Smartphone-based molecular sensing for advanced characterization of asphalt concrete materials

Pavement systems deteriorate with time due to the aging of materials, excessive use, overloading, climatic conditions, inadequate maintenance, and deficiencies in inspection methods. Proper evaluation of pavement conditions provides important decision-support to implement preventative rehabilitation. This study presents an innovative smartphone-based monitoring method for advanced characterization of asphalt concrete materials. The proposed method is based on deploying a pocket-sized near-infrared (NIR) molecular sensor that is fully integrated with smartphones. The NIR spectrometer illuminates a sample with a broad-spectrum of near-infrared light, which can be absorbed, transmitted, reflected, or scattered by the sample. The light intensity is measured as a function of wavelength before and after interacting with the sample. Thereafter, the diffuse reflectance, a combination of absorbance and scattering, caused by the sample is calculated. This portable smartphone-based NIR method is used to detect asphalt binders with various performance grading (PG) and aging levels. To this end, a number of binder samples are tested in a wavelength range of 740 to 1070 nm. The results indicate that asphalt binders with different grades and aging levels yield significantly different spectrums. These distinctive spectrums can be attributed to the variations of binder components such as saturate, asphaltenic, resin, and aromatic. Furthermore, the molecular sensor is successfully deployed to detect and classify asphalt mixtures fabricated with a various binder and recycled material types such as styrene-butadiene-styrene (SBS), ground tire rubber (SBS), engineered crumbed rubber (ECR), reclaimed asphalt pavement (RAP), and recycled asphalt shingles (RAS). The proposed monitoring technology is not only a viable tool for asphalt material characterization but also a cost-effective platform capable of transforming the current physical and chemical methods for civil engineering material characterization.Includes bibliographical reference

Calibration-Free Estimation of User-Specific Bending of a Head-Mountable Device

Disclosed is an approach for determining camera rotation relative to an individual’s eye, which could then be used for applications such as calibration-free estimation of user-specific bending of a device (e.g., a head-mountable device (HMD)), among others. Due to biological conditions, an average gaze vector of an eye most often corresponds to a straight-forward gaze by an individual. Therefore, the average gaze vector is often known with respect to a coordinate system of an individual’s eye. Additionally, when the HMD is worn by a user, the HMD uses an eye-facing camera to determine the average gaze vector of the user’s eye with respect to the eye-facing camera’s coordinate system. Given information about the average gaze vector with respect to multiple coordinate systems, the HMD uses this information as basis for determining an orientation of the eye-facing camera when the HMD is worn by the user. By then comparing the determined orientation to a known orientation of the eye-facing camera when the HMD is unworn or otherwise not bent, the HMD determines rotation of the eye-facing camera in three-dimensional space, which corresponds to an extent that the HMD (e.g., the HMD’s frame) has bent from an unworn position to a worn position

An investigation on the surface austempering of ductile cast iron

This research presents surface austempering of ductile cast iron. Surface of pearlitic ductile cast iron samples were austenitised and heated to 810 and 850°C and held at these temperatures for 90 and 105 sec and then austempered at a temperature of 325°C for 60 and 90 min. The microstructure of samples was evaluated by optical microscopy. The hardness profile in polished cross section was also determined. In addition, the depth of austmpered layer was measured. The result indicated that temperature and time of austenitisation intensely effect on surface austempering process. The test results also revealed that the hardness of austempered layer increase when the austenitising temperature and time increase. After surface austempering of ductile cast iron samples, the highest hardness achieved 450 HV in austempered surface-layer. The highest depth of austempered layer 1.7 mm was obtained

Modeling User Transportation Patterns Using Mobile Devices

Participatory sensing frameworks use humans and their computing devices as a large mobile sensing network. Dramatic accessibility and affordability have turned mobile devices (smartphone and tablet computers) into the most popular computational machines in the world, exceeding laptops. By the end of 2013, more than 1.5 billion people on earth will have a smartphone. Increased coverage and higher speeds of cellular networks have given these devices the power to constantly stream large amounts of data. Most mobile devices are equipped with advanced sensors such as GPS, cameras, and microphones. This expansion of smartphone numbers and power has created a sensing system capable of achieving tasks practically impossible for conventional sensing platforms. One of the advantages of participatory sensing platforms is their mobility, since human users are often in motion. This dissertation presents a set of techniques for modeling and predicting user transportation patterns from cell-phone and social media check-ins. To study large-scale transportation patterns, I created a mobile phone app, Kpark, for estimating parking lot occupancy on the UCF campus. Kpark aggregates individual user reports on parking space availability to produce a global picture across all the campus lots using crowdsourcing. An issue with crowdsourcing is the possibility of receiving inaccurate information from users, either through error or malicious motivations. One method of combating this problem is to model the trustworthiness of individual participants to use that information to selectively include or discard data. This dissertation presents a comprehensive study of the performance of different worker quality and data fusion models with plausible simulated user populations, as well as an evaluation of their performance on the real data obtained from a full release of the Kpark app on the UCF Orlando campus. To evaluate individual trust prediction methods, an algorithm selection portfolio was introduced to take advantage of the strengths of each method and maximize the overall prediction performance. Like many other crowdsourced applications, user incentivization is an important aspect of creating a successful crowdsourcing workflow. For this project a form of non-monetized incentivization called gamification was used in order to create competition among users with the aim of increasing the quantity and quality of data submitted to the project. This dissertation reports on the performance of Kpark at predicting parking occupancy, increasing user app usage, and predicting worker quality

A Study on Causes and Types of Abnormal Increase in Infants’ Head Circumference in Kashan/Iran

How to Cite This Article: Talebian A, Soltani B, Moravveji AR, Salamati L, Davami M. A Study on Causes and Types of Abnormal Increase in infants’ Head Circumference in Kashan/Iran. Iran J Child Neurol. 2013 Summer; 7(3): 28- 33. ObjectiveHead circumference is a valuable index of brain growth and its disturbances can indicate different disorders of nervous system. Abnormal increased head circumference (macrocephaly) is common and observed in about 2% of infants. In this study, the causes and clinical types of abnormal increase in infants’ head circumference were investigated in Kashan, Iran.Materials & MethodsThis cross-sectional study was performed on 90 infants less than 2 years of age with abnormal increase in head circumference in Kashan, during 2009- 2011. The data were collected by history taking, physical examination, growth chart, and imaging.Results65 (72%) cases out of 90 infants were male and 25 ( 28%) cases were female. Fifty-three (58.8%) cases had familial megalencephaly, 30 (33.4%) had hydrocephalus, and other causes were observed in 7 (7.8%) cases. Eighty-three percent of Infants with familial megalencephaly and 50% with hydrocephalus had normal fontanels. In 90.6% of cases withfamilial megalencephaly, family history for large head was positive. Motor development was normal in 100% of cases with familial megalencephaly and 76.7% of hydrocephalic infants.Conclusion Familial megalencephaly was the most common cause of macrocephaly in the studied infants, and most of them had normal physical examination and development, so, parental head circumferences should be considered in the interpretation of infant’s head circumference and in cases of abnormal physical examination or development, other diagnostic modalities, including brain imaging should be done. References1. Lunde A, Melve KK, Gjessing HK, Skjaerven R, Irgens LM. Genetic and environmental influences on birth weight, Birth length, Head circumference, and gestational age by use of population-based parentoffspring data. American J Epidemiol 2007;165(7):734-41.2. Sankaran S, Das A, Bauer CR, Bada HS, Lester B, Wright LL, et al. Association between patterns of maternal substance use and infant birth weight, length and head circumference.Pediatrics 2004;114(2):e226-34.3. Demestre Guasch X, Raspall Torrent F, Vila Ceren C, Sala Castellvi P, Elizari Saco MJ, Martinez-Nadal S, et al. Influence of socioeconomic factors on weight, length and head circumference measurements in newborns from 35 to 42 weeks gestational. An Pediatr (Barc) 2009;70(3):241-52.4. Fenichel, GM. Disorders of cranial volume and shape. In: Clinical Pediatric Neurology: A Signs and Symptoms Approach, 6th ed. Philadelphia: Elsevier Saunders; 2009.p. 368.5. Kinsman SL, , Johnston MV. Hydrocephalus. In: Kliegman RM, Stanton BF, St Geme JW, Schor NF, Behrman RE, editors. Nelson textbook of pediatrics. 19th ed. Philadelphia, PA: Elsevier/Saunders, Philadelphia; 2011. p. 2008-11.6. Nard, JA. Abnormal head size and shape. In: Gartner JC,Zitelli BJ, editors. Common and Chronic Symptoms in Pediatrics. St. Louis: Mosby; 1997.7. Menkes JH, Sarnat HB, Flores-Sarnat L. Malformations of the central nervous system. In: Menkes JH, Sarnat HB, Maria BL, editors. Child Neurology. 7th ed. Philadelphia:  Lippincott Williams & Wilkins; 2006. p. 284.8. Williams CA, Dagli A, Battaglia A. Genetic disorders associated with macrocephaly. Am J Med Genet A 2008;146A(15):2023-37.9. Varma R, Williams SD, Wessel HB. Neurology. In: Zitelli BJ, Davis HW, edtors. Atlas of Pediatric Physical Diagnosis. 5th ed. Philadelphia: Mosby Elsevier; 2007. p. 563.10. Rekate HL. Hydrocephalus in children. In: Winn HR, Youmans JR, editors. Youmans Neurological Surgery. 5th ed. St Louis: Saunders. 2003. 3387-404.11. Gupta SN, Belay B. Intracranial incidental findings on brain MR images in a pediatric neurology practice: a retrospective study. J Neurol Sci 2008;264(1-2):34-7.12. Alper G, Ekinci G, Yilmaz Y, Arikan C, Telyar G, Erzen C. Magnetic resonance imaging characteristics of benign macrocephaly in children. J Child Neurol 1999;14(10):678-82.13. Smith R, Leonidas JC, Maytal J. The value of head ultrasound in infants with macrocephaly. Pediatr Radiol 1998;28(3):143-6.14. Day RE, Schutt WH. Normal children with large heads benign familial megalencephaly. Arch Dis Child 1979;54(7):512-7.15. Kumar R. External hydrocephalus in small children. Childs Nerv Syst 2006;22(10):1237-41.16. Rollins JD, Collins JS, Holden KR. United states head circumference growth reference charts: birth to 21 years. J Pediatr 2010;156(6):907-13.17. Medina LS, Frawley K, Zurakowski D, Buttros D, DeGrauw AJ, Crone KR. Children with macrocrania: Clinical and imaging predictors of disorders requiring surgery. AJNR Am J Neuroradiol 2001;22(3):564-70.18. Lorber J, Priestly BL. Children with large heads: a practical approach to diagnosis in 557 children, with special reference to 109 children with megalencephaly. Dev Med Child Neurol 1981;23(4):494-504.19. Zahl SM, Wester K. Routine measurement of head circumference as a tool for detecting intracranial expansion in infants: what is the gain? A nationwide survey. Pediatrics 2008;121(3):e416-20.20. Alvarez LA, Maytal J, Shinnar S. Idiopathic external hydrocephalus: natural history and relationship to benignfamilial macrocephaly. Pediatrics 1986;77(6):901-7.21. Yew AY, Maher CO, Muraszko KM, garton HJ. Longterm health status in benign external hydrocephalus. Pediatr Neurosurg 2011;47(1):1-6.22. Muenchberger H, Assad N, Joy P, Brunsdon R, Shores EA. Idiopathic macrocephaly in the infant: long-term neurological and neuropsychological outcome. Childs Nerv Syst 2006;22(10):1242-48

Adiabatic Shear Banding in Nickel and Nickel-Based Superalloys: A Review

This review paper discusses the formation and propagation of adiabatic shear bands in nickel-based superalloys. The formation of adiabatic shear bands (ASBs) is a unique dynamic phenomenon that typically precedes catastrophic, unpredicted failure in many metals under impact or ballistic loading. ASBs are thin regions that undergo substantial plastic shear strain and material softening due to the thermo-mechanical instability induced by the competitive work hardening and thermal softening processes. Dynamic recrystallization of the material’s microstructure in the shear region can occur and encourages shear localization and the formation of ASBs. Phase transformations are also often seen in ASBs of ferrous metals due to the elevated temperatures reached in the narrow shear region. ASBs ultimately lead to the local degradation of material properties within a narrow band wherein micro-voids can more easily nucleate and grow compared to the surrounding material. As the micro-voids grow, they will eventually coalesce leading to crack formation and eventual fracture. For elevated temperature applications, such as in the aerospace industry, nickel-based superalloys are used due to their high strength. Understanding the formation conditions of ASBs in nickel-based superalloys is also beneficial in extending the life of machining tools. The main goal of the review is to identify the formation mechanisms of ASBs, the microstructural evolutions associated with ASBs in nickel-based alloys, and their consequent effect on material properties. Under a shear strain rate of 80,000 s−1, the critical shear strain at which an ASB forms is between 2.2 and 3.2 for aged Inconel 718 and 4.5 for solution-treated Inconel 718. Shear band widths are reported to range between 2 and 65 microns for nickel-based superalloys. The shear bands widths are narrower in samples that are aged compared to samples in the annealed or solution treated condition

Microstructural study of Al-20Si-5Fe Alloys produced by melt-spinning

Al-20si-5Fe ribbons were produced by melt spinning at the rotating speed of 20 and 40m/s. The microstructure of ribbons and conventionally cast alloys were characterized using scanning electron microscopy (SEM) together with the energy dispersive spectroscopy (EDS), X-ray diffractometry (XRD) method. The microhardness of the ribbons and as cast ingots was also measured. SEM observations showed that the wheel side of the ribbons exhibited a finer microstructure than those on the air side which exposed to the atmosphere. The phase constitution of the hypereutectic Al–20Si-5Fe alloy was considerably affected by rapid solidification. XRD results showed that the phases present in the as cast hypereutectic Al-20Si-5Fe alloy were identified to be α-Al, Si and intermetallic β-Al5FeSi phases while only α-Al and Si were identified in the melt spun ribbons. Moreover, the values of Vickers microhardness of melt spun ribbons were three times as high as those of conventionally cast ingots of the same alloy

Single-crystalline CdTe nanowire field effect transistors as nanowire-based photodetector

The electronic and photoconductive characteristics of CdTe nanowire-based field effect transistors were studied systematically. The electrical characterization of a single CdTe nanowire FET verifies p-type behavior. The CdTe NW FETs respond to visible-near infrared (400-800 nm) incident light with a fast, reversible and stable response characterized by a high responsivity (81 A W-1), photoconductive gain (similar to 2.5 x 10(4)%) and reasonable response and decay times (0.7 s and 1 s, respectively). These results substantiate the potential of CdTe nanowire-based photodetectors in optoelectronic applications.open112423sciescopu