Medium-sized Metal Research Articles

Evaluation of green mine construction level in Tibet based on entropy method and TOPSIS

Green mine construction is a systematic project involving the whole life cycle of mineral resources exploitation and utilization, representing the overall level of development potential. As an important strategic mineral resources reserve base in China, Tibet is rich in mineral resources. In order to calculate the level of green mine construction in Tibet, we obtained different data sources such as statistical yearbooks and mine construction information through field research and discussion. We establish the EMUCIMH evaluation system, select a total of 20 indexes from seven aspects(ecological mining environment, scientific mining method, efficient resource utilization, standardization of energy conservation and emission reduction, intelligent mine construction, standardization of enterprise management and harmonization of mining community),using the Entropy Weight TOPSIS Method to study the problems existing in the process of green mine construction, expecting to provide some references for government departments to make management decisions and for mining enterprises to improve green mine construction. The results show that among the 11 national green mines in Tibet, the construction status is uneven, and there are large differences in the mining methods, the comprehensive utilization of resources, and the ecological environment of mining areas. In contrast, The difference of standardization of enterprise management, intelligent mine construction and the harmonization of mining community is small. Among the specific indicators, in terms of exhaust emissions, mining community harmony and corporate culture are doing well, while they are relatively poor in terms of environmental management and monitoring, technological innovation, and intelligent mine, which need to be improved. Large and medium-sized mines, especially metal mines, the overall level of green mine construction is high, followed by small and medium-sized metal mines and individual Non-metal large mines, and mines with more historical problems faced more difficulties and challenges.

Thermochemical production of green hydrogen using ferrous scrap materials

Thermochemical water splitting is one of the methods to produce green hydrogen. In this study, metal scrap is used to split water by thermochemical process in a packed-bed reactor. Hydrogen production conditions are optimized by varying the particle size of the metal wastes in the range of 250 μm to greater than 1000 μm and the temperatures from 900 °C to 1200 °C. The maximum yield of hydrogen obtained is ∼500 mL of H2 per gram of the scrap sample. This study demonstrates that the discarded metal wastes can be utilized as feed-materials for thermochemical production of green hydrogen. The process has good conversion efficiency and is a promising solution for both metal waste management and the production of green hydrogen. Medium size metal particles show higher hydrogen production capacity compared to both smaller (<250 μm) and larger (600–1180 μm) size particles.

STRUCTURE AND VIBRATIONS OF FREE NIN CLUSTERS (N &lt; 20)

The binding energy, equilibrium geometry, and vibration frequencies of small free Nin clusters (n &lt; 20) were calculated using interatomic interaction potentials calculated in an embedded atom method. Calculations of the energy parameter of stability АЕ2 and dissociation energy showed that the most energetically stable clusters are those with the magic numbers of atoms n = 4, 6, 13, 19. Calculations of atomic vibrations revealed that the dynamic contribution to the stability of clusters is determined by the minimum vibration frequency, whose extreme values fall on clusters with the magic numbers of atoms n = 4, 6, 13, 19. The maximum vibration frequency varies nonmonotonically and for clusters with n &lt; 19 it has no clear extreme values. This result is consistent with available experimental data on stable structures of small and medium-sized metal clusters.

Benchmark Model of Medium-Sized Metal Fuel Fast Reactor MET-1000_T for Simulating Movement of Control Rods: Calculations Performed by the ShIPR

Benchmark Model of Medium-Sized Metal Fuel Fast Reactor MET-1000_T for Simulating Movement of Control Rods: Calculations Performed by the ShIPR

Barriers of Implementing Integrated Management System in Small and Medium-sized Metal Enterprises: A Conceptual Model

سیستم‌ مدیریت یکپارچه شامل یک استراتژی برای مدیریت چندین سیستم و افزایش بهره‌وری به منظور برآورده‌سازی نیازهای ذی‌نفعان است که از استانداردهای مختلفی برای توسعه این سیستم‌ها استفاده می‌شود. این سیستم‌ها به منابعی مانند نیروی انسانی، زمان و هزینه نیاز دارند که فشار زیادی را بر سازمان‌ها وارد می-کنند و منجر به ایجاد موانعی در هنگام اجرای آن و کاهش بهره‌وری می‌شوند. در این راستا مقاله حاضر با هدف طراحی الگوی مفهومی موانع استقرار سیستم مدیریت یکپارچه و با استفاده از روش ترکیبی (تحلیل محتوا و مدلسازی ساختاری-تفسیری) انجام شد. جامعه آماری این تحقیق شرکت‌های کوچک و متوسط در حوزه صنایع فلزی استان قزوین است. نمونه‌گیری به صورت هدفمند و تا رسیدن به اشباع نظری انجام و بر همین اساس با دوازده نفر از مختصصان و فعالان این حوزه مصاحبه شد. ضمن استخراج مؤلفه‌های مربوط به موانع استقرار سیستم مدیریت یکپارچه، الگوی مفهومی تحقیق تدوین گردید و با توجه به مرور پیشینه تحقیق و مصاحبه با خبرگان و روش تحلیل محتوا، 90 کد باز، 28 مفهوم و هفت مقوله با عنوان‌های ذی‌نفعان خارجی، کارکنان، منابع و مدیریت، عامل مقرراتی و قانونی، عامل فرهنگی-سازمانی، استقرار و مؤلفه مالی-اقتصادی استخراج و بر اساس روش مدلسازی ساختاری-تفسیری، الگوسازی شد. همچنین میزان وابستگی و قدرت هدایت هر یک از مؤلفه‌ها ارائه شده است.

Association between shift rotation and 30-year Framingham risk of cardiovascular disease among male workers in a medium-sized manufacturing factory.

Rotating shift work is associated with an increased risk of cardiovascular disease (CVD). This study compared the CVD risk score in 129 male line workers aged 22-49 years on different shifts in a medium-sized metal production factory from 2017 to 2020. We classified workers into four groups: permanent day shift, weekly rotation involving five consecutive nights, weekly rotation involving 3-4 consecutive nights, and monthly rotation involving two consecutive nights. We used the Framingham Risk Score to estimate the 30-yr risks of general and hard CVD (CVD risk estimates). We investigated the differences in CVD risk estimates between different groups using linear mixed models. The average 30-yr Framingham CVD risk estimates of each group ranged from 17.5% to 31.2% for general CVD and from 10.5% to 20.5% for hard CVD. Workers on weekly rotations involving 3-5 consecutive nights had 5%-10% significantly higher CVD risk estimates than workers on the permanent day shift. Workers on weekly rotations also had 6%-8% higher BMI-based CVD risk estimates than those on the monthly rotation involving two consecutive nights. While 24-h shift rotations are unavoidable, our findings underscored the potential CVD risk among workers on weekly rotations involving more consecutive nights.

Recertification of a Quality Management System based on ISO 9001 - is it a must for a modern manufacturing company?

Abstract The ISO 9000 series of standards are among the best-known standards developed by the International Organisation for Standardisation ISO. They provide guidance and guidelines for companies and organisations that want their products and services to satisfy customer requirements and their quality to be continuously improved. However, the need for recertification of the Quality Management System (QMS) based on ISO 9001 is increasingly being discussed by managers. The questions asked are: is it necessary to have such a certificate in order to maintain high product quality and customer satisfaction? What is the balance of benefits and losses for maintaining a certificate of this standard? The authors of the paper will try to answer these questions based on the experience of a medium-sized metal manufacturing company.

중소 금속가공 기업의 경쟁력 향상을 위한 스마트공장 도입 요인 연구

In order to improve manufacturing competitiveness in Korea, the government aims to improve the productivity of manufacturing enterprises through 20,000 smart factories by 2022. However, many SMEs are not actively investing in new facilities in smart factories due to the deteriorating manufacturing industry. The purpose of this study is to analyze smart factory construction factors and the effect of introduction of smart factory on the competitiveness medium-sized metal processing companies. For this purpose, we conducted an empirical analysis of 140 employees of SMEs in Daejeon TechnoValley, Sangseo-dong, Pyeongchon-dong small and medium manufacturing enterprises. As a result, corporate participation, participation of government support projects, and manufacturing capability have a positive impact on the smart factory construction effect. The results of this study can be a policy reference factor for the successful introduction of smart factory in SMEs and it is meaningful that construction of smart factory plays an important role in enhancing corporate competitiveness.

Isolation and Crystallographic Characterization of Lu3 N@C2n (2n=80-88): Cage Selection by Cluster Size.

The small Sc3 N cluster has only been found in such small cages as C2n (2n=68, 78, 80, 82), whereas the large M3 N (M=Y, Gd, Tb, Tm) clusters choose those larger cages C2n (2n=82-88). Herein, concrete experimental evidence is presented to establish the size effect of the internal metallic cluster on selecting the outer cage of endohedral metallofullerenes (EMFs) by using a medium-sized metal, lutetium, which possesses an ionic radius between Sc and Gd. A series of lutetium-containing EMFs have been obtained and their structures are unambiguously determined as Lu3 N@Ih (7)-C80 , Lu3 N@D5h (6)-C80 , Lu3 N@C2v (9)-C82 , Lu3 N@Cs (51365)-C84 , Lu3 N@D3 (17)-C86 , and Lu3 N@D2 (35)-C88 by single-crystal X-ray diffraction crystallography. It was confirmed that the encaged Lu3 N cluster always adopts a planar geometry in Lu3 N@C80-88 isomers to ensure substantial metal-cage/metal-nitrogen interactions. As a result, the Lu3 N cluster selects the C2v (9)-C82 cage, which also encapsulates Sc3 N, instead of the Cs (39663)-C82 cage which is more suitable for M3 N (M=Y, Gd, Tb, Tm). However, different from Sc3 N, Lu3 N can also template the C84-88 cages which are absent for Sc3 N-containing EMFs, confirming clearly the size effect of the internal cluster on selecting the outer cage.

The Effects of Employee-Led Process Design on Welder Set-Up Intervals

This study focused on improving manufacturing efficiency and production by designing new steps to the work process with an employee focus group. The set-up behaviors of two regular stock welders at a medium-size metal furniture manufacturer were observed via video recordings. The videos of the welders completing their tasks were reviewed in an employee focus group, during which it was determined that designing the welding process to include the use of walkie-talkies would successfully alter the contingencies surrounding set-up behaviors, thereby leading to a decrease in average set-up time. Results for the two welders combined showed a decrease in average set-up time of 2.27 min, with Welder A exhibiting a larger decrease overall and Welder B’s set-up time showing a greater reduction in variability.

Synthesis and structural characterization of amido scorpionate rare earth metals complexes

The reactivity of hybrid scorpionate/cyclopentadienyl ligands in the form of the protio derivatives as a mixture of two regioisomers, namely bpzcpH [1-{2,2-bis(3,5-dimethylpyrazol-1-yl)-1,1-diphenylethyl}-1,3-cyclopentadiene and 2-{2,2-bis(3,5-dimethylpyrazol-1-yl)-1,1-diphenylethyl}-1,3-cyclopentadiene] and bpztcpH [1-{2,2-bis(3,5-dimethylpyrazol-1-yl)-1-tert-butylethyl}-1,3-cyclopentadiene and 2-{2,2-bis(3,5-dimethylpyrazol-1-yl)-1-tert-butylethyl}-1,3-cyclopentadiene], with the tris(silylamide) precursors [M{N(SiHMe2)2}3(thf)x] of rare earth metals (including the group 3 metals scandium and yttrium) is related to the atomic radii of the metal centres. The reaction with the precursor containing the smallest ion, [Sc{N(SiHMe2)2}3(thf)], did not proceed even heating at reflux temperature in toluene. The reaction with the precursors that contain a medium-sized metal ion, i.e., [M{N(SiHMe2)2}3(thf)2] (M = Y, Lu), proceeded only at high temperature and gave good yields of the silylenediamide-containing derivatives [M{κ(2)-NN-Me2Si(NSiHMe2)2}(bpzcp)] (M = Y , Lu ) and [M{κ(2)-NN-Me2Si(NSiHMe2)2}(bpztcp)] (M = Y , Lu ) by an double activation of Si-H and Si-N bonds. However, the reaction with the precursors that contained the largest metal ions, i.e., [M{N(SiHMe2)2}3(thf)2] (M = Nd, Sm), proceeded rapidly at room temperature to afford the bis(silylamide) complexes [M{N(SiHMe2)2}2(bpzcp)] (M = Nd , Sm ) and [M{N(SiHMe2)2}2(bpztcp)] (M = Nd , Sm ). Additionally, the alkyl heteroscorpionate yttrium and lutetium complexes [M(CH2SiMe3)2(NNCp)] (M = Y, Lu) reacted with an excess of HN(SiHMe2)2 to give the mixed alkyl/amide derivatives [M{N(SiHMe2)2}(CH2SiMe3)(bpzcp)] (M = Y , Lu ) and [M{N(SiHMe2)2}(CH2SiMe3)(bpztcp)] (M = Y , Lu ). The structures of the complexes were determined by spectroscopic methods and the X-ray crystal structures of , and were also established.

Validating a Safety Climate Model in Metal Processing Industries: A Replication Study

This paper attempts to replicate a safety climate model originally tested in Australia to assess its applicability in a different context: namely, across production workers in 22 medium-sized metal processing organizations in Austria. The model postulates that safety knowledge and safety motivation mediate the relation between safety climate on the one hand and safety compliance and participation on the other. Self-report data from 1075 employees were analyzed using structural equation modeling (SEM). The results of the replication study largely confirmed the original safety climate model. However, in addition to indirect effects, direct links between safety climate and actual safety behavior were found.

Valence photoionization of free, neutral, and size-varied alkali metal clusters

The valence photoelectron spectra of free, neutral, and size-varied K and Rb alkali metal clusters are studied. The experimental spectra are simulated with jellium model-based calculations with and without inclusion of dipole matrix elements and continuum wavefunctions. The simple jellium model used is found to provide good qualitative correspondence with the experimental results. It is shown that the dipole matrix elements provide a remarkable improvement to the standard density of states approach in understanding the photoelectron spectra of small to medium size metal clusters.

From 'silicon steel' to 'iron lady': how a metal company's novel, responsible identity affects its business environment

A gentle, middle-aged teacher woman inherits a medium-sized metal industry company from her autocratic engineer father who established the company over 35 years ago. Is that a road to disaster, business as usual or a new beginning? This paper investigates the effects on the business environment of the path chosen by this female entrepreneur. The case study is based on action research, conducted during 2006–2009, aiming to solve the threatening organisational identity crisis of the company. The responsible identity adopted by the organisation through a bottom-up reflection process aroused mixed feelings among stakeholders. While the exhausted employees welcomed the change, the sceptical corporate clients, financiers, local politicians and competitors found it strange. By remaining true to its adopted identity the company gradually turned the initial doubts, mistrust and ridicule into gentle humour, trust and appreciation. The economic crisis that started in 2008 actually increased trust in this company whose new, responsible mission, adopted during the boom, had enabled it to prepare itself for the recession. Local competitors, who were on the brink of bankruptcy, posed a serious ethical problem to the case company, and this initiated a second round of identity reflection.

Drivers of solid waste minimisation in Finnish metal engineering SMEs: the role of Environmental Management Systems

The paper reports on a survey in Finnish small- and medium-sized metal engineering enterprises (SMEs) with certified Environmental Management System (EMS). Waste awareness has increased after certifying EMS and the treatment of solid waste has improved; source separation of solid waste facilitated the recovery of recyclables and their diversion from landfill. EMS has raised knowledge levels, in particular on recycling of solid waste, and the attitudes toward environmental improvements have improved. However, it is concluded that, while certified EMS brought positive changes in waste treatment, it did not promote waste minimisation and prevention.

Metal Combs Used for Hair Separation in Scalp Surgery

Many head and neck surgery procedures are performed in the scalp area. However, during these procedures, hair usually interferes with the visualization of the surgical area, reducing the surgeons’ comfort. Other technical difficulties originating from hair include suturing and hemostasis problems, infection, and bad scar formation. Removal of the hair in the incisional area seems to be a promising method, yet it remains an inefficient solution, especially for patients with long hair. Removal of hair from a wide area around the planned incision also is not desired because it usually takes a long time for that scalp area to be covered with hair again, and most of these patients remain worried or annoyed until that time. To provide better exposure of the incisional area, certain methods are described in the literature, including petrolatum or ointment usage to keep hair flat [1], grouping of hair with rubber materials [2], and use of hair clips [3]. However, none of these applications has reached sufficiently wide acceptance to be implemented as a standard method. A new and simple technique for hair separation to increase surgical comfort has been designed. With this method, two or three pieces of medium-sized metal hair combs are used (Fig. 1). The combs are reusable after sterilization in an autoclave. The number and the size of the hair combs can be arranged according to the dimension of the surgical field and the needs of the surgeon. Thus, the hair surrounding the incisional area can be grouped in two to four opposite directions and held in place with the help of the hair combs (Fig. 2). The teeth of the combs secure the hair in place, and the combs can be left in position by themselves, diminishing the need for assistance. Nevertheless, an assistant also can hold the combs and apply gentle pressure on them for even better exposure. Hair constitutes a major obstacle in scalp surgery. It blocks visualization of the surgical field; makes it difficult to locate the suture thread, complicating the suturing process; and gets into the suture line, increasing infection risk, all of which contribute to an increase in the overall duration of the intervention. The hair gel or ointment used to keep hair flat must be carefully removed at the end of the procedure. Otherwise, it gives discomfort to the patient and blocks hair follicles, which can cause infection or hair loss. Application and removal of hair gel are time-consuming procedures, and the assistance they can offer during surgery is limited. Rubber bands and hair clips also are cheap and useful tools for hair partition, but their use is time consuming as well, and although grouped together, hair can still get between the surgical instruments and the surgical field. The aforementioned tools also are subject to frequent loosening during the procedure. Yet another drawback is the small but annoying pain they can provoke when they are removed from the hair postoperatively. The metal hair combs described in this report are designed to overcome these problems. They offer a practical approach that can effectively simplify and accelerate the procedure, enable the surgeon to work alone without any need for assistance, and improve the postoperative comfort of the patient. B. Ersoy (&) H. Şirinoglu Department of Plastic, Reconstructive and Aesthetic Surgery, Marmara University School of Medicine, Tophanelioglu Cad. No:13-15, Altunizade, 81190 Istanbul, Turkey e-mail: bubu77@gmail.com

Fractional phase transition in medium size metal clusters

Based on the Riemann and Caputo definition of the fractional derivative we use the fractional extensions of the standard rotation group S O ( 3 ) to construct a higher dimensional representation of a fractional rotation group with mixed derivative types. An analytic extended symmetric rotor model is derived, which correctly predicts the sequence of magic numbers in metal clusters. It is demonstrated, that experimental data may be described by assuming a sudden change in the fractional derivative parameter α which is interpreted as a second order phase transition in the region of cluster size with 200 ≤ N ≤ 300 .

The effects of job characteristics and working conditions on job performance

In performance evaluation literature, although the combination of some variables such as age, gender, experience, observation time, and interpersonal affect has been widely considered in determining employee performance, no investigation has indicated the influence of workplace conditions on job performance. This study reports the effects of job characteristics (physical efforts and job grade), and working conditions (environmental conditions and hazards) in addition to experience and education level on task performance and contextual performance. A total of 154 employees in 18 teams at a medium-sized metal company participated in this study. Seven criteria for task performance and 16 for contextual performance were used for measuring employee performance. The results showed that there were substantial relationships between employee performance both job grade and environmental conditions. Poor workplace conditions (physical efforts, environmental conditions, and hazards) result in decreasing employee performance consisted of following organization rules, quality, cooperating with coworkers to solve task problems, concentrating the tasks, creativity, and absenteeism. Relevance to industry Unpleasant working conditions in workshops have different effects on each of the job performance indicators. This study highlighted that training program designed to enhance job performance of the employees working under poor workplace conditions should focus on organizational rules in terms of occupational health and safety.

Charge transfer, excitation and evaporation in low energy collisions of simple metal clusters and fullerenes with atomic targets

We present charge transfer, excitation and evaporation cross sections in low energy collisions of small and medium-size metal clusters (Nanq+, Linq+) and C60 with atomic targets (H+, He2+ and Cs) using a molecular close-coupling formalism and a post-collision rate equation model. The theoretical model benefits from different time scales associated with the collision and the internal motion of the cluster nuclei. The collision description includes the many-electron aspect of the problem and makes use of a realistic cluster potential obtained with density functional theory and a spherical jellium model. The evaporation model takes into account the non-harmonic effects of the ionic motion and describes sequential evaporation to any order within the framework of the microcanonical statistical model of Weisskopf. We show that the relative abundance of different fragments depends critically on the cluster temperature and the spectrometer time of flight window. We have found good agreement with recent experimental results [Eur. Phys. J. D 12 (2000) 185].

New methods of ultrasonic welding of metal and plastic materials

New ultrasonic welding methods of metal and plastic materials have been proposed by the author and have shown their effectiveness. For welding of thick and large metal specimens, (1) an ultrasonic butt welding method of joining thick metal specimens end to end is proposed. Large capacity vibration sources and solid-state power amplifiers of 50, 100 kW have been developed. (2) The welding method of using two vibration systems crossed at a right angle is effective, and 10 mm thick aluminum plates have been joined successfully. For medium size metal welding specimens, (3) complex vibration welding tips have been shown to be very effective, and one-dimensional complex vibration systems are developed to simplify the systems. For welding of small metal specimens, (4) higher vibration frequency, and complex vibration wire bonding systems are proposed and it is shown that they are significantly effective. Bonding systems of 60 to 600 kHz have been designed. For welding of plastic materials, (5) high frequency and two-vibration-system welding methods are effective.