Measurement of residual stresses induced by sequential weld buttering and cladding operations involving a 2.25Cr-1Mo substrate material

Dissimilar metal welds are necessary in high-pressure subsea systems and in cases where forged components must be welded to pipelines. F22 (2.25Cr-1Mo) steel is often used in such forged steel components and, since this steel cannot enter service without undergoing post-weld heat treatment (PWHT), the components are usually prepared for field welds through the application of a buttering layer. Furthermore, a weld overlay is deposited for the purpose of mitigating corrosion. This combination of multiple welding tasks and dissimilar materials leads to the possibility of developing substantial residual stresses. This study aims to provide insights to the evolution of residual stresses at each stage of the welding operation. The assessment has been undertaken on laboratory-scale weld mock-ups using the contour method for residual stress measurement, and incremental centre hole drilling. It was found that both buttering and cladding introduce near-yield levels of tensile residual stresses, but that these stresses are successfully relieved upon PWHT

Gallium-assisted diffusion bonding of stainless steel to titanium; microstructural evolution and bond strength

Strong joints between stainless steel 304L and pure titanium (grade-2) were made using the novel method of “gallium-assisted diffusion bonding”. The microstructural evolution and interfacial reactions were investigated in detail. The possible mechanisms of phase changes at the joint interface when bonding with and without a nickel interlayer were identified. Layers of FeTi and (Fe,Cr)2Ti intermetallic compounds were found at the reaction zone in the case of direct bonding, whereas (Fe,Ni)Ti and Fe2Ti phases were identified in the reaction zone of the samples bonded using nickel interlayers. A layer of αFe was observed on the steel side of the reaction zone in both the cases, probably due to the enrichment of Cr at the interface. The diffusion of gallium led to formation of a layer of αTi, while the diffusion of Fe and Ni assisted in the formation of a duplex (α+β)Ti phase in the inter-diffusion zone. The joints fractured along the intermetallic layers at the interface, during tensile testing, with limited ductility. The maximum tensile strengths of the bonded samples were 280 and 313 MPa with and without nickel interlayer, respectively. The latter equals 92% of the tensile strength of the pure grade-2 titanium used in this work (i.e. 340 MPa)

Stress, Anxiety, and Depression Symptoms in a Population Sample in The Initial Stage of The Coronavirus (COVID-19) Pandemic Outbreak

Context: Changes in everyday life have been rapid and drastic, with the virus surge outbreaks, the death rate escalating, and stringent steps to control the disease spread increasing across regions of the world. While significant attention has been paid to efforts to diagnose people with the coronavirus infection, recognizing the mental health needs of people affected by this pandemic has been ignored relatively. The psychological impact of the Coronavirus Disease 2019 (COVID-19) outbreak and lockdown measures on the Egyptian population are unknown. Aim: This study assesses levels of stress, anxiety, and depression symptoms in a population sample in the initial stage of the coronavirus pandemic (COVID-19) outbreak and explores its related potential risk factors.Methods: A cross-sectional design was used to conduct the study on a convenience sample of 1010 subjects residing at Benha City, Qalyubiyah Governorate, Egypt. The tool utilized in this study consists of two parts: Self-administered questionnaire, which was designed to assess people's socio-demographic and family data, and Depression, Anxiety, and Stress Scale (DASS) that measures the symptoms of the emotional state of depression, anxiety, and stress. Results: The result reveals a mean of total stress scale as 15.44±3.62, mean of total anxiety scale as 13.56±3.74, and mean of total depression scale as 12.41±3.86. There was a high statistically significant positive correlation between anxiety, stress, and depression at p-value <0.01.Conclusion: This study concluded that more than two-thirds of the studied population suffered from a moderate level of stress, less than two-thirds of the studied population suffered from moderate anxiety, while around one-tenth of them were normal, and more than one-third of the studied population suffered from a moderate level of depression, while one-fifth of them were normal. The current result revealed that age (year), marital status, having children, educational level, income, and occupation were predictors of stress, anxiety, and depression. The study suggested the need for additional research on predictive factors affecting people's stress in the era of the COVID-19 outbreak and carried out psychological intervention activities through various mediums to help people become more resilient during the COVID-19 epidemic

Exercise protects against obesity induced semen abnormalities via downregulating stem cell factor, upregulating Ghrelin and normalizing oxidative stress

Increased oxidative stress and hormonal imbalance have been hypothesized to underlie infertility in obese animals. However, recent evidence suggests that Ghrelin and Stem Cell Factor (SCF) play an important role in fertility, in lean individuals. Therefore, this study aimed at investigating whether changes in the levels of Ghrelin and SCF in rat testes underlie semen abnormal parameters observed in obese rats, and secondly, whether endurance exercise or Orlistat can protect against changes in Ghrelin, SCF, and/or semen parameters in diet induced obese rats. Obesity was modelled in male Wistar rats using High Fat Diet (HFD) 12-week protocol. Eight week-old rats (n=40) were divided into four groups, namely, Group I: fed with a standard diet (12 % of calories as fat); Group II: fed HFD (40 % of calories as fat); Group III: fed the HFD with a concomitant dose of Orlistat (200 mg/kg); and Group IV: fed the HFD and underwent 30 min daily swimming exercise. The model was validated by measuring the levels of testosterone, FSH, LH, estradiol, leptin, triglycerides, total, HDL, and LDL cholesterol, and final change in body weight. Levels were consistent with published obesity models (see Results). As predicted, the HFD group had a 76.8 % decrease in sperm count, 44.72 % decrease in sperm motility, as well as 47.09 % increase in abnormal sperm morphology. Unlike the control group, in the HFD group (i.e. obese rats) Ghrelin mRNA and protein were elevated, while SCF mRNA and protein were diminished in the testes. Furthermore, in the HFD group, SOD and GPx activities were significantly reduced, 48.5±5.8 % (P=0.0012) and 45.6±4.6 % (P=0.0019), respectively, while TBARS levels were significantly increased (112.7±8.9 %, P≤0.0001). Finally, endurance exercise training and Orlistat administration individually and differentially protected semen parameters in obese rats. The mechanism includes, but is not limited to, normalizing the levels of Ghrelin, SCF, SOD, GPx and TBARS. In rat testes, diet induced obesity down regulates SCF expression, upregulates Ghrelin expression, and deteriorate oxidative stress levels, which are collectively detrimental to semen parameters. Exercise, and to a lesse r extent Orlistat administration, protected effectively against this detrimental effect

Analysis of a centreline failure of a lead alloy anode used in the copper electro-winning process

Thousands of lead anodes are currently used in the electro-winning of copper across the globe. The corrosion and the electrochemical performance of these anodes significantly affect the economy of the process. Premature failure of anodes is often a problem for the commercial operators of tank houses. Recently, the authors were asked to advise on an unusual case where a lead alloy anode split at almost the centreline of the cross section. Different characterization techniques were employed to detect the cause of failure. The fractured samples were metallographically examined with an optical microscope and a Scanning Electron Microscope (SEM) equipped with Energy-Dispersive X-ray Spectroscopy (EDS) analysis. Different phase at the fracture surface were also identified by X-Ray Diffraction technique.The failure mechanism of this anode appears to be manganese contaminated electrolyte attacking the anode perimeter, leading to initial corrosion sites and compounded by subsequent exfoliation corrosion through inter-granular attack and further formation of manganese dioxide. The established practice of producing lead alloy anodes via rolling confers beneficial properties to the finished anodes. However, the resulting elongated grains can in some cases, where the electrolyte is contaminated with elements that are prejudicial to stable oxide layer formation, cause susceptibility to exfoliation corrosion

Painful Small Fiber Neuropathy Associated With Teriflunomide: A Case Series and Literature Review Related to Teriflunomide and Leflunomide

Teriflunomide and its prodrug, leflunomide, are disease-modifying medications used to treat relapsing-remitting multiple sclerosis (RRMS) and rheumatoid arthritis (RA), respectively. Peripheral neuropathy is a rare side effect associated with both medications, although the incidence rate and exact pathological mechanism remain unknown. We present a retrospective case series of three patients with RRMS, who developed painful small fiber neuropathy at various timeframes (\u3c6 \u3emonths, one year, and four years, respectively) while on teriflunomide treatment (14 mg/day); we also engage in a literature review of small and large fiber neuropathy associated with teriflunomide and leflunomide use. All three patients developed small fiber neuropathy following teriflunomide exposure. Laboratory workup was negative for metabolic, infectious, vitamin deficiency-related, and autoimmune etiologies, except for one patient who had chronic metabolic syndromes (impaired glucose, hyperlipidemia) before medication intake. However, the patient developed neuropathy following teriflunomide treatment. Electrophysiological findings were negative for large fiber neuropathy in all three patients with positive skin biopsy, with reduced epidermal nerve fiber density (ENFD) in two of the three patients. Teriflunomide was discontinued in all cases, after which symptoms stabilized. Current literature on leflunomide supports a direct neurotoxic effect or buildup of toxic intermediates from uridine synthesis inhibition. Cessation of teriflunomide use in the described cases resulted in symptom stabilization. Early recognition and treatment may lead to good clinical outcomes in these patients