Non-Destructive Evaluation—A Pivotal Technology for Qualification of Composite Aircraft Structures

Tremendous advances in composite materials and a deeper understanding of their behavior have been responsible for the increased use of composites in the development of advanced, new generation civil and military aircraft. Composites play an important role in any aircraft development programme and are strong contenders to their metal counterparts due to their significant contributions towards improving strength, stiffness, fatigue properties & weight reduction. As materials, structural design & processing have evolved, strong emphasis is placed on effective & reliable damage detection, durability and damage tolerance. As a consequence, Non-destructive Evaluation (NDE) has also undergone significant advances towards meeting the growing demands of quality assurance. Advanced Composites Division (ACD) of National Aerospace Laboratories (NAL), has been involved in the development of composite structures for both civil and military aircraft for over a decade and a half. Innovative composite processing methods like co-curing/co-bonding have been successfully employed to realize airworthy structures. The role of NDE in the development of these structures has been critical and not limited to damage detection alone. On several occasions, NDE has provided valuable inputs towards improving design and process parameters. In-spite of the complexity of the structures, stringent quality requirements and tight delivery schedules, NDE has been successful in certifying these composite structures for airworthiness. This paper discusses the implementation of key NDE techniques like ultrasonics, radiography, acoustic emission and thermography for reliable flaw detection, characterization and quality assurance of composite aircraft structures

Development and Evaluation of Palmyrah (Borassus Flabellifer L.) Fruit Pulp

Palmyrah(Borassus flabellifer L) fruit pulp is available abundantly and has high potential for food in rural areas, useful for pharmaceutical and cosmetic applications, however, the main hindrance for these pulp is lack of mechanisation and availability of pulp in sufficient quantity at one place. The pulp of this fruit is usually used by rural communities where the processors use manual pulping, which are not only time-consuming but yields seasonal during July and August in India. Therefore, the objective of this work was to develop and evaluate the efficiency of fruit pulp extractor. The pulper was developed to be compact and easy to operate, consisting of main housing with stainless steel teeth on rotating shaft and pulping performed by beating and shearing. The performance evaluation of the machine was carried out with different rpm (320, 360, 410) input capacity(8,10 and 12 kg) for fixed time of operation is 6 minutes.. The pulp weight was evaluated during the pulping process period. The highest pulping efficiency (84.78%) and pulp recovery (33.9%) was obtained rpm of 410, with 6 minutes of pulping, and batch capacity of 10 kg of fruits which resulted in a capacity of 50 kg fruits per hour. This high efficiency makes this mechanized effective for pulping palmyrah fruits and, thus, it can replace manual pulping, especially in rural communities involved with the palmyrah fruit pulping. &nbsp

Orientational distribution function in nematic liquid crystals by x-rays: Fourier method

The existing methods for the determination of the orientational distribution function f(beta) in the nematic liquid crystals using X-rays have been reviewed. A simple Fourier method which gives f(beta) in terms of the measured intensity is analysed. Using this distribution function, the accuracy with which the order parameters could be evaluated is discussed and the results show the elegance of the Fourier method used here

Human XPC-hHR23B interacts with XPA-RPA in the recognition of triplex-directed psoralen DNA interstrand crosslinks

DNA interstrand crosslinks (ICLs) represent a severe form of damage that blocks DNA metabolic processes and can lead to cell death or carcinogenesis. The repair of DNA ICLs in mammals is not well characterized. We have reported previously that a key protein complex of nucleotide excision repair (NER), XPA-RPA, recognizes DNA ICLs. We now report the use of triplex technology to direct a site-specific psoralen ICL to a target DNA substrate to determine whether the human global genome NER damage recognition complex, XPC-hHR23B, recognizes this lesion. Our results demonstrate that XPC-hHR23B recognizes psoralen ICLs, which have a structure fundamentally different from other lesions that XPC-hHR23B is known to bind, with high affinity and specificity. XPC-hHR23B and XPA-RPA protein complexes were also observed to bind psoralen ICLs simultaneously, demonstrating not only that psoralen ICLs are recognized by XPC-hHR23B alone, but also that XPA-RPA may interact cooperatively with XPC-hHR23B on damaged DNA, forming a multimeric complex. Since XPC-hHR23B and XPA-RPA participate in the recognition and verification of DNA damage, these results support the hypothesis that interplay between components of the global genome repair sub-pathway of NER is critical for the recognition of psoralen DNA ICLs in the mammalian genome

Hysterosalpingographic findings in infertile women diagnosed with genital tuberculosis

Background: Objectives of the study were to describe the hysterosalpingographic (HSG) findings among infertile women with genital tuberculosis (GTB).Methods: This is a retrospective analytical study conducted at Sri Muthu Kumaran Medical College Hospital and Research Institute, Chennai, from January 2016 to January 2020. Study population included 51 infertile women with genital tuberculosis. GTB was diagnosed by either culture/histopathological examination (HPE) or polymerase chain reaction (PCR) studies. In these proved cases of tuberculosis, HSG findings were analysed. Permission from the institutional review board was obtained for the retrospective analysis of the hospital data.Results: Among 113 women who underwent hysterosalpingography, 51 were diagnosed with GTB. In these 51 women, the HSG finding were normal in 23.5% and were abnormal in 76.5% of cases. The abnormal HSG findings noted in association with GTB were calcification (3.9%) , distorted uterine cavity (3.9%), beaded tubes, intravasation with blocked tubes (5.9%), fimbrial block with hydrosalpinx (15.6%), cornual block (35.3%) and mid tubal block.Conclusions: Though imaging findings may be highly suggestive of tuberculosis, some of the features such as tubal block and hydrosalpinx are not specific for tuberculosis and may be seen in other infective causes of tubal damage also. Therefore, specific investigations for tuberculosis are still required to make a de­finite diagnosis. The presence of HSG features indicate that considerable tubal damage has occurred

Tibia Fracture Healing Prediction Using First-Order Mathematical Model

The prediction of healing period of a tibia fracture in humans across limb using first-order mathematical model is demonstrated. At present, fracture healing is diagnosed using X-rays. Recent studies have demonstrated electric stimulation as a diagnostic tool in fracture healing. A DC electric voltage of 0.7 V was applied across the fracture and stabilized with Teflon coated carbon rings and the data was recorded at different time intervals until the fracture heals. The experimental data fitted a first-order plus dead time zero model (FOPDTZ) that coincided with the mathematical model of electrical simulated tibia fracture limb. Fracture healing diagnosis was proposed using model parameter process gain. Current stabilization in terms of process gain parameter becoming constant indicates that the healing of fracture is a new finding in the work. An error analysis was performed and it was observed that the measured data correlated to the FOPDTZ model with an error of less than 2 percent. Prediction of fracture healing period was done by one of the identified model parameters, namely, process gain. Moreover, mathematically, it is justified that once the fracture is completely united there is no capacitance present across the fracture site, which is a novelty of the work

Sensor-based Automated Continuous Grader for Spherical Fruits

244-253Weight grading is capable of more scrupulous separation than dimensional grading and reduces labor cost, damage, time, and power demand and also improves grading efficiency and accuracy. Hence a low-cost sensor-based grader for spherical fruits was developed and evaluated. The developed grader comprises of fruit feeding tray, fruit controlling shaft with gate arrangement, Electronic Control Unit (ECU), mainframe, belt conveyor, power transmission system, and collection baskets. The ECU consists of a load cell to sense the weight of the fruit, an amplifier to amplify the sensor data, a microcontroller to process the sensor signal and activate the corresponding motor and servo motors to push the fruit towards the basket by activating lever mounted on it. The machine is capable of weighing and grading the fruits into four different grades (grade I: >150 g, grade II: 130–150 g, grade III: 110–130 g and grade IV: <110 g), however, the grades can be altered as per the need by uploading in the program via USB cable. The grader was evaluated in terms of efficiency of grading, capacity and mechanical damage to the fruits at grader speeds of 3, 4, 5, and 6 rpm, respectively. The capacity of grader varied from 47.32 to 156.13 kg/h under different grader speeds. The developed grader is easy to operate and it doesn’t require skilled persons. It can be used for any spherical fruits and varying grades by changing the threshold values in the controller

Hypothermia for encephalopathy in low-income and middle-income countries: feasibility of whole-body cooling using a low-cost servo-controlled device

Although therapeutic hypothermia (TH) is the standard of care for hypoxic ischaemic encephalopathy in high-income countries, the safety and efficacy of this therapy in low-income and middle-income countries (LMICs) is unknown. We aimed to describe the feasibility of TH using a low-cost servo-controlled cooling device and the short-term outcomes of the cooled babies in LMIC. Design: We recruited babies with moderate or severe hypoxic ischaemic encephalopathy (aged <6 hours) admitted to public sector tertiary neonatal units in India over a 28-month period. We administered whole-body cooling (set core temperature 33.5°C) using a servo-controlled device for 72 hours, followed by passive rewarming. We collected the data on short-term neonatal outcomes prior to hospital discharge. Results: Eighty-two babies were included-61 (74%) had moderate and 21 (26%) had severe encephalopathy. Mean (SD) hypothermia cooling induction time was 1.7 hour (1.5) and the effective cooling time 95% (0.08). The mean (SD) hypothermia induction time was 1.7 hour (1.5 hour), core temperature during cooling was 33.4°C (0.2), rewarming rate was 0.34°C (0.16°C) per hour and the effective cooling time was 95% (8%). Twenty-five (51%) babies had gastric bleeds, 6 (12%) had pulmonary bleeds and 21 (27%) had meconium on delivery. Fifteen (18%) babies died before discharge from hospital. Heart rate more than 120 bpm during cooling (P=0.01) and gastric bleeds (P<0.001) were associated with neonatal mortality. Conclusions: The low-cost servo-controlled cooling device maintained the core temperature well within the target range. Adequately powered clinical trials are required to establish the safety and efficacy of TH in LMICs. Clinical trial registration number: NCT01760629

Worldwide variation in the relative importance of hepatitis B and hepatitis C viruses in hepatocellular carcinoma: a systematic review

We combined information published worldwide on the seroprevalence of hepatitis B surface antigen (HbsAg) and antibodies against hepatitis C virus (anti-HCV) in 27 881 hepatocellular carcinomas (HCCs) from 90 studies. A predominance of HBsAg was found in HCCs from most Asian, African and Latin American countries, but anti-HCV predominated in Japan, Pakistan, Mongolia and Egypt. Anti-HCV was found more often than HBsAg in Europe and the United States