameter becomes activated only in the interfacial region.

Correlating the internal length in strain gradient plasticity theory with the microstructure of material

NASA Astrophysics Data System (ADS)

Zhao, Jianfeng; Zhang, Xu; Konstantinidis, Avraam A.; Kang, Guozheng

2015-06-01

The internal length is the governing parameter in strain gradient theories which among other things have been used successfully to interpret size effects at the microscale. Physically, the internal length is supposed to be related with the microstructure of the material and evolves during the deformation. Based on Taylor hardening law, we propose a power-law relationship to describe the evolution of the variable internal length with strain. Then, the classical Fleck-Hutchinson strain gradient theory is extended with a strain-dependent internal length, and the generalized Fleck-Hutchinson theory is confirmed here, by comparing our model predictions to recent experimental data on tension and torsion of thin wires with varying diameter and grain size. Our work suggests that the internal length is a configuration-dependent parameter, closely related to dislocation characteristics and grain size, as well as sample geometry when this affects either the underlying microstructure or the ductility of the material.

Effects of temperature distribution and elastic properties of materials on gas-turbine-disk stresses

NASA Technical Reports Server (NTRS)

Holms, Arthur G; Faldetta, Richard D

1947-01-01

Calculations were made to determine the influence of changes in temperature distribution and in elastic material properties on calculated elastic stresses for a typical gas-turbine disk. Severe temperature gradients caused thermal stresses of sufficient magnitude to reduce the operating safety of the disk. Small temperature gradients were found to be desirable because they produced thermal stresses that subtracted from the centrifugal stresses in the region of the rim. The thermal gradients produced a tendency for a severe stress condition to exist near the rim but this stress condition could be shifted away from the region of blade attachment by altering the temperature distribution. The investigation of elastic material properties showed that centrifugal stresses are slightly affected by changes in modulus of elasticity, but that thermal stresses are approximately proportional to modulus of elasticity and to coefficient of thermal expansion.

Interfacial free energy and stiffness of aluminum during rapid solidification

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brown, Nicholas T.; Martinez, Enrique; Qu, Jianmin

Using molecular dynamics simulations and the capillary fluctuation method, we have calculated the anisotropic crystal-melt interfacial free energy and stiffness of aluminum in a rapid solidification system where a temperature gradient is applied to enforce thermal non-equilibrium. To calculate these material properties, the standard capillary fluctuation method typically used for systems in equilibrium has been modified to incorporate a second-order Taylor expansion of the interfacial free energy term. The result is a robust method for calculating interfacial energy, stiffness and anisotropy as a function of temperature gradient using the fluctuations in the defined interface height. This work includes the calculationmore » of interface characteristics for temperature gradients ranging from 11 to 34 K/nm. The captured results are compared to a thermal equilibrium case using the same model and simulation technique with a zero gradient definition. We define the temperature gradient as the change in temperature over height perpendicular to the crystal-melt interface. The gradients are applied in MD simulations using defined thermostat regions on a stable solid-liquid interface initially in thermal equilibrium. The results of this work show that the interfacial stiffness and free energy for aluminum are dependent on the magnitude of the temperature gradient, however the anisotropic parameters remain independent of the non-equilibrium conditions applied in this analysis. As a result, the relationships of the interfacial free energy/stiffness are determined to be linearly related to the thermal gradient, and can be interpolated to find material characteristics at additional temperature gradients.« less

Interfacial free energy and stiffness of aluminum during rapid solidification

DOE PAGES

Brown, Nicholas T.; Martinez, Enrique; Qu, Jianmin

2017-05-01

Using molecular dynamics simulations and the capillary fluctuation method, we have calculated the anisotropic crystal-melt interfacial free energy and stiffness of aluminum in a rapid solidification system where a temperature gradient is applied to enforce thermal non-equilibrium. To calculate these material properties, the standard capillary fluctuation method typically used for systems in equilibrium has been modified to incorporate a second-order Taylor expansion of the interfacial free energy term. The result is a robust method for calculating interfacial energy, stiffness and anisotropy as a function of temperature gradient using the fluctuations in the defined interface height. This work includes the calculationmore » of interface characteristics for temperature gradients ranging from 11 to 34 K/nm. The captured results are compared to a thermal equilibrium case using the same model and simulation technique with a zero gradient definition. We define the temperature gradient as the change in temperature over height perpendicular to the crystal-melt interface. The gradients are applied in MD simulations using defined thermostat regions on a stable solid-liquid interface initially in thermal equilibrium. The results of this work show that the interfacial stiffness and free energy for aluminum are dependent on the magnitude of the temperature gradient, however the anisotropic parameters remain independent of the non-equilibrium conditions applied in this analysis. As a result, the relationships of the interfacial free energy/stiffness are determined to be linearly related to the thermal gradient, and can be interpolated to find material characteristics at additional temperature gradients.« less

Functionally gradient material for membrane reactors to convert methane gas into value-added products

DOEpatents

Balachandran, U.; Dusek, J.T.; Kleefisch, M.S.; Kobylinski, T.P.

1996-11-12

A functionally gradient material for a membrane reactor for converting methane gas into value-added-products includes an outer tube of perovskite, which contacts air; an inner tube which contacts methane gas, of zirconium oxide, and a bonding layer between the perovskite and zirconium oxide layers. The bonding layer has one or more layers of a mixture of perovskite and zirconium oxide, with the layers transitioning from an excess of perovskite to an excess of zirconium oxide. The transition layers match thermal expansion coefficients and other physical properties between the two different materials. 7 figs.

Functionally gradient material for membrane reactors to convert methane gas into value-added products

DOEpatents

Balachandran, Uthamalingam; Dusek, Joseph T.; Kleefisch, Mark S.; Kobylinski, Thadeus P.

1996-01-01

A functionally gradient material for a membrane reactor for converting methane gas into value-added-products includes an outer tube of perovskite, which contacts air; an inner tube which contacts methane gas, of zirconium oxide, and a bonding layer between the perovskite and zirconium oxide layers. The bonding layer has one or more layers of a mixture of perovskite and zirconium oxide, with the layers transitioning from an excess of perovskite to an excess of zirconium oxide. The transition layers match thermal expansion coefficients and other physical properties between the two different materials.

Numerical Study on Density Gradient Carbon-Carbon Composite for Vertical Launching System

NASA Astrophysics Data System (ADS)

Yoon, Jin-Young; Kim, Chun-Gon; Lim, Juhwan

2018-04-01

This study presents new carbon-carbon (C/C) composite that has a density gradient within single material, and estimates its heat conduction performance by a numerical method. To address the high heat conduction of a high-density C/C, which can cause adhesion separation in the steel structures of vertical launching systems, density gradient carbon-carbon (DGCC) composite is proposed due to its exhibiting low thermal conductivity as well as excellent ablative resistance. DGCC is manufactured by hybridizing two different carbonization processes into a single carbon preform. One part exhibits a low density using phenolic resin carbonization to reduce heat conduction, and the other exhibits a high density using thermal gradient-chemical vapor infiltration for excellent ablative resistance. Numerical analysis for DGCC is performed with a heat conduction problem, and internal temperature distributions are estimated by the forward finite difference method. Material properties of the transition density layer, which is inevitably formed during DGCC manufacturing, are assumed to a combination of two density layers for numerical analysis. By comparing numerical results with experimental data, we validate that DGCC exhibits a low thermal conductivity, and it can serve as highly effective ablative material for vertical launching systems.

Resistance to forced airflow through layers of composting organic material.

PubMed

Teixeira, Denis Leocádio; de Matos, Antonio Teixeira; Melo, Evandro de Castro

2015-02-01

The objective of this study was to adjust equations to estimate the static pressure gradient of airflow through layers of organic residues submitted to two stages of biochemical degradation, and to evaluate the static pressure drop of airflow thought the material layer. Measurements of static pressure drop in the layers of sugarcane bagasse and coffee husks mixed with poultry litter on day 0 and after 30 days of composting were performed using a prototype with specific airflow rates ranging from 0.02 to 0.13 m(3) s(-1) m(-2). Static pressure gradient and specific airflow rate data were properly fit to the Shedd, Hukill & Ives and Ergun models, which may be used to predict the static pressure gradient of air to be blown through the organic residue layers. However, the Shedd model was that which best represented the phenomenon studied. The static pressure drop of airflow increased as a power of the material layer thickness and showed tendency for decreasing with the biochemical degradation time of the organic material. Copyright © 2014 Elsevier Ltd. All rights reserved.

Aeroelastic Tailoring of the NASA Common Research Model via Novel Material and Structural Configurations

NASA Technical Reports Server (NTRS)

Jutte, Christine V.; Stanford, Bret K.; Wieseman, Carol D.; Moore, James B.

2014-01-01

This work explores the use of tow steered composite laminates, functionally graded metals (FGM), thickness distributions, and curvilinear rib/spar/stringer topologies for aeroelastic tailoring. Parameterized models of the Common Research Model (CRM) wing box have been developed for passive aeroelastic tailoring trade studies. Metrics of interest include the wing weight, the onset of dynamic flutter, and the static aeroelastic stresses. Compared to a baseline structure, the lowest aggregate static wing stresses could be obtained with tow steered skins (47% improvement), and many of these designs could reduce weight as well (up to 14%). For these structures, the trade-off between flutter speed and weight is generally strong, although one case showed both a 100% flutter improvement and a 3.5% weight reduction. Material grading showed no benefit in the skins, but moderate flutter speed improvements (with no weight or stress increase) could be obtained by grading the spars (4.8%) or ribs (3.2%), where the best flutter results were obtained by grading both thickness and material. For the topology work, large weight reductions were obtained by removing an inner spar, and performance was maintained by shifting stringers forward and/or using curvilinear ribs: 5.6% weight reduction, a 13.9% improvement in flutter speed, but a 3.0% increase in stress levels. Flutter resistance was also maintained using straightrotated ribs although the design had a 4.2% lower flutter speed than the curved ribs of similar weight and stress levels were higher. These results will guide the development of a future design optimization scheme established to exploit and combine the individual attributes of these technologies.

Diffusion pore imaging with generalized temporal gradient profiles.

PubMed

Laun, Frederik B; Kuder, Tristan A

2013-09-01

In porous material research, one main interest of nuclear magnetic resonance diffusion (NMR) experiments is the determination of the shape of pores. While it has been a longstanding question if this is in principle achievable, it has been shown recently that it is indeed possible to perform NMR-based diffusion pore imaging. In this work we present a generalization of these previous results. We show that the specific temporal gradient profiles that were used so far are not unique as more general temporal diffusion gradient profiles may be used. These temporal gradient profiles may consist of any number of "short" gradient pulses, which fulfil the short-gradient approximation. Additionally, "long" gradient pulses of small amplitude may be present, which can be used to fulfil the rephasing condition for the complete profile. Some exceptions exist. For example, classical q-space gradients consisting of two short gradient pulses of opposite sign cannot be used as the phase information is lost due to the temporal antisymmetry of this profile. Copyright © 2013 Elsevier Inc. All rights reserved.

Inferring regional vertical crustal velocities from averaged relative sea level trends: A proof of concept

NASA Astrophysics Data System (ADS)

Bâki Iz, H.; Shum, C. K.; Zhang, C.; Kuo, C. Y.

2017-11-01

We report the design of a high-throughput gradient hyperbolic lenslet built with real-life materials and capable of focusing a beam into a deep sub-wavelength spot of λ/23. This efficient design is achieved through high-order transformation optics and circular effective-medium theory (CEMT), which are used to engineer the radially varying anisotropic artificial material based on the thin alternating cylindrical metal and dielectric layers. The radial gradient of the effective anisotropic optical constants allows for matching the impedances at the input and output interfaces, drastically improving the throughput of the lenslet. However, it is the use of the zeroth-order CEMT that enables the practical realization of a gradient hyperlens with realistic materials. To illustrate the importance of using the CEMT versus the conventional planar effective-medium theory (PEMT) for cylindrical anisotropic systems, such as our hyperlens, both the CEMT and PEMT are adopted to design gradient hyperlenses with the same materials and order of elemental layers. The CEMT- and PEMT-based designs show similar performance if the number of metal-dielectric binary layers is sufficiently large (9+ pairs) and if the layers are sufficiently thin. However, for the manufacturable lenses with realistic numbers of layers (e.g. five pairs) and thicknesses, the performance of the CEMT design continues to be practical, whereas the PEMT-based design stops working altogether. The accurate design of transformation optics-based layered cylindrical devices enabled by CEMT allow for a new class of robustly manufacturable nanophotonic systems, even with relatively thick layers of real-life materials.

Synthesis of Polycrystalline CdSiP2 in a Gradient Temperature Field

NASA Astrophysics Data System (ADS)

Bereznaya, S. A.; Korotchenko, Z. V.; Kurasova, A. S.; Sarkisov, S. Yu.; Sarkisov, Yu. S.; Chernyshov, A. I.; Korolkov, I. V.; Kuchumov, B. M.; Saprykin, A. I.; Atuchin, V. V.

2018-05-01

A procedure for the synthesis of a CdSiP2 compound from the initial elementary components in a gradient thermal field has been developed. The phase and chemical composition of the synthesized and recrystallized material is confirmed by the data of X-ray diffraction analysis and scanning electron microscopy with an energy-dispersive system. The polycrystalline material obtained by the developed method will be used to grow bulk nonlinear optical CdSiP2 crystals.

Bending efficiency through property gradients in bamboo, palm, and wood-based composites.

PubMed

Wegst, Ulrike G K

2011-07-01

Nature, to a greater extent than engineering, takes advantage of hierarchical structures. These allow for optimization at each structural level to achieve mechanical efficiency, meaning mechanical performance per unit mass. Palms and bamboos do this exceptionally well; both are fibre-reinforced cellular materials in which the fibres are aligned parallel to the stem or culm, respectively. The distribution of these fibres is, however, not uniform: there is a density and modulus gradient across the section. This property gradient increases the flexural rigidity of the plants per unit mass, mass being a measure of metabolic investment made into an organism's construction. An analytical model is presented with which a 'gradient shape factor' can be calculated that describes by how much a plant's bending efficiency is increased through gradient structures. Combining the 'gradient shape factor' with a 'microstructural shape factor' that captures the efficiency gained through the cellular nature of the fibre composite's matrix, and a 'macroscopical shape factor' with which the tubular shape of bamboo can be described, for example, it is possible to explore how much each of these three structural levels of the hierarchy contributes to the overall bending performance of the stem or culm. In analogy, the bending efficiency of the commonly used wood-based composite medium-density fibreboard can be analysed; its property gradient is due to its manufacture by hot pressing. A few other engineered materials exist that emulate property gradients; new manufacturing routes to prepare them are currently being explored. It appears worthwhile to pursue these further. Copyright © 2011. Published by Elsevier Ltd.

Ternary gradient metal-organic frameworks.

PubMed

Liu, Chong; Rosi, Nathaniel L

2017-09-08

Gradient MOFs contain directional gradients of either structure or functionality. We have successfully prepared two ternary gradient MOFs based on bMOF-100 analogues, namely bMOF-100/102/106 and bMOF-110/100/102, via cascade ligand exchange reactions. The cubic unit cell parameter discrepancy within an individual ternary gradient MOF crystal is as large as ∼1 nm, demonstrating the impressive compatibility and flexibility of the component MOF materials. Because of the presence of a continuum of unit cells, the pore diameters within individual crystals also change in a gradient fashion from ∼2.5 nm to ∼3.0 nm for bMOF-100/102/106, and from ∼2.2 nm to ∼2.7 nm for bMOF-110/100/102, indicating significant porosity gradients. Like previously reported binary gradient MOFs, the composition of the ternary gradient MOFs can be easily controlled by adjusting the reaction conditions. Finally, X-ray diffraction and microspectrophotometry were used to analyse fractured gradient MOF crystals by comparing unit cell parameters and absorbance spectra at different locations, thus revealing the profile of heterogeneity (i.e. gradient distribution of properties) and further confirming the formation of ternary gradient MOFs.

The effects of thermal gradients on the Mars Observer Camera primary mirror

NASA Technical Reports Server (NTRS)

Applewhite, Roger W.; Telkamp, Arthur R.

1992-01-01

The paper discusses the effect of thermal gradients on the optical performance of the primary mirror of Mars Observer Camera (MOC), which will be launched on the Mars Observer spacecraft in September 1992. It was found that mild temperature gradients can have a large effect on the mirror surface figure, even for relatively low coefficient-of-thermal-expansion materials. However, in the case of the MOC primary mirror, it was found that the radius of curvature (ROC) of the reflective surface of the mirror changed in a nearly linear fashion with the radial temperature gradient, with little additional aberration. A solid-state ROC controller using the thermal gradient effect was implemented and verified.

A Simple Temperature Gradient Apparatus To Determine Thermal Preference in "Daphnia."

ERIC Educational Resources Information Center

Fenske, Christiane; McCauley, Robert

2002-01-01

Explores the dominant factor controlling the distribution of Daphnia. Describes components of a temperature gradient apparatus that can be assembled from materials readily obtainable in the laboratory and hardware stores. Investigates whether the mean depth of Daphnia is determined by temperature. (KHR)

Gradient Tempering Of Bearing Races

NASA Technical Reports Server (NTRS)

Parr, Richardson A.

1991-01-01

Gradient-tempering process increases fracture toughness and resistance to stress-corrosion cracking of ball-bearing races made of hard, strong steels and subject to high installation stresses and operation in corrosive media. Also used in other applications in which local toughening of high-strength/low-toughness materials required.

Evaluation of the effect of different methods of microabrasion and polishing on surface roughness of dental enamel.

PubMed

Bertoldo, Carlos; Lima, Debora; Fragoso, Larissa; Ambrosano, Glaucia; Aguiar, Flavio; Lovadino, Jose

2014-01-01

The microabrasion technique of enamel consists of selectively abrading the discolored areas or causing superficial structural changes in a selective way. In microabrasion technique, abrasive products associated with acids are used, and the evaluation of enamel roughness after this treatment, as well as surface polishing, is necessary. This in-vitro study evaluated the enamel roughness after microabrasion, followed by different polishing techniques. Roughness analyses were performed before microabrasion (L1), after microabrasion (L2), and after polishing (L3).Thus, 60 bovine incisive teeth divided into two groups were selected (n=30): G1- 37% phosphoric acid (37%) (Dentsply) and pumice; G2- hydrochloric acid (6.6%) associated with silicon carbide (Opalustre - Ultradent). Thereafter, the groups were divided into three sub-groups (n=10), according to the system of polishing: A - Fine and superfine granulation aluminum oxide discs (SofLex 3M); B - Diamond Paste (FGM) associated with felt discs (FGM); C - Silicone tips (Enhance - Dentsply). A PROC MIXED procedure was applied after data exploratory analysis, as well as the Tukey-Kramer test (5%). No statistical differences were found between G1 and G2 groups. L2 differed statistically from L1 and showed superior amounts of roughness. Differences in the amounts of post-polishing roughness for specific groups (1A, 2B, and 1C) arose, which demonstrated less roughness in L3 and differed statistically from L2 in the polishing system. All products increased enamel roughness, and the effectiveness of the polishing systems was dependent upon the abrasive used.

First Results of the Juno Magnetometer Investigation in Jupiter's Magnetosphere

NASA Astrophysics Data System (ADS)

Connerney, J. E. P.; Oliversen, R. J.; Espley, J. R.; Schnurr, R.; Sheppard, D.; Odom, J.; Lawton, P.; Murphy, S.; Joergensen, J. L.; Joergensen, P. S.; Merayo, J. M. G.; Denver, T.; Benn, M.; Bjarno, J. B.; Malinnikova Bang, A.; Bloxham, J.; Smith, E. J.; Bolton, S. J.

2016-12-01

The Juno spacecraft entered polar orbit about Jupiter on July 4, 2016, after a picture perfect Jupiter Orbit Insertion (JOI) main engine burn lasting 35 minutes. Juno's science instruments were not powered during the critical maneuver sequence ( 5 days) but were fully operational shortly afterward. The 53.5-day capture orbit provides Juno's science instruments with the first opportunity to sample the Jovian environment close up and in polar orbit on August 27, 2016 (PJ1). Following a successful PJ1, a period reduction maneuver (PRM) will drop the spacecraft into its 14-day science orbit to begin the science phase of the mission. During this phase, the gravity and magnetic fields will be mapped with unprecedented accuracy as Juno conducts a study of Jupiter's interior structure and composition, in addition to the first comprehensive exploration of the polar magnetosphere. The magnetic field investigation onboard Juno is equipped with two magnetometer sensor suites, located at 10 and 12 m from the spacecraft body at the end of one of the three solar panel wings. Each contains a vector fluxgate magnetometer (FGM) sensor and a pair of co-located non-magnetic star tracker camera heads which provide accurate attitude determination for the FGM sensors. This very capable magnetic observatory samples the Jovian magnetic field at a rate of up to 64 vector samples/second. We present the first observations of Jupiter's magnetic field obtained in polar orbit and in context with prior observations and those acquired by Juno's other science instruments (waves and particles instruments, and remote-sensing infrared and ultraviolet imaging spectrographs).

Unraveling submicron-scale mechanical heterogeneity by three-dimensional X-ray microdiffraction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Runguang; Xie, Qingge; Wang, Yan-Dong

Shear banding is a ubiquitous phenomenon of severe plastic deformation, and damage accumulation in shear bands often results in the catastrophic failure of a material. Despite extensive studies, the microscopic mechanisms of strain localization and deformation damage in shear bands remain elusive due to their spatial-temporal complexities embedded in bulk materials. Here we conducted synchrotron-based X-ray microdiffraction (μXRD) experiments to map out the 3D lattice strain field with a submicron resolution around fatigue shear bands in a stainless steel. Both in situ and postmortem μXRD results revealed large lattice strain gradients at intersections of the primary and secondary shear bands.more » Such strain gradients resulted in severe mechanical heterogeneities across the fatigue shear bands, leading to reduced fatigue limits in the high-cycle regime. The ability to spatially quantify the localized strain gradients with submicron resolution through μXRD opens opportunities for understanding the microscopic mechanisms of damage and failure in bulk materials.« less

Unraveling submicron-scale mechanical heterogeneity by three-dimensional X-ray microdiffraction

DOE PAGES

Li, Runguang; Xie, Qingge; Wang, Yan-Dong; ...

2017-12-28

Shear banding is a ubiquitous phenomenon of severe plastic deformation, and damage accumulation in shear bands often results in the catastrophic failure of a material. Despite extensive studies, the microscopic mechanisms of strain localization and deformation damage in shear bands remain elusive due to their spatial-temporal complexities embedded in bulk materials. Here we conducted synchrotron-based X-ray microdiffraction (μXRD) experiments to map out the 3D lattice strain field with a submicron resolution around fatigue shear bands in a stainless steel. Both in situ and postmortem μXRD results revealed large lattice strain gradients at intersections of the primary and secondary shear bands.more » Such strain gradients resulted in severe mechanical heterogeneities across the fatigue shear bands, leading to reduced fatigue limits in the high-cycle regime. The ability to spatially quantify the localized strain gradients with submicron resolution through μXRD opens opportunities for understanding the microscopic mechanisms of damage and failure in bulk materials.« less

Unraveling submicron-scale mechanical heterogeneity by three-dimensional X-ray microdiffraction

PubMed Central

Li, Runguang; Xie, Qingge; Wang, Yan-Dong; Liu, Wenjun; Wang, Mingguang; Wu, Guilin; Li, Xiaowu; Zhang, Minghe; Lu, Zhaoping; Geng, Chang; Zhu, Ting

2018-01-01

Shear banding is a ubiquitous phenomenon of severe plastic deformation, and damage accumulation in shear bands often results in the catastrophic failure of a material. Despite extensive studies, the microscopic mechanisms of strain localization and deformation damage in shear bands remain elusive due to their spatial−temporal complexities embedded in bulk materials. Here we conducted synchrotron-based X-ray microdiffraction (μXRD) experiments to map out the 3D lattice strain field with a submicron resolution around fatigue shear bands in a stainless steel. Both in situ and postmortem μXRD results revealed large lattice strain gradients at intersections of the primary and secondary shear bands. Such strain gradients resulted in severe mechanical heterogeneities across the fatigue shear bands, leading to reduced fatigue limits in the high-cycle regime. The ability to spatially quantify the localized strain gradients with submicron resolution through μXRD opens opportunities for understanding the microscopic mechanisms of damage and failure in bulk materials. PMID:29284751

Gradient Refractive Index Lenses.

ERIC Educational Resources Information Center

Morton, N.

1984-01-01

Describes the nature of gradient refractive index (GRIN) lenses, focusing on refraction in these materials, focal length of a thin Wood lens, and on manufacturing of such lenses. Indicates that GRIN lenses of small cross section are in limited production with applications suggested for optical communication and photocopying fields. (JN)

Fabrication of high wettability gradient on copper substrate

NASA Astrophysics Data System (ADS)

Huang, Ding-Jun; Leu, Tzong-Shyng

2013-09-01

Copper is one of the most widely used materials in condensation heat transfer. Recently there has been great interest in improving the condensation heat transfer efficiency through copper surface modification. In this study, we describe the fabrication processes of how copper surfaces were modified to be superhydrophilic (CA ≤ 10°) and superhydrophobic (CA > 150°) by means of H2O2 immersion and fluorination with Teflon. The wettability gradient of copper surfaces with contact angles (CA) changing from superhydrophilic to superhydrophobic are also demonstrated. Unlike previous studies on gradient surfaces in which the wettability gradient is controlled either non-precisely or entirely uncontrolled, in this study, the contact angles along wettability gradient copper surfaces vary with a precisely designed gradient. It is demonstrated that a high wettability gradient copper surface can be successfully fabricated using photolithography to define the area ratios between superhydrophilic and superhydrophobic patterns within a short distance. The fabricated wettability gradient of copper surfaces is expected to be able to enhance the condensation heat transfer efficiency.

Advanced Ceramic Armor Materials

DTIC Science & Technology

1990-05-11

materials, toughened alumina, fiber -reinforced glass matrix composites, and multilayer-gradient materials for ballistic testing. Fabrication and...material systems: Multilayer advanced armor materials consisting of a hard ceramic faceplate bonded to a graphite fiber -reinforced glass matrix...toughened alumina, and fiber - applied studies of advanced reinforced ceramic matrix glass and glass -ceramic composites for ballistic testing. technologies

Broadband absorption with gradient metasurfaces

NASA Astrophysics Data System (ADS)

Kwon, Hoyeong; Chalabi, Hamidreza; Alù, Andrea

2018-03-01

A metasurface with appropriately designed transverse spatial inhomogeneities can provide the desired phase redistribution in response to an incident wave with arbitrary incident angle. This property of gradient metasurfaces has been used to modify light propagation in unusual manners, to transform the impinging optical wavefront with large flexibility. In this work, we show how gradient metasurfaces can be tailored to offer high absorption in thin absorptive layers, and how to design realistic metasurfaces for this purpose using dielectric materials.

Continuous gradient scaffolds for rapid screening of cell-material interactions and interfacial tissue regeneration

PubMed Central

Bailey, Brennan M.; Nail, Lindsay N.; Grunlan, Melissa A.

2013-01-01

In tissue engineering, the physical and chemical properties of the scaffold mediates cell behavior including regeneration. Thus, a strategy that permits rapid screening of cell-scaffold interactions is critical. Herein, we have prepared eight “hybrid” hydrogel scaffolds in the form of continuous gradients such that a single scaffold contains spatially varied properties. These scaffolds are based on combining an inorganic macromer [methacrylated star polydimethylsiloxane, PDMSstar-MA] and organic macromer [poly(ethylene glycol)diacrylate, PEG-DA] as well both aqueous and organic fabrication solvents. Having previously demonstrated its bioactivity and osteoinductivity, PDMSstar-MA is a particularly powerful component to incorporate into instructive gradient scaffolds based on PEG-DA. The following parameters were varied to produce the different gradients or gradual transitions in: (1) the wt% ratio of PDMSstar-MA to PEG-DA macromers, (2) the total wt% macromer concentration, (3) the number average molecular weight (Mn) of PEG-DA and (4) the Mn of PDMSstar-MA. Upon dividing each scaffold into four “zones” perpendicular to the gradient, we were able to demonstrate the spatial variation in morphology, bioactivity, swelling and modulus. Among these gradient scaffolds are those in which swelling and modulus are conveniently decoupled. In addition to rapid screening of cell-material interactions, these scaffolds are well-suited for regeneration of interfacial tissues (e.g. osteochondral tissues) that transition from one tissue type to another. PMID:23707502

Creep and Environmental Durability of EBC/CMCs Under Imposed Thermal Gradient Conditions

NASA Technical Reports Server (NTRS)

Appleby, Matthew; Morscher, Gregory N.; Zhu, Dongming

2013-01-01

Interest in SiC fiber-reinforced SiC ceramic matrix composite (CMC) environmental barrier coating (EBC) systems for use in high temperature structural applications has prompted the need for characterization of material strength and creep performance under complex aerospace turbine engine environments. Stress-rupture tests have been performed on SiC/SiC composites systems, with varying fiber types and coating schemes to demonstrate material behavior under isothermal conditions. Further testing was conducted under exposure to thermal stress gradients to determine the effect on creep resistance and material durability. In order to understand the associated damage mechanisms, emphasis is placed on experimental techniques as well as implementation of non-destructive evaluation; including electrical resistivity monitoring. The influence of environmental and loading conditions on life-limiting material properties is shown.

Effect of a Diffusion Zone on Fatigue Crack Propagation in Layered FGMs

NASA Astrophysics Data System (ADS)

Hauber, Brett; Brockman, Robert; Paulino, Glaucio

2008-02-01

Research into functionally graded materials (FGMs) has led to advances in our ability to analyze cracks. However, two prominent aspects remain relatively unexplored: 1) development and validation of modeling methods for fatigue crack propagation in FGMs, and 2) experimental validation of stress intensity models in engineered materials such as two phase monolithic and graded materials. This work addresses some of these problems for a limited set of conditions, material systems (e.g., Ti/TiB), and material gradients. Numerical analyses are conducted for single edge notch bend (SENB) specimens. Stress intensity factors are computed using the specialized finite element code I-Franc (Illinois Fracture Analysis Code), which is tailored for both homogeneous and graded materials, as well as Franc2DL and ABAQUS. Crack extension is considered by means of specified crack increments, together with fatigue evaluations to predict crack propagation life. Results will be used to determine linear material gradient parameters that are significant for prediction of fatigue crack growth behavior.

Effect of Interface Shape and Magnetic Field on the Microstructure of Bulk Ge:Ga

NASA Technical Reports Server (NTRS)

Cobb, S. D.; Szofran, F. R.; Volz, M. P.

1999-01-01

Thermal and compositional gradients induced during the growth process contribute significantly to the development of defects in the solidified boule. Thermal gradients and the solid-liquid interface shape can be greatly effected by ampoule material. Compositional gradients are strongly influenced by interface curvature and convective flow in the liquid. Results of this investigation illustrate the combined influences of interface shape and convective fluid flow. An applied magnetic field was used to reduce the effects of convective fluid flow in the electrically conductive melt during directional solidification. Several 8 mm diameter boules of Ga-doped Ge were grown at different field strengths, up to 5 Tesla, in four different ampoule materials. Compositional profiles indicate mass transfer conditions ranged from completely mixed to diffusion controlled. The influence of convection in the melt on the developing crystal microstructure and defect density was investigated as a function of field strength and ampoule material. Chemical etching and electron backscattered electron diffraction were used to map the crystal structure of each boule along the center plane. Dislocation etch pit densities were measured for each boule. Results show the influence of magnetic field strength and ampoule material on overall crystal quality.

Unraveling Deformation Mechanisms in Gradient Structured Metals

NASA Astrophysics Data System (ADS)

Moering, Jordan Alexander

Gradient structures have demonstrated high strength and high ductility, introducing new mechanisms to challenge conventional mechanics. This work develops a method for characterizing the shear strain in gradient structured steel and presents evidence of a texture gradient that develops in Surface Mechanical Attrition Treatment (SMAT). Mechanics underlying some theories of the strengthening mechanisms in gradient structured metals are introduced, followed by the fabrication and testing of gradient structured aluminum rod. The round geometry is intrinsically different from its flat counterparts, which leads to a multiaxial stress state evolving in tension. The aluminum exhibits strengthening beyond rule of mixtures, and texture evolution in the post-mortem sample indicates that out of plane stresses operate within the gradient. Finally, another gradient structured aluminum rod is shown to exhibit higher strength and higher elongation to failure in a variety of sample diameters and processing conditions. The GND density and microstructural evolution showed no significant changes during mechanical testing, and high resolution strain mapping was successfully completed within the core of the material. These discoveries and contributions to the field should help continue unraveling the deformation mechanisms of gradient structured metals.

Differential heating: A versatile method for thermal conductivity measurements in high-energy-density matter

DOE PAGES

Ping, Y.; Fernandez-Panella, A.; Sio, H.; ...

2015-09-04

We propose a method for thermal conductivity measurements of high energy density matter based on differential heating. A temperature gradient is created either by surface heating of one material or at an interface between two materials by different energy deposition. The subsequent heat conduction across the temperature gradient is observed by various time-resolved probing techniques. Conceptual designs of such measurements using laser heating, proton heating, and x-ray heating are presented. As a result, the sensitivity of the measurements to thermal conductivity is confirmed by simulations.

Randomized clinical trial of two resin-modified glass ionomer materials: 1-year results.

PubMed

Perdigão, J; Dutra-Corrêa, M; Saraceni, S H C; Ciaramicoli, M T; Kiyan, V H

2012-01-01

With institutional review board approval, 33 patients who needed restoration of noncarious cervical lesions (NCCL) were enrolled in this study. A total of 92 NCCL were selected and randomly assigned to three groups: (1) Ambar (FGM), a two-step etch-and-rinse adhesive (control), combined with the nanofilled composite resin Filtek Supreme Plus (FSP; 3M ESPE); (2) Fuji II LC (GC America), a traditional resin-modified glass ionomer (RMGIC) restorative material; (3) Ketac Nano (3M ESPE), a nanofilled RMGIC restorative material. Restorations were evaluated at six months and one year using modified United States Public Health Service parameters. At six months after initial placement, 84 restorations (a 91.3% recall rate) were evaluated. At one year, 78 restorations (a 84.8% recall rate) were available for evaluation. The six month and one year overall retention rates were 93.1% and 92.6%, respectively, for Ambar/FSP; 100% and 100%, respectively, for Fuji II LC; and 100% and 100%, respectively, for Ketac Nano with no statistical difference between any pair of groups at each recall. Sensitivity to air decreased for all three adhesive materials from the preoperative to the postoperative stage, but the difference was not statistically significant. For Ambar/FSP, there were no statistical differences for any of the parameters from baseline to six months and from baseline to one year. For Fuji II LC, surface texture worsened significantly from baseline to six months and from baseline to one year. For Ketac Nano, enamel marginal staining increased significantly from baseline to one year and from six months to one year. Marginal adaptation was statistically worse at one year compared with baseline only for Ketac Nano. When parameters were compared for materials at each recall, Ketac Nano resulted in significantly worse color match than any of the other two materials at any evaluation period. At one year, Ketac Nano resulted in significantly worse marginal adaptation than the other two materials and worse marginal staining than Fuji II LC. Surface texture was statistically worse for Fuji II LC compared with the other two materials at all evaluation periods. The one-year retention rate was statistically similar for the three adhesive materials. Nevertheless, enamel marginal deficiencies and color mismatch were more prevalent for Ketac Nano. Surface texture of Fuji II LC restorations deteriorated quickly.

HPMSS(High Precision Magnetic Survey System) and InterRidge

NASA Astrophysics Data System (ADS)

Isezaki, N.; Sayanagi, K.

2012-12-01

From the beginning of 1990s to the beginning of 2000s, the Japanese group of IntreRidge conducted many cruises for three component magnetic survey using Shipboard Three Component Magnetometer (STCM) and Deep Towed Three Component Magnetometer (DTCM) in the world wide oceans. We have been developing HPMSS during this time with support of Dr.Tamaki(the late representative of InterRidge Japan) who understood the advantages of three component geomagnetic anomalies (TCGA). TCGA measured by STCM determines the direction of geomagnetic anomaly lineations precisely at every point where TCGA were observed, which playes the important role in magnetic anomaly lineation analysis. Even in the beginning of 2000s, almost all marine magnetic scientists believed that the total intensity anomly (TIA) is the better data than TCGA for analysis because the scalar magnetometers (e.g. proton precession magnetometer) have the better accuracy than any other magnetometers (e.g.flux gate magnetometer (FGM)). We employed the high accrate gyroscope (e.g.ring lase gyroscope (RLG)/optical fiber gyroscope (OFG)) to improve the accuracy of STCM/DTCM equipped with FGM. Moreover we employed accurate and precise FGM which was selected among the market. Finally we developed the new magnetic survey system with high precision usable as airborn, shipboard and dee-ptowed magnetometers which we call HPMSS(High Precision Magnetic Survey System). As an optional equipment, we use LAN to communicate between a data aquisiitin part and a data logging part, and GPS for a position fix. For the deep-towed survey, we use the acoustic position fix (super short base line method) and the acoustic communication to monitor the DTCM status. First we used HPMSS to obtain the magnetization structure of the volcanic island, Aogashima located 300km south of Tokyo using a hellcopter in 2006 and 2009. Next we used HPMSS installed in DTCM in 2010,2011 and 2012 using R/V Bosei-maru belonging to Tokai University. Also we used HPMSS installed in AUV (automonous undersea vehicle), belonging to JAMSTEC in 2009,2010 and 2011. We have been emphasizing the importnace of TCGA compared to TIA because TIA does not obey the Laplace equation which means TIA is not harmonic, then we cannot apply the Fourier analysis on TIA. We will show the structure of three component magnetization of the mineral deposit in the volcanic thermal area in Izu-Ogasawara island Arc, called Hakurei Deposit. TCGA of DTCM and AUV survey data were used and the depth section and the vertical section of three components of magnetization of Hakurei Deposit area will be presented. We emphasize that reliable 3D structure of three component of magnetization was obtained from TCGA using HPMSS as the result of deep support of InterRidge Japan, especially deep support of Dr. Tamaki.

Microfluidic approaches for the fabrication of gradient crosslinked networks based on poly(ethylene glycol) and hyperbranched polymers for manipulation of cell interactions

PubMed Central

Pedron, S; Peinado, C; Bosch, P; Benton, J A; Anseth, K S

2011-01-01

High-throughput methods allow rapid examination of parameter space to characterize materials and develop new polymeric formulations for biomaterials applications. One limitation is the difficulty of preparing libraries and performing high-throughput screening with conventional instrumentation and sample preparation. Here, we describe the fabrication of substrate materials with controlled gradients in composition by a rapid method of micromixing followed by a photopolymerization reaction. Specifically, poly(ethylene glycol) dimethacrylate was copolymerized with a hyperbranched multimethacrylate (P1000MA or H30MA) in a gradient manner. The extent of methacrylate conversion and the final network composition were determined by near-infrared spectroscopy, and mechanical properties were measured by nanoindentation. A relationship was observed between the elastic modulus and network crosslinking density. Roughness and hydrophilicity were increased on surfaces with a higher concentration of P1000MA. These results likely relate to a phase segregation process of the hyperbranched macromer that occurs during the photopolymerization reaction. On the other hand, the decrease in the final conversion in H30MA polymerization reactions was attributed to the lower termination rate as a consequence of the softening of the network. Valvular interstitial cell attachment was evaluated on these gradient substrates as a demonstration of studying cell morphology as a function of the local substrate properties. Data revealed that the presence of P1000MA affects cell–material interaction with a higher number of adhered cells and more cell spreading on gradient regions with a higher content of the multifunctional crosslinker. PMID:21105168

Nanofiber scaffold gradients for interfacial tissue engineering.

PubMed

Ramalingam, Murugan; Young, Marian F; Thomas, Vinoy; Sun, Limin; Chow, Laurence C; Tison, Christopher K; Chatterjee, Kaushik; Miles, William C; Simon, Carl G

2013-02-01

We have designed a 2-spinnerette device that can directly electrospin nanofiber scaffolds containing a gradient in composition that can be used to engineer interfacial tissues such as ligament and tendon. Two types of nanofibers are simultaneously electrospun in an overlapping pattern to create a nonwoven mat of nanofibers containing a composition gradient. The approach is an advance over previous methods due to its versatility - gradients can be formed from any materials that can be electrospun. A dye was used to characterize the 2-spinnerette approach and applicability to tissue engineering was demonstrated by fabricating nanofibers with gradients in amorphous calcium phosphate nanoparticles (nACP). Adhesion and proliferation of osteogenic cells (MC3T3-E1 murine pre-osteoblasts) on gradients was enhanced on the regions of the gradients that contained higher nACP content yielding a graded osteoblast response. Since increases in soluble calcium and phosphate ions stimulate osteoblast function, we measured their release and observed significant release from nanofibers containing nACP. The nanofiber-nACP gradients fabricated herein can be applied to generate tissues with osteoblast gradients such as ligaments or tendons. In conclusion, these results introduce a versatile approach for fabricating nanofiber gradients that can have application for engineering graded tissues.

Method and means for a spatial and temporal probe for laser-generated plumes based on density gradients

DOEpatents

Yeung, Edward S.; Chen, Guoying

1990-05-01

A method and means for a spatial and temporal probe for laser generated plumes based on density gradients includes generation of a plume of vaporized material from a surface by an energy source. The probe laser beam is positioned so that the plume passes through the probe laser beam. Movement of the probe laser beam caused by refraction from the density gradient of the plume is monitored. Spatial and temporal information, correlated to one another, is then derived.

Finite Element Analysis of Multilayered and Functionally Gradient Tribological Coatings With Measured Material Properties (Preprint)

DTIC Science & Technology

2006-11-01

gradient coatings with diamond like carbon (DLC) coating on 440C stainless steel substrate were assumed as a series of perfectly bonded layers with...resistance and low friction. Ti1-xCx (0≤ x ≤1) gradient coatings with diamond like carbon (DLC) coating on 440C stainless steel substrate were...indenter tip was used for the FEA model. Each coating sample consists of 1 μm thick coating and 440C stainless steel substrate. The area function for

Manufacturing of PZT-nickel functionally graded piezoelectric ceramics

NASA Astrophysics Data System (ADS)

Rubio, Wilfredo M.; Silva, Emílio C. N.; Buiochi, Flávio

2012-05-01

A recent approach for designing and manufacturing piezoelectric ceramics consists of using the functionally graded materials (FGM) concept. In this work, nickel (Ni) is used to generate a new PZT-Ni graded ceramic and its dynamic behavior is experimentally explored. The PZT-Ni graded ceramic is manufactured by using the technique of Spark Plasma Sintering (SPS). The ceramic is graded from the top to the bottom surface (along 6 mm of thickness). Specifically, five layers of green powders are sintered: 100 wt% PZT-5A, 90 wt% PZT-5A and 10 wt% Ni, 80 wt% PZT-5A and 20 wt% Ni, 70 wt% PZT-5A and 30 wt% Ni, 60 wt% PZT-5A and 40 wt% Ni. Thus, Ni is used as a second phase, which is added to a PZT-5A matrix, changing its concentration. No manufacturing defects or cracks or exfoliated layers are observed. However, graphite diffusion is observed from the graphite die into the graded ceramic, which does not affect its performance; hence, the ceramic contains enough piezoelectric properties, which allows its polarization and dynamic characterization by determining the impedance curve of the PZT-Ni graded ceramic. The PZT-Ni graded ceramic vibrates at 1.04 MHz, 1.55 MHz and 2.07 MHz.

Preparation of asymmetric porous materials

DOEpatents

Coker, Eric N [Albuquerque, NM

2012-08-07

A method for preparing an asymmetric porous material by depositing a porous material film on a flexible substrate, and applying an anisotropic stress to the porous media on the flexible substrate, where the anisotropic stress results from a stress such as an applied mechanical force, a thermal gradient, and an applied voltage, to form an asymmetric porous material.

Solution of the Eshelby problem in gradient elasticity for multilayer spherical inclusions

NASA Astrophysics Data System (ADS)

Volkov-Bogorodskii, D. B.; Lurie, S. A.

2016-03-01

We consider gradient models of elasticity which permit taking into account the characteristic scale parameters of the material. We prove the Papkovich-Neuber theorems, which determine the general form of the gradient solution and the structure of scale effects. We derive the Eshelby integral formula for the gradient moduli of elasticity, which plays the role of the closing equation in the self-consistent three-phase method. In the gradient theory of deformations, we consider the fundamental Eshelby-Christensen problem of determining the effective elastic properties of dispersed composites with spherical inclusions; the exact solution of this problem for classical models was obtained in 1976. This paper is the first to present the exact analytical solution of the Eshelby-Christensen problem for the gradient theory, which permits estimating the influence of scale effects on the stress state and the effective properties of the dispersed composites under study.We also analyze the influence of scale factors.

Combinatorial techniques to efficiently investigate and optimize organic thin film processing and properties.

PubMed

Wieberger, Florian; Kolb, Tristan; Neuber, Christian; Ober, Christopher K; Schmidt, Hans-Werner

2013-04-08

In this article we present several developed and improved combinatorial techniques to optimize processing conditions and material properties of organic thin films. The combinatorial approach allows investigations of multi-variable dependencies and is the perfect tool to investigate organic thin films regarding their high performance purposes. In this context we develop and establish the reliable preparation of gradients of material composition, temperature, exposure, and immersion time. Furthermore we demonstrate the smart application of combinations of composition and processing gradients to create combinatorial libraries. First a binary combinatorial library is created by applying two gradients perpendicular to each other. A third gradient is carried out in very small areas and arranged matrix-like over the entire binary combinatorial library resulting in a ternary combinatorial library. Ternary combinatorial libraries allow identifying precise trends for the optimization of multi-variable dependent processes which is demonstrated on the lithographic patterning process. Here we verify conclusively the strong interaction and thus the interdependency of variables in the preparation and properties of complex organic thin film systems. The established gradient preparation techniques are not limited to lithographic patterning. It is possible to utilize and transfer the reported combinatorial techniques to other multi-variable dependent processes and to investigate and optimize thin film layers and devices for optical, electro-optical, and electronic applications.

Advanced Gradient Heating Facility

NASA Technical Reports Server (NTRS)

2004-01-01

The Advanced Gradient Heating Facility (AGHF) is a European Space Agency (ESA) developed hardware. The AGHF was flown on STS-78, which featured four European PI's and two NASA PI's. The AGHFsupports the production of advanced semiconductor materials and alloys using the directional process, which depends on establishing a hot side and a cold side in the sample.

Microstructures and Mechanical Properties of Commercially Pure Ti Processed by Rotationally Accelerated Shot Peening

PubMed Central

Huang, Zhaowen; Cao, Yang; Nie, Jinfeng; Zhou, Hao; Li, Yusheng

2018-01-01

Gradient structured materials possess good combinations of strength and ductility, rendering the materials attractive in industrial applications. In this research, a surface nanocrystallization (SNC) technique, rotationally accelerated shot peening (RASP), was employed to produce a gradient nanostructured pure Ti with a deformation layer that had a thickness of 2000 μm, which is thicker than those processed by conventional SNC techniques. It is possible to fabricate a gradient structured Ti workpiece without delamination. Moreover, based on the microstructural features, the microstructure of the processed sample can be classified into three regions, from the center to the surface of the RASP-processed sample: (1) a twinning-dominated core region; (2) a “twin intersection”-dominated twin transition region; and (3) the nanostructured region, featuring nanograins. A microhardness gradient was detected from the RASP-processed Ti. The surface hardness was more than twice that of the annealed Ti sample. The RASP-processed Ti sample exhibited a good combination of yield strength and uniform elongation, which may be attributed to the high density of deformation twins and a strong back stress effect. PMID:29498631

Minimizing hot spot temperature in asymmetric gradient coil design.

PubMed

While, Peter T; Forbes, Larry K; Crozier, Stuart

2011-08-01

Heating caused by gradient coils is a considerable concern in the operation of magnetic resonance imaging (MRI) scanners. Hot spots can occur in regions where the gradient coil windings are closely spaced. These problem areas are particularly common in the design of gradient coils with asymmetrically located target regions. In this paper, an extension of an existing coil design method is described, to enable the design of asymmetric gradient coils with reduced hot spot temperatures. An improved model is presented for predicting steady-state spatial temperature distributions for gradient coils. A great amount of flexibility is afforded by this model to consider a wide range of geometries and system material properties. A feature of the temperature distribution related to the temperature gradient is used in a relaxed fixed point iteration routine for successively altering coil windings to have a lower hot spot temperature. Results show that significant reductions in peak temperature are possible at little or no cost to coil performance when compared to minimum power coils of equivalent field error.

Multiphysics Modelling of Sodium Sulfur Battery

NASA Astrophysics Data System (ADS)

Mason, Jerry Hunter

Due to global climate change and the desire to decrease greenhouse gas emissions, large scale energy storage has become a critical issue. Renewable energy sources such as wind and solar will not be a viable energy source unless the storage problem is solved. One of the practical and cost effective solutions for this problem is sodium sulfur batteries. These batteries are comprised of liquid electrode materials suspended in porous media and operate at relatively high temperatures (>300°C). The sodium anode and the sulfur/sodium-polysulfide cathode are separated by a solid electrolyte made of beta-alumina or NASICON material. Due to the use of porous materials in the electrodes, capillary pressure and the combination of capillary action and gravity become important. Capillary pressure has a strong dependence on the wetting phase (liquid electrode material) saturation; therefore sharp concentration gradients can occur between the inert gas and the electrode liquid, especially within the cathode. These concentration gradients can have direct impacts on the electrodynamics of the battery as they may produce areas of high electrical potential variation, which can decrease efficiency and even cause failures. Then, thermal management also becomes vital since the electrochemistry and material properties are sensitive to temperature gradients. To investigate these phenomena in detail and to attempt to improve upon battery design a multi-dimensional, multi-phase code has been developed and validated in this study. Then a porous media flow model is implemented. Transport equations for charge, mass and heat are solved in a time marching fashion using finite volume method. Material properties are calculated and updated as a function of time. The porous media model is coupled with the continuity equation and a separate diffusion equation for the liquid sodium in the melt. The total mass transport model is coupled with charge transport via Faraday's law. Results show that overpotential is significantly higher in the porous region of the cathode as was predicted by models in the literature. Overpotential is also high on the electrolyte surface and wall. Alternative electrode configurations with high resistive layers recommended by previous researchers also produce areas of high potential gradient. New electrode designs including conductivity gradients and porous media property variations are simulated and compared to previous designs and then recommendations are made for optimum cell operating conditions.

Analytical instrumentation infrastructure for combinatorial and high-throughput development of formulated discrete and gradient polymeric sensor materials arrays

NASA Astrophysics Data System (ADS)

Potyrailo, Radislav A.; Hassib, Lamyaa

2005-06-01

Multicomponent polymer-based formulations of optical sensor materials are difficult and time consuming to optimize using conventional approaches. To address these challenges, our long-term goal is to determine relationships between sensor formulation and sensor response parameters using new scientific methodologies. As the first step, we have designed and implemented an automated analytical instrumentation infrastructure for combinatorial and high-throughput development of polymeric sensor materials for optical sensors. Our approach is based on the fabrication and performance screening of discrete and gradient sensor arrays. Simultaneous formation of multiple sensor coatings into discrete 4×6, 6×8, and 8×12 element arrays (3-15μL volume per element) and their screening provides not only a well-recognized acceleration in the screening rate, but also considerably reduces or even eliminates sources of variability, which are randomly affecting sensors response during a conventional one-at-a-time sensor coating evaluation. The application of gradient sensor arrays provides additional capabilities for rapid finding of the optimal formulation parameters.

New head gradient coil design and construction techniques

PubMed Central

Handler, William B; Harris, Chad T; Scholl, Timothy J; Parker, Dennis L; Goodrich, K Craig; Dalrymple, Brian; Van Sass, Frank; Chronik, Blaine A

2013-01-01

Purpose To design and build a head insert gradient coil to use in conjunction with body gradients for superior imaging. Materials and Methods The use of the Boundary Element Method to solve for a gradient coil wire pattern on an arbitrary surface has allowed us to incorporate engineering changes into the electromagnetic design of a gradient coil directly. Improved wire pattern design has been combined with robust manufacturing techniques and novel cooling methods. Results The finished coil had an efficiency of 0.15 mT/m/A in all three axes and allowed the imaging region to extend across the entire head and upper part of the neck. Conclusion The ability to adapt your electromagnetic design to necessary changes from an engineering perspective leads to superior coil performance. PMID:24123485

Microsphere-based gradient implants for osteochondral regeneration: a long-term study in sheep

PubMed Central

Mohan, Neethu; Gupta, Vineet; Sridharan, Banu Priya; Mellott, Adam J; Easley, Jeremiah T; Palmer, Ross H; Galbraith, Richard A; Key, Vincent H; Berkland, Cory J; Detamore, Michael S

2015-01-01

Background: The microfracture technique for cartilage repair has limited ability to regenerate hyaline cartilage. Aim: The current study made a direct comparison between microfracture and an osteochondral approach with microsphere-based gradient plugs. Materials & methods: The PLGA-based scaffolds had opposing gradients of chondroitin sulfate and β-tricalcium phosphate. A 1-year repair study in sheep was conducted. Results: The repair tissues in the microfracture were mostly fibrous and had scattered fissures with degenerative changes. Cartilage regenerated with the gradient plugs had equal or superior mechanical properties; had lacunated cells and stable matrix as in hyaline cartilage. Conclusion: This first report of gradient scaffolds in a long-term, large animal, osteochondral defect demonstrated potential for equal or better cartilage repair than microfracture. PMID:26418471

Temperature-gradient-induced

NASA Astrophysics Data System (ADS)

Park, Cheol; Glaser, Matt; Maclennan, Joe; Clark, Noel; Trittel, Torsten; Stannarius, Ralf

Freely-suspended smectic films of sub-micrometer thickness and lateral extensions of several millimeters were used to study thermally driven migration and convection in the film plane. Film experiments were performed during the 6 minute microgravity phase of a TEXUS suborbital rocket flight (Texus 52, launched April 27, 2015). We have found an attraction of the smectic material towards the cold edge of the film in a temperature gradient, similar to the Soret effect. This process is reversed when this edge is heated up again. Thermal convection driven by two thermocontacts in the film is practically absent, even at temperature gradients up to 10 K/mm, with thermally driven convection only setting in when the hot post reaches the transition temperature to the nematic phase. The Observation and Analysis of Smectic Islands in Space (OASIS) flight hardware was launched on SpaceX-6 in April 2015 and experiments on smectic bubbles were carried out on the International Space Station using four different smectic A and C liquid crystal materials in separate sample chambers. We observed that smectic islands on the surface of the bubbles migrated towards the colder part of the bubble in a temperature gradient. This work was supported by NASA Grant No. NNX-13AQ81G, by the Soft Materials Research Center under NSF MRSEC Grants No. DMR-0820579 and No. DMR-1420736, and by DLR Grants 50WM1127 and 50WM1430.

Design and fabrication of a metamaterial gradient index diffraction grating at infrared wavelengths.

PubMed

Tsai, Yu-Ju; Larouche, Stéphane; Tyler, Talmage; Lipworth, Guy; Jokerst, Nan M; Smith, David R

2011-11-21

We demonstrate the design, fabrication and characterization of an artificially structured, gradient index metamaterial with a linear index variation of Δn ~ 3.0. The linear gradient profile is repeated periodically to form the equivalent of a blazed grating, with the gradient occurring across a spatial distance of 61 μm. The grating, which operates at a wavelength of 10.6 μm, is composed of non-resonant, progressively modified "I-beam" metamaterial elements and approximates a linear phase shift gradient using 61 distinguishable phase levels. The grating structure consists of four layers of lithographically patterned metallic I-beam elements separated by dielectric layers of SiO(2). The index gradient is confirmed by comparing the measured magnitudes of the -1, 0 and +1 diffracted orders to those obtained from full wave simulations incorporating all material properties of the metals and dielectrics of the structures. The large index gradient has the potential to enable compact infrared diffractive and gradient index optics, as well as more exotic transformation optical media. © 2011 Optical Society of America

Continuous gradient scaffolds for rapid screening of cell-material interactions and interfacial tissue regeneration.

PubMed

Bailey, Brennan M; Nail, Lindsay N; Grunlan, Melissa A

2013-09-01

In tissue engineering, the physical and chemical properties of the scaffold mediates cell behavior, including regeneration. Thus a strategy that permits rapid screening of cell-scaffold interactions is critical. Herein, we have prepared eight "hybrid" hydrogel scaffolds in the form of continuous gradients such that a single scaffold contains spatially varied properties. These scaffolds are based on combining an inorganic macromer (methacrylated star polydimethylsiloxane, PDMSstar-MA) and organic macromer (poly(ethylene glycol)diacrylate, PEG-DA) as well as both aqueous and organic fabrication solvents. Having previously demonstrated its bioactivity and osteoinductivity, PDMSstar-MA is a particularly powerful component to incorporate into instructive gradient scaffolds based on PEG-DA. The following parameters were varied to produce the different gradients or gradual transitions in: (1) the wt.% ratio of PDMSstar-MA to PEG-DA macromers, (2) the total wt.% macromer concentration, (3) the number average molecular weight (Mn) of PEG-DA and (4) the Mn of PDMSstar-MA. Upon dividing each scaffold into four "zones" perpendicular to the gradient, we were able to demonstrate the spatial variation in morphology, bioactivity, swelling and modulus. Among these gradient scaffolds are those in which swelling and modulus are conveniently decoupled. In addition to rapid screening of cell-material interactions, these scaffolds are well suited for regeneration of interfacial tissues (e.g. osteochondral tissues) that transition from one tissue type to another. Copyright © 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Strain gradient drives shear banding in metallic glasses

NASA Astrophysics Data System (ADS)

Tian, Zhi-Li; Wang, Yun-Jiang; Chen, Yan; Dai, Lan-Hong

2017-09-01

Shear banding is a nucleation-controlled process in metallic glasses (MGs) involving multiple temporal-spatial scales, which hinders a concrete understanding of its structural origin down to the atomic scale. Here, inspired by the morphology of composite materials, we propose a different perspective of MGs as a hard particle-reinforced material based on atomic-scale structural heterogeneity. The local stable structures indicated by a high level of local fivefold symmetry (L5FS) act as hard "particles" which are embedded in the relatively soft matrix. We demonstrate this concept by performing atomistic simulations of shear banding in CuZr MG. A shear band is prone to form in a sample with a high degree of L5FS which is slowly quenched from the liquid. An atomic-scale analysis on strain and the structural evolution reveals that it is the strain gradient effect that has originated from structural heterogeneity that facilitates shear transformation zones (STZs) to mature shear bands. An artificial composite model with a high degree of strain gradient, generated by inserting hard MG strips into a soft MG matrix, demonstrates a great propensity for shear banding. It therefore confirms the critical role strain gradient plays in shear banding. The strain gradient effect on shear banding is further quantified with a continuum model and a mechanical instability analysis. These physical insights might highlight the strain gradient as the hidden driving force in transforming STZs into shear bands in MGs.

Jupiter's Magnetic Field and Magnetosphere after Juno's First 8 Orbits

NASA Astrophysics Data System (ADS)

Connerney, J. E. P.; Oliversen, R. J.; Espley, J. R.; Gruesbeck, J.; Kotsiaros, S.; DiBraccio, G. A.; Joergensen, J. L.; Joergensen, P. S.; Merayo, J. M. G.; Denver, T.; Benn, M.; Bjarno, J. B.; Malinnikova Bang, A.; Bloxham, J.; Moore, K.; Bolton, S. J.; Levin, S.; Gershman, D. J.

2016-12-01

The Juno spacecraft entered polar orbit about Jupiter on July 4, 2016, embarking upon an ambitious mission to map Jupiter's magnetic and gravitational potential fields and probe its deep atmosphere, in search of clues to the planet's formation and evolution. Juno is also instrumented to conduct the first exploration of the polar magnetosphere and to acquire images and spectra of its polar auroras and atmosphere. Juno's 53.5-day orbit trajectory carries her science instruments from pole to pole in approximately 2 hours, with a closest approach to within 1.05 Rj of the center of the planet (one Rj = 71,492 km, Jupiter's equatorial radius), just a few thousand km above the clouds. Repeated periapsis passes will eventually encircle the planet with a dense net of observations equally spaced in longitude (<12° at the equator) and optimized for characterization of the Jovian dynamo. Such close passages are sensitive to small spatial scale variations in the magnetic field and therefore many such passes are required to bring the magnetic field into focus. Nevertheless, after only 8 orbits, low-degree spherical harmonics can be extracted from a partial solution to a much more complicated representation (e.g., 20 degree/order), providing the first new information about Jupiter's magnetic field in decades. Juno is equipped with two magnetometer sensor suites, located 10 and 12 m from the center of the spacecraft at the end of one of Juno's three solar panel wings. Each contains a vector fluxgate magnetometer (FGM) sensor and a pair of co-located non-magnetic star tracker camera heads, providing accurate attitude determination for the FGM sensors. We present an overview of the magnetometer observations obtained during Juno's first year in orbit in context with prior observations and those acquired by Juno's other science instruments.

Effectiveness of and Dental Sensitivity to At-home Bleaching With 4% and 10% Hydrogen Peroxide: A Randomized, Triple-blind Clinical Trial.

PubMed

Chemin, K; Rezende, M; Loguercio, A D; Reis, A; Kossatz, S

To evaluate the risk for and intensity of tooth sensitivity and color change of at-home dental bleaching with 4% and 10% hydrogen peroxide (HP). For this study, 78 patients were selected according to the inclusion and exclusion criteria and randomized into two groups: HP 4 (White Class 4%, FGM) and HP 10 (White Class 10%, FGM). In both groups, the at-home bleaching was performed for a period of 30 minutes twice a day for two weeks. The color was assessed by Vita Classical, Vita Bleachedguide 3D-MASTER and spectrophotometer Vita Easyshade (Vita Zahnfabrik) at baseline, during bleaching (first and second weeks) and after bleaching (one month). Patients recorded their tooth sensitivity using a numeric rating scale (0-4) and visual analog scale (0-10). Data from color change (DeltaE data) was submitted to two-way analysis of variance. The color change data in Delta SGU from the two shade guide units were compared with the Mann Whitney test. The risk of tooth sensitivity was evaluated by χ 2 test and the intensity of tooth sensitivity from both scales was evaluated by a Mann-Whitney test (α=0.05). The absolute risk and intensity of tooth sensitivity was higher in the group that used HP 10 than the one that used HP 4. Data from change in the number of shade guide units and color variation after one month of bleaching for both groups showed significant whitening, with no difference between groups. At-home bleaching is effective with 4% and 10% HP concentrations, but 10% HP increased the absolute risk and intensity of tooth sensitivity during at-home bleaching.

Jupiter's Magnetic Field and Magnetosphere after Juno's First 8 Orbits

NASA Astrophysics Data System (ADS)

Connerney, J. E. P.; Oliversen, R. J.; Espley, J. R.; Gruesbeck, J.; Kotsiaros, S.; DiBraccio, G. A.; Joergensen, J. L.; Joergensen, P. S.; Merayo, J. M. G.; Denver, T.; Benn, M.; Bjarno, J. B.; Malinnikova Bang, A.; Bloxham, J.; Moore, K.; Bolton, S. J.; Levin, S.; Gershman, D. J.

2017-12-01

The Juno spacecraft entered polar orbit about Jupiter on July 4, 2016, embarking upon an ambitious mission to map Jupiter's magnetic and gravitational potential fields and probe its deep atmosphere, in search of clues to the planet's formation and evolution. Juno is also instrumented to conduct the first exploration of the polar magnetosphere and to acquire images and spectra of its polar auroras and atmosphere. Juno's 53.5-day orbit trajectory carries her science instruments from pole to pole in approximately 2 hours, with a closest approach to within 1.05 Rj of the center of the planet (one Rj = 71,492 km, Jupiter's equatorial radius), just a few thousand km above the clouds. Repeated periapsis passes will eventually encircle the planet with a dense net of observations equally spaced in longitude (<12° at the equator) and optimized for characterization of the Jovian dynamo. Such close passages are sensitive to small spatial scale variations in the magnetic field and therefore many such passes are required to bring the magnetic field into focus. Nevertheless, after only 8 orbits, low-degree spherical harmonics can be extracted from a partial solution to a much more complicated representation (e.g., 20 degree/order), providing the first new information about Jupiter's magnetic field in decades. Juno is equipped with two magnetometer sensor suites, located 10 and 12 m from the center of the spacecraft at the end of one of Juno's three solar panel wings. Each contains a vector fluxgate magnetometer (FGM) sensor and a pair of co-located non-magnetic star tracker camera heads, providing accurate attitude determination for the FGM sensors. We present an overview of the magnetometer observations obtained during Juno's first year in orbit in context with prior observations and those acquired by Juno's other science instruments.

Development and Testing of UCLA's Electron Losses and Fields Investigation (ELFIN) Instrument Payload

NASA Astrophysics Data System (ADS)

Wilkins, C.; Bingley, L.; Angelopoulos, V.; Caron, R.; Cruce, P. R.; Chung, M.; Rowe, K.; Runov, A.; Liu, J.; Tsai, E.

2017-12-01

UCLA's Electron Losses and Fields Investigation (ELFIN) is a 3U+ CubeSat mission designed to study relativistic particle precipitation in Earth's polar regions from Low Earth Orbit. Upon its 2018 launch, ELFIN will aim to address an important open question in Space Physics: Are Electromagnetic Ion-Cyclotron (EMIC) waves the dominant source of pitch-angle scattering of high-energy radiation belt charged particles into Earth's atmosphere during storms and substorms? Previous studies have indicated these scattering events occur frequently during storms and substorms, and ELFIN will be the first mission to study this process in-situ.Paramount to ELFIN's success is its instrument suite consisting of an Energetic Particle Detector (EPD) and a Fluxgate Magnetometer (FGM). The EPD is comprised of two collimated solid-state detector stacks which will measure the incident flux of energetic electrons from 50 keV to 4 MeV and ions from 50 keV to 300 keV. The FGM is a 3-axis magnetic field sensor which will capture the local magnetic field and its variations at frequencies up to 5 Hz. The ELFIN spacecraft spins perpendicular to the geomagnetic field to provide 16 pitch-angle particle data sectors per revolution. Together these factors provide the capability to address the nature of radiation belt particle precipitation by pitch-angle scattering during storms and substorms.ELFIN's instrument development has progressed into the late Engineering Model (EM) phase and will soon enter Flight Model (FM) development. The instrument suite is currently being tested and calibrated at UCLA using a variety of methods including the use of radioactive sources and applied magnetics to simulate orbit conditions during spin sectoring. We present the methods and test results from instrument calibration and performance validation.

First Results of the Juno Magnetometer Investigation in Jupiter's Magnetosphere

NASA Astrophysics Data System (ADS)

Connerney, Jack; Oliversen, Ronald; Espley, Jared; Kotsiaros, Stavros; Joergensen, John; Joergensen, Peter; Merano, Jose; Denver, Troelz; Benn, Mathias; Bloxham, Jeremy; Bolton, Scott; Levin, Steve

2017-04-01

The Juno spacecraft entered polar orbit about Jupiter on July 4, 2016, after a Jupiter Orbit Insertion (JOI) main engine burn lasting 35 minutes. Juno's science instruments were not powered during the critical maneuver sequence ( 5 days) but were fully operational shortly afterward. The 53.5-day capture orbit provides Juno's science instruments with the opportunity to sample the Jovian environment close up (to 1.06 Jovian radii, Rj) and in polar orbit extending to the outer reaches of the Jovian magnetosphere. Jupiter's gravity and magnetic fields will be globally mapped with unprecedented accuracy as Juno conducts a study of Jupiter's interior structure and composition, as well as the first comprehensive exploration of the polar magnetosphere. The magnetic field investigation onboard Juno is equipped with two magnetometer sensor suites, located at 10 and 12 m from the spacecraft body at the end of one of the three solar panel wings. Each contains a vector fluxgate magnetometer (FGM) sensor and a pair of co-located non-magnetic star tracker camera heads which provide accurate attitude determination for the FGM sensors. The first few periapsis passes available to date revealed an extraordinary spatial variation of the magnetic field close to the planet's surface, suggesting that Juno may be sampling the field closer to the dynamo region than widely anticipated, i.e., portending a dynamo surface extending to relatively large radial distance ( 0.9Rj?). We present the first observations of Jupiter's magnetic field obtained in close proximity to the planet, and speculate on what wonders await as more longitudes are drawn across the global map (32 polar orbits separated by <12° longitude) that the Juno mission was designed to acquire.

Gelatin freeze casting of biomimetic titanium alloy with anisotropic and gradient pore structure.

PubMed

Zhang, Lei; Le Coz-Botrel, Ronan; Beddoes, Charlotte; Sjöström, Terje; Su, Bo

2017-01-17

Titanium is a material commonly used for dental and orthopaedic implants. However, due to large differences in properties between the titanium metal and the natural bone, stress shielding has been observed in the surrounding area, resulting in bone atrophy, and thus has raised concerns of the use of this material. Ideally implant materials should possess similar properties to the surrounding tissues in order to distribute the load as the joint would naturally, while also possessing a similar porous structure to the bone to enable interaction with the surrounding material. In this paper we report the formation of aligned porous titanium alloy scaffolds with the use of unidirectional freeze casting with a temperature gradient. The resulting scaffolds had a dense bottom part with sufficient strength for loading, while the top part remaining porous in order to allow bone growth in the scaffold and fully integrating with the surrounding tissue. The anisotropic nature of the pores within the titanium alloy samples were observed via micro computed tomography, where a gradient structure similar to bone was observed. The compressive strength of the fabricated scaffolds was found to be up to 427 MPa when measured with the pores aligned with the applied load, depending on the pore density. This is within the range of cortical bone.

Some opinions about matter and material substances: from inanimate system -- to living according to A. Einstein general theory of relativity.

PubMed

Topuria, T; Gogebashvili, N; Korsantia, B

2005-11-01

During transformation from inanimate to living, change of the space position of the matter causes the change of the field, as the space does not exist without the field, therefore the time-space as the properties of material substances, should undergo certain changes. The outside inanimate system, in this case a matrix, has its own time. The living system, in this case a cell, where the matter undergoes space conformation with the change of field and space-time, has its own time and it has begun to flow more rapidly than in matrix. From the surface of the body, from different energetic reservoirs oppositely charged matter substances following from special transport systems from the life system transmitted into lifeless one and change their matter space conformation, create transmission gradient that is the gradient border of time from lifeless system into live. In the case of a human, hypothetically, the gradient system of time must be of a complex scheme counting the inter-transformation and interaction gradients of outer and inner abdominal systems. Subconscious and consciousness by means of special links and messages, information selection interact and form unique connection between the systems. Subconscious serves for accelerated time system. Conscious by means of permanent contact with the environment collects and reacts in matrix time system By interconnection of these two systems ideal adaptation with the environment takes place. Time difference gradient system is an additional energy factor, by means of which respective ordered geometrical structures special for the given types are formed. The living organism is an inter-regulated interconnection global system resulting from the changes of matter and material substances space configuration.

Gradients of microhabitat and crappie (Pomoxis spp.) distributions in reservoir coves

USGS Publications Warehouse

Kaczka, Levi J.; Miranda, Leandro E.

2013-01-01

Embayments are among the most widespread littoral habitats found in Mississippi flood-control reservoirs. These macrohabitats represent commonly used nursery zones for age-0 crappies, Pomoxis spp., despite barren and eroded shorelines formed over 60–70 years of annual water level fluctuations. We tested if embayments displayed microhabitat gradients linked to the effect of water level fluctuations on riparian vegetation and if these gradients were paralleled by gradients in age-0 crappie distribution. Habitat composition changed longitudinally along the embayments with the most pronounced gradient representing a shift from nonvegetated mudflats near the mouth of embayments to herbaceous material upstream. The degree of habitat change depended on the water level. Similarly, catch rates of crappies increased upstream toward the rear of embayments, differing among water levels and reservoirs, but the longitudinal pattern persisted. Our results indicate that habitat composition gradients occur in embayments of northwest Mississippi flood-control reservoirs and that these gradients may influence a similar gradient in age-0 crappie distribution. While the biotic interactions behind the gradients may be less clear, we speculate that water level is the main factor influencing the observed gradients in habitat composition and fish. Management to benefit age-0 crappies may involve habitat improvement along embayment shorelines and water level regimes that foster growth of herbaceous plants.

Biomaterials with persistent growth factor gradients in vivo accelerate vascularized tissue formation.

PubMed

Akar, Banu; Jiang, Bin; Somo, Sami I; Appel, Alyssa A; Larson, Jeffery C; Tichauer, Kenneth M; Brey, Eric M

2015-12-01

Gradients of soluble factors play an important role in many biological processes, including blood vessel assembly. Gradients can be studied in detail in vitro, but methods that enable the study of spatially distributed soluble factors and multi-cellular processes in vivo are limited. Here, we report on a method for the generation of persistent in vivo gradients of growth factors in a three-dimensional (3D) biomaterial system. Fibrin loaded porous poly (ethylene glycol) (PEG) scaffolds were generated using a particulate leaching method. Platelet derived growth factor BB (PDGF-BB) was encapsulated into poly (lactic-co-glycolic acid) (PLGA) microspheres which were placed distal to the tissue-material interface. PLGA provides sustained release of PDGF-BB and its diffusion through the porous structure results in gradient formation. Gradients within the scaffold were confirmed in vivo using near-infrared fluorescence imaging and gradients were present for more than 3 weeks. The diffusion of PDGF-BB was modeled and verified with in vivo imaging findings. The depth of tissue invasion and density of blood vessels formed in response to the biomaterial increased with magnitude of the gradient. This biomaterial system allows for generation of sustained growth factor gradients for the study of tissue response to gradients in vivo. Published by Elsevier Ltd.

On the combined gradient-stochastic plasticity model: Application to Mo-micropillar compression

DOE Office of Scientific and Technical Information (OSTI.GOV)

Konstantinidis, A. A., E-mail: akonsta@civil.auth.gr; Zhang, X., E-mail: zhangxu26@126.com; Aifantis, E. C., E-mail: mom@mom.gen.auth.gr

2015-02-17

A formulation for addressing heterogeneous material deformation is proposed. It is based on the use of a stochasticity-enhanced gradient plasticity model implemented through a cellular automaton. The specific application is on Mo-micropillar compression, for which the irregularities of the strain bursts observed have been experimentally measured and theoretically interpreted through Tsallis' q-statistics.

Material and Optical Densities

ERIC Educational Resources Information Center

Gluck, Paul

2007-01-01

The bending of a laser beam in a medium with a density and refractive index gradient in the same direction has been described previously. When a transparent container is half filled with a salt or sugar solution and an equal amount of water is floated on top of it, then diffusion will create a concentration gradient from top to bottom. A laser…

Method for single crystal growth of photovoltaic perovskite material and devices

DOE Office of Scientific and Technical Information (OSTI.GOV)

Huang, Jinsong; Dong, Qingfeng

Systems and methods for perovskite single crystal growth include using a low temperature solution process that employs a temperature gradient in a perovskite solution in a container, also including at least one small perovskite single crystal, and a substrate in the solution upon which substrate a perovskite crystal nucleates and grows, in part due to the temperature gradient in the solution and in part due to a temperature gradient in the substrate. For example, a top portion of the substrate external to the solution may be cooled.

Method and means for a spatial and temporal probe for laser-generated plumes based on density gradients

DOEpatents

Yeung, E.S.; Chen, G.

1990-05-01

A method and means are disclosed for a spatial and temporal probe for laser generated plumes based on density gradients includes generation of a plume of vaporized material from a surface by an energy source. The probe laser beam is positioned so that the plume passes through the probe laser beam. Movement of the probe laser beam caused by refraction from the density gradient of the plume is monitored. Spatial and temporal information, correlated to one another, is then derived. 15 figs.

Bioinspired large-scale aligned porous materials assembled with dual temperature gradients

PubMed Central

Bai, Hao; Chen, Yuan; Delattre, Benjamin; Tomsia, Antoni P.; Ritchie, Robert O.

2015-01-01

Natural materials, such as bone, teeth, shells, and wood, exhibit outstanding properties despite being porous and made of weak constituents. Frequently, they represent a source of inspiration to design strong, tough, and lightweight materials. Although many techniques have been introduced to create such structures, a long-range order of the porosity as well as a precise control of the final architecture remain difficult to achieve. These limitations severely hinder the scale-up fabrication of layered structures aimed for larger applications. We report on a bidirectional freezing technique to successfully assemble ceramic particles into scaffolds with large-scale aligned, lamellar, porous, nacre-like structure and long-range order at the centimeter scale. This is achieved by modifying the cold finger with a polydimethylsiloxane (PDMS) wedge to control the nucleation and growth of ice crystals under dual temperature gradients. Our approach could provide an effective way of manufacturing novel bioinspired structural materials, in particular advanced materials such as composites, where a higher level of control over the structure is required. PMID:26824062

Purification of Piscirickettsia salmonis and partial characterisation of antigens

USGS Publications Warehouse

Barnes, M.N.; Landolt, M.L.; Powell, D.B.; Winton, J.R.

1998-01-01

Piscirickettsia salmonis is the etiological agent of salmonid rickettsial septicemia, an economically significant disease affecting the salmon aquaculture industry. As with other rickettsial pathogens, antigenic analysis of P. salmonis has been limited by the inherent difficulties of purifying an intracellular organism away from host cell material. In this report, we describe the use of diatrizoate meglumine and diatrizoate sodium (DMDS) density gradient centrifugation to purify P. salmonis grown in chinook salmon embryo (CHSE-214) cells. Plaque assay titers and total protein assays confirmed that viable P. salmonis was consistently concentrated in a visible band within the DMDS density gradient at a density of 1.15 to 1.16 g ml-1. Recovery of purified, viable organisms from DMDS density gradients varied from 0.6 to 3%. Preparations of uninfected CHSE-214 cells, CHSE-214 cells infected with P. salmonis, and gradient-purified P. salmonis were compared using sodium dodecyl sulfate polyacrylamide gel electrophoresis to assess the degree of purification and to identify P. salmonis-specific proteins. Although gradient-purified P. salmonis preparations were not completely free of host cell material, 8 bacterial proteins were identified. Polyclonal rabbit antiserum was used in an immunoblot of proteins from purified P. salmonis to identify 3 major and 5 minor antigens. The major antigens of 56, 30 and 20 kDa were potential candidates for experimental vaccines and development of novel diagnostic assays.

Experimental and Finite Element Modeling of Near-Threshold Fatigue Crack Growth for the K-Decreasing Test Method

NASA Technical Reports Server (NTRS)

Smith, Stephen W.; Seshadri, Banavara R.; Newman, John A.

2015-01-01

The experimental methods to determine near-threshold fatigue crack growth rate data are prescribed in ASTM standard E647. To produce near-threshold data at a constant stress ratio (R), the applied stress-intensity factor (K) is decreased as the crack grows based on a specified K-gradient. Consequently, as the fatigue crack growth rate threshold is approached and the crack tip opening displacement decreases, remote crack wake contact may occur due to the plastically deformed crack wake surfaces and shield the growing crack tip resulting in a reduced crack tip driving force and non-representative crack growth rate data. If such data are used to life a component, the evaluation could yield highly non-conservative predictions. Although this anomalous behavior has been shown to be affected by K-gradient, starting K level, residual stresses, environmental assisted cracking, specimen geometry, and material type, the specifications within the standard to avoid this effect are limited to a maximum fatigue crack growth rate and a suggestion for the K-gradient value. This paper provides parallel experimental and computational simulations for the K-decreasing method for two materials (an aluminum alloy, AA 2024-T3 and a titanium alloy, Ti 6-2-2-2-2) to aid in establishing clear understanding of appropriate testing requirements. These simulations investigate the effect of K-gradient, the maximum value of stress-intensity factor applied, and material type. A material independent term is developed to guide in the selection of appropriate test conditions for most engineering alloys. With the use of such a term, near-threshold fatigue crack growth rate tests can be performed at accelerated rates, near-threshold data can be acquired in days instead of weeks without having to establish testing criteria through trial and error, and these data can be acquired for most engineering materials, even those that are produced in relatively small product forms.

Improved incorporation of strain gradient elasticity in the flexoelectricity based energy harvesting from nanobeams

NASA Astrophysics Data System (ADS)

Zhou, Yarong; Yang, Xu; Pan, Dongmei; Wang, Binglei

2018-04-01

Flexoelectricity, the coupling of strain gradient and polarization, exists in all the dielectric materials and numerous models have been proposed to study this mechanism. However, the contribution of strain gradient elasticity has typically been underestimated. In this work, inspired by the one-length scale parameter model developed by Deng et al. [19], we incorporate three length-scale parameters to carefully capture the contribution of the purely mechanical strain gradients on flexoelectricity. This three-parameter model is more flexible and could be applied to investigate the flexoelectricity in a wide range of complicated deformations. Accordingly, we carry out our analysis by studying a dielectric nanobeam under different boundary conditions. We show that the strain gradient elasticity and flexoelectricity have apparent size effects and significant influence on the electromechanical response. In particular, the strain gradient effects could significantly reduce the energy efficiency, indicating their importance and necessity. This work may be helpful in understanding the mechanism of flexoelectricity at the nanoscale and sheds light on the flexoelectricity energy harvesting.

Optimized operation of dielectric laser accelerators: Single bunch

NASA Astrophysics Data System (ADS)

Hanuka, Adi; Schächter, Levi

2018-05-01

We introduce a general approach to determine the optimal charge, efficiency and gradient for laser driven accelerators in a self-consistent way. We propose a way to enhance the operational gradient of dielectric laser accelerators by leverage of beam-loading effect. While the latter may be detrimental from the perspective of the effective gradient experienced by the particles, it can be beneficial as the effective field experienced by the accelerating structure, is weaker. As a result, the constraint imposed by the damage threshold fluence is accordingly weakened and our self-consistent approach predicts permissible gradients of ˜10 GV /m , one order of magnitude higher than previously reported experimental results—with unbunched pulse of electrons. Our approach leads to maximum efficiency to occur for higher gradients as compared with a scenario in which the beam-loading effect on the material is ignored. In any case, maximum gradient does not occur for the same conditions that maximum efficiency does—a trade-off set of parameters is suggested.

Aligned coaxial tungsten oxide-carbon nanotube sheet: a flexible and gradient electrochromic film.

PubMed

Yao, Zhaojun; Di, Jiangtao; Yong, Zhenzhong; Zhao, Zhigang; Li, Qingwen

2012-08-25

We develop a simple dry wrapping method to fabricate a tungsten oxide (WO(3))/carbon nanotube (CNT) cable, in which WO(3) layers act as an electrochromic component while aligned CNTs as the core provide mechanical support and an anisotropic, continuous electron transport pathway. Interestingly, the resultant cable material exhibits an obvious gradient electrochromic phenomenon.

Macroscale Transformation Optics Enabled by Photoelectrochemical Etching.

PubMed

Barth, David S; Gladden, Christopher; Salandrino, Alessandro; O'Brien, Kevin; Ye, Ziliang; Mrejen, Michael; Wang, Yuan; Zhang, Xiang

2015-10-28

Photoelectrochemical etching of silicon can be used to form lateral refractive index gradients for transformation optical devices. This technique allows the fabrication of macroscale devices with large refractive index gradients. Patterned porous layers can also be lifted from the substrate and transferred to other materials, creating more possibilities for novel devices. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Interface Effects of the Properties and Processing of Graded Composite Aluminum Alloys

DTIC Science & Technology

2015-08-31

diffuse interface. Produced by the Alcoa sequential casting process, the material has a gradient in composition from a stronger, precipitation...strengthened alloy (7055) to a softer, strain-hardenable alloy (5456) [1], [2]. Alcoa donated material, 30x30x2 cm3 in volume. The material was cast, rolled

Surface treatment of alumina-based ceramics using combined laser sources

NASA Astrophysics Data System (ADS)

Triantafyllidis, D.; Li, L.; Stott, F. H.

2002-01-01

Alumina-based refractory materials are extensively used as linings in incinerators and furnaces. These materials are subject to molten salt corrosion and chemical degradation because of the existence of porosity and material inhomogeneity. Efforts to improve the performance of these materials have so far concentrated mainly on the optimisation of the manufacturing processes (e.g. producing denser refractory bricks) and in-service monitoring. Laser surface treatment has also been used to improve performance. The main problem identified with laser surface treatment is solidification cracking due to the generation of very large temperature gradients. The aim of this paper is to investigate the surface modification of alumina-based ceramics by using two combined laser sources in order to control the thermal gradients and cooling rates during processing so that crack formation can be eliminated. The material under investigation is 85% alumina refractory ceramic, used as lining material in incineration plants. The surface morphology and cross-section of the treated samples are analysed using optical and scanning electron microscopy (SEM) and compared with single laser beam treated samples.

Spherical gradient-index lenses as perfect imaging and maximum power transfer devices.

PubMed

Gordon, J M

2000-08-01

Gradient-index lenses can be viewed from the perspectives of both imaging and nonimaging optics, that is, in terms of both image fidelity and achievable flux concentration. The simple class of gradient-index lenses with spherical symmetry, often referred to as modified Luneburg lenses, is revisited. An alternative derivation for established solutions is offered; the method of Fermat's strings and the principle of skewness conservation are invoked. Then these nominally perfect imaging devices are examined from the additional vantage point of power transfer, and the degree to which they realize the thermodynamic limit to flux concentration is determined. Finally, the spherical gradient-index lens of the fish eye is considered as a modified Luneburg lens optimized subject to material constraints.

Dispersion of acoustic surface waves by velocity gradients

NASA Astrophysics Data System (ADS)

Kwon, S. D.; Kim, H. C.

1987-10-01

The perturbation theory of Auld [Acoustic Fields and Waves in Solids (Wiley, New York, 1973), Vol. II, p. 294], which describes the effect of a subsurface gradient on the velocity dispersion of surface waves, has been modified to a simpler form by an approximation using a newly defined velocity gradient for the case of isotropic materials. The modified theory is applied to nitrogen implantation in AISI 4140 steel with a velocity gradient of Gaussian profile, and compared with dispersion data obtained by the ultrasonic right-angle technique in the frequency range from 2.4 to 14.8 MHz. The good agreement between experiments and our theory suggests that the compound layer in the subsurface region plays a dominant role in causing the dispersion of acoustic surface waves.

Temperature and porosity effects on wave propagation in nanobeams using bi-Helmholtz nonlocal strain-gradient elasticity

NASA Astrophysics Data System (ADS)

Reza Barati, Mohammad

2018-05-01

In this paper, applying a general nonlocal strain-gradient elasticity model with two nonlocal and one strain-gradient parameters, wave dispersion behavior of thermally affected and elastically bonded nanobeams is investigated. The two nanobeams are considered to have material imperfections or porosities evenly dispersed across the thickness. Each nanobeam has uniform thickness and is modeled by refined shear deformation beam theory with sinusoidal transverse shear strains. The governing equations of the system are derived by Hamilton's rule and are analytically solved to obtain wave frequencies and the velocity of wave propagation. In the presented graphs, one can see that porosities, temperature, nonlocal, strain gradient and bonding springs have great influences on the wave characteristics of the system.

Broadband gradient index microwave quasi-optical elements based on non-resonant metamaterials.

PubMed

Liu, Ruopeng; Cheng, Qiang; Chin, Jessie Y; Mock, Jack J; Cui, Tie Jun; Smith, David R

2009-11-09

Utilizing non-resonant metamaterial elements, we demonstrate that complex gradient index optics can be constructed exhibiting low material losses and large frequency bandwidth. Although the range of structures is limited to those having only electric response, with an electric permittivity always equal to or greater than unity, there are still numerous metamaterial design possibilities enabled by leveraging the non-resonant elements. For example, a gradient, impedance matching layer can be added that drastically reduces the return loss of the optical elements due to reflection. In microwave experiments, we demonstrate the broadband design concepts with a gradient index lens and a beam-steering element, both of which are confirmed to operate over the entire X-band (roughly 8-12 GHz) frequency spectrum.

Numerical methods for the design of gradient-index optical coatings.

PubMed

Anzengruber, Stephan W; Klann, Esther; Ramlau, Ronny; Tonova, Diana

2012-12-01

We formulate the problem of designing gradient-index optical coatings as the task of solving a system of operator equations. We use iterative numerical procedures known from the theory of inverse problems to solve it with respect to the coating refractive index profile and thickness. The mathematical derivations necessary for the application of the procedures are presented, and different numerical methods (Landweber, Newton, and Gauss-Newton methods, Tikhonov minimization with surrogate functionals) are implemented. Procedures for the transformation of the gradient coating designs into quasi-gradient ones (i.e., multilayer stacks of homogeneous layers with different refractive indices) are also developed. The design algorithms work with physically available coating materials that could be produced with the modern coating technologies.

Modeling the zonal disintegration of rocks near deep level tunnels by gradient internal variable continuous phase transition theory

NASA Astrophysics Data System (ADS)

Haoxiang, Chen; Qi, Chengzhi; Peng, Liu; Kairui, Li; Aifantis, Elias C.

2015-12-01

The occurrence of alternating damage zones surrounding underground openings (commonly known as zonal disintegration) is treated as a "far from thermodynamic equilibrium" dynamical process or a nonlinear continuous phase transition phenomenon. The approach of internal variable gradient theory with diffusive transport, which may be viewed as a subclass of Landau's phase transition theory, is adopted. The order parameter is identified with an irreversible strain quantity, the gradient of which enters into the expression for the free energy of the rock system. The gradient term stabilizes the material behavior in the post-softening regime, where zonal disintegration occurs. The results of a simplified linearized analysis are confirmed by the numerical solution of the nonlinear problem.

Characterization of the thermal conductivity for Advanced Toughened Uni-piece Fibrous Insulations

NASA Technical Reports Server (NTRS)

Stewart, David A.; Leiser, Daniel B.

1993-01-01

Advanced Toughened Uni-piece Fibrous Insulations (TUFI) is discussed in terms of their thermal response to an arc-jet air stream. A modification of the existing Ames thermal conductivity program to predict the thermal response of these functionally gradient materials is described in the paper. The modified program was used to evaluate the effect of density, surface porosity, and density gradient through the TUFI materials on the thermal response of these insulations. Predictions using a finite-difference code and calculated thermal conductivity values from the modified program were compared with in-depth temperature measurements taken from TUFI insulations during short exposures to arc-jet hypersonic air streams.

Utilization of nuclear methods for materials analysis and the determination of concentration gradients

NASA Technical Reports Server (NTRS)

Darras, R.

1979-01-01

The various types of nuclear chemical analysis methods are discussed. The possibilities of analysis through activation and direct observation of nuclear reactions are described. Such methods make it possible to analyze trace elements and impurities with selectivity, accuracy, and a high degree of sensitivity. Such methods are used in measuring major elements present in materials which are available for analysis only in small quantities. These methods are well suited to superficial analyses and to determination of concentration gradients; provided the nature and energy of the incident particles are chosen judiciously. Typical examples of steels, pure iron and refractory metals are illustrated.

METHOD OF PRODUCING NEUTRONS

DOEpatents

Imhoff, D.H.; Harker, W.H.

1964-01-14

This patent relates to a method of producing neutrons in which there is produced a heated plasma containing heavy hydrogen isotope ions wherein heated ions are injected and confined in an elongated axially symmetric magnetic field having at least one magnetic field gradient region. In accordance with the method herein, the amplitude of the field and gradients are varied at an oscillatory periodic frequency to effect confinement by providing proper ratios of rotational to axial velocity components in the motion of said particles. The energetic neutrons may then be used as in a blanket zone containing a moderator and a source fissionable material to produce heat and thermal neutron fissionable materials. (AEC)

Infiltration of MHD liquid into a deformable porous material

NASA Astrophysics Data System (ADS)

Naseem, Anum; Mahmood, Asif; Siddique, J. I.; Zhao, Lifeng

2018-03-01

We analyze the capillary rise dynamics for magnetohydrodynamics (MHD) fluid flow through deformable porous material in the presence of gravity effects. The modeling is performed using mixture theory approach and mathematical manipulation yields a nonlinear free boundary problem. Due to the capillary rise action, the pressure gradient in the liquid generates a stress gradient that results in the deformation of porous substrate. The capillary rise process for MHD fluid slows down as compared to Newtonian fluid case. Numerical solutions are obtained using a method of lines approach. The graphical results are presented for important physical parameters, and comparison is presented with Newtonian fluid case.

Enhanced electrochemical performance and storage property of LiNi0.815Co0.15Al0.035O2 via Al gradient doping

NASA Astrophysics Data System (ADS)

Duan, Jianguo; Hu, Guorong; Cao, Yanbing; Tan, Chaopu; Wu, Ceng; Du, Ke; Peng, Zhongdong

2016-09-01

LiNi1-x-yCoxAlyO2 is a commonly used Ni-rich cathode material because of its relatively low cost, excellent rate capability and high gravimetric energy density. Surface modification is an efficient way to overcome the shortcomings of Ni-rich cathodes such as poor cycling stability and poor thermal stability. A high-powered concentration-gradient cathode material with an average composition of LiNi0.815Co0.15Al0.035O2 (LGNCAO) has been successfully synthesized by using spherical concentration-gradient Ni0.815Co0.15Al0.035(OH)2 (GNCA)as the starting material. An efficient design of the Al3+ precipitation method is developed, which enables obtaining spherical GNCA with ∼10 μm particle size and high tap density. In LGNCAO, the nickel and cobalt concentration decreases gradually whereas the aluminum concentration increases from the centre to the outer layer of each particle. Electrochemical performance and storage properties of LGNCAO have been investigated comparatively. The LGNCAO displays better electrochemical performance and improved storage stability than LNCAO.

Dielectrophoresis-Based Particle Sensor Using Nanoelectrode Arrays

NASA Technical Reports Server (NTRS)

Li, Jun; Cassell, Alan M.; Arumugam, Prabhu U.

2013-01-01

A method has been developed for concentrating, or partly separating, particles of a selected species from a liquid or gas containing these particles, and flowing in a channel. An example of this is to promote an accumulation (and thus concentration) of the selected particle (e.g., biological species such as E. coli, salmonella, anthrax, tobacco mosaic virus or herpes simplex, and non-biological materials such as nano- and microparticles, quantum dots, nanowires, nano - tubes, and other inorganic particles) adjacent to the first surface. Additionally, this method can also determine if the particle species is present in the liquid. This is accomplished by providing an insulating material in an interstitial volume between two or more adjacent nanostructure electrodes. It can also be accomplished by providing a functionalizing substance, located on a selected region of the insulating material surface, which promotes attachment of the selected species particles to the functionalized surface, and measuring a selected electrical property such as electrical impedance, conductance, or capacitance. A time-varying electrical field E, having a root-mean-square intensity of E(sup 2) rms, with a non-zero gradient in a direction transverse to the liquid or fluid flow direction, is produced by a nanostructure electrode array with a very high-magnitude gradient near exposed electrode tips. A dielectrophoretic force causes the selected particles to accumulate near the electrode tips, if the medium and selected particles have substantially different dielectric constants. An insulating material surrounds most of the nanostructure electrodes, and a region of the insulating material surface is functionalized to promote attachment of the selected particle species to the surface. An electrical property value Z(meas) is measured at the functionalized surface, and is compared with a reference value Z(ref) to determine if the selected species particles are attached to the functionalized surface. Some advantages of this innovation are that an array of nanostructure electrodes can provide an electric field intensity gradient that is one or more orders of magnitude greater than the corresponding gradient provided by a conventional microelectrode arrangement, and that, as a result of the high-magnitude field intensity gradients, a nanostructure concentrator can trap particles from high-speed microfluidic flows. This is critical for applications where the entire analysis must be performed in a few minutes

Implementation and application of a gradient enhanced crystal plasticity model

NASA Astrophysics Data System (ADS)

Soyarslan, C.; Perdahcıoǧlu, E. S.; Aşık, E. E.; van den Boogaard, A. H.; Bargmann, S.

2017-10-01

A rate-independent crystal plasticity model is implemented in which description of the hardening of the material is given as a function of the total dislocation density. The evolution of statistically stored dislocations (SSDs) is described using a saturating type evolution law. The evolution of geometrically necessary dislocations (GNDs) on the other hand is described using the gradient of the plastic strain tensor in a non-local manner. The gradient of the incremental plastic strain tensor is computed explicitly during an implicit FE simulation after each converged step. Using the plastic strain tensor stored as state variables at each integration point and an efficient numerical algorithm to find the gradients, the GND density is obtained. This results in a weak coupling of the equilibrium solution and the gradient enhancement. The algorithm is applied to an academic test problem which considers growth of a cylindrical void in a single crystal matrix.

The Effect of Temperature on Moisture Transport in Concrete.

PubMed

Wang, Yao; Xi, Yunping

2017-08-09

Most concrete structures and buildings are under temperature and moisture variations simultaneously. Thus, the moisture transport in concrete is driven by the moisture gradient as well as the temperature gradient. This paper presents an experimental approach for determining the effect of different temperature gradients on moisture distribution profiles in concrete. The effect of elevated temperatures under isothermal conditions on the moisture transport was also evaluated, and found not to be significant. The non-isothermal tests show that the temperature gradient accelerates the moisture transport in concrete. The part of increased moisture transfer due to the temperature gradient can be quantified by a coupling parameter D HT , which can be determined by the present test data. The test results indicated that D HT is not a constant but increases linearly with the temperature variation. A material model was developed for D HT based on the experimental results obtained in this study.

The Effect of Temperature on Moisture Transport in Concrete

PubMed Central

Wang, Yao; Xi, Yunping

2017-01-01

Most concrete structures and buildings are under temperature and moisture variations simultaneously. Thus, the moisture transport in concrete is driven by the moisture gradient as well as the temperature gradient. This paper presents an experimental approach for determining the effect of different temperature gradients on moisture distribution profiles in concrete. The effect of elevated temperatures under isothermal conditions on the moisture transport was also evaluated, and found not to be significant. The non-isothermal tests show that the temperature gradient accelerates the moisture transport in concrete. The part of increased moisture transfer due to the temperature gradient can be quantified by a coupling parameter DHT, which can be determined by the present test data. The test results indicated that DHT is not a constant but increases linearly with the temperature variation. A material model was developed for DHT based on the experimental results obtained in this study. PMID:28792460

Multi-functional materials by powder processing for a thermal protection system with self-cooling capability: Perspirable skin

NASA Astrophysics Data System (ADS)

Sun, Li

Aerodynamic heating generated by the friction between the atmosphere and the space vehicle's surface at reentry can enhance the temperature on the surface as high as 1700°C. A Thermal Protection System (TPS) is needed to inhibit the heat entering into the vehicle. Presently, the completely passive thermal protection is used for TPS. The thermal ablation/erosion and oxidization reaction of the current TPS is the major threat to the safety of the space vehicle. Therefore, a new design for TPS with actively self-cooling capability was proposed by bio-mimicking the perspiration of the human body, henceforth called Perspirable skin. The design of Perspirable Skin consists of core material shrink-fitted into a skin panel such as Reinforced Carbon-Carbon (RCC) Composite. The core material contains a very small Coefficient of Thermal Expansion (CTE) compared to the panel material. As temperature increases, the gap between the core and the skin are produced due to the CTE difference. Compressed gas on board the space vehicle will blow out from the gap once the surface temperature reaches a critical value. The cold gas flows over the surface and mixes with the atmospheric air to compensate for the frictional heat. With Perspirable Skin, the highest temperature on the surface is expected to decrease, and we assumed it to be around half of the present temperature. This dissertation focuses on the selection of the core materials and their manufacturing by powder processing. Based on a series of experiments, several results were obtained: (1) the effect of powder mixing on the compaction capability and sintering capability was determined; (2) a flat 3-layered Al 2O3/ZrO2 Functionally Graded Material (FGM) without cracks was fabricated; (3) the factors contributing to the cracks in the multi-layered materials were investigated; (4) an isotropic negative thermal expansion material, ZrW2O8, as well as its composites with ZrO2 were processed by in-situ reaction of WO3 and ZrO2; (5) several CTE prediction models on composites containing ZrW2O 8 were studied and proposed as a better scheme for applying the contiguity of phase; (6) a novel processing technique to produce ZrW2O 8-ZrO2 continuous FGMs was developed; and (7) the thermal and mechanical properties of the various materials were measured. Finally, using finite element analysis (FEA), the complete design of Perspirable Skin has been accomplished.

A Theoretical and Experimental Study of Emission Spectroscopy of Planetary Surfaces

NASA Astrophysics Data System (ADS)

Henderson, Bradley Gray

1995-01-01

This thesis explores the spectral emissivity of particulate materials on planetary surfaces through theoretical modeling and supporting laboratory and field investigations. In the first part of the thesis, I develop a Monte Carlo ray tracing model to calculate the directional and spectral emissivity and the polarization state of the radiation emitted from a particulate, isothermal surface for emission angles 0^circ-90^ circ and wavelengths 7-16 mu m. The results show that roughness and scattering significantly affect the character of the emitted radiation field and should be taken into account when interpreting the physical properties of a planetary surface from IR spectrophotometry or spectropolarimetry. The remainder of the thesis focuses on understanding near-surface thermal gradients and their effects on emission spectra for different planetary environments. These gradients are formed by radiative cooling in the top few hundred microns of low conductivity particulate materials on planetary surfaces with little or no atmosphere. I model the heat transfer by conduction and radiation in the top few millimeters of a planetary regolith for scattering and non-scattering media. In conjunction with the modeling, I measure emission spectra of fine-grained quartz in an environment chamber designed to simulate the conditions on other planetary surfaces. The results show that significant thermal gradients will form in the near surface of materials on the surface of the Moon and Mercury. Their presence increases spectral contrast and creates emission maxima in the transparent regions of the spectrum. Thermal gradients are shown to be responsible for the observed wavelength shifts of the Christiansen emission peak with variations in thermal conductivity and grain size. The results are also used to analyze recent telescopic spectra of the Moon and Mercury and can explain certain features seen in those data. Thermal gradients are shown to be minor for the surface of Mars and negligible on Earth. I conclude that the spectral effects created by near-surface thermal gradients are predictable and might even provide an extra source of information about the physical nature of a planetary surface, and mid-IR emission spectroscopy should therefore prove to be useful for remote sensing of airless bodies.

Development and kinetic analysis of cobalt gradient formation in WC-Co composites

NASA Astrophysics Data System (ADS)

Guo, Jun

2011-12-01

Functionally graded cemented tungsten carbide (FG WC-Co) is one of the main research directions in the field of WC-Co over decades. Although it has long been recognized that FG WC-Co could outperform conventional homogeneous WC-Co owing to its potentially superior combinations of mechanical properties, until recently there has been a lack of effective and economical methods to make such materials. The lack of the technology has prevented the manufacturing and industrial applications of FG WC-Co from becoming a reality. This dissertation is a comprehensive study of an innovative atmosphere heat treatment process for producing FG WC-Co with a surface cobalt compositional gradient. The process exploited a triple phase field in W-C-Co phase diagram among three phases (solid WC, solid Co, and liquid Co) and the dependence of the migration of liquid Co on temperature and carbon content. WC-Co with a graded surface cobalt composition can be achieved by controlling the diffusion of carbon transported from atmosphere during sintering or during postsintering heat treatment. The feasibility of the process was validated by the successful preparations of FG WC-Co via both carburization and decarburization process following conventional liquid phase sintering. A study of the carburization process was undertaken to further understand and quantitatively modeled this process. The effects of key processing parameters (including heat treating temperature, atmosphere, and time) and key materials variables (involving Co content, WC grain size, and addition of grain growth inhibitors) on the formation of Co gradients were examined. Moreover, a carbon-diffusion controlled kinetic model was developed for simulating the formation of the gradient during the process. The parameters involved in this model were determined by thermodynamic calculations and regression-fit of simulation results with experimental data. In summary, this research first demonstrated the principle of the approach. Second, a model was developed to predict the gradients produced by the carbon-controlled atmosphere heat treatment process, which is useful for manufacturing WC-Co with designed gradients. FG WC-Co materials produced using this method are expected to exhibit superior performance in many applications and to have a profound impact on the manufacturing industries that use tungsten carbide tools.

NASA-UVA light aerospace alloy and structures technology program (LA(sup 2)ST)

NASA Technical Reports Server (NTRS)

Gangloff, Richard P.; Haviland, John K.; Herakovich, Carl T.; Pilkey, Walter D.; Pindera, Marek-Jerzy; Scully, John R.; Starke, Edgar A., Jr.; Stoner, Glenn E.; Thornton, Earl A.; Wawner, Franklin E., Jr.

1992-01-01

The general objective of the Light Aerospace Alloy and Structures Technology (LA(sup 2)ST) Program is to conduct interdisciplinary graduate student research on the performance of next generation, light weight aerospace alloys, composites, and thermal gradient structures in collaboration with Langley researchers. Specific technical objectives are established for each research project. We aim to produce relevant data and basic understanding of material behavior and microstructure, new monolithic and composite alloys, advanced processing methods, new solid and fluid mechanics analyses, measurement advances, and critically, a pool of educated graduate students for aerospace technologies. Four research areas are being actively investigated, including: (1) Mechanical and Environmental Degradation Mechanisms in Advanced Light Metals and Composites; (2) Aerospace Materials Science; (3) Mechanics of Materials and Composites for Aerospace Structures; and (4) Thermal Gradient Structures.

Flight Performance of an Advanced Thermal Protection Material: Toughened Uni-Piece Fibrous Insulation

NASA Technical Reports Server (NTRS)

Leiser, Daniel B.; Gordon, Michael P.; Rasky, Daniel J. (Technical Monitor)

1995-01-01

The flight performance of a new class of low density, high temperature thermal protection materials (TPM) is described and compared to "standard" Space Shuttle TPM. This new functionally gradient material designated as Toughened Uni-Piece Fibrous Insulation (TUFI), was bonded on a removable panel attached to the base heat shield of Orbiter 105, Endeavour.

Flight Performance of an Advanced Thermal Protection Material: Toughened Uni-Piece Fibrous Insulation

NASA Technical Reports Server (NTRS)

Leiser, Daniel B.; Gordon, Michael P.; Rasky, Daniel J. (Technical Monitor)

1995-01-01

The flight performance of a new class of low density, high temperature, thermal protection materials (TPM), is described and compared to "standard" Space Shuttle TPM. This new functionally gradient material designated as Toughened Uni-Piece Fibrous Insulation (TUFI), was bonded on a removable panel attached to the base heatshield of Orbiter 105, Endeavor.

Drop casting of stiffness gradients for chip integration into stretchable substrates

NASA Astrophysics Data System (ADS)

Naserifar, Naser; LeDuc, Philip R.; Fedder, Gary K.

2017-04-01

Stretchable electronics have demonstrated promise within unobtrusive wearable systems in areas such as health monitoring and medical therapy. One significant question is whether it is more advantageous to develop holistic stretchable electronics or to integrate mature CMOS into stretchable electronic substrates where the CMOS process is separated from the mechanical processing steps. A major limitation with integrating CMOS is the dissimilar interface between the soft stretchable and hard CMOS materials. To address this, we developed an approach to pattern an elastomeric polymer layer with spatially varying mechanical properties around CMOS electronics to create a controllable material stiffness gradient. Our experimental approach reveals that modifying the interfaces can increase the strain failure threshold up to 30% and subsequently decreases delamination. The stiffness gradient in the polymer layer provides a safe region for electronic chips to function under a substrate tensile strain up to 150%. These results will have impacts in diverse applications including skin sensors and wearable health monitoring systems.

Tessellated permanent magnet circuits for flow-through, open gradient separations of weakly magnetic materials

PubMed Central

Moore, Lee R.; Williams, P. Stephen; Chalmers, Jeffrey J.; Zborowski, Maciej

2017-01-01

Emerging microfluidic-based cell assays favor label-free red blood cell (RBC) depletion. Magnetic separation of RBC is possible because of the paramagnetism of deoxygenated hemoglobin but the process is slow for open-gradient field configurations. In order to increase the throughput, periodic arrangements of the unit magnets were considered, consisting of commercially available Nd-Fe-B permanent magnets and soft steel flux return pieces. The magnet design is uniquely suitable for multiplexing by magnet tessellation, here meaning the tiling of the magnet assembly cross-sectional plane by periodic repetition of the magnet and the flow channel shapes. The periodic pattern of magnet magnetizations allows a reduction of the magnetic material per channel with minimal distortion of the field cylindrical symmetry inside the magnet apertures. A number of such magnet patterns are investigated for separator performance, size and economy with the goal of designing an open-gradient magnetic separator capable of reducing the RBC number concentration a hundred-fold in 1 mL whole blood per hour. PMID:29104346

Tessellated permanent magnet circuits for flow-through, open gradient separations of weakly magnetic materials.

PubMed

Moore, Lee R; Williams, P Stephen; Chalmers, Jeffrey J; Zborowski, Maciej

2017-04-01

Emerging microfluidic-based cell assays favor label-free red blood cell (RBC) depletion. Magnetic separation of RBC is possible because of the paramagnetism of deoxygenated hemoglobin but the process is slow for open-gradient field configurations. In order to increase the throughput, periodic arrangements of the unit magnets were considered, consisting of commercially available Nd-Fe-B permanent magnets and soft steel flux return pieces. The magnet design is uniquely suitable for multiplexing by magnet tessellation, here meaning the tiling of the magnet assembly cross-sectional plane by periodic repetition of the magnet and the flow channel shapes. The periodic pattern of magnet magnetizations allows a reduction of the magnetic material per channel with minimal distortion of the field cylindrical symmetry inside the magnet apertures. A number of such magnet patterns are investigated for separator performance, size and economy with the goal of designing an open-gradient magnetic separator capable of reducing the RBC number concentration a hundred-fold in 1 mL whole blood per hour.

Plastic deformation treated as material flow through adjustable crystal lattice

NASA Astrophysics Data System (ADS)

Minakowski, P.; Hron, J.; Kratochvíl, J.; Kružík, M.; Málek, J.

2014-08-01

Looking at severe plastic deformation experiments, it seems that crystalline materials at yield behave as a special kind of anisotropic, highly viscous fluids flowing through an adjustable crystal lattice space. High viscosity provides a possibility to describe the flow as a quasi-static process, where inertial and other body forces can be neglected. The flow through the lattice space is restricted to preferred crystallographic planes and directions causing anisotropy. In the deformation process the lattice is strained and rotated. The proposed model is based on the rate form of the decomposition rule: the velocity gradient consists of the lattice velocity gradient and the sum of the velocity gradients corresponding to the slip rates of individual slip systems. The proposed crystal plasticity model allowing for large deformations is treated as the flow-adjusted boundary value problem. As a test example we analyze a plastic flow of an single crystal compressed in a channel die. We propose three step algorithm of finite element discretization for a numerical solution in the Arbitrary Lagrangian Eulerian (ALE) configuration.