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The purpose of this paper is to formulate a benchmark to increase the tyre curing press production rate while minimizing tyre curing press downtime and maintenance cost with the help of a maintenance management technique based on overall equipment effectiveness (OEE).

The methodology is based on determining the OEE of tyre curing press before and after rectifying the causes of failures. The failure mode and effect analysis (FMEA) technique is used to find out the root causes of repetitive failures in tyre curing press by using the risk priority number.

A significant change in the value of OEE is observed after rectifying the repetitive failures, which were determined using the FMEA technique. Thus, it is concluded that the OEE and FMEA assist in improving the industrial performance and competitiveness of the production equipment studied.

This study is limited to determining the OEE of single equipment only, not the whole production system. Manufacturing facilities are dependent on the operating environment; therefore a comparison of two different manufacturing plants based on the OEE value would not be justified.

This study can be applied in any tyre manufacturing industry in order to take competitive benefits, such as reduction in equipment downtime, increased production and reduction in maintenance cost.

The angle from which the paper approaches the bottleneck problem in a tyre production line is original for the studied company and shows positives results. It allows the company to apply the same approach in its other production equipment, lines and factories to achieve improvement in industrial performance and competitiveness.

THIS report aims at giving a broad outline of German variable‐pitch propellers. Only the characteristic features and principles of operation arc described.

THE Bristol Aeroplane Company entered the field of helicopter production when a design office was inaugurated at the wartime dispersal factory at Banwell, Somerset, in July 1944. The first Bristol helicopter flew in July 1947.

The purpose of this paper is to explore the possibilities of improving the quality of existing maintenance task of the atomizer of milk powder manufacturing unit of a dairy plant. Looking to the past business volume and expected growth, the milk powder manufacturing unit forms a noticeable sector of processing plant. The lack of quality in maintenance standards leads to reliability losses of about 20–25% with low productivity and profit. Such facts and challenges of keeping the system in ready-state motivate a definite maintenance plan to be modeled based on a live failure analysis to be executed during shutdown or scheduled period.

The deliverables are achieved by collecting the historical failure data i.e. downtime and failure frequencies; from January 2020 to July 2020 at Dudhsagar dairy, Gujarat, India. Reliability modeling is done in a view to understand the failure pattern behavior of the milk powder manufacturing unit. The atomizer is discriminated as a critical component based on these data and their functional failures, failure causes, effects and repercussions of failures with existing control and maintenance practices has been modeled based on live shop-floor study. Scores are assigned on 1 to 10 levels by analyzing attributes effects from lowest to highest concern respectively for every modes of failure through realistic brain-storming among maintenance team by incorporating some advanced attributes like maintainability, economic safety, economic cost and spares with basic criteria in this study. The maintainability criticality index (MCI) is narrated by these score values through multi-attribute decision-making (MADM) based failure analysis models like Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS).

The primary findings of this research work are to propose improvements in the quality of the maintenance plan of critical component like; atomizer of a milk powder manufacturing unit which is commonly representing critical component in a major range of industrial processes. The case study recommended four silent maintenance strategies i.e. scheduled maintenance scheduled discard, scheduled failure finding and redesign as a qualified maintenance plan for the atomizer based on MCI and rankings of its potential failure causes. The results are helpful in upgrading quality standards for the maintenance activities of a process industry of alike or of dissimilar kinds in accordance with the failure analysis.

Originality mainly consists of investigating the scope of enhancing the existing maintenance practices through actual failure analysis with the help of TOPSIS. The criteria employed in this study are probability of chances of failure, degree of detectability and degree of severity as basic criteria along with some advanced criteria like; maintainability, spare parts, economic cost, economic safety are selected based on the outcome of shop-floor study and reliability modeling. The notable past failure statistics (downtime, frequency of failures) of a milk powder manufacturing unit were recorded and these data are analyzed based on reliability to extract an explicative component i.e. atomizer.

The purpose of this study is to investigate the transport phenomena of smoke flow in a semi-open vertical shaft.

The large eddy simulation (LES) method was used to model the movement of fire-induced thermal flow in a full-scale vertical shaft. With this model, different fire locations and heat release rates (HRRs) were considered simultaneously.

It was determined that the burning intensity of the fire is enhanced when the fire attaches to the sidewall, resulting in a larger continuous flame region in the compartment and higher temperatures of the spill plume in the shaft compared to a center fire. In the initial stage of the fire with a small HRR, the buoyancy-driven spill plumes incline toward the side of the shaft opposite the window. Meanwhile, the thermal plumes are also directed away from the center of the shaft by the entrained airflow, but the inclination diminishes as HRR increases. This is because a greater HRR produces higher temperatures, resulting in a stronger buoyancy to drive smoke movement evenly in the shaft. In addition, a dimensionless equation was proposed to predict the rise-time of the smoke plume front in the shaft.

The results need to be verified with experiments.

The results could be applied for design and assessment of semi-open shafts.

This study shows the transport phenomena of smoke flow in a vertical shaft with one open side.

The purpose of this paper is to study the behavior of smoke flow in building fires and optimize the design of smoke control systems.

A total of 435 3-D fire simulations were conducted through NIST fire dynamics simulator to analyze thermal behavior of combined buoyancy-induced and pressure-driven smoke flow in complex vertical shafts, under consideration of influence of heat release rate (HRR) and locations of heat sources. This influence was evaluated through neutral pressure plane (NPP), which is a critical plane depicting the flow velocity distributions. Hot smoke flows out of shafts beyond the NPP and cold air flows into shafts below the NPP.

Numerical simulation results show that HRR of heat source has little influence on NPP, while location of heat source can make a significant difference to NPP, particularly in cases of multi-heat source. Identifying the location of NPP helps to develop a more effective way to control the smoke with less energy consumption. Through putting an emphasis on smoke exhausting beyond the NPP and air supplying below the NPP, the smoke control systems can make the best use of energy.

Because of the chosen research approach, the research results may need to be tested by further experiments.

The paper includes implications for the optimization of smoke control systems design in buildings.

This paper fulfills an identified need to research the behavior of hot smoke in building fires and optimize the design of smoke control systems.

ACCORDING to historical records the earliest known drawings for an aerial machine that can be classified under the heading of helicopter were made in the fifteenth century by the world renowned Italian scientist and artist Leonardo da Vinci (1452–1519). Probably the Chinese had been making their helicopter toy for some considerable time before da Vinci commenced his experiments. This toy consisted of two feathers, joined together by means of a cork or soft wood boss, to form a crude type of propeller which was pushed up a threaded stick so that upon leaving the stick the propeller rotated at high speed and continued to screw itself up in the air. When the speed of rotation decreased the propeller slowly windmilled down to the ground. A similar toy is still being sold today.

Shaft orbit is an important characteristic for vibration monitoring and diagnosing system of hydroelectric generating set. Because of the low accuracy and poor reliability of traditional methods in identifying the shaft orbit moving direction (MD), the purpose of this paper is to present a novel automatic identification method based on trigonometric function and polygon vector (TFPV).

First, some points on shaft orbit were selected with inter‐period acquisition method and joined together orderly to form a complex plane polygon. Second, by using the coordinate transformation and rotation theory, TFPV were applied comprehensively to judge the concavity or convexity of the polygon vertices. Finally, the shaft orbit MD is identified.

The simulation and experiment demonstrate that the method proposed can effectively identify the common shaft orbit MD.

In order to identity the shaft orbit MD effectively, a novel automatic identification method based on TFPV is proposed in this paper. The problem of identifying the shaft orbit MD is transformed into the problem about orientation of complex polygons, which are formed orderly by points on orbit shaft, and TFPV are applied comprehensively to judge the concavity or convexity of the polygon vertices.

The purpose of this paper is to investigate experimentally the effect of external vertical vibration on wear property of mild steel.

A pin‐on‐disc apparatus capable of vibrating the test samples in a vertical direction is designed and fabricated. The experimental setup has the ability to vary the amplitudes and frequencies of vibration while velocity of vibration is kept constant. During the experiment, the frequency and amplitude of vibration are varied from 0 to 500 Hz and 0 to 200 μm, respectively.

Results show that the wear rate decreases with the increase of amplitude and frequency of vibration for mild steel. These results are analyzed by dimensional analysis to correlate the wear rate with sliding velocity, normal load, frequency and amplitude of vibration. The experimental results are also compared with those available in literature and simple physical explanations are provided. Considering the lack of correlation between wear rate and other vibration‐related operating parameters, the present research is started to find out suitable correlation and a way of reducing wear rate by applying known frequency and amplitude of vibration at a particular direction.

It is expected that the applications of these results will contribute to the improvement of different concerned mechanical systems.

The paper can be used for design‐related purposes.

The purpose of this paper is to investigate experimentally the effect of external vertical vibration on the friction property of mild steel, glass fiber‐reinforced plastic and cloth‐reinforced ebonite.

A pin‐on‐disc apparatus having the facility of vibrating the test samples in a vertical direction was designed and fabricated. The experimental setup has the facility to vary the amplitudes and frequencies of vibration, while the velocity of vibration is kept constant. During the experiment, the frequency and amplitude of vibration were varied from 0 to 500 Hz and 0 to 200 μm, respectively. Studies have shown that the friction coefficient decreases with the increase of amplitude and frequency of vertical vibration for the above‐said materials. The rate of decrease of friction coefficient is different for different materials. The results of these materials are analyzed by dimensional analysis to correlate the friction coefficient with sliding velocity, frequency and amplitude of vibration. The experimental results are also compared with those available in the literature and simple physical explanations are provided.

It was found that reducing the friction coefficient of different materials was achieved by way of reducing the friction force by applying known frequency and vibration and correlating the friction coefficient with frequency, amplitude and sliding velocity.

The paper presents a way of reducing friction force by applying known frequency and vibration so that the mechanical process can be considerably improved (by considering the appropriate design of vibration).

The paper's originality lies in demonstrating the correlation among friction coefficient, amplitude, frequency and sliding velocity for different types of materials.