How human resource management can improve organizational occupational health and safety performance in Singapore

The objective of this research was to examine the impact of human resource management (HRM) on occupational health and safety (OHS) performance in small and medium-sized enterprises (SMEs) in Singapore. To achieve this, the study aimed to identify the factors that influence OHS performance in organizations in Singapore and the standards, protocols, and policies that contribute to effective OHS performance. Additionally, the study aimed to explore how HR practices can enhance OHS performance within Singapore SMEs. The research design adopted was qualitative and semi-structured interviews were conducted with 10 individuals in OHS leadership positions working in Singapore SMEs. Thematic analysis was used to analyze the data collected. The results showed that the main factors impacting OHS performance in organizations in Singapore are financial resources and capacity, company culture and goals, education and training, and risk assessments and audits. These factors were compared to existing literature and studies to verify similar findings. Furthermore, the study also achieved its second objective by identifying the current standards and policies that contribute to effective OHS performance in Singapore. These were classified as either part of national policies or under international standards. Similarly, the research identified three HR practices, management, engagement, and building relations, and how these practices can improve OHS performance in Singapore SMEs. The study discussed how these practices can enhance OHS performance by highlighting their benefits. Overall, the study emphasizes the significance of HRM in enhancing OHS performance in organizations and provides valuable insights for future research in this field. The findings suggest that organizations in Singapore can benefit from adopting HR practices that support OHS performance. Organizations should also consider the factors that impact OHS performance and adopt relevant standards and policies. These results can be utilized by organizations to enhance their OHS performance and by researchers as a guide for future research in this area

Effective Flow And Force Areas Of Discharge Valve In A Rotary Compressor

In this paper, two fluid–structure interaction (FSI) models of the discharge valve are presented to study the effect of partly covering the discharge port by the cylinder and the roller on the effective flow and force areas. One is the full FSI model and another is the simplified FSI model in which the discharge port is not covered and the cylinder shape is simplified to be cylindrical. The pressure in the compression chamber, the displacement of the valve reed, the volumetric flow rate through the valve and the gas force acting on the valve reed head are obtained by the two FSI model. The results comparison between the two FSI models shows the effective flow and force area in the full FSI model are much different from those in the simplified FSI model. The factors which affect the covering area of the discharge port must be taken into consideration in the calculations of these two areas

Flexible-body Dynamics Simulation of Crankshaft Torsional Vibration System

Abstract:The crankshaft accidents due to vibration become severe with increasing number of rows of reciprocating compressors.The crankshaft vibration needs to be studied thoroughly to promote development of the reciprocating compressor.Early calculations of crankshaft torsional vibration was mainly with discretization method, the crankshaft is discretized into a series of lumped inertia and lumped stiffness,then calculate the swing angle of crankshaft in the gas force and inertia force,but because of the simplified calculation,which has low precision.The currently calculation method of crankshaft torsional vibration is simplified into an equivalent system model,the model is composed of a lumped mass disc,massless elastic shaft and a damping.In calculation the torsional natural frequency and forced vibration usually adopt the Holzer method and transfer matrix method,due to this method only calculation the crankshaft torsional direction, so it can only obtained the crankshaft natural frequency and vibration characteristics in the direction.To make the crankshaft torsional vibration calculation more accurately,we proposed a new calculation model based on the flexible multibody dynamics theory.The process of the model establishment and solving by ADAMS was introduced.The torsional vibration of a crankshaft, which often suffers from the crankpin fracture,was calculated before and after the structure change.Results show that before the structure change,the crankshaft natural frequency was closed to the excitation frequency,so that the tortional vibration amplitude of the crankshaft is very large.The stress of piston pins in the first and second row increase so rapidly along the directionof the cylinder center line that the impact factor ofthe crank pin bearing reache the upper limit,thus the oil film of it is damaged.After the structure change,the natural frequency of crankshaft is away from the excitation frequency,the vibration amplitude of the crankshaft torsional vibration decrease substantially,and the crankpin fracture does not happen anymore.This is a successful validation of the proposed calculation method

A Reconfigurable Active Huygens' Metalens

Metasurfaces enable a new paradigm of controlling electromagnetic waves by manipulating subwavelength artificial structures within just a fraction of wavelength. Despite the rapid growth, simultaneously achieving low-dimensionality, high transmission efficiency, real-time continuous reconfigurability, and a wide variety of re-programmable functions are still very challenging, forcing researchers to realize just one or few of the aforementioned features in one design. In this study, we report a subwavelength reconfigurable Huygens' metasurface realized by loading it with controllable active elements. Our proposed design provides a unified solution to the aforementioned challenges of real-time local reconfigurability of efficient Huygens' metasurfaces. As one exemplary demonstration, we experimentally realized a reconfigurable metalens at the microwave frequencies which, to our best knowledge, demonstrates for the first time that multiple and complex focal spots can be controlled simultaneously at distinct spatial positions and re-programmable in any desired fashion, with fast response time and high efficiency. The presented active Huygens' metalens may offer unprecedented potentials for real-time, fast, and sophisticated electromagnetic wave manipulation such as dynamic holography, focusing, beam shaping/steering, imaging and active emission control.Comment: 20 pages, 4 figures, accepted for publication in Advanced Material