Ibrahim Salama - Academia.edu (original) (raw)

Papers by Ibrahim Salama

Academy of Management Proceedings, 2018

Goal-setting theory (Locke & Latham, 1990) has been one of the most influential frameworks fo... more Goal-setting theory (Locke & Latham, 1990) has been one of the most influential frameworks for understanding the motivational effects of goals on performance and satisfaction. This research extends...

The vertices of the Cayley graph of a finitely generated semigroup form a set of sites which can ... more The vertices of the Cayley graph of a finitely generated semigroup form a set of sites which can be labeled by elements of a finite alphabet in a manner governed by a nonnegative real interaction matrix, respecting nearest neighbor adjacency restrictions. To the set of these configurations there is associated a pressure, which is defined as the limit of averages over certain finite subgraphs of the logarithm of the partition function. We consider families of such systems and prove that the limit of the values of the pressure as the number of generators grows without bound, which we call the asymptotic pressure, equals the logarithm of the maximum row sum of the interaction matrix.

Organizational Behavior and Human Decision Processes, 2020

When striving to meet goals, individuals monitor their progress towards achieving them. The discr... more When striving to meet goals, individuals monitor their progress towards achieving them. The discrepancy between their current performance and their goal determines task (dis)satisfaction, and thus whether they will make greater effort. We propose and test a theoretical extension of goal-setting theory, namely that different types of goal standards (minimal or maximal) fundamentally change this monitoring process. Through four experiments we demonstrate that with maximal goals ("ideal" standards), individuals experience greater task satisfaction the nearer their current performance comes to the goal. In contrast, with minimal goals ("at least" standards), their satisfaction level remains low, regardless of how close their performance is to the goal. When goals are exceeded, the reverse applies: with maximal goals, satisfaction remains high regardless of the level of overperformance, while with minimal goals, satisfaction is determined by the level of overperformance. We also demonstrate that task satisfaction levels influence subsequent decisions on goal striving.

Theoretical Computer Science, 2018

We give a definition of topological entropy for tree shifts, prove that the limit in the definiti... more We give a definition of topological entropy for tree shifts, prove that the limit in the definition exists, and show that it dominates the topological entropy of the associated one-dimensional shift of finite type when the labeling of the tree shares the same restrictions.

Fuel, 2020

A hypothetical mechanism of degradation of the fuel droplet leaking out from the injector nozzle ... more A hypothetical mechanism of degradation of the fuel droplet leaking out from the injector nozzle in a direct injection combustion engine has been proposed recently. This involves as a key step a radical chain oxidation initiated by NO2 and branched by nitric oxide, NO, both produced by the combustion. The degradation causes the formation of injector nozzle carbonaceous deposits. The present work gives an experimental validation of some of the assumptions behind this model. An autoclave is used to oxidize isooctane under conditions relevant to the cylinder wall near the nozzle (~150 °C, 10 bar, 5% O2, 100 xppm of NO2 and 500 xppm NO in the gas phase), and the degradation products are monitored via gas chromatography-mass spectrometry (GC-MS). The results show that no fuel degradation is observed in the absence of NOx. NO appears to be able to initiate a radical chain by producing NO2. Nitric oxide also alters the radical chain by transforming the alkyl peroxy radicals to more reactive alkoxy radicals, resulting in a range of different products. In addition, NO tends to terminate the radical chain by neutralizing a fraction of the alkyl peroxy radicals, producing alkyl nitrates as termination products. The existence of a radical chain is supported by demonstrating antioxidative action of a radical scavenger. The chemical reaction mechanism is investigated, based on the detected products, and the key species involved in the degradation process are identified. Highlights:  Isooctane degradation is studied under conditions prevalent at engine cylinder wall.  NO2 initiates oxidation radical chain in impinged gasoline; >50 products identified.  O2 alone, in the absence of NOx, does not produce significant liquid fuel degradation.  If only NO2 is present, the key reactive intermediates are alkylperoxy radicals.  If both NOx (NO+NO2) are present, the key reactive intermediates are alkoxy radicals.

Journal of the American College of Cardiology, 2020

Zagazig Journal of Agricultural Research, 2019

Gurma melon (Nubian or Seed melon) Citrullus lantus var. colocynthoides, became an important crop... more Gurma melon (Nubian or Seed melon) Citrullus lantus var. colocynthoides, became an important crop in Egypt. It was cultivated for seeds only, while the residue of fruits are removed as waste. The main objective of the study is to investigate the possibility of utilization Gurma melon pulp in an economic nutrient food products as jam. The obtained results declared that Gurma melon wastes which represented about 95% of crop contained moisture 94.55%, protein 0.84%, fat 0.19%, crude fiber 0.12%, mineral matter 0.21, TSS 4.32° Brix and acidity 0.18%. Gurma melon pulp were used to prepare both flavored jam by adding up to 1.5% of cinnamon and mixed jam by substituting up to 30% of fig with Gurma melon. All the jam samples were stored in sterilized glass jars at room temperature for 6 months and the physicochemical and organoleptic characteristics were studied. The results indicated that high acceptance jam could be processed from Gurma melon pulp plain or flavored by 1% cinnamon. Also Gurma pulp up to 20% could incorporated in blends with fig fruits for producing good quality fig-melon mixed jam.

Proceedings of the 1993 Alexandria Conference

Proceedings of the Annual Meeting (American Society of International Law), 2011

The research that will be published in more detail later this year distinguished between explicit... more The research that will be published in more detail later this year distinguished between explicit invocations of treaty body recommendations, and those recommendations that so resembled treaty body recommendations that they could be said to be based implicitly on the latter recommendations, but without express reference to the treaty body source. What emerged was a marked difference between the rate of acceptance or rejection, depending on whether the recommendations were implicit or explicit. Thus, around four out of five implicit recommendations were accepted, and one in five rejected, while around half of the explicit recommendations were accepted and rejected; as far as the recommendations of the Committee on Economic, Social and Cultural Rights were concerned, they were overwhelmingly accepted, whether explicit or implicit. I suspect the latter figure reflects what may be expected to be the less neuralgic nature of the latter recommendations. As to those pertaining to the Human Rights Committee and the Committee Against Torture, the nature of the data requires caution, but I would hazard that states wishing to promote respect for the ideas contained in treaty body recommendations would be best advised to be inspired by them, but not necessarily to advertise the source of their inspiration. Meanwhile, I am very pleased to note that my governmental colleague, Sarah McCosker, acknowledges that, from the perspective of individuals who are victims of human rights violations, having multiple human rights bodies reinforce particular human rights concerns is better, even if it may entail some duplication and overlap.

Pacific Journal of Mathematics, 1989

The Supporting Institutions listed above contribute to the cost of publication of this Journal, b... more The Supporting Institutions listed above contribute to the cost of publication of this Journal, but they are not owners or publishers and have no responsibility for its content or policies. Mathematical papers intended for publication in the Pacific Journal of Mathematics should be in typed form or offset-reproduced (not dittoed), double spaced with large margins. Please do not use built up fractions in the text of the manuscript. However, you may use them in the displayed equations. Underline Greek letters in red, German in green, and script in blue. The first paragraph must be capable of being used separately as a synopsis of the entire paper. In particular it should contain no bibliographic references. Please propose a heading for the odd numbered pages of less than 35 characters. Manuscripts, in triplicate, may be sent to any one of the editors. Please classify according to the scheme of Math. Reviews, Index to Vol.

Journal of Statistical Computation and Simulation, 2002

Consider the exact distribution of Spearman's" footrule", D (σ, π)= i=... more Consider the exact distribution of Spearman's" footrule", D (σ, π)= i= 1^ n | σ (i)-π (i) |, where σ and π are chosen independently at random from S_n, the set of all permutations of the first n integers; or, equivalently, where σ is chosen at random and π=(1, 2, ..., n). This can ...

Journal of Nonparametric Statistics, 2003

Spearman&#x27;s footrule, a well-known measure of rank correlation, is extended here to p... more Spearman&#x27;s footrule, a well-known measure of rank correlation, is extended here to progressively censored rankings. Under the hypothesis of randomness (ie, under random ranking), a martingale characterization is exploited in the formulation of a functional ...

Journal of Multivariate Analysis, 1992

Biometrics, 1975

Page 1. BIOMETRICS 31, 953-956 December 1975 395: A NOTE ON MINIMUM CHI-SQUARE STATISTICS IN CONT... more Page 1. BIOMETRICS 31, 953-956 December 1975 395: A NOTE ON MINIMUM CHI-SQUARE STATISTICS IN CONTINGENCY TABLES DANA QUADE AND IBRAHIM A. SALAMA University of North Carolina, Chapel Hill, North Carolina, 27514 USA ...