Mechanical Workshop Research Articles

Application of Steam Enhanced Extraction Method on BTEX Contaminated Soil in A Nigerian Petroleum Depot and Automobile Workshop Sites in Ilorin Metropolis, Nigeria

The contamination of soil in the environment is a natural consequence of industrialization and urbanization. Organic chemical pollutants dissolve into groundwater, absorb and adsorb into soil grains. Benzene, toluene, ethylbenzene and xylene (BTEX) are major causes of contaminated soil. This is due to fuel leakages or spillages, various forms of hydrocarbon burning/combustion and land disposal petroleum base oil. Contaminated soil samples were excavated from two different locations within the Ilorin metropolis; pipelines and products marketing company, a Nigerian petroleum depot, Ilorin depot and auto mechanic workshop of over ten years. Steam enhanced extraction method was employed through injection of steam to contaminated soil from steam generator into soil pot where contaminated soil was placed. The condensation of steam on soil particles provides energy to release desorbed contaminants molecules from the soil and the mobilized contaminants vapor was transferred into the recovery pot via the pipe that was connected to the soil pot. After the remediation process, the steamed soil samples were taken to the laboratory where the sonication extraction technique was used to extract the contaminants (BTEX) from the steamed soil samples of 30, 60 and 90 minutes respectively. The extract from the steamed soil samples of 30, 60 and 90 minutes was subjected to Gas Chromatography fitted with flame ionization detector analysis to determine the exact amount of BTEX removed after the remediation process. Pre-treated soil sample of auto mechanics workshop was found to be 4.5004 x 10-1 mg/kg and post-treated soil samples were found to be 1.8164 x10-1 mg/kg, 8.7519 x10-1 mg/kg and 5.7006 x10-2 mg/kg for 30, 60 and 90 minutes respectively after remediation process while Pre-treated soil sample of a Nigerian petroleum depot was found to be 6.6049 x 10-1 mg/kg and post-treated soil samples were found to be 2.9320 x10-1 mg/kg, 1.9855 x10-1 mg/kg and 1.0237 x10-1 mg/kg for 30, 60 and 90 minutes respectively after the remediation process. This study established the effectiveness of the remediation process of hydrocarbon contaminated soil using steam enhanced extraction method an In situ remediation technique.

Evaluation of risk caused by intake of trace metal through consumption of Pleurotus tuber-regium collected around automobile village in Abia State

ABSTRACT. The bioaccumulation of trace metals in mushrooms poses a health risk to consumers. Despite the fact that mushroom eating has been linked to numerous health advantages, little attention has been paid to the relative health risks associated with trace metal build-up in this nutritional source in Nigeria. Pb, Cd, Fe, Hg and As in Pleurotus tuber-regium collected from mechanic workshops in Umuahia were analysed and the associated health risks for the consumers were evaluated. The trace metal contents in the mushroom and its substrates showed a descending order of Fe > Pb > Cd > As > Hg. The heavy metals concentration ranges in fruity body of the Pleurotus tuber-regium were Fe (62.16-98.17 mg kg-1), Pb (0.18-1.21 mg kg-1), Cd (0.05-0.34 mg kg-1), As (0.25-0.51 mg kg-1) and Hg (0.009-0.021 mg kg-1). The estimation of weekly intake values was lower than PTWIs of mushroom species except for Fe. According to the THQ and the HI calculations for trace metal contents in the mushrooms, mercury did not pose any risk on human health; whereas the other determined trace metals gave THQ values of 1 < THQ < 10 and showed the possibility of long-term risk.
 
 KEY WORDS: Trace metals. Mushroom, Estimated weekly intake, Target hazard quotient, Bioaccumulation
 
 Bull. Chem. Soc. Ethiop. 2021, 35(2), 229-241.
 DOI: https://dx.doi.org/10.4314/bcse.v35i2.2

Tipping bucket device for measuring runoff in small catchments

ABSTRACT A tipping bucket is an accurate and reliable device that is used to measure runoff water flows, especially in small-scale catchments. However, the performance of the tipping bucket device depends on the magnitude of the runoff water flow, the dimensions of the tipping bucket and the accuracy of the calibration. This paper discusses technical guidelines that govern the design, construction, field installation, calibration and error minimisation of tipping bucket gauges used for runoff estimation in small-scale catchments under agricultural land-use systems. The proposed tipping bucket system is a cost-effective and simple device that can be fabricated in a basic mechanical workshop. The device proved to be a sensitive and reliable instrument on which accurate measurements can be read out easily with minimal maintenance.

Assessment of Mycoremediation Potential of Fusarium Spp. On Polycyclic Aromatic Hydrocarbon in Western India

Motor or engine oil is a lubricant for engines containing majorly of base oils; these base oils include petrol-based hydrocarbons. Petroleum hydrocarbon contamination is one of the major environmental problems resulting from its large scale uses in transportation, industrial and other sectors. Accidental release and workshop seepage of petroleum products are the key concern of the environment. Fresh engine oil contains polycyclic aromatic hydrocarbons (PAHs). Used engine oil also leads to further generation of PAHs. As an attempt to clean up such hydrocarbons, bioremediation or biodegradation methods are adapted. Bioremediation is a cost effective and eco-friendly treatment for oil contaminated materials by the use of micro-organisms. The present study is an attempt to isolate and find out hydrocarbon degrading fungi from oil and petroleum contaminated regions. Biodegradation potential of soil mycobiota isolated from automobile mechanic workshop in Virar on engine oil was investigated using standard methods. The most capable oil degrading fungi was identified morphologically by wet mount technique as Fusarium sp. The biodegradation of hydrocarbons and oil was determined by using 2,6 Dichlorophenol-indophenol (DCPIP) assay and gravimetric analysis. The quantitative estimation of engine oil degradation showed rate of degradation as 87% and 89%. This study confirms that isolated Fusarium sp. has the potential exploited in the bio-treatment and removal of hydrocarbons from the polluted soil. Results were recorded in the form of biodegradation percentage of hydrocarbon. The present study and their results can give unique future prospects in the field of bioremediation and biodegradation of petroleum contaminated soil.

Developing Workshop Safety Management Skills for Kyambogo University Mechanical Production Engineering Students in Uganda

Effective workshop management skills are vital for the occupational safety of the students, lecturers, instructors, support staff, or technicians who use mechanical production or manufacturing workshops at universities. The main purpose of the paper is to examine the status of the undergraduate university students’ skills practice in safety management in the engineering educational workshops assess the common occupational hazards and risks in the workshops, and explain the prospects of promoting occupational safety standards. The paper was informed by a recent study that was done in Kyambogo University, Uganda with a focus on employable skills outputs. The paper objectives were to identify the safety measures to be used in skills practice, design precautionary signs for skills practice, implement safety measures for skills practice in the department of mechanical production Engineering. In the study, a descriptive research design was used, where both qualitative and quantitative research methods were used. The total number of respondents who participated in the study was 30. The respondents included the head of the department, lecturers, students, technicians from the Mechanical Production Engineering Department of Kyambogo University. Data were collected from respondents through the use of questionnaires and interview guides. Data were analyzed and presented using tables and then descriptions were done using percentages. The findings revealed the following occupational hazards and risks, physical hazard, ergonomic hazards, chemical hazards, psychological hazards, and biological hazards. The study also revealed that accidents always occurred in the department of mechanical and production workshops. The major causes of the accidents were due to lack of knowledge or skills, safety policy gears, carelessness, safety protective wears, proper storage of materials, and instructions’ manuals or guidelines. In addition, there are problems of lack of modern tools, digital technology, good supervision, adequate space, and awareness of the ICT led safety systems. The cost-cutting strategies for workshop safety management were warning signs, alerts, and clear labels, use of protective gear, providing first aid kits, vocationalised training, and awareness campaigns on occupation safety. There is a need for routine monitoring, renovations, replacing obsolete machines, safety tags, fire drills, industry-university benchmarking, or industrial placements

Human health risk assessment of the levels of dioxin-like polychlorinated biphenyls (PCBs) in soils from mechanic workshops within Nekede mechanic village, Imo State, Nigeria

ABSTRACT Dioxin-like polychlorinated biphenyls (DL-PCBs) are a class of persistent toxic substances with a high potential to accumulate in the soil as an organic pollutant and bioaccumulate in humans. The study determined the level and human health risk of twelve (12) DL-PCBs in soils from mechanic workshops within Nekede mechanic village (NMV), Imo State. In this study, soil samples (0–15 cm depth) were collected at four different sampling points within Nekede mechanic village. At each sampling point, composite samples consisting of 10 sub-samples were collected with pre-cleaned pet bottles using soil auger and were labelled SA, SB, SC, SD. The control sample was taken 500 metres away from the mechanic village where there was no form of auto-mechanic activities. Sample analysis was conducted using Agilent GC 6890 N coupled with Agilent MS 5970B to determine the levels of DL-PCBs. The data were analysed using SPSS version 23. The results revealed that the mean concentration of 12 DL-PCB congeners (Σ12PCBs) in soil ranged from 0.31–16.31 µg kg−1, which was significantly higher than that in the control sample (0.006–0.087 µg kg−1). PCB-126 was the major contributor (58.99%) while the least contributor was PCB-157 (0.0040%) of the Σ12 DL-PCBs TEQ. The sum total LCR (adults 1.29 × 101, children 4.42 × 101) and HQs (adults 6.68 × 102, children 2.29 × 103) were above the acceptable risk limit (LCR = 10−4, HQ = 1); indicating a very high adverse effect of DL-PCBs on humans especially children.

Biodegradation of Escravos light crude oil by three indigenous bacteria, isolated from mechanic workshop in Lagos State Nigeria

Introduction: Petroleum hydrocarbons can be degraded by microorganisms such as bacteria, fungi, yeast and microalgae. However, bacteria play an imperative role in hydrocarbon degradation. Microorganisms are endowed with metabolism machinery to use petroleum products as a carbon and energy source Aims: The aim of the study is to isolate hydrocarbon degrading bacteria from hydrocarbon polluted site (mechanic workshops) in Lagos state. Materials and Methods: The physical, chemical and microbiological properties of the three soil sample were analyzed using standard procedure. Hydrocarbon degraders were isolated on 1% crude oil mineral salt medium via enrichment technique. The best hydrocarbon degrader were identified on the basis of their colonial morphology, biochemical characteristics and complemented with analytical profile index (API) kit. Hydrocarbon degradation were monitored using total viable count and residual oil was determined by Gas Chromatography equipped with Flame Ionized detector (GC-FID). Results: Alkaline pH were observed for all three soil samples, the total nitrogen detected were 0.07, 0.04 and 0.1. The total heterotrophic bacteria (THB) estimated were 3 x 1010, 6.5 x 109 and 1.7 x 1010 cfu/ml while the total hydrocarbon utilizing bacteria estimated via vapour phase were 1.89 x 106 , 4x104 and 9.62 x 107 cfu/ml for Ikeja, Iyana-Iba and Mushin sample. The organisms had a generation time of 5.56, 9.09 and 10.9 (d), the degradation half-life were 3.85, 6.3 and 7.5 (d) respectively. Over 60% hydrocarbon degradation were determined within 10 days for all three isolates. The Gc-fid prints shows reduction in peak area of various hydrocarbon fractions with a decrease in pH of the medium. Conclusion: The study showed that hydrocarbon degraders are ubiquitously distributed in the hydrocarbon polluted soil sample. Their degradation potential can be optimized so as curtail the adverse effect of petroleum in the environment

Study the effect of cement dust exposure on the hematological variables in the workers of new badoosh cement factory in mosul city, Iraq

The present study was carried in the New Badoosh Cement factory in Mosul city belonged to Ministry of Industry and Minerals/Iraq. The continuous exposure to cement dustleads to many respiratory and health problems. So the current study aimed to determine the negative effects of this dust and the continuous exposure to them in hematological variables in the blood of 150 workers of non-smoking males working, by 25 blood samples for each of the units and productive stages as following: The administrative unit (indirect exposure group), and the groups of the productive stages (direct exposure), which included stage of mechanical workshop, material milling, ovens, cement milling and packing. Their ages ranged between (23-59)years, exposure periods were divided according to the working years into (5-10), (11-20) and ( >20 ) years, then comparison with 30 healthy, non-smoking males of the same age as workers residents in the Rabea sub-district (Al-Owainat village) outside the city and were used as a control group. The results showed a significant decrease in the hemoglobin concentration (Hb), packed cell volume (PCV%)andred blood cells count (RBCs). Also the results showed a significant increase in count of white blood cells (WBCs), lymphocytes and granules in the blood of workers inadministrators (indirect exposure group) and indifferent productive stages (direct exposure group) during the three exposure periods, as these results showed that different exposure periods and special ( >20 ) years had a clear effect on these studied blood components. It is concluded from this study that exposure of workers in different productive stages and administrative unit to cement dusthas caused clear negative effects on the blood components with an increase in the exposure period and a disrupted in metabolic and physiological processes.

Development of Virtual Reality Automotive Lab for Training in Engineering Students

A Virtual Reality application was developed to be used as an immersive virtual learning strategy for Oculus Rift S Virtual Reality glasses and through Leap Motion Controller™ infrared sensors, focused on students of the Automotive Systems Engineering academic program, as a practical teaching-learning tool in the context of Education 4.0 and the pandemic caused by COVID-19 that has kept schools closed since March 2020. The technological pillars of Industry 4.0 were used to profile students so that they can meet the demands of their professional performance at the industrial level. Virtual Reality (VR) plays a very important role for the production-engineering sector in areas such as design and autonomous cars, as well as in training and driving courses. The VR application provides the student with a more immersive and interactive experience, supported by 3D models of both the main parts that make up the four-stroke combustion engine and the mechanical workshop scenario; it allows the student to manipulate the main parts of the four-stroke combustion engine through the Oculus Rift S controls and the Leap Motion Controller™ infrared sensors, and relate them to the operation of the engine, through the animation of its operation and the additional information shown for each part that makes it up in the application.

Assessment of Heavy Metal Bioaccumulation Capacity of Calopogonium muconoides and Senna obtusifolia as Potential Bioremediation Agents

A wide range of inorganic and organic compounds such as combustibles, and putrescible substances, hazardous waste, explosives, petroleum products and heavy metals (HM) can cause contamination. In addition, the non-biodegradability of heavy metals further exacerbates environmental pollution with its attendant health consequences on the biotic components of the ecosystem including humans. The use of living organisms such as plants and microbes is increasingly becoming acceptable practice of sustainable environmental sanitation. However, identification of potential bioremediation agents is still challenging. This study was carried out to bridge this gap by assessing heavy metal bioaccumulation properties of Calopogoniun Muconoides and Senna obtusifolia plants at contaminated site of mechanic workshop (site 1) in comparative to a physically non-contaminated site (site 2) within Makurdi metropolis of Benue State Nigeria. The selected plants were obtained from both sites and evaluated for their bioaccumulation capacities using standard procedures. The results revealed the sample plants accumulated high levels of heavy metals particularly in the leaves and roots, suggesting the utilization of phytoextraction, phytostabilization and phytovolatilization mechanisms of remediation. The plants and HM generally presented an order of concentration and bioaccumulation as: Senna obtusifolia > Calopogonium Muconoides; Zn > Fe > Pb > Cu > Cd > Cr > Ni. These findings suggest that these novel plants, especially Senna obtusifolia are good agents of bioremediation of heavy metals. Studies involving isotopic labeling to determine the exact mechanism of remediation as well molecular techniques such as transcriptomics and proteomics to identify genes/molecules that confer phytoremediation potential on the plants would be the next focus of our research in this emerging field of environmental biochemistry.

EFFECT OF THE APPLICATION OF GOAT DUNG ON THE BIOREMEDIATION OF POLLUTED SOIL BY HYDROCARBON DEGRADING BACTERIA: A MICROCOSM STUDY

Biostimulation is an effective means of enhancing bioremediation of toxic compounds. In this study, goat dung was used as an additional source of nutrients to improve the degradation of petroleum hydrocarbons in a heavily contaminated soil. Soil samples collected from a mechanic workshop in Zaria, Nigeria, was subjected to microcosm studies in a screen house and three proportions (2%w/w, 3%w/w, 4%w/w kg-1.soil) of goat dung added to the soil samples. The effect of the addition of nutrients from the goat dung on the hydrocarbon degrading bacterial community in the soil was determined by measuring the hydrocarbon utilizing bacterial counts, percentage degradation of hydrocarbon and biostimulation efficiency. At the end of the seven-week experiment, it was observed that 4% w/w of goat dung had the highest hydrocarbon utilizing bacterial count but, the maximum percentage hydrocarbon degradation occurred in the treatment with 2% w/w goat dung and biostimulation efficiency was optimum with both 2% w/w and 4% w/w goat dung. Nutrient addition can be an effective tool during bioremediation, however, laboratory scale studies should be conducted prior to field studies in order to achieve maximum results

HÖVSAN AERASİYA STANSİYASINDA TEXNOLOJİ PROSES ZAMANI ƏMƏLƏ GƏLƏN İZAFİ LİLİN TƏDQİQİ

Abstract. hovsan Aeration Station provides treatment and processing of wastewater in baku. The amount of annual sludge here reaches 2 million cubic meters. These sludges contain complex multicomponent substances of organic and mineral origin. Taking this into consideration, we analyzed surplus sludge that generated during the technological process at hovsan Aeration Station. The studied surplus sample is a substance that is thickened in the mechanical workshop of the station, and then the substances are dehydrated in a centrifuge. They consist of a complex polydisperse system. The study of surplus sludge formed during the technological process at hovsan aeration station revealed that the main component of sludge consists of organic substances. The mineralogical composition is dominated by silicon dioxide and magnesium calcite. Keywords: wastewater, surplus sludge, mineral service, organic matter

Which access to which assets for an effective liberalization of the railway sector?

In the European rail industry, to enable competition in the market, entrants should be granted access to a large set of complementary services, beyond access to the tracks. For an efficient and effective entry, temporary access to quasi-essential complementary assets like rolling stock, mechanical maintenance workshops, data, schedules, etc. is required. In the liberalized rail sector, several observed anticompetitive practices involve distorted access to these quasiessential facilities. Therefore, competition agencies must deal with litigation between the incumbent and new entrants. Most cases have been settled, resulting in commitments from the incumbent. We argue that such transitory and case-by-case remedies fail to produce favorable conditions for a secure and efficient entry. Thus, we propose to systematize such remedies through asymmetric and enduring ex-ante regulation.

Large-Size Honeycomb-Shaped and Iris-Like Liquid Crystal Elastomer Actuators

Large-Size Honeycomb-Shaped and Iris-Like Liquid Crystal Elastomer Actuators

Fabrication and Development of Portable 3-Axis Computer Numerical Control Machine

Machining is a prerequisite fundamental process of manufacturing without which no production can be deemed possible. Conventional machining methods were tedious, costly, time and space consuming, as well as inefficient. With development of computer and numerical control, modern day machining devices have been developed which have made the process a smooth ride. The machining processes are now controllable with the finest accuracies and save time and cost. CNC machines have been the most useful developments that have contributed to the modern day machining task. Computed Numerical Control has thus been our inspiration. This lead us to conceiving and fabricating a 3- axis CNC machine that is designed as a router but could perform several operations such as drilling, cutting, printing, milling etc. on attachment of different tools. The machine has a main driving mechanical subsystem that drives the tool through lead screws attached to motors that are driven by a microcontroller that is under our control through a computer. Any design can be drawn and fed to the Arduino microcontroller from across the world through a Java applet and the machining proceeds by calculating the coordinates of the three axes and the relative movement between the points whose combination is actually the design. The process is thus very accurate and versatile. The fabrication has been achieved by using simple and cheap materials and done in the mechanical workshop located inside the campus.

Screening and Characterization of Biosurfactant-Producing Bacillus Species Isolated from Contaminated Soils in Makurdi Metropolis

Biosurfactants synthesized by microorganisms are chemically diverse and have gained interest industrially due to their surface and interfacial tensions-reducing activities. In this study Bacillus species from contaminated soils were screened and characterized for biosurfactant production. The study was carried out at the Microbiology Laboratory, Federal University of Agriculture Makurdi, Nigeria. The Bacillus species were isolated from kerosene shops, palm oil shops, nearby restaurants, mechanic workshops and abattoir effluents- contaminated soil samples collected from Makurdi metropolis. The Bacillus spp. were screened for biosurfactants production potentials using various screening methods (oil spreading, beta haemolysis, drop collapse and emulsification index). Specific primers were used to amplify the srfAA (surfactin gene) gene in the Bacillus isolates and the nucleotide sequences were determined at Inqaba Biotec, South Africa. The screening results were statistically analysed using analysis of variance (ANOVA) at 95 % confidence level. Isolate RT7(4)B exhibited the ability to produce biosurfactant, as well as the highest emulsification index (E24) of 73.25 % while isolate PO7(3)C gave the highest oil displacement of 6.77 mm. The supernatant obtained from isolate RT7(4)B showed reduction in surface tension of up to 30.26 mN/m. The isolates gave positive results for biosurfactant production when subjected to drop collapse and Beta haemolytic tests. The Polymerase chain reaction (PCR) results revealed amplifications of srfAA gene from 7 isolates. Based on these findings, the isolates used in this study can be utilized for biosurfactant production, and can also be useful for bioremediation and industrial biotechnology applications.
 Keywords: Biosurfactants; emulsification index; Bacillus; surface tension; Drop collapse

Isolation and Identification of Hydrocarbons- Degrading Bacteria from Panteka Stream, Kaduna, Nigeria, and Assessment of their Potential for Bioremediation

Water bodies become hydrocarbon-polluted when petroleum and other toxic organic matters are discharged into them. Panteka, located in northern Kaduna, Nigeria, is home to Panteka market, which is an industrial hub where different kinds of automobile spare parts are sold and mechanic workshops are situated. The Panteka stream flows through an entry point at Rafin guza, through Panteka market and towards the National Eye Centre. The indiscriminate disposal of spent engine oils and the discharge of other untreated effluents from car servicing workshops into the Panteka stream can lead to hydrocarbon contamination. Consequently, there is a need to identify these hydrocarbons and determine the capability of bacteria isolated from the stream to degrade the hydrocarbon pollutants. Using the pour plate method, and Bushnell Haas agar supplemented with 1% used engine oil, five bacterial isolates with the potential to degrade hydrocarbons were identified as Streptococcus pnuemoniae, Klebsiella pneumoniae, Shigella dysenteriae, Streptococcus pyogenes and Salmonella enterica. Salmonella enterica was confirmed by 16S rRNA gene sequencing and Basic Local Alignment search tool (BLAST) with a similarity index of 99%. The ability of the bacterial isolates to tolerate the spent engine oil was determined by turbidi metry. The results show that all the five bacterial isolates were able to tolerate the 1% (v/v) concentration of the spent engine oil. The highest growth rates (O.D 0.565 and O.D 0.695) were obtained from the pure cultures of Streptococcus pyogenes and the mixed bacterial consortium, respectively. The potentials of the bacteria to degrade hydrocarbons in the stream was analysed using Gas Chromatography Flame Ionization Detector (GC-FID), and the results showed reduction of the Total Petroleum Hydrocarbon (TPH) content from 6,056 mg/ml to 100.17 mg/ml (98.3% degradation) after 28 days of treatment with the mixed bacterial culture. The hydrocarbon fractions degraded were n-Nonane, n-Decane, n-Undecane, n- Dodecane, n-Tridecane, n-Tetradecane, n-Heptadecane, Pristane, n-octadecane, Phytane, n-Eicosane, n-Tricosane, n-Tetracosane, n-Octacosane, n-Triacontane, n-Dotriacontane, n-Tritriacontane, n-Heptriacontane; while n-Pentadecane, n-Hexadecane, n-Nonadecane, n-Heneicosane, n-Docosane, n-Pentacosane, n-Hexacosane, n-Heptacosane, n-Nonacosane, n-Hentriacontane, n-Tetratriacontane, n-Pentatriacontane, and n-Hexatriacontane were not degraded. This study shows that these bacterial strains isolated from the Panteka stream have great potential for bioremediation of the hydrocarbons found in the stream.
 Keywords: Bioremediation, Panteka stream, Automobile workshop, Hydrocarbon pollution, Bacteria isolates

The competency of vocational graduates in the fields of mechanics and workshop management according to the needs of the automotive motorcycle industry

This study aims to determine the mechanics competence and workshop management needs of the competencies in the vocational education engineering curriculum and the motorcycle business according to the automotive motorcycle industry. Research subjects were eight motorcycle automotive companies in the field of production and services. The data of the study were collected by using a questionnaire survey and analyzed by quantitative descriptive statistics with percentages. The results of the study showed that the needed competencies according to the Automotive Motorcycle Industry were mechanics competence and workshop management competence. The vocational education curriculum produced 39 mechanics competencies and 18 workshop management competencies. There were 37 basic competencies in mechanics competence in the very needed category and 2 basic competencies in the sufficiently needed category. Workshop management competencies found 18 basic competencies that were all needed by the industry. Competency from the mechanics field and workshop management had competencies in the very needed category relatively. In total there were 15 competencies that not exist yet in the curriculum which taught in vocational education.

WARM: Wearable AR and Tablet-Based Assistant Systems for Bus Maintenance

This paper shows two developed digital systems as an example of intelligent garage and maintenance that targets the applicability of augmented reality and wearable devices technologies to the maintenance of bus fleets. Both solutions are designed to improve the maintenance process based on verification of tasks checklist. The main contribution of the paper focuses on the implementation of the prototypes in the company’s facilities in an operational environment with real users and address the difficulties inherent in the transfer of a technology to a real work environment, such as a mechanical workshop. The experiments have been conducted in real operation thanks to the involvement of the public transport operator DBUS, which operates public transport buses in the city of Donostia—San Sebastian (Spain). Two solutions have been developed and compared against the traditional process: one based on Tablet and another one based on Microsoft HoloLens. The results show objective metrics (Key Performance Indicators, KPI) as well as subjective metrics based on questionnaires comparing the two technological approaches against the traditional one based on manual work and paper.

Effect of Noise and Room Temperature on Employee Productivity in Mechanical Maintenance Workshop PT. Semen Bosowa Maros

The work environment is a place where employees do work activities. The work environment can bring positive and negative impacts on employees in order to achieve their work. The work environment in a company is very important to be considered by management. If the work environment can be managed properly, employees can work safely and comfortably so that the company’s objectives can be achieved and productivity can be improved. This study aimed to determine the effect of noise and room temperature on worker productivity at the Mechanical Maintenance Workshop PT. Semen Bosowa Maros. The method used in this study uses questionnaires and interviews directly to determine the effect of noise and room temperature on worker productivity at the Mechanical Maintenance Workshop PT. Semen Bosowa Maros. The questionnaire data was then processed using the SPSS program and multiple linear regression analysis. From the results of processing questionnaire data regarding noise and room temperature to productivity, it is known that noise and room temperature are important factors that affect productivity with a percentage of 57.7%. Noise and room temperature simultaneously (together) have a significant effect on productivity with sig values. 0,000 <0,05