RESUMO
A new layered heterostructure composite material system (TC4 as front layer and 2024Al alloy as back layer) was developed and analyzed for its design and performance in terms of an enhanced absorption capability and anti-penetration behavior. The Florence model for energy absorption was modified, so that it can be utilized for the layered heterostructure composite material system with more efficacy. Numerical simulation through Ls-Dyna validated the analytical model findings regarding the energy absorption of the system and both were in good agreement. Results showed that two ductile materials with diverse properties, the hardness gradient and varied layer thickness joined together, specifically behaved like a unified structure and exhibited elastic collision after slight bending, which is possibly due to the decreased yield strength of the front layer and increased yield strength of the second layer. To validate the analytical and numerical findings, the samples of the layered heterostructure composite material system were subjected to a SHPB (Split Hopkinson pressure bar) compression test. The deformation behavior was analyzed in the context of the strain energy density and stain rate sensitivity parameter at different strain rates. The encouraging results proposed that two ductile materials with a hardness gradient can be used as an alternate structure instead of a brittle-ductile combination in a layered structure.
RESUMO
Background: Non-anemic iron deficiency precedes iron deficiency anaemia and has an estimated prevalence of 1-2 billion worldwide. Few studies have comprehensively researched the idea of treating non-anemic iron deficiency (NAID) with iron to improve the outcome of the mother and the offspring. Methods and Analysis: FAIR will be a multicenter randomized controlled trial that will be conducted in multiple clinical academic obstetrics units in Lahore (including Services Institute of Medical Sciences, Lahore, Allama Iqbal Medical College, Lahore and Fatima Jinnah Medical University). Pregnant women at gestational age <20 weeks with hemoglobin 11-13 g/L and ferritin below the threshold (<30 ng/ml) will be invited to take part in the study. Randomization will be done by computer based generated random numbers. One group (usual care or oral group) will be offered routine care prophylactic dose of oral iron (30-45 mg/day) and the other group (intervention arm or IV group) will be offered therapeutic dose of IV iron (dose calculated by Ganzoni formula) in addition to usual care. All patients will be followed up till delivery. Primary maternal outcome will be hemoglobin at 36 weeks' gestation. Secondary outcomes are fetal birthweight or small for gestational age, preterm birth, preeclampsia, multidimensional fatigue inventory, breast feeding initiation, blood transfusion, and fetal cord ferritin and hemoglobin. Discussion: The study will generate evidence as to whether screening serum ferritin in non-anemic pregnant women and replenishing their iron stores will likely reduce the rate of predelivery anemia in pregnant women, improve birthweight and preventing perinatal complications. Roles and responsibilities: Tayyiba Wasim is principal Investigator and other members of data management team are Natasha Bushra, Shamsa Humayoun, Khalid Saeed Khan, Fatima Shehbaz, Saba Rasool, Anam Riaz and Sonia Irshad. Principal investigator will assume the full responsibility of Fair trial including training of research assistants, administration of informed consent and protecting participants confidentiality. Data management team will help in the management, development and execution of trial. Khadija Irfan Khawaja is the operational lead for fair trial´s technology team comprising of Aziz Fatima and Zubia Zafar, responsible for gathering requirements from study teams and supporting the operational implementation of technology to drive the collection of high-quality study data. Protocol contributors are Gynae unit I of Services Institute of Medical Sciences/ Services hospital, Lahore, Gynae Unit II of Allama Iqbal Medical College/ Jinnah hospital, Lahore and Gynae unit 1 of Fatima Jinnah Medical College/ Sir Ganga Ram hospital, Lahore. These coordinating centres will recruit patients (sample size=600) and will discuss their progress in trial management meetings quarterly. Steering committee: has an independent chair Prof Samia Malik, one expert member Prof Faiza Bashir and Ms Neelam to represent patients, public and consumers. Trial steering committee with independent chair and member with a patient representative will oversee the study. Chair of steering committee has the authority to stop the trial whenever needed in case of positive or negative results. Steering committee meetings will be held on annual basis. Independent Data monitoring committee: comprises of Dr. Shehnoor Azhar as chair and Prof Ejaz Hussain and Dr. Shehla Javed Akram as members. Data monitoring committee will assess the progress, data safety and if needed critical efficacy points of the clinical study and will show their results quarterly in data interim meetings. The committee will focus on integrity of the whole process and compliance of all sites with all aspects of the protocol. It will perform confidential interim analyses quarterly, which may be used to determine if an effect is observed and if the study should continue to its planned sample size. Data monitoring committee will report to the Chair of the steering committee.