Mark E. Heaton, Massimo Rogante, Adél Len and David Denieffe
The purpose of this paper is to determine the nano‐sized characteristics of SU‐8 polymer micro‐electromechanical systems airflow metrology turbines samples. These microturbines…
Abstract
Purpose
The purpose of this paper is to determine the nano‐sized characteristics of SU‐8 polymer micro‐electromechanical systems airflow metrology turbines samples. These microturbines were made to be the first using axial airflow for low air pressure response. This polymer may be affected during curing by UV and heat baking, as well as confined heat from laser ablation. Defects in the resin matrix may influence the material quality and hence the final turbine performance.
Design/methodology/approach
Small angle neutron scattering investigations were performed using the instrumentation of the Budapest Research Reactor.
Findings
The average sizes of the voids/cracks in the resin matrix of the turbines were determined and allowed the viability of making smaller even thinner rotor blades for higher spin and electrical output capability to be considered.
Originality/value
The obtained results have advanced the industrial applicability of the adopted technique in the considered sector of polymer analysis.
M. Rogante, V.T. Lebedev, S. Kralj, L. Rosta and Törö
This paper addresses important technical problems related with methodological limitations of welding project methods currently adopted, mostly regarding numerical modelling…
Abstract
This paper addresses important technical problems related with methodological limitations of welding project methods currently adopted, mostly regarding numerical modelling procedure of welding processes. The progress in high nano‐technologies give rise to the same approaches to be applied in traditional mechanics and material science, really concerning welding processes using various methods and techniques. Recent investigations of welded joints have shown the benefits related to the employment of neutron techniques, to obtain substantial information advancing quality and durability that cannot be found by using other means. Small Angle Neutron Scattering (SANS) and Neutron Diffraction (ND), in particular, consent materials characterization at atomic and nanoscale level, offering to the existing technologies the essential contribution of precise structural methods. The basic theoretical aspects are described, and some SANS investigations of weldments are reported. An experimental programme has been recently projected to develop welding processes, with quality assurance improvement, safety enhancement, life‐time management and cost effectiveness of the considered joints.
Details
Keywords
M. Rogante, F.G. Cesari and G. Ferrari
Residual stresses (RS) in welded joints can contribute to the stress enhancement concentrated in the connection of different components, mainly concerning structures and piping. A…
Abstract
Residual stresses (RS) in welded joints can contribute to the stress enhancement concentrated in the connection of different components, mainly concerning structures and piping. A fast method for assessing RS in a thin weld through the calculation of heat flow and thermal expansion data is explained ‐ obtained by implementing a previous programme in a personal computer (PC) code ‐ to evaluate the through‐wall temperature distribution and the RS field due to multi‐pass welding of flat or axi‐symmetric joints. The calculation of temperature distribution, axial and hoop thermal stresses through the finite thickness of a specimen is described, in particular, considering some basic simplifying assumptions. Validation of experimental is shown, related to thin welded joints, comparing finite elements method (FEM) analysis, direct measurements and the considered analytical method results.
Details
Keywords
M.E. Heaton, M. Rogante and A. Len
In this paper, Gamma‐Butyrolactone (GLB) mixed with Triarylsulfonia and Hexafluroantimonate in the substrate of a microturbine is considered for a Small Angle Neutron Scattering…
Abstract
In this paper, Gamma‐Butyrolactone (GLB) mixed with Triarylsulfonia and Hexafluroantimonate in the substrate of a microturbine is considered for a Small Angle Neutron Scattering (SANS) diagnostic study, paying particular attention to molecular orientations and other micro‐characteristics in connection with the mechanical properties of the substrate. The investigated microturbine is a new MEMS device for the first pioneering study of either gas or airflow sensing using the low pressurehead characteristics of axial‐flow. The substrate material of the microturbine is a negative photoresist composed of an epoxy resin organic solvent. This study wishes to demonstrate the feasibility of the SANS process for examining this substrate on the nano‐scale prior to a full materials investigation, which aims to provide both the information to both improve the characteristics and performance of the microturbine and estimate its maximum lifetime more accurately. The data could also be used to match microturbines to appropriate applications in either flow‐sensing or micro‐power generation in accordance with structural strength limits.
Details
Keywords
Mo’tasem M. Aldaieflih, Rabia H. Haddad and Ayman M. Hamdan-Mansour
This study aims to examine the predictive power of childhood adversity and severity of positive symptoms on suicidality, controlling for selected sociodemographics factors, among…
Abstract
Purpose
This study aims to examine the predictive power of childhood adversity and severity of positive symptoms on suicidality, controlling for selected sociodemographics factors, among hospitalized patients diagnosed with schizophrenia in Jordan.
Design/methodology/approach
This study used a descriptive-explorative design. The study was conducted at two major psychiatric hospitals in Jordan. The targeted sample was 66 patients diagnosed with schizophrenia. Data was collected using a structured format in the period February–April 2024.
Findings
A two-step multiple hierarchical regression analysis was conducted. In the first model, childhood adversity and the severity of positive symptoms were entered. In the second model, sociodemographic variables were entered. The analysis revealed that the first model (F = 5.35, p = 0.007) was statistically significant. The second model (F = 717, p < 0.001) was statistically significant. Furthermore, the analysis revealed that childhood adversity was not a significant predictor for suicidality. However, positive symptoms and patients’ demographics (age, number of hospitalizations and length of being diagnosed with schizophrenia) were significant predictors of suicidality. The analysis revealed that childhood adversity was not a significant predictor of suicidality. However, positive symptoms and patients’ demographics (age, number of hospitalizations and length of being diagnosed with schizophrenia) were significant predictors of suicidality.
Research limitations/implications
One limitation of this study is related to the sample and the setting where there were only 66 patients recruited from governmental hospitals within inpatient wards. Thus, the upcoming studies should include more participants from private hospitals and different hospital settings including outpatient and emergency departments.
Practical implications
The research provides empirical insights that positive symptoms, age hospitalization and schizophrenia diagnosis length were significant predictors of suicidality. At the same time, childhood adversity was not a significant predictor of suicidality.
Social implications
The current research contributes to expanding mental health studies. Moreover, this study enlarges the body of knowledge in the academic world and clinical settings. It supports the disciplines of psychology, mental health and social sciences by increasing knowledge of the complicated relationships among childhood adversity, positive symptoms and suicidality.
Originality/value
This paper fulfills an identified need to study childhood adversity with comorbid psychiatric disorders such as schizophrenia, as well as psychiatric mental health covariates.