Conventional and Additively Manufactured Stainless Steels: A Review

© The Indian Institute of Metals - IIM 2021. This is the accepted manuscript version of an article which has been published in final form at https://doi.org/10.1007/s12666-021-02305-7For the last three decades, enormous manufacturing processes have been widely employed in the field of transportation (aviation, automobile and marine) as well as various industrial sectors. Among the invented techniques, conventional manufacturing plays a versatile and cost effective role, but additive manufacturing (AM) possesses a more significant advantage of handling complicated parts or complex geometrical structures. The conventional processes were used from ancient times until the development of other advanced techniques. In recent development of technology, AM technology has shown a tremendous change in the manufacturing field. The process of development in AM began with polymers, then to composites and advanced to nanocomposites, continuously. AM provides a waste-free production management system with enhanced processes. Therefore, this detailed and compendious review describes the different stainless steels fabricated through conventional and AM techniques. It is evident that AM proves better than other several conventional techniques, by three dimensional (3D) printing of quality and complex stainless steels components that are impossible to manufacture through other methods. Notwithstanding, there still need of much efforts to improve AM technique by reducing the manufacturing cost, supporting mass production and printing large stainless steel components. With an increase in invention of various efficient state-of-the-art engineering software, robots in manufacturing, artificial intelligence and smart manufacturing, the aforementioned drawbacks of AM technique/3D printing of various stainless steel structures will be soon eradicated.Peer reviewe

Novel ZnO hollow-nanocarriers containing paclitaxel targeting folate-receptors in a malignant pH-microenvironment for effective monitoring and promoting breast tumor regression

Low pH in the tumor micromilieu is a recognized pathological feature of cancer. This attribute of cancerous cells has been targeted herein for the controlled release of chemotherapeutics at the tumour site, while sparing healthy tissues. To this end, pH-sensitive, hollow ZnO-nanocarriers loaded with paclitaxel were synthesized and their efficacy studied in breast cancer in vitro and in vivo. The nanocarriers were surface functionalized with folate using click-chemistry to improve targeted uptake by the malignant cells that over-express folate-receptors. The nanocarriers released ~75% of the paclitaxel payload within six hours in acidic pH, which was accompanied by switching of fluorescence from blue to green and a 10-fold increase in the fluorescence intensity. The fluorescence-switching phenomenon is due to structural collapse of the nanocarriers in the endolysosome. Energy dispersion X-ray mapping and whole animal fluorescent imaging studies were carried out to show that combined pH and folate-receptor targeting reduces off-target accumulation of the nanocarriers. Further, a dual cell-specific and pH-sensitive nanocarrier greatly improved the efficacy of paclitaxel to regress subcutaneous tumors in vivo. These nanocarriers could improve chemotherapy tolerance and increase anti-tumor efficacy, while also providing a novel diagnostic read-out through fluorescent switching that is proportional to drug release in malignant tissues

A comparative study of the outcomes of mandibular fractures treated with and without per and post operativemaxillo-mandibular fixation.

Background: Mandible being prominent and mobile gets fractured commonly. Fracture healing is important for restoring chewing abilities andaesthetic appearance. The fracture healing in mandibles is painful and maintaining reduction is difficult due to the action of various the musclesattached to mandible. There are few reports about fixing mandible fracture with intraoperative manual maintenance of occlusion without applyingtraditional arch bars and MMF.Aims: to study the outcome following rigid fixation of mandibular fractures without per operative or postoperativemaxillo- mandibular fixation and immediate mobilisation.Materials and methods: This is a prospective study conducted in theDepartment of Plastic and Reconstructive Surgery in a Government tertiary care centre over a duration of 18 months in 30 patients with anteriormandibular fractures in which each 15 patients belonging to Group I and Group 2 received ORIF with MMF.Results: Mean time of fixation inGroup 1 (ORIF without MMF) was 22.27 minutes whereas in Group 2 (ORIF with MMF) it was 38 minutes which is statistically significant.There was statistically no significant difference in occlusal disturbances in both groups compared in the study. There was no significantdifference after fixation with or without MMF in stability of fracture segment.There was no statistically significant difference between bothgroups in terms of neurosensory deficits and masticatory efficiency. Patients of both groups were kept on soft diet for a period of 1 month. Mouthopening in patients in both the groups showed a gradual recovery till 1 month after which it stabilized. There was gradual decrease in pain inpatients of both groups.Conclusion: Maxillomandibulary fixation reduces the operative time and aids in early mobilisation and better intake ofdiet. Mandible fractures can be managed by Open reduction and internal fixation with intra operative manual maintenance of occlusion andsatisfactory results can be obtained

Effect of the Cryogenically Treated Copper Nozzle Used in Plasma Arc Machining of S235 Steel

The investigation was carried out by making use of the design of experiments method in order to achieve its objective, which was to study wear analysis in relation to a cryogenically treated nozzle that was utilized in plasma arc machining. Kerf width and surface roughness are two output characteristics that are key variables in deciding the quality of the cut and the efficiency of the operation. Both of these metrics are outputted by the process. While machining S235 steel, an investigation into the impact that nozzle treatment has on various quality metrics is currently under way. The examination is carried out with the arc voltage, the cutting speed, and the gas pressure, all serving as important components. A cryogenic treatment of the nozzle material using liquid nitrogen at a temperature of −194°C has been attempted in an effort to increase the life of the nozzle. Machining is performed using two different nozzle conditions, such as cryogenically treated and cryogenically untreated, with regard to the input parameter combinations that have been selected. To have a better understanding of the wear behavior of nozzles, an image from a scanning electron microscope is studied. Because of the treatment, the production of wear tracks in the direction that gas flow takes has been drastically decreased. This, in turn, has increased the cutting efficiency by decreasing the amount of arc current that was necessary. In addition, a grey relational analysis is carried out in order to find the best possible machining settings in both conditions. The parameters that were optimized for a nozzle that had been cryogenically treated were 6 bar of gas pressure, 120 amperes of arc current, and 1800 of cutting speed per minute. The use of cryogenic treatment resulted in a reduction of surface roughness by 0.4670 µm and a narrowing of the kerf width by 0.96 mm. It is clear from the SEM pictures of untreated and cryogenically treated nozzles that thermal distortion and wear in the nozzle tip area are minimized to a greater extent in the treated nozzle. This is evidenced by the fact that the treated nozzle has a more uniform appearance

A Clinical Study on Post Burn Contracture of Axilla at a Tertiary Care Centre

Introduction: The joint problems and deformities noted in burn patients are mostly due to physical inactivity combined with limitation of joint movement because of scar contracture. Restoration of function in upper limb varies according to the surgical procedure opted and post operative compliance. Surgical intervention is still a challenge, because the axilla is a unique three dimensional pyramid. Aim :To study the outcome of various surgical procedures done for post burn contracture of axilla and their complications.Materials and methods: This prospective study was done on 20 patients who presented with PBC axilla to Department of Plastic & Reconstructive Surgery, Osmania General Hospital, Hyderabad during the period of study i.e., July 2019 to January 2021.Results: 20 patients were included in the study.8 patients presented 6 to 12 months after sustaining burns,7 patients between 13 to 24 months and 5 patients presented after 3 years. Patients gave history of no physiotherapy and splinting for their axilla during the acute burn stage treatment, pre operative abduction ranged between 20° and 90° with a mean of 48°. Post operative abduction achieved was between 90° and 160° with a mean of 130°. 10 patients(50%) had undergone contracture release and SSG, multiple Z plasties were done in 5 patients(25%), one patient had undergone transposition flap and SSG(5%), thoracodorsal artery perforator flap was done in one patient(5%), propeller flap was done in two patients (10%), parascapular flap was done in one patient (5%). One patient had partial graft loss(5%) following contracture release and SSG, one patient had reccurence (5%), one patient had tip necrosis (5%).Conclusion: Axillary burn contracture can be prevented by proper management of acute burns stage, positioning of the shoulder joint, use of abducted split, aggressive early physiotherapy and early resurfacing of raw area. Z plasty and local flaps are used in mild cases. Release and SSG is the best treatment for severe PBC axilla

Clinical study of Latissimus Dorsi Flap for Various Defects Following Cancer Resections

Introduction: The purpose of reconstruction is to restore every resected tissue and its function, as well as to achieve primary wound healing so that rehabilitation and adjuvant therapy can begin as soon as possible. It is no longer enough to simply close a wound in modern reconstructive surgery. It's critical to aim for the absolute best functional and aesthetic outcomes. Aims: To evaluate the role of latissimus dorsi flap in reconstruction of Various defects following cancer resections in arm, axilla, shoulder, chest wall, breast, head and neck and scalp. Materials and methods:It is a prospective study in Twenty patients with cancers were identified during the study period of one year after thorough workup and after obtaining fitness for anaesthesia, the patients and their attendants are explained about the surgical ablative procedure and the reconstructive procedure contemplated. Results: In this study 20 cases the role of using latissimus dorsimyocutaneous flap (LDMF) for soft tissue defects involving breast, chest wall, shoulder and arm was explored. The patients were in the age range of 24 to 80 years. Maximum flap dimension was 30 X 20 cms. All patients underwent immediate reconstruction of the primary defect. In our series out of 20 patients, 13 flaps had healed primarily without flap congestion, margin necrosis, or infection, 3 flaps had medial edge necrosis of about 3-4cms which were debrided and closed primarily. These 3 flaps were extremely large and the lumbar extension of the flap was done to cover the defect. Seroma formation was seen in 3 patients. Out of the 2 cases closed primarily in 1 case donor site had seroma formation which was managed conservatively by serial aspiratons and drain was kept in situ for about 18 days and compression dressing was done with dynaplast application. Out 20 cases 2 patients had recurrence through the inferior aspect of the flap. Conclusion: Additional care and precautions donor site morbidity can be reduced and overall, the donor site is well tolerated and the patients are functionally satisfied with the reconstruction

Management of Panfacial Fractures- A Clinical Study at Tertiary Care Centre- Osmania General Hospital

Introduction: Panfacial fractures commonly occur due to road traffic accidents in developing countries like India. Submental intubation can be an effective technique for upper airway management in few panfacial trauma patients associated with fracture of skull base or displaced nasal fracture and it offers an effective alternative to short term tracheostomy.Aims:To study different patterns of Panfacial fractures, their management and complications and to study the pattern and distribution of fractures at different sites of the maxillofacial skeleton.Materials and methods: This study is a prospective clinical study conducted in department of plastic surgery for a period of 2 years. Panfacial fractures divided as fracture involving the upper, middle, and lower face. The patients were followed at 2 weekly interval for the first 3 visits, followed by monthly interval up to a maximum of 6months.Results: Mandible is the most common in the mid face fractures in facial fractures. In the mandible, parasymphysis was the most common fractured site constituting 43.33% of patient population. 27 patients(90%) were treated by open reduction and internal fixation and 3 patients (10%) were treated by closed reduction arch bar/eyelets and inter maxillary fixation .Out of 30 patients studied, 1 patient had zygomatic arch prominence,1 patient had wound infection, In two patients, malocclusion was identified in the in post operative period, and was managed by reapplication of IMF in the operation theatre.Conclusion: Treatment to be focused on re-establishing proper occlusal, vertical and horizontal dimensions in the facial frame, as well as restoration of orbital, oral volumes. The high frequency of panfacial fractures due to RTA in our country

Clinical study of upper one third leg defects

Large soft tissue leg defect involving upper and middle third remains a therapeutic challenge. Clinical study of management of upper one third defects was done to analyze the various reconstructive procedures for leg defects and also to enhance the quality of work done to produce good results with minimal complications as possible. This Prospective Clinical study conducted in the department of Plastic and Reconstructive surgery, includes 20 cases of upper one third of leg defects admitted. Patients >15years of age with Soft-tissue defects of upper one third leg requiring flap cover are included in this study. The operative procedure was chosen according to the nature and size of the defect. The earliest flap cover was given within 1 week of trauma. Primary flap cover was given in 10 (50%)patients, delayed primary flap cover in 9 (45%) patients and secondary flap cover in 1 (5%) patient. In 14 (70%) patients Gastrocnemius flaps were done, of which Gastrocnemius muscle flaps with SSG were done in 9 patients (45%) and Gastrocnemius Myocutaneous flap in 5 patients (25%). Fasciocutaneous Flaps in 4 patients (20%), Venous flap in one patient (5%) and Advancement Flap in 1 patient (5%) were done

Seasonal variations in the phenolic profile, antioxidant activity, and mineral content of south Indian black tea (Camellia sinensis (L.) O. Kuntze)

Abstract In the Anamallais region of south India, crop shoots from the UPASI-3, UPASI-9, UPASI-17, Assam seedlings, and TRI-2043 cultivars were examined for seasonal variations in total phenolics, antioxidant activity, and minerals during four harvest seasons: summer (January to March), premonsoon (April and May), monsoon (June to September), and winter (October to December) of two consecutive years. The total phenolics of all cultivars were lower in monsoon period and grew over rest of the seasons and it was greater during summer. Crop shoot antioxidant activity as measured by the DPPH radical scavenging experiment exhibited a similar pattern to total phenolics. Summer was the season with the highest antioxidant activity across all cultivars, followed by premonsoon, winter, and monsoon. On the other hand, the employed cultivars differed noticeably in terms of seasonal change of minerals. These results appear to indicate that the harvest period is hypercritical in deciding the antioxidant potency of tea crop shoots

Applicability of cellulosic-based Polyalthia longigolia seed filler reinforced vinyl ester biocomposites on tribological performance

This is the peer reviewed version of the article which has been published in final form at https://doi.org/10.1002/pc.25865. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions.The focus of this work was to analyze the effect of weight percentage (wt.%) of Polyalthia longigolia seed filler (PLSF) on the wear responses (wear loss and coefficient of friction) of the vinyl ester (VE) matrix composites, using signal-to-noise (SN) ratio and analysis of variance (ANOVA) methods. The Polyalthia longigolia seed filler/vinyl ester (PLSF-VE) composites were produced by compression molding (CM) technique. Scanning electron microscopy (SEM) analysis showed that the PLSF content was homogeneously distributed in the matrix. Pin on disc (POD) wear tester was employed to carry out the experiments. Both SN ratio and ANOVA were performed to determine the process parameters that exhibited lower wear responses. The wear of the composite was minimized by optimizing the four diverse process factors: load, P (N), sliding speed, N (rpm) and filler content (wt.%), based on Taguchi's L9 orthogonal array. The process parameters at which minimum wear loss (WL) occurred were identified with 25 wt.% sample at 10 N and 300 rpm. Also, the process parameters for minimum coefficient of friction (COF) were observed with 25 wt.% sample at 5 N and 700 rpm. From the ANOVA results obtained, it was evident that P mostly influenced the WL and COF of the PLSF-VE composites during POD wear testing. This kind of lightweight composite can be a suitable alternative for small scale loading conditions, such as brake pads and clutch plates in the automobile industry.Peer reviewe