In variable manual assembly production of highly customised products, effective allocation of workers to products is required. To support decision making here, industrial managers should be aware of the performance effects of the number of workers and learning within individual products. Evidence on such fundamental effects requires laboratory studies with products similar to those in real assembly industries. Because of the lack of such studies, this paper studies experimentally the effects of group size (one to four workers) and learning (up to four repetitions per group) on the performance of product assembly. The product, built for the purpose of the present study, consists of representative elements from real products in the mechanical engineering industry. A total of 68 undergraduate students participated in the experiments. The results from the experiments are in line with the hypotheses that the mean assembly time decreases at a decelerating rate as a function of both group size and repetitions, and that productivity per worker decreases as a function of group size. The results are explained in more detail through the experiences of the participants. Managerial implications and aspects for future research are also discussed.

On the basis of results of the performed collaborative study, the 49th Annual General Meeting of the Nordic Committee on Food Analysis (NMKL) in The Faroe Islands, August 1995, approved this method to be printed and included in NMKL's collection of methods of analysis of foods. Eleven laboratories participated in an interlaboratory methods-performance (collaborative) study of a method for determining magnesium and calcium in foodstuffs by atomic absorption spectrometry (AAS) after wet microwave digestion. The study was preceded by a practice round of familiarization samples. The method was tested on 7 materials: 5 foods (apple, milk powder, minced fish, wheat bran, and chocolate cake) and 2 composite diets ranging in Mg content from 240 to 3900 mg/kg and in Ca content from 290 to 9300 mg/kg. The materials were presented to study participants as blind duplicates, and participants were asked to perform single determinations on each sample. Repeatability relative standard deviations (RSDr) ranged from 1.9 to 4.9% for Mg and from 2.2 to 8.1 % for Ca. Reproducibility relative standard deviations (RSDR) ranged from 4.0 to 13% for Mg and from 5.9 to 23% for Ca. For Ca, lowest RSDR values were found for samples with high concentrations of Ca (>3800 mg/kg sample) and with nitrate ion residues of <1.3% (w/v).

The surface composition of CuIaSe, thin films, made by co-evaporation of the elements, has been shown to be strongly dependent on the bulk composition of the films. This is explained by the presence of a secondary phase, most likely Cu,Se, on the surface of Cu-rich Alms. The fast variation of the surface Concentration is also found for films that, according to the equilibrium pseudobinary phase diagram (Cu,Se-In,Se,), should be singlephase chalcopyrite. An explanation, suggesting the presence of a Cu-rich compound also on the surface of films with a composition in the single phase region, is proposed.Surface atomic concentrations have been shown to be modified in CuIaSe, films by a 4.5 keV Ar' sputter etch Heating in vacuum at the film deposition temperature restores the surface atomic concentrations to an asdeposited condition, with the exception of the selenium concentration. The missing selenium atoms are substituted by oxygen atoms still remaining in the film after sputtering and heating.

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Implementing additive manufacturing in an industry, particularly for critical applications of lightweight aluminum (AlSi10Mg), requires part properties that are both accurate and precise to conform to the intent of a robust design. In this experimental study, the objective was to evaluate anisotropy in part properties (i.e., flatness, surface roughness, surface porosity, surface hardness, pre-hole shrinkage, drilling thrust force, and thread-stripping force) when the part orientation (i.e., print inclination and recoater angle) was independently changed. This study developed and investigated an innovative procedure for determining anisotropy in part properties. The part properties were evaluated by designing specific features on a tailor-made flat plate. The replicas of the aluminum plate were additively manufactured at varying orientations using two commercial EOS parameter sets for the laserbased powder bed fusion technique. Conventional measurement equipment was used to analyze all the part properties, except the thread-stripping force, which was measured using a custom-made setup. All the part properties indicated a considerable degree of anisotropy, excluding the drilling thrust force. The printing parameters dictate the significance of the anisotropy. The anisotropy in flatness and pre-hole shrinkage decreases with an increased substrate temperature and a decrease in energy input and thermal gradient. The presence of surface overlapping contours in the scan strategy and an increased energy input can reduce anisotropy in surface roughness and hardness. No significant anisotropy was detected when the recoater angle was changed. This study helps designers establish and substantiate design for additive manufacturing that is within the limits of appropriate anisotropy for a robust design.