Improvement in barrier properties of polymers used in packaging industry: pet/N-MXD6 blends

Traditional packaging materials like glass and metal are increasingly replaced by plastics due to several advantages of plastics which are low density, less energy consumption, ease of processing, weight reduction and cost savings. Unfortunately plastics are permeable to gases while glass and metal are absolute barrier materials. Permeability is an important issue in packaging that relates to product quality and a reasonable shelf life. Improvement in barrier properties of polyester/polyamide blends used in packaging industry is the main objective of the present study. For this purpose polyethylene terephthalate (PET)/ poly (m-xylene adipamide) (Nylon-MXD6) (95/5 w/w) and PET-co-10I (polyethylene terephthalate-co-isophtahalate random copolymer containing 10 wt. % isophthalic acid (IPA)) / N-MXD6 (95/5 w/w) blends have been prepared with different compatibilizer types and combinations by using a co-rotating intermeshing twin screw extruder. The effects of biaxial orientation, crystallinity, morphology (tortuous pathway), and chemistry on oxygen gas permeability were analyzed by using different characterization techniques like scanning electron microscopy (SEM), differential scanning calorimetry (DSC), spectral-birefringence, and gas permeability analyzer. The morphological analysis revealed that PET copolymer that consists of 5% sodium sulfonated isophthalate (PET-co-5SIPA) was an effective compatibilizer for both PET/N-MXD6 and PET-co-10I/N-MXD6 blends. Spectral-birefringence technique and DSC analysis were used to understand the crystallization behaviour of the blends. Morphological analysis of films after biaxial stretching indicated that the spherical nylon phase was converted to 75 nm thick ellipsoids during stretching (aspect ratio L/W=6) that creates tortuous pathway for oxygen ingress. PET-co-10I films had low permeability before biaxial stretching compared to unoriented PET films. Stretching ameliorated barrier properties of PET/N-MXD6 films but increased the permeability of PET-co-10I/N-MXD6 blends

Analysis of Symmetric and Asymmetric Nonlinear Causal Relationship between Stock Prices and Exchange Rates for Selected Emerging Market Economies

Bu çalışma BRICS ülkeleri ve Türkiye'de hisse senedi fiyatları ve döviz kurları arasındaki doğrusal olmayan simetrik ve asimetrik nedensellik ilişkisini araştırmaktadır. Bu amaçla, ilgili değişkenlerin geri bildirimlerinin türlerini saptayarak doğrusal olmayan simetrik ve asimetrik nedensellik ilişkisinin test edilmesine imkân sağlayan Mackey-Glass modeli kullanılmıştır. Doğrusal olmayan simetrik nedensellik testinin sonuçları ilişkinin varlığına ilişkin zayıf kanıtlar sunarken, testin asimetrik biçimi güçlü bir nedensellik ilişkisi olduğunu göstermektedir. Sonuç olarak, bu bulgular döviz ve hisse senedi piyasısında gürültülü işlemlerin ve spekülatif davranışların olduğunu ifade etmektedir.This study investigates the symmetric and the asymmetric nonlinear causal relationship between exchange rates and stock prices in BRICS and Turkey. To this end, the Mackey-Glass model allowing to test the symmetric and asymmetric nonlinear causality by identifying the types of feedbacks of the related variables has been employed. While the results of the symmetric nonlinear causality test present little evidence for the relationship, the asymmetric counterpart of the test indicates strong evidence for the causal relationship. As a result, these findings imply the existence of the noisy tradings and speculative behaviours in both exchange rate and stock markets

Beklentilerin Ekonomi Uzerine Etkileri: MS-VAR Yaklasimi

Calismanin temel amaci, coklu denge baglaminda beklentinin, belirsizligin ve inancin ekonomi uzerindeki etkisini olcmektir. Bu cercevede, Hamilton (1989) tarafindan gelistirilen, ekonometrik uygulamalarda yaygin olarak kullanilan ve rejim degisim modeli olarak bilinen Markov degisim modeline iliskin kuramsal cercevenin incelenmesi ve soz konusu dogrusal olmayan zaman serisi modelinin Krolzig (1997) tarafindan gelistirilen cok degiskenli versiyonunun (MS-VAR) Turkiye icin uygulanmasini icermektedir. Beklentinin ekonomi uzerindeki etkisini test etmek icin Sanayi Uretim Endeksi (SUE), Reel Kesim Guven Endeksi (RKGE) ve Istanbul Menkul Kiymetler Borsasi Ulusal 100 Endeksinden (IMKB) hareket edilecektir. Oncelikle degiskenlere derinlik, diklik ve keskinlik asimetrileri uygulanacaktir. Daha sonra ise MS-VAR modeli baglaminda iki ayrý model kullanilarak, beklentinin ve inancin ekonomi uzerindeki etkisi analiz edilecektir.MS-VAR, Beklentiler

Analysis of Symmetric and Asymmetric Nonlinear Causal Relationship between Stock Prices and Exchange Rates for Selected Emerging Market Economies

Bu çalışma BRICS ülkeleri ve Türkiye'de hisse senedi fiyatları ve döviz kurları arasındaki doğrusal olmayan simetrik ve asimetrik nedensellik ilişkisini araştırmaktadır. Bu amaçla, ilgili değişkenlerin geri bildirimlerinin türlerini saptayarak doğrusal olmayan simetrik ve asimetrik nedensellik ilişkisinin test edilmesine imkân sağlayan Mackey-Glass modeli kullanılmıştır. Doğrusal olmayan simetrik nedensellik testinin sonuçları ilişkinin varlığına ilişkin zayıf kanıtlar sunarken, testin asimetrik biçimi güçlü bir nedensellik ilişkisi olduğunu göstermektedir. Sonuç olarak, bu bulgular döviz ve hisse senedi piyasısında gürültülü işlemlerin ve spekülatif davranışların olduğunu ifade etmektedir.This study investigates the symmetric and the asymmetric nonlinear causal relationship between exchange rates and stock prices in BRICS and Turkey. To this end, the Mackey-Glass model allowing to test the symmetric and asymmetric nonlinear causality by identifying the types of feedbacks of the related variables has been employed. While the results of the symmetric nonlinear causality test present little evidence for the relationship, the asymmetric counterpart of the test indicates strong evidence for the causal relationship. As a result, these findings imply the existence of the noisy tradings and speculative behaviours in both exchange rate and stock markets

Seçilmiş gelişmekte olan ülkeler için hisse senedi fiyatları ve döviz kurları arasındaki doğrusal olmayan simetrik ve asimetrik nedensellik ilişkisinin analizi

This study investigates the symmetric and the asymmetric nonlinear causal relationship between exchange rates and stock prices in BRICS and Turkey. To this end, the Mackey-Glass model allowing to test the symmetric and asymmetric nonlinear causality by identifying the types of feedbacks of the related variables has been employed. While the results of the symmetric nonlinear causality test present little evidence for the relationship, the asymmetric counterpart of the test indicates strong evidence for the causal relationship. As a result, these findings imply the existence of the noisy tradings and speculative behaviours in both exchange rate and stock markets.Bu çalışma BRICS ülkeleri ve Türkiye'de hisse senedi fiyatları ve döviz kurları arasındaki doğrusal olmayan simetrik ve asimetrik nedensellik ilişkisini araştırmaktadır. Bu amaçla, ilgili değişkenlerin geri bildirimlerinin türlerini saptayarak doğrusal olmayan simetrik ve asimetrik nedensellik ilişkisinin test edilmesine imkân sağlayan Mackey-Glass modeli kullanılmıştır. Doğrusal olmayan simetrik nedensellik testinin sonuçları ilişkinin varlığına ilişkin zayıf kanıtlar sunarken, testin asimetrik biçimi güçlü bir nedensellik ilişkisi olduğunu göstermektedir. Sonuç olarak, bu bulgular döviz ve hisse senedi piyasısında gürültülü işlemlerin ve spekülatif davranışların olduğunu ifade etmektedir

NOVAC, PRIHOD I KAUZALNOST: ISPITIVANJE TURSKE EKONOMIJE

This paper examines the direction of causality between money and income for the Turkish economy using quarterly data over the period of 1987 to 2011. A vector autoregression model consisting of the real gross domestic product, the broad money supply, the three months deposit rate as short-term interest rate, and the consumer price index is constructed to implement causality tests. Also, a leveraged bootstrapped simulation technique is used when conducting causality tests in order to make the results more robust. The empirical results suggest a bidirectional causation between the two variables and that monetary aggregates may provide relevant information in the implementation of monetary policy.Ovaj rad istražuje smjer kauzalnosti između novca i dohotka u turskoj ekonomiji koristeći kvartalne podatke za period od 1987. do 2011. Vektorski autoregresijski model koji sadržava realni bruto domaći proizvod, opskrbu novcem u širem smislu, tromjesečnu stopu depozita kao kratkoročnu kamatu i potrošački cjenovni indeks sastavljen je u svrhu provođenja testova kauzalnosti. Osim toga, „leveraged bootstrap“ simulacijska tehnika je korištena pri provođenju testova kauzalnosti kako bi rezultati bili robustniji. Empirijski rezultati sugeriraju postojanje dvosmjerne kauzalnosti između dvije varijable te da novčani agregati mogu pružiti relevantne informacije za implementaciju monetarne politike

The effect of annealing temperature on the structural, optical, and electrical properties of CdS films

Cadmium sulfide (CdS) photocatalyst films were grown on glass by chemical bath deposition (pH 9.4, 70 °C) and then annealed in nitrogen from 423 K to 823 K in steps of 100 K. The XRD crystallite size increases in a sigmoidal manner from 60 nm to 100 nm while the optical band gap energy decreases from 2.42 eV to 2.28 eV. This trend is paralleled by the decreasing Urbach energy, but only up to 623 K, where it increases again. This is the temperature where the Cd effectively surpasses the phase transformation from cubic to hexagonal, and the activation energy for electronic transport drops by a factor of nearly tw

Energy Consumption, CO2 Emissions, and Economic Growth: An Ethical Dilemma

In this study we examine the dynamic interrelationship in the output–energy–environment nexus by applying panel vector autoregression (PVAR) and impulse response function analyses to data on energy consumption (and its subcomponents), carbon dioxide emissions and real GDP in 106 countries classified by different income groups over the period 1971–2011. Our results reveal that the effects of the various types of energy consumption on economic growth and emissions are heterogeneous on the various groups of countries. Moreover, causality between total economic growth and energy consumption is bidirectional, thus making a case for the feedback hypothesis. However, we cannot report any statistically significant evidence that renewable energy consumption, in particular, is conducive to economic growth, a fact that weakens the argument that renewable energy consumption is able to promote growth in a more efficient and environmentally sustainable way. Finally, in analysing the case for an inverted U-shaped EKC, we find that the continued process of growth aggravates the greenhouse gas emissions phenomenon. In this regard, we cannot provide any evidence that developed countries may actually grow-out of environmental pollution. In the light of these findings, the efficacy of recent government policies in various countries to promote renewable energy consumption as a means for sustainable growth is questioned. Put differently, there seems to be an ethical dilemma, between high economic growth rates and unsustainable environment and low or zero economic growth and environmental sustainability

The nexus between prices, employment and output growth: a global and national evidence

This paper investigates how output growth, employment growth and inflation influence each other in the short/long run. It builds on Phillips (1962) and Blanchard Fischer (1989) assessment that empirical links between output, employment and prices are central issue in modern macroeconomics. This paper brings a global perspective on short and long term links between employment growth, inflation and output growth using panel cointegration framework with non-stationary heterogeneous panel (119 countries over 1970–2010). The empirical results (on global and national level) strongly support the existence of a long-run equilibrium relationship between output growth, employment growth and inflation. A central finding is that possible trade-off effects between growth, employment and prices varies significantly among economies. Therefore, universal answers to questions Is inflation good for growth or Is there a trade-off between employment and growth are not straightforward for general macroeconomic theory. Each country must design own economic policy (targeting) taking into account the quantitative relationships between growth, employment and prices. This has important policy implications also for price setting policies, cost management, market strategy and risk management through productivity-demand disturbances effects on the business environment

A review of energy systems models in the UK: Prevalent usage and categorisation

In this paper, a systematic review of academic literature and policy papers since 2008 is undertaken with an aim of identifying the prevalent energy systems models and tools in the UK. A list of all referenced models is presented and the literature is analysed with regards sectoral coverage and technological inclusion, as well as mathematical structure of models. The paper compares available models using an appropriate classification schema, the introduction of which is aimed at making the model landscape more accessible and perspicuous, thereby enhancing the diversity of models within use. The distinct classification presented in this paper comprises three sections, which specify the model purpose and structure, technological detail and mathematical approach. The schema is not designed to be comprehensive, but rather to be a broad classification with pertinent level of information required to differentiate between models. As an example, the UK model landscape is considered and 22 models are classified in three tables, as per the proposed schema