Development of a co-cured composite torque shaft for rudder of high speed aircraft

The Carbon Fibre reinforced Composites are widely used in developing various composite parts of civil and13; military aircraft due to its high specific strength and specific stiffness. Rudder being a primary control surface in an aircraft, it is subjected to various loads and needs high degree of structural integrity. Usually rudders are made of metal with many fasteners. In NAL we have designed and developed a composite rudder. Specialty of this13; rudder is that it has a torque shaft made up of carbon composite and has only few rivets. Conventionally torque13; shaft s are made up of special metals like titanium. The objective of this paper is to highlight the development of13; various tooling techniques used to fabricate the composite torque shaft . All major parts of the torque shaft are13; made by Co-curing technique and the metal attachments are embedded to the composite parts by self locking13; mechanism design. To qualify the torque shaft fatigue tests are done and ageing studies performed to prove13; structural integrity of the torque shaft under extreme environmental conditions. This paper portrays the13; development efforts, tolling and fabrication approaches for successful realization of the CFRP Torque Shaft

Formulation and Evaluation of Mouth Dissolving Tablets of Tramadol Hydrochloride

Purpose: To prepare, and evaluate in vitro and in vivo tramadol hydrochloride mouth dissolving tablets (MDT).Methods: Tramadol HCl MDT were prepared by direct compression using Pharmaburst as coprocessed excipient and compared with a reference product (Rybix ODT, 50 mg). Physicochemical parameters including hardness, friability, weight variation, disintegration time and dissolution studies were determined for all the formulations. In-vivo studies were performed for the optimized formulation (F13), using as reference, a commercial product (Trambax IR, 50 mg), by a two-way crossover design under fasting conditions on eight healthy adult human subjects. Drug-plasma concentrations obtained from the bioequivalence study for test and reference products were analyzed in each subject by high performance liquid chromatography (HPLC), and basic pharmacokinetic parameters, including Cmax, Tmax, AUC0-t, AUC0-∞, t½ and λz, were calculated.Results: The tablet formulation prepared with Pharmaburst (F13) showed good flow properties, low disintegration time (15 s) and improved drug release (99 % at 30 min) compared with those of the reference product (88 % at 30 min) and passed 6 months accelerated stability test. Bioequivalence of the test product with that of the reference product under fasting conditions was established by computing 90 % confidence interval for the In-transformed pharmacokinetic parameters of Cmax, AUC0-t and AUC0-∞ for tramadol. The 90 % confidence intervals for Cmax were 99.70 - 114.31, for AUC0-t 97.31 - 108.87 and for AUC0-∞ 97.17 - 109.75. This confidence interval, in each case, was within bioequivalence criteria limitConclusion: A suitable preparation of tramadol HCl MDT that is bioequivalent with a reference commercial product under fasting condition can be obtained when Pharmaburst is used as a disintegrant.Keywords: Bioequivalence, dissolution, Mouth dissolving tablets, Pharmaburst, Tramadol hydrochloride, Disintegration tim

Out of Africa: The role of institutional distance and host-home colonial tie in South African Firms’ post-acquisition performance in developed economies

The colonial ties and institutional distance affect the cross-border acquisition performance of internationalizing South African firms who acquire targets in developed economies. Along with these main effects, this paper examines the moderating effect of the colonial tie on the effects of institutional distance on post-acquisition long-term operating performance. Using data on South African acquisitions in developed economies, this study finds that the colonial tie has a negative impact on the long-term operating performance of South African acquirers. Yet, the colonial tie also moderates the effects of institutional distance. This work contributes to the discussion on host-home country institutional distance and its impact on post-acquisition long-term operating performance and how colonial past can influence the performance of acquirers from South Africa and other such countries with colonial history

Age Matters: The Contingency of Economic Distance and Economic Freedom in Emerging Market Firm’s Cross-Border M&A Performance

The primary studies on emerging market multinational firms (EMFs) thus far have depicted a picture of accelerated internationalization in which EMFs conduct a series of aggressive cross-border acquisitions to further enhance their competitive advantage. However, it is not clear whether the EMFs which conducted the acquisitions at a young age experience better performance. EMFs constrained by their home market development in economic institutions may encounter different challenges in their cross-border acquisitions. Using a sample of South African firms’ acquisitions between 1994 and 2012, we find support for the benefit of foreign acquisitions at a young age as well as the moderation effects of economic distance and economic freedom. While early inorganic growth provides an excellent opportunity to propel South African firms’ growth, the country level factors present important boundary conditions to examine the benefit of early internationalization. While facing a significant economic distance, older firms are better at utilizing their experience and experience better post-acquisition operating performance. By contrast, the younger firms benefit more from the post-acquisition when the home country has weaker economic freedom

Presence of Multiple Tendinous Insertions of Palmaris Longus: A Unique Variation of a Retrogressive Muscle

Background: Palmaris longus, being the most variable muscle of the upper extremity is generally considered important morphologically rather than functionally. The palmar aponeurosis represents the distal part of the tendon of Palmaris longus.Case Details: We report here a unique case of palmaris longus presenting variation distally as its tendon divides to gain multiple attachments with the fascia covering the abductor pollicis brevis, flexor retinaculum and the tendon of flexor carpi ulnaris. In addition, it also continues as palmar aponeurosis as its normal course.Conclusion: Presence of this kind of variation might result in compression of the median and ulnar nerves and may aggravate the complications in case of inflammation of palmar aponeurosis thus mimicking the manifestations of Dupuytren’s contracture.Keywords: Palmaris longus, palmar aponeurosis, Dupuytren’s contractur

Case Report: Variant Origin of an Arterial Trunk from Axillary Artery Continuing as Profunda Brachii Artery- A Unique Arterial Variation in the Axilla and its Clinical Implications

Background: Axillary artery is known to show different variations mostly in its branching pattern. Similarly, the origin of profunda brachii is often encountered with abnormality. Therefore, when the vascular variations in the upper limb persist, mostly it is confined to its branching pattern followed by its variant origin. But, among all the reported variations of profunda brachii, its variant origin from the 3rd part of the axillary artery with common trunk for the branches of axillary artery is unique.Case Details: We report here an anomalous origin of profunda brachii as continuation of an arterial trunk arising from 3rd part of the axillary artery. This common trunk at its commencement passed between 2 roots of median nerve and gave branches of 3rd part of axillary artery before it continued as profunda brachii artery. The further course and branching pattern of profunda brachii were normal.Conclusion: Since the axillary artery is next choice of artery for arterial canulation in cardiopulmonary bypass procedures, prior knowledge of existence of such variation in its branching pattern helps in avoiding possible diagnostic or interventional therapeutic errors.Keywords: axillary artery, common trunk, profunda brachii, vascular variatio

Inhibition of free radical generation and improved survival by protection of the hepatic microvascular endothelium by targeted erythrocytes in orthotopic rat liver transplantation

The capacity of specifically targeted erythrocytes to inhibit free radical—mediated injury to the endothelial cell after cold preservation, and improve liver function was studied in two experimental models: An isolated perfused rat liver (IPRL) system and syngeneic orthotopic rat liver transplantation. In the IPRL model, livers were preserved in University of Wisconsin solution for 24 h at 4°C. At the end of the preservation period, livers were flushed with lactated Ringer’s (control), immu- noerythrocytes (IES), or blank intact erythrocytes prior to warm reperfusion for 2 h using an assanguinous Krebs-Henseleit buffer. Production of superoxide (O2-) anion during warm reperfusion in the IES-treated liver was reduced by 65% as compared with controls (P<0.001) and by 74% (P<0.001) when compared with blank erythrocyte—treated livers. Endothelial cell preservation, as assessed by levels of purine nucleoside phos- phorylase (PNP), was much better in the IES-treated group (P<0.001) when compared with untreated livers. Hepatocellular preservation was markedly improved in the IES-treated livers. In the syngeneic liver transplantation model, livers were preserved in UW solution for 24 h at 4°C. Prior to implantation, livers were flushed with 5 ml of cold lactated Ringer’s or immunoerythrocytes. Survival after three weeks was 60% in the IES-treated group and 30% in the untreated group. Survival in the IES-treated group was not significantly different from a control (no preservation) group. IES-treated livers in both models demonstrated better endothelial cell integrity and ultimate liver function. IES treatment therefore appears to protect the hepatic microvascular endothelial cell from reperfusion injury and could prove to be an easy reproducible method of donor organ preparation after cold preservation. © 1990 by Williams & Wilkins

A modified deep learning weather prediction using cubed sphere for global precipitation

Deep learning (DL), a potent technology to develop Digital Twin (DT), for weather prediction using cubed spheres (DLWP-CS) was recently proposed to facilitate data-driven simulations of global weather fields. DLWP-CS is a temporal mapping algorithm wherein time-stepping is performed through U-NET. Although DLWP-CS has shown impressive results for fields, such as temperature and geopotential height, this technique is complicated and computationally challenging for a complex, non-linear field, such as precipitation, which depends on other prognostic environmental co-variables. To address this challenge, we modify the DLWP-CS and call our technique “modified DLWP-CS” (MDLWP-CS). In this study, we transform the architecture from a temporal to a spatio-temporal mapping (multivariate setup), wherein precursor(s) of precipitation can be used as input. As a proof of concept, as a first simple case, a 2-m surface air temperature is used to predict precipitation using MDLWP-CS. The model is trained using hourly ERA-5 reanalysis and the resulting experimental findings are compared to two benchmark models, viz, the linear regression and an operational numerical weather prediction model, which is the Global Forecast System (GFS). The fidelity of MDLWP-CS is much better compared to linear regression and the results are equivalent to GFS output in terms of daily precipitation prediction with 1 day lag. These results provide an encouraging framework for an efficient DT that can facilitate speedy, high fidelity precipitation predictions.</jats:p

Remote sensing of spectral signatures of tropospheric aerosols

With the launch of the German Aerospace Agency's (DLR) Modular Opto-electronic Scanner (MOS) sensor on board the Indian Remote Sensing satellite (IRS-P3) launched by the Indian Space Research Organization (ISRO) in March 1996, 13 channel multi-spectral data in the range of 408 to 1010nm at high radiometric resolution, precision, and with narrow spectral bands have been available for a variety of land, atmospheric and oceanic studies. We found that these data are best for validation of radiative transfer model and the corresponding code developed by one of the authors at Space Applications Centre, and called ATMRAD (abbreviated for ATMospheric RADiation). Once this model/code is validated, it can be used for retrieving information on tropospheric aerosols over ocean or land. This paper deals with two clear objectives, viz., (1) Validation of ATMRAD model/code using MOS data and synchronously measured atmospheric data, and if found performing well, then to (2) derive relationship between MOS radiances and Aerosol Optical Thickness (AOT). The data validation procedure essentially involves near-synchronous measurements of columnar aerosol optical thickness and altitude profiles of aerosol concentration using ground-based multi-filter solar radiometers and Argon-ion Lidar, respectively and computation of the top-of-the-atmosphere (TOA) radiances from a low reflecting target (near clear water reservoir in the present study) using the ATMRAD model. The results show that the model performance is satisfactory and a relationship between the spectral parameters of MOS radiances and aerosol optical thickness can be established. In this communication, we present the details of the experiments conducted, database, validation of the ATMRAD model and development of the relationship between AOT and MOS radiance

Carotid shunt provides cerebral protection during emergency coronary artery bypass grafting in a patient with bilateral high grade carotid stenosis: a case report

<p>Abstract</p> <p>Background</p> <p>Management of patients with co-existent coronary and carotid disease is a controversial and challenging issue. The risk for stroke after coronary artery bypass grafting (CABG) in patients with hemodynamically significant carotid stenosis is up to 30%. In these patients a common practice is to proceed first with the restoration of cerebral perfusion and then perform the coronary revascularization. The rationale is that this strategy will reduce perioperative neurological morbidity and mortality. However, what happens when the carotid procedure is acutely complicated by cardiac instability which necessitates the interruption of the carotid procedure?</p> <p>Case report</p> <p>We describe a case of a patient with unstable angina and high grade asymptomatic bilateral carotid stenosis who underwent emergency combined CABG and carotid endarterectomy (CEA). Due to hemodynamic instability, ST-T changes, hypotension and bradycardia, upon completion of endarterectomy we placed a carotid shunt and the patient was put on cardiopulmonary bypass through median sternotomy. After triple CABG (duration of 90 minutes) we concluded the interrupted CEA procedure with primary closure of the carotid arteriotomy with the shunt in place. The postoperative course was uneventful and the patient was discharged after a week. In extreme cases with bilateral severe carotid stenosis and coronary artery disease where the carotid procedure should be interrupted, we suggest the use of carotid shunt which can provide adequate cerebral perfusion giving time to cardiac surgeon to perform the life saving cardiac procedure first.</p