In the present work, sheets of high-density polyethylene, reinforced with strips of polypropylene using a friction stir welding technique were executed. Welding was carried out using a friction stir welding tool of 20 mm shoulder diameter and 5 mm for both pin diameter and pin length with zero tilt angle, the percentages of polypropylene added to the welding zone were 15, 20, 25, 30% (as a percentage of the added polypropylene to the welding zone), the recommended high tool rotation speed and low tool travel speed (520 rpm, 20 mm/min, respectively) were applied in all tests, the plunge depth was 0.5 mm (the penetration depth of tool shoulder from workpiece surface), dwell time at the event of submerging the pin into the faying surfaces and before initiating the tool travel speed was 45 seconds. Mechanical tests, represented by flexural and impact tests, exhibited an improvement in the mechanical properties of the welded specimens for the case of 25% added polypropylene. Friction stir welding has extraordinary potential to create imperfection-free joints and to initiate a high-quality weldment of high-density polyethylene sheets reinforced by polypropylene strips.

Cell Formation (CF) problem considers as the most important issue in the CellularManufacturing (CM) system particularly the design step. CF deals with the creation ofmachine cells (MCs) and part families (PFs). Numerous methods, algorithms andmathematical models were proposed and used in the literature for solving the CF problem.The current paper used a heuristic method based on the hamming distance to form MCs&PFs, this proposed method calculates the hamming distance for the parts, firstly thenrearranges them based on the results to shape the PFs. Afterward, the hamming distance wascalculated for machines, then the machines rearranged based on the results to form the MCs.Three datasets from the literature were utilized to validate the proposed method. Fiveperformance measures were used for comparison and evaluation, these measures areExceptional Elements EE, Percent of Exceptional elements PE, Voids, Grouping EfficiencyGE and Machine Utilization MU. The results referred to the outperforms of the hammingdistance based method comparing with the best known results in the literature. Among thetotal 20 performance indexes: three are better than, twelve are equal to and five are almostequivalent to the best known results. On the other hand, the proposed hamming distancebased method is effectual particularly in terms of the number of machine cells and PE.

The cell formation (CF) problem is considered the most essential issue in cellular manufacturing systems (CMS). CF deals with the arrangement of similar parts into groups known as part families (PFs) and organizes machines also into groups, called machine cells (MCs). In the literature, numerous methods, models and algorithms have been proposed and developed to handle CF problems. However, very few studies have dealt with the assessment and comparison of these methods, to identify the most effective. This has provided strong motivation for the study presented here. The present paper focuses on two methods that are used infrequently to form MCs and PFs, and applies them in three strategies: the first is based on the use of a hamming distance only, while the second uses only a self-organization map (SOM). However, the third method applies a hybrid approach based on SOM and hamming distance. The outputs of the selected methods were compared, to select the best one. A set of five benchmark datasets and three performance measures was used for comparison and evaluation. These performance measures are: percent of the exceptional elements (PE), grouping efficiency (GE), and machine utilization (MU). The results refer to the outperforms of the hamming distance in terms of PE, GE and MU for most of the selected benchmark problems.