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The purpose of this paper is to design a modified version of the double sampling plan to handle the inspection processes requiring a minimum sample size to assure the median life for the products under the new Weibull–Pareto distribution. The economic design of the proposed plan is also considered to assure the product's lifetime with minimum cost.

The authors have developed an optimization model for obtaining the required plan parameters by solving simultaneously two non-linear inequalities and such inequalities have been formed based on the two points on the operating characteristic curve approach.

The results show that the average sample number, average total inspection and total inspection cost under the proposed plan are smaller than the same of a single sampling plan. This means that the proposed plan will be more efficient than a single sampling plan in reducing inspection effort and cost while providing the desired protection.

The proposed modified double sampling plan designed to assure the median life of the products under the new Weibull–Pareto distribution is not available in the literature. The proposed plan will be very useful in assuring the product median lifetime with minimum sample size as well as minimum cost in all the manufacturing industries.

This case allows students to critically analyse the business model of Zomato which is a multi-sided platform/in the foodtech industry. It helps students to critically analyse how firms enter into the global market to create value and maintain dominance over the local market (especially in a large market such as India). The case can also be used to introduce students to the business canvas model by analysing foodtech start-ups. The outcomes are as follows: to understand the Business Model Canvas as a tool to describe and analyse the foodtech business such as Zomato’s, based on its value proposition and the way it sells its services; to conduct a value chain analysis and analyse the business models adopted by foodtech companies; to understand how Zomato can aim at global value creation; and to design a clear growth strategy and evaluate Zomato’s options to internationalize or expand locally.

The year 2018 was an important year for Zomato as it geared up to chart new heights amidst the changing dynamics of the industry on one hand and a co-founder exiting the company on the other hand. Zomato was incepted in 2008 as a restaurant discovery platform offering users the ability to access restaurant menus and post online reviews. It provided a range of value-added services for both its restaurant partners and end customers. Its vertical integration enabled it to grow its revenues across its three lines of business, namely, dining out, delivery and sustainability. Zomato was an early internet start-up that expanded rapidly in the international markets. In the past ten years, the company both scaled and rolled back its operations with unique lessons learned in each market that paved its path for success both locally and globally. The domestic market was being dominated by a few large players sharing the market. Reports by market intelligence firms showed that Swiggy, the closest competitor was starting to dominate Zomato in India [1]. Deepinder, CEO, Zomato’s dilemma for adding value and increasing revenues by weighing options of whether the company should strengthen its presence in the domestic market, or, venture into foreign markets or serve both local and foreign markets.

This case is appropriate for postgraduate courses in Strategic Management or International Business.

Teaching notes are available for educators only.

CSS 5: International Business.

The objective of this paper is to study the effect of a commercial lubricant, which contains a 50‐50 mixture of zinc diamyldithiocarbamate and petroleum oil, on the fretting corrosion of tin‐plated copper alloy contacts.

The change in contact resistance as a function of fretting cycles was used to assess the effectiveness of the lubricant in preventing the fretting corrosion of tin‐plated contacts. The surface profile, surface roughness, extent of fretting damage and extent of oxidation of the contact zone were assessed by a laser scanning microscope and surface analytical techniques to correlate the change in contact resistance with fretting cycles.

The lubricant film provides a surface coverage of 6.76±1 mg/cm² and it easily establishes metallic asperity contact between the mated tin‐plated contacts. The contact resistance of lubricated contacts remains stable for several thousand fretting cycles. Lubricated contacts reach a threshold value of 0.1 Ω around 100,000 cycles, whereas unlubricated contact reaches this value around 13,500 cycles itself. For lubricated contacts, the extent of mechanical wear of the tin coating is significantly reduced. As a result, they experience a lesser damage at the contact zone and exhibit a smoother profile. The formation of tin oxide is not appreciable and there is no oxide accumulation at the contact zone even at 380,000 cycles. The lubricant is very effective in delaying the fretting wear during the initial stages and in preventing the oxidation and accumulation of oxidation products at the contact zone in the later stages.

Metallic dialkyldithiocarbamates are useful anti‐wear and extreme pressure additives for lubricating oils. Dithiocarbamates improve the antioxidant properties of the lubricants and are effective in reducing the wear and increasing the friction‐reducing and load‐carrying ability of the base stock. The use of molybdenum dithiocarbamate as a grease additive is found to be effective in reducing fretting corrosion of ball bearings under random rotary vibrating conditions. The effect of dithiocarbamate containing lubricant oils or greases on the fretting corrosion of electrical contacts has not far been studied. The paper explores the effect of a lubricant that contains a 50‐50 mixture of petroleum oil and zinc diamyldithiocarbamate on the fretting corrosion of tin‐plated contact.

Phosphate pretreatment has proved to be a promising surface treatment method, not only for ferrous and non‐ferrous metals, but also for modified steel.

This paper aims to coat ternary composite NiBP-graphite films by Dynamic Chemical Plating “DCP” technique with a growth rate of at least 5 μm/h, which makes this technique a worthy candidate for production of composite films. Electroless nickel plating method can be used to deposit nickel–phosphorous and nickel–boron coatings on metals or plastic surface. However, restrictions such as toxicity, short lifetime of the plating-bath and limited plating rate have limited applications of conventional electroless processes.

DCP is an alternative for producing metallic deposits on non-conductive materials and can be considered as a modified electroless coating process. Using a double-nozzle gun, two different solutions containing the precursors are sprayed simultaneously and separately onto the surface. With this technique, NiBP-graphite films are fabricated and their corrosion and tribological properties are investigated.

With a film thickness of 2 μm, tribological analysis confirms that these coatings have favorable anti-friction and anti-wear properties. Corrosion resistance of NiBP-graphite composite films was investigated, and it was found that graphite incorporation significantly enhances corrosion resistance of NiBP films.

DCP is faster and simpler to perform compared to other electroless deposition techniques. Using a double-nozzle gun, metal salt solution and reducing agents are sprayed to the surface, forming a deposit. Previously, coatings such as Cu, Cu-graphite, Cu-PTFE, Ni-B-TiO2, Ni-P, Ni-B-P and Ni-B-Zn with favorable compactness and adherence by DCP were reported. In this paper, the authors report the application of the DCP technique for depositing NiBP-PTFE nanocomposite films.

The purpose of this paper is to evaluate the corrosion resistance of the electroless Ni‐P coatings in two aggressive media 3.5 wt.% NaCl and Synthetic industrial waste water. Also to study the effect of Phosphorous content in the electroless Ni‐P deposits on its surface nature, morphology and corrosion resistance.

The corrosion behavior of electroless Ni‐P coatings generated on mild steel coupons from an acidic and an alkaline baths and their anti‐corrosion performance of was compared systematically in 3.5 wt.% of NaCl solution and also in synthetic industrial waste water. Microstructure and surface composition of coatings were analyzed using X‐ray diffraction, scanning electron microscopy and energy dispersive spectroscopy techniques, respectively. The Ni‐P coated mild steel specimens were subjected to corrosion and the rate of corrosion was studied by chemical and electrochemical methods. The linear sweep voltammetry, Tafel and electrochemical impedance spectroscopy were employed to obtain corrosion data.

The electroless Ni‐P coatings with higher P content possess homogeneous, uniform and amorphous surface nature and exhibited higher corrosion resistance in the aggressive corrosive media chosen.

This paper provides corrosion behavior of electroless Ni‐P coatings in 3.5 wt.% NaCl and synthetic industrial waste water, and establishes the importance of phosphorous content on nature and properties of the coatings.

Corrosion protection is one of the important performance properties of organic coatings. The purpose of this paper is to develop a paint system for the protection of steel substrates from corrosion at high temperature atmospheres using silicone resin blend materials.

An anti‐corrosion paint system for high temperature atmosphere has been developed using silicone polyester resins. Silicone resin has been chosen due to its good resistance for corrosion in all kinds of environments. The paint system was prepared from the best performing binder system with the addition of inorganic pigments. Heat stability was studied according to ASTM D2485 standards. Adhesion, impact resistance, film formation, thermal stability and electrochemical properties of the prepared coatings were evaluated by cross hatch adhesion method, tubular impact testing, scanning electron microscopy, differential scanning calorimetry (DSC), and electrochemical impedance spectroscopy (ELS), respectively.

The paint system possessed good adhesion properties and had high‐impact resistance. The SEM graphs showed the uniform formation of the film surface. From thermal analyses, the prepared paint system withstood temperatures up to 400°C. The heat‐treated specimen has also been evaluated for corrosion protection by EIS, which showed high resistance after 30 days of immersion in 3 percent NaCl solution.

In this work, an attempt has been made to develop a good paint system using silicone resin and polyester resin blend materials. This research will be useful for the application for high temperature atmosphere and it can give a valuable guidance to the students who are interested in pursuing research in organic coatings.

This paper aims to evaluate the ability of Aubepine and Molokhia extract, obtained by cathodic electrochemical treatment (CET), to protect steel rebar against attack by chloride ions in environment of reinforced concrete marine structures. The effect of Aubepine and Molokhia extract was investigated by electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization techniques.

This experimental work has achieved particularity to compare the behaviour of two types of treatment (carbon steel treated one time by Aubepine extract and one time by Molokhia extract) submitted to the presence and absence of chloride ions.

The results obtained show that the extract solution of the plant could serve as an effective inhibitor for the corrosion of steel. Inhibition was found to increase with increasing concentration of Molokhia extract and for Aubepine extract maximum concentration is 1 g/L.

Plant extracts and traditional medicinal herbs have become important as an environmentally acceptable, readily available and renewable source for wide range of inhibitors.

Aubepine and Molokhia extract are novel green plants extract as corrosion inhibiting coating for steel embedded in concrete. Aubepine is a genus of trees in the family Rosaceae and Molokhia is the leaves of Corchorus olitorius. Flavonoids content was found in both of Aubepine and Molokhia extract as green inhibitors for corrosion of metals.

The objective of this paper is to determine fretting parameters of hoisting rope according to the hoisting parameters in coalmine and to explore the effect of contact load on fretting-fatigue behavior of steel wires.

Based on the mechanical model of hoisting rope in coalmine, the dynamic tension simulation of hoisting rope was performed. Static equations of hoisting rope under tension and torsion and theories of contact mechanics were applied to obtain fretting parameters. Fretting-fatigue tests of steel wires at different contact loads were conducted using a fretting-fatigue test rig. The fretting regime, normalized tangential force and fretting-fatigue life were studied. The morphologies of fretting contact scars and fracture surfaces were observed by scanning electron microscopy and optical microscopy to examine wear and failure mechanisms.

Dynamic tension changes from 0 to 30,900 N. In outer strand layer, contact loads between steel wires in certain wire layers are 60.5 and 38.3 N compared with 378 and 102.7 N between wire layers; relative displacements between wires are 62.5 and 113.2 μm, respectively. Mixed fretting regimes develop in all cases. Increasing contact load decreases the stabilized relative slip and normalized tangential force, reduces the fretting fatigue life, induces accelerated adhesive wear and fatigue wear and results in rougher fracture surface topographies. In all cases, fretting zone induces crack initiation; crack propagation and rupture zones present brittle cleavage and longitudinal splitting, respectively.

This paper presents the systemic study on determination of fretting parameters of hoisting rope according to the hoisting parameters in coalmine and the fretting-fatigue behavior of its internal steel wires. The results of fretting-fatigue tests show that the increase of contact load decreases the stabilized relative slip in mixed fretting regime and normalized tangential force, reduces the fretting fatigue life, induces accelerated adhesive wear and fatigue wear and results in rougher fracture surface topographies.

The authors warrant that the paper is original submission and is not being submitted to any other journal. And the research does not involve confidentiality, copyright infringement, leaks and other issues, all the responsibilities that the authors will take.

This paper aims to investigate the effects of deposition time on the structure and anti-corrosion properties of a micro-arc oxidation (MAO)/Al coating on AZ31B Mg alloy.

The study describes the fabrication of the coating via a combined process of MAO with multi-arc ion plating. The structure, composition and corrosion resistance of the coatings were evaluated using scanning electron microscopy, energy dispersive spectroscopy, X-ray diffraction and electrochemical methods.

The Al-layer is tightly deposited with a good mechanical interlock along the rough interface due to the Al diffusion. However, the Al layer reduces the anti-corrosion of MAO-coated Mg alloy because of structural defects such as droplets and cavities, which act as channels for corrosive media infiltration towards the substrate. Fortunately, the Al layer improves the substrate corrosion resistance owing to its passive behaviour, and the corrosion resistance can be enhanced with increasing deposition time. All results indicate that a buffer layer fabricated through the duplex process improves the interfacial compatibility between the hard coating and soft Mg alloys.

An MAO/Al duplex coating was fabricated via a combined process of MAO and physical vapour deposition. MAO/Al duplex coatings exhibit obviously passive behaviours on AZ31 Mg alloy. The structure and corrosion resistance of MAO/Al coatings were investigated.