Waiting Time of Public Transport Passengers in Jordan: Magnitude and Cost

Aim: This paper is a research study investigating the magnitude and cost of waiting time as experienced by public transport users in Jordan. This study also used spatial analysis to measure services provided for public transport routes according to the average waiting time. Methods: The data for waiting time of public transport users were collected using field observation and a professional spatial analysis applied to identify several locations experiencing short time delays. Results: This study found a relationship between the total costs of waiting time, including wasted time and money, and revealed that the money spent by the passengers was more than their average monthly income. Conclusion: The findings can be used as valuable information for researchers, government policy-makers, and transport agencies to firstly, develop more punctual public transport modes; and secondly, manage public transport trips to minimize time delays

Modern microwave methods in solid state inorganic materials chemistry: from fundamentals to manufacturing

No abstract available

Phosphate removal from aqueous solutions by using natural Jordanian zeolitic tuff

In this study, a naturally occurring zeolitic tuff located in Jordan was investigated as a potential adsorbent for phosphate removal from aqueous solution. Adsorption kinetics and thermodynamics of phosphate adsorption under different temperatures were studied. The pseudo-second-order kinetic model adequately fitted the collected experimental data under different initial ion concentrations. The Langmuir model is found to be successfully fitting the experimental data. Thermodynamic parameters such as Gibbs's free energy change, standard enthalpy change, and entropy change were evaluated and the results indicated that the sorption process is spontaneous, exothermic with small degree of randomness during the sorption process

Pyrolysis kinetics of tetrabromobisphenol a (TBBPA) and electric arc furnace dust mixtures

This work assesses the decomposition kinetics and the overall pyrolysis behavior of Tetrabromobisphynol A (TBBPA) mixed with Electric Arc Furnace Dust (EAFD) using experimental data from thermogravimetric analysis (TGA). Mixtures of both materials with varying EAFD:TBBPA ratios (1:1, 1:2, 1:3 and 1:4) were pyrolyzed in an inert atmosphere under dynamic heating conditions at different heating rates (5, 10, 30 and 50 °C/min). The pyrolysis of pure TBBPA proceeded through two decomposition steps: debromination and volatilization of debromination products. This is followed by char formation that also involves release of volatile organic matter. However, the pyrolysis of EAFD:TBBPA mixture proves to be more complex in nature due to the occurrence of parallel solid-liquid reactions that result in the release of HBr and other volatile organic compounds (VOC) coupled with bromination of metal oxides. Subsequent chemical events encompass evaporation of metal bromides and finally reduction of the remaining metal oxides, most notably iron oxide, into their metallic form by the char. Three models, namely, Kissinger, Flynn-Wall-Ozawa (FWO) and Kissinger-Akahira-Sunose (KAS), were deployed to derive kinetics parameters. Generally, it was found that the presence of EAFD has led to an increase in the apparent activation energy for the first stage of TBBPA decomposition due to the reduced evaporation of TBBPA

Thermal decomposition of brominated flame retardants (BFRs): Products and mechanisms

Brominated flame retardants (BFRs) are bromine-bearing hydrocarbons added or applied to materials to increase their fire resistance. As thermal treatment and recycling are common disposal methods for BFR-laden objects, it is essential to precisely describe their decomposition chemistry at elevated temperatures pertinent to their thermal recycling. Laboratory-level and pilot-scale investigations have addressed the thermal decomposition of pure BFRs and/or BFR-laden polymers under oxidative and pyrolytic environments, typically at temperatures of 280–900°C. These studies shed light on the effects of various factors influencing the decomposition behaviour of BFRs such as chemical character, polymer matrix, residence time, bromine input, oxygen concentration, and temperature. Although BFRs decomposition mainly occurs in a condensed phase, gas phase reactions also contribute significantly to the overall decomposition of BFRs. Exposing BFRs to temperatures higher than their melting points results in evaporation. Quantum chemical calculations have served to provide mechanistic and kinetic insights into the chemical phenomena operating in decomposition of BFRs and subsequent emissions of polybrominated dibenzo-p-dioxins and dibenzofurans (PBDD/Fs). Under thermal conditions such as smouldering, municipal waste incineration, pyrolysis, thermal recycling, uncontrolled burning and fires, BFRs degrade and form brominated products of incomplete combustion (BPICs). Thermal degradation of BFRs often proceeds in the presence of bromine atoms which inhibit complete combustion. Major BPICs comprise brominated benzenes and phenols in addition to a wide range of brominated aromatics. Pyrolytic versus oxidative conditions seems to have very little influence on the thermal stability and decomposition behaviour of commonly-deployed BFRs. Thermal degradation of BFRs produces potent precursors to PBDD/Fs. Experimental studies have established inventories of PBDD/F emissions with alarming high yields for many BFRs. Co-combustion of BFRs-containing objects with a chlorine source (e.g. polyvinyl chlorides) results in the emission of significant concentrations of mixed halogenated dibenzo-p-dioxins and dibenzofurans (i.e. PXDD/Fs). Formation of PBDD/Fs from incomplete BFRs decomposition occurs primarily due to the condensations of gas phase precursors, including unaltered structural entities of some BFRs in their own right. Complete destruction of BFRs promotes PBDD/Fs formation via de novo synthesis. Bromination of PBDD/Fs in gas phase reactions is more prevalent if compared with chlorination mechanisms of PCDD/Fs, which is largely dominated by heterogeneous pathways. In uncontrolled burning and in simulated fly ash experiments, a strong correlation between congeners patterns of polybrominated diphenyl ethers (PBDEs) and PBDD/Fs indicate that PBDEs function as direct precursors for PBDD/Fs, even in the de novo synthesis route. In this review, we critically discuss current literature on BFRs thermal decomposition mechanisms; gather information regarding the contribution of homogenous and heterogeneous routes to overall BFRs decomposition; survey all studies pertinent to the emission of PBDD/Fs and their analogous mixed halogenated counterparts from open burning of e-waste, and finally, highlight knowledge gaps and potential directions that warrant further investigations

Thermal analysis on the pyrolysis of tetrabromobisphenol A and electric arc furnace dust mixtures

The pyrolysis of Tetrabromobisphenol A (TBBPA) mixed with electric arc furnace dust (EAFD) was studied using thermogravimetric analysis (TGA) and theoretically analyzed using thermodynamic equilibrium calculations. Mixtures of both materials with varying TBBPA loads (1:1 and 1:3) were prepared and pyrolyzed in a nitrogen atmosphere under dynamic heating conditions at heating rates of 5 and 10 °C/min. The mixtures degraded through several steps, including decomposition of TBBPA yielding mainly HBr, bromination of metal oxides, followed by their evaporation in the sequence of CuBr3, ZnBr2, PbBr2, FeBr2, MnBr2, KBr, NaBr, CaBr2, and MgBr2, and finally reduction of the remaining metal oxides by the char formed from decomposition of TBBPA. Thermodynamic calculations suggest the possibility of selective bromination of zinc and lead followed by their evaporation, leaving iron in its oxide form, while the char formed may serve as a reduction agent for iron oxides into metallic iron. However, at higher TBBPA volumes, iron bromide forms, which can also be evaporated at a temperature higher than those of ZnBr2 and PbBr2. Results from this work provide practical insight into selective recovery of valuable metals from EAFD while at the same time recycling the hazardous bromine content in TBBPA

Curiosity Thinking Level and its Relationship to the Level of Decision - Making Ability of Secondary School Students in the Directorate of Education for the University District in Jordan مستوى تفكير حب الاستطلاع وعلاقته بمستوى المقدرة على اتخاذ القرار لدى طلبة المرحلة الثانوية في مديرية التربية والتعليم للواء الجامعة بالإردن

Abstract: The study aimed at investigating the level of curiosity thinking and its relationship to the level of decision-making ability of secondary school students in the Directorate of Education for the University District in Jordan. In order to achieve the goal of the study, two tools were developed: the measure of curiosity thinking and the decision – making scale. Their psychometric characteristics were assured. The sample of the study consisted of (358) secondary school students in public schools. The results of the study showed that the level of curiosity thinking and the ability to make decisions were medium. The results of the analysis of variance showed that there were differences in the level of curiosity thinking and decision-making in favor of first-year secondary students, and that there was a correlation between the level of curiosity thinking and the ability to make decisions. The study recommended training teachers on strategies that would develop Curiosity thinking and decision – making skills among learners. ملخص: هدفت الدراسة إلى تحري مستوى تفكير حب الاستطلاع وعلاقته بالمقدرة على اتخاذ القرار لدى طلبة المرحلة الثانوية في مديرية تربية وتعليم لواء الجامعة بالأردن, ولتحقيق هدف الدراسة تم تطوير أداتين هما: مقياس تفكير حب الاستطلاع, ومقياس اتخاذ القرار, والتأكد من الخصائص السيكومترية لهما, تكونت عينة الدراسة من (358) طالبا وطالبة من طلبة المرحلة الثانوية في المدارس الحكومية في مديرية لواء الجامعة, أظهرت نتائج الدراسة أن مستوى تفكير حب الاستطلاع والمقدرة على اتخاذ القرار كان متوسطاً, كما أظهرت نتائج تحليل التباين وجود فروق في مستوى تفكير حب الاستطلاع واتخاذ القرار لصالح طلبة الصف الأول ثانوي, وأظهرت نتائج الدراسة وجود علاقة ارتباطية إيجابية بين مستوى تفكير حب الاستطلاع والمقدرة على اتخاذ القرار, وأوصت الدراسة بتدريب المعلمين على الاستراتيجيات التي من شانها تطوير مهارات تفكير حب الاستطلاع واتخاذ القرار لدى المتعلمين