Materials behaviour analysis of 3D printed brass-PLA filament

The current study aims to bridge a crucial gap in existing research, potentially paving the way for a groundbreaking transformation in the development and application of PLA/Brass composites within diverse industries such as aerospace, automotive, consumer goods, and medical devices. The primary objective of this research is to assess the mechanical properties of a composite material made up of Polylactic Acid (PLA) and Brass, produced using Fused Deposition Modelling (FDM) 3D printing technology. Brass, renowned for its exceptional mechanical properties, has been integrated into PLA to form this composite material. The study employs various analytical techniques, including Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), and Energy-Dispersive X-ray Spectroscopy (EDX), to scrutinize the chemical and physical characteristics of the PLA/Brass composite. This research revolves around exploring the impact of different printing parameters on the mechanical behavior of the printed specimens. The investigation delves into aspects such as tensile strength, compression resistance, bending properties, and impact resistance. To achieve this, test specimens with varying compositions have been produced using a Raise3D N2 Plus FDM 3D printer, with careful manipulation of printing parameters such as layer height and printing speed. The compositional variations range from 15% wt. to 80% wt., with layer height values spanning 0.25 mm, 0.30 mm, and 0.35 mm, and printing speeds ranging from 20 mm/s to 40 mm/s. The outcomes of this research have revealed the distinct influences of specific printing parameters on various mechanical properties. For example, in the context of tensile testing, it was observed that the combination of a layer height of 0.25 mm and a printing speed of 30 mm/s resulted in the highest elastic modulus. Similarly, the study provides crucial insights into optimizing PLA/Brass composite material properties through controlled additive manufacturing parameters, catering to diverse application requirements. Key findings include an elastic modulus of 0.870 GPa, ultimate tensile strength of 17.53 MPa, yield strength (0.2% offset) of 15.47 MPa, bending strength of 42.25 MPa, bending modulus of 3.679 GPa, compression strength of 33.46 MPa, compression modulus of 5.748 GPa, and energy absorption of 0.246 J. This study advances our knowledge of PLA/brass composite while also providing a chance to create innovative materials

Performance of solar air-conditioning system using heat pipe evacuated tube collector

This is a study on the performance of solar air-conditioning system using heat pipe evacuated tube collector. The objective of this project is to analysis the performance solar air-conditioning system by determining the solar collector efficiency, coefficient of performance (COP) of the absorption chiller, and overall system efficiency and also the electrical energy consumption and operation cost for the system and compare it with the conventional air-conditioning system from the previous case study. The existing solar air-conditioning system is not competitive with electricity driven air-conditioning system because of their high investment and installation cost. Its overall thermal energy conversion efficiency is relatively low, and from an economical point of view, solar cooling and refrigeration are not competitive with the conventional systems. The experiment is conducted at Solar District Cooling Sdn. Bhd and data collected from building automation system for 30 days from 1st-30th June 2010. The data analysed using the theoretical analysis and plotted in graph to discuss about it. The solar collector efficiency varies from 50 to 80% during day time and stored energy can be used during night time. The COP varies from 2.961-2.966 and the overall system efficiency is from 30 to 50%. The investment cost is higher and electrical consumption is relatively lower than conventional air-conditioning system. The economical view is profitable after 18 years and 7 months of installation and environmental view is green energy without pollution. Although all the above findings refer to a particular application in Malaysia, the similar results can be obtained in the country with high solar availability. Finally by considering the problem of pollution of the planet due to the burning of fossil fuels the adoption of solar energy to power absorption chillers, even with marginal economic benefits, should not be underestimated

An Experimental comparison study between Single-Axis Tracking and Fixed Photovoltaic Solar Panel Efficiency and Power Output: Case Study in East Coast Malaysia

A sustainable energy supply is required in Malaysia to meet the increasing electricity demand with rapid growing in population and economy. Photovoltaic solar panel is most suitable alternative way to generate electricity in Malaysia where most of its location receives large number of solar radiation throughout the year. However, fixed solar panel is more preferred than tracking panel because it is cost effective. In present work, the power output and efficiency of single-axis tracking solar panel is compared with fixed solar panel by experimentally in East Coast Malaysia. A single-axis tracking panel produces higher power output than fixed panel up to 28W. During this time, the average efficiency of tracking panel was about 66.70% and fixed panel was 39.96%. Hence, the percentage increment on average power output using tracking panel reached up to 66.92% compare to fixed panel during this period. The tracking panel module efficiency was higher than fixed panel for the same period and can reach up to 28.9% at 6.00p.m. In conclusion, single-axis tracking panel is more efficient than fixed panel in premeridian and postmeridian. Thus, it produces higher power output than fixed panel which means it utilize the most of available solar radiation effectively and this will reduce payback period of the initial investment cost

Performance Evaluation of Evacuated Tube Solar Collector Using Water-Based Titanium Oxide (TiO2) Nanofluid

Experiments are undertaken to determine the efficiency of evacuated tube solar collector using water-based Titanium Oxide (TiO2) nanofluid at Pekan campus (3˚32’ N, 103˚25’ E) Faculty of Mechanical Engineering, University Malaysia Pahang for conversion of solar thermal energy. Malaysia lies in the equatorial zone with an average daily solar insolation of more than 900 W/m² and can reach a maximum of 1200 W/m² for most of the year. Traditionally, water is pumped through the collector at an optimum flow rate, for extraction of solar thermal energy. If the outlet temperature of water is high, further circulation of water through the collector is useless. This is due to low thermal conductivity of water of 0.6 W/m.K compared to metals which is many orders higher. Hence, it is necessary to reduce the surface temperature either by pumping water at higher flow rate or by enhancing the fluid properties by dispersing with nanoparticles. Pumping water at higher flow rates is not advantageous as the overall efficiency of the system is lowered. Liquids in which nanosize particles of metal or their oxides are dispersed in a base liquid such as water are known as 'Nanofluid'. It results in higher values of thermal conductivity compared to the base liquid. The thermal conductivity increases with concentration and temperature of the nanofluid. The increase in thermal conductivity with temperature is advantageous for applications in collectors, as the solar insolation varies throughout the day, with a minimum in the morning reaching a maximum at 2.00p.m and reducing thereafter. The efficiency of the collector estimated using TiO2 nanofluid of 0.3% concentration is about 0.73, compared to water which is about 0.58. The efficiency is enhanced by 16.7% maximum with 30-50nm size TiO2 nanoparticles dispersed in water, compared to the system working with water. The flow rate is fixed at 2.7 litres per minute for both liquids

The Efficiency Enhancement on the Direct Flow Evacuated Tube Solar Collector Using Water-Based Titanium Oxide Nanofluids

In the present study, the efficiency of an evacuated-tube solar collector was investigated experimentally by using water and water-based titanium oxide nanofluids as the working fluids. The titanium oxide nanofluids with the average nanoparticles size between 30-50nm were prepared and tested at volume concentration of 1.0%, 2.0% and 3.0%. The volume flow rate of the working fluids in the solar collector varied from 2.0 to 3.0 liter/min. The experiments were performed at outdoor conditions according to the ASHRAE standard 93-2000. The result shows the efficiency of evacuated solar collector have increased up to 42.5% by using 2.0% concentration nanofluids compared to its base fluid at 2.0litre/min flow rate. In conclusion, the efficiency of collector shows greater enhancement at the low volume flow rate and concentration of nanofluids compared to its base fluid which was water

Anastomotic leak following oesophagectomy: research priorities from an international Delphi consensus study

Background: The Oesophago-Gastric Anastomosis Audit (OGAA) is an international collaborative group set up to study anastomotic leak outcomes after oesophagectomy for cancer. This Delphi study aimed to prioritize future research areas of unmet clinical need in RCTs to reduce anastomotic leaks.Methods: A modified Delphi process was overseen by the OGAA committee, national leads, and engaged clinicians from high-income countries (HICs) and low/middle-income countries (LMICs). A three-stage iterative process was used to prioritize research topics, including a scoping systematic review (stage 1), and two rounds of anonymous electronic voting (stages 2 and 3) addressing research priority and ability to recruit. Stratified analyses were performed by country income.Results: In stage 1, the steering committee proposed research topics across six domains: preoperative optimization, surgical oncology, technical approach, anastomotic technique, enhanced recovery and nutrition, and management of leaks. In stages 2 and stage 3, 192 and 171 respondents respectively participated in online voting. Prioritized research topics include prehabilitation, anastomotic technique, and timing of surgery after neoadjuvant chemo(radio)therapy. Stratified analyses by country income demonstrated no significant differences in research priorities between HICs and LMICs. However, for ability to recruit, there were significant differences between LMICs and HICs for themes related to the technical approach (minimally invasive, width of gastric tube, ischaemic preconditioning) and location of the anastomosis.Conclusion: Several areas of research priority are consistent across LMICs and HICs, but discrepancies in ability to recruit by country income will inform future study design

The impact of surgical delay on resectability of colorectal cancer: An international prospective cohort study

AimThe SARS-CoV-2 pandemic has provided a unique opportunity to explore the impact of surgical delays on cancer resectability. This study aimed to compare resectability for colorectal cancer patients undergoing delayed versus non-delayed surgery.MethodsThis was an international prospective cohort study of consecutive colorectal cancer patients with a decision for curative surgery (January-April 2020). Surgical delay was defined as an operation taking place more than 4 weeks after treatment decision, in a patient who did not receive neoadjuvant therapy. A subgroup analysis explored the effects of delay in elective patients only. The impact of longer delays was explored in a sensitivity analysis. The primary outcome was complete resection, defined as curative resection with an R0 margin.ResultsOverall, 5453 patients from 304 hospitals in 47 countries were included, of whom 6.6% (358/5453) did not receive their planned operation. Of the 4304 operated patients without neoadjuvant therapy, 40.5% (1744/4304) were delayed beyond 4 weeks. Delayed patients were more likely to be older, men, more comorbid, have higher body mass index and have rectal cancer and early stage disease. Delayed patients had higher unadjusted rates of complete resection (93.7% vs. 91.9%, P = 0.032) and lower rates of emergency surgery (4.5% vs. 22.5%, P ConclusionOne in 15 colorectal cancer patients did not receive their planned operation during the first wave of COVID-19. Surgical delay did not appear to compromise resectability, raising the hypothesis that any reduction in long-term survival attributable to delays is likely to be due to micro-metastatic disease

The impact of surgical delay on resectability of colorectal cancer: An international prospective cohort study

The SARS-CoV-2 pandemic has provided a unique opportunity to explore the impact of surgical delays on cancer resectability. This study aimed to compare resectability for colorectal cancer patients undergoing delayed versus non-delayed surgery