Chemistry Research Papers - Academia.edu (original) (raw)

Recognizing the imperiled status of biodiversity and its benefit to human well-being, the world's governments committed in 2010 to take effective and urgent action to halt biodiversity loss through the Convention on Biological Diversity's "Aichi Targets". These targets, and many conservation programs, require monitoring to assess progress toward specific goals. However, comprehensive and easily understood information on biodiversity trends at appropriate spatial scales is often not available to the policy makers, managers, and scientists who require it. We surveyed conservation stakeholders in three geographically diverse regions of critical biodiversity concern (the Tropical Andes, the African Great Lakes, and the Greater Mekong) and found high demand for biodiversity indicator information but uneven availability. To begin to address this need, we present a biodiversity "dashboard"--a visualization of biodiversity indicators designed to enable tracking o...

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- Engineering, Physics, Chemistry, Biology
- by Iris Herrmann
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- Chemical Engineering, Chemistry, Electrochemistry, Catalysis

The activation of the G-protein transducin (Gt) by rhodopsin (Rho) has been intensively studied for several decades. It is the best understood example of GPCR activation mechanism and serves as a template for other GPCRs. The structure of the Rho/G protein complex, which is transiently formed during the signaling reaction, is of particular interest. It can help understanding the molecular details of how retinal isomerization leads to the G protein activation, as well as shed some light on how GPCR recognizes its cognate G protein. The native Rho/Gt complex isolated from bovine retina suffers from low stability and loss of the retinal ligand. Recently, we reported that constitutively active mutant of rhodopsin E113Q forms a Rho/Gt complex that is stable in detergent solution. Here, we introduce methods for a large scale preparation of the complex formed by the thermo-stabilized and constitutively active rhodopsin mutant N2C/M257Y/D282C(RhoM257Y) and the native Gt purified from bovine...

- by Gebhard F X Schertler and +3
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- Engineering, Physics, Chemistry, Biology
- by Paulo Cezar Vieira
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- Chemistry, CHEMICAL SCIENCES

O presente trabalho teve por objetivos avaliar a composição de rizomas do lírio-do-bejo (Hedychium coronarium) e isolar e caracterizar seu amido, por meio de análises físicas e físico-químicas. A composição química dos grânulos de amido isolados dos rizomas também foi determinada, bem como o formato, tamanho, distribuição de tamanho de partícula por difração a laser, viscosidade de pasta em analisador rápido de viscosidade, poder de inchamento, índice de solubilidade em água, propriedade térmica por calorimetria diferencial de varredura e cristalinidade por difração de raios X. Observou-se que os rizomas apresentaram elevado teor de água e baixos teores de matéria graxa, carboidratos, cinzas, proteínas e fibras. Os rizomas de lírio-do-brejo apresentam-se inadequados para produção de amido, devido ao baixo teor de matéria seca (17,3%), com 21,97% de amido, bem como fibras longas e látex, que dificultam a extração do amido. O amido extraído apresentou pureza de 99,2%, com 37,2% de ami...

- by Wellington F E R R E I R A Moura
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- Mathematics, Physics, Thermodynamics, Chemistry
- by Yashowanta N. Mohapatra
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- Physics, Materials Science, Chemistry, Physical Chemistry
- by Ekasith Somsook
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- Chemistry, Inquiry Based Learning, Active Learning, Kinetics
- by Shankar Prinja
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- Engineering, Physics, Chemistry, Health Care
- by Stephen Parker
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- Materials Engineering, Geochemistry, Chemistry, Surface Structure

Investigating the multidimensional integration between different microbiological kingdoms possesses potential toward engineering next-generation bionic architectures. Bacterial and fungal kingdom exhibits mutual symbiosis that can offer advanced functionalities to these bionic architectures. Moreover, functional nanomaterials can serve as probing agents for accessing newer information from microbial organisms due to their dimensional similarities. In this article, a bionic mushroom was created by intertwining cyanobacterial cells with graphene nanoribbons (GNRs) onto the umbrella-shaped pileus of mushroom for photosynthetic bioelectricity generation. These seamlessly merged GNRs function as agents for mediating extracellular electron transport from cyanobacteria resulting in photocurrent generation. Additionally, three-dimensional (3D) printing technique was used to assemble cyanobacterial cells in anisotropic, densely packed geometry resulting in adequate cell-population density for efficient collective behavior. These 3D printed cyanobacterial colonies resulted in comparatively higher photocurrent (almost 8-fold increase) than isotropically casted cyanobacteria of similar seeding density. An insight of the proposed integration between cyanobacteria and mushroom derives remarkable advantage that arises from symbiotic relationship, termed here as engineered bionic symbiosis. Existence of this engineered bionic symbiosis was confirmed by UV− visible spectroscopy and standard plate counting method. Taken together, the present study augments scientific understanding of multidimensional integration between the living biological microworld and functional abiotic nanomaterials to establish newer dimensionalities toward advancement of bacterial nanobionics.

- by SUDEEP JOSHI
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- Chemistry, Cyanobacteria, Nanotechnology, Additive Manufacturing

This document has been developed by a EURACHEM Working Group from a draft originally produced by LGC. The membership of the EURACHEM group is listed in Annex C. Ruling language The text may be freely translated into other languages, but where such action results in a dispute over interpretation, the guidance given in this English version is taken as being the definitive version. Copyright of the guidance presented in this guide is the property of the organisations represented by the working group members as listed in Annex C. All rights are reserved. This guidance may be downloaded for personal and non-commercial use, but no part of the guide may be distributed, published or stored in any retrieval system, in any media, by persons other than EURACHEM members, without the written consent of the EURACHEM Secretariats. Similarly, enquiries regarding the translation, production and distribution of new editions of this guide should be directed to the EURACHEM Secretariats This edition is...

- by Florent Vanstapel
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- Chemistry
- by Peter Blain
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- Chemistry, Chromatography, In Vitro Toxicology, Elsevier
- by Isa Bertling
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- Chemistry, Horticultural production
- by Neerja Trivedi
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- Pharmacology, Chemistry, Pharmacy, Dosage Form
- by Sasidhar Varanasi*
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- Chemistry, RSC, Levulinic Acid, corn stover
- by Gordon Warren
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- Engineering, Physics, Chemistry, Skeletal muscle biology

This chapter is dedicated to the systems that add chemicals to the saline source water, which allow the conditioning of this water before its further pretreatment or direct reverse osmosis (RO) membrane separation. Source water conditioning is of critical importance for the efficient and cost-effective sedimentation and filtration of particulate and organic compounds contained in water as well as prevention of formation of scale on the RO membrane surface. This chapter describes the purpose and dosing of commonly applied source water conditioning chemicals such as coagulants, flocculants, scale inhibitors, biocides, acids, and bases.

- by Nikolay Voutchkov
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- Chemistry
- by Jie Ge
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- Chemical Engineering, Physics, Materials Science, Solid State Physics
- by Jahangir Emrani
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- Chemistry, Organic Chemistry
- by Huanchun Chen
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- Chemistry, Organic Chemistry, Thymelaeaceae, Humans
- by David Gurwitz
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- Engineering, Genetics, Physics, Chemistry

TALAT Lecture 1252- Corrosion and Corrosion Protection 1252.01.02 Corrosion Types ....................................................................................4 (a) General... more

TALAT Lecture 1252- Corrosion and Corrosion Protection
1252.01.02 Corrosion Types ....................................................................................4
(a) General corrosion.............................................................................................5
(b) Crevice corrosion.............................................................................................6
(c) Poultice corrosion ............................................................................................7
(d) Fretting corrosion (also called traffic marking)...............................................7
(e) Stress corrosion................................................................................................8
(f) Galvanic Corrosion ..........................................................................................9
(g) Pitting Corrosion............................................................................................10
(h) Intergranular corrosion and exfoliation .........................................................11
1252.02 Electrochemistry and Aluminium...........................................................11
1252.02.01 Introduction .........................................................................................11
1252.02.02 Kinetic Reactivity................................................................................12
1252.02.03 The Electrochemical Circuit ...............................................................13
1252.02.04 Aluminium as a Cathode.....................................................................13
1252.02.05 Aluminium as an Anode......................................................................14
1252.02.06 Summary of Electrolytic Corrosion .

- by Professor Dr. Loutfy H . Madkour
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- Chemistry, Corrosion Science, Corrosion
- by Dermot Diamond
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- Chemistry
- by Carole Garofalo and +3
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- Engineering, Physics, Chemistry, Biology

In this paper, a study on the batch processing and characterization of microcellular foamed high-density polyethylene (HDPE/iPP) blends is reported. A microcellular plastic is a foamed polymer with a cell density greater than 109 cells/cm3 and fully grown cells smaller than 10 µm. Recent studies have shown that the morphology and crystallinity of semicrystalline polymers have a great influence on the solubility and diffusivity of the blowing agent and on the cellular structure of the resulting foam in microcellular batch processing. In this research, blends of HDPE and iPP were used to produce materials with variety of crystalline and phase morphologies to enhance the subsequent microcellular foaming. It was possible to produce much finer and more uniform foams with the blends than with neat HDPE and iPP. Moreover, the mechanical properties and in particular the impact strength of the blends were significantly improved by foaming.
(citation # 293)

- by Saeed Doroudiani, PhD, P.Eng.
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- Chemical Engineering, Physics, Chemistry, Physical Chemistry
- by Baneenah Amharib
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- Chemistry, Iodine, Lemna minor
- by Fernanda Mora
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- Chemistry

Minkowski famously introduced the concept of a space-time continuum in 1908, merging the three dimensions of space with an imaginary time dimension $ i c t ,withtheunitimaginaryproducingthecorrectspacetimedistance, with the unit imaginary producing the correct spacetime distance ,withtheunitimaginaryproducingthecorrectspacetimedistance x^2 - c^2 t^2 ,andtheresultsofEinstein′sthenrecentlydevelopedtheoryofspecialrelativity,thusprovidinganexplanationforEinstein′stheoryintermsofthestructureofspaceandtime.AsanalternativetoaplanarMinkowskispace−timeoftwospacedimensionsandonetimedimension,wereplacetheunitimaginary, and the results of Einstein's then recently developed theory of special relativity, thus providing an explanation for Einstein's theory in terms of the structure of space and time. As an alternative to a planar Minkowski space-time of two space dimensions and one time dimension, we replace the unit imaginary ,andtheresultsofEinstein′sthenrecentlydevelopedtheoryofspecialrelativity,thusprovidinganexplanationforEinstein′stheoryintermsofthestructureofspaceandtime.AsanalternativetoaplanarMinkowskispace−timeoftwospacedimensionsandonetimedimension,wereplacetheunitimaginary i = \sqrt{-1} ,withtheCliffordbivector, with the Clifford bivector ,withtheCliffordbivector \iota = e_1 e_2 $ for the plane that also squares to minus one, but which can be included without the addition of an extra dimension, as it is an integral part of the real Cartesian plane with the orthonormal basis $ e_1 $ and $ e_2 $. We find that with this model of planar spacetime, using a two-dimensional Clifford multivector, the spacetime metric and the Lorentz transformations follow immediately as properties of the algebra. This also leads to momentum and energy being represented as components of a multivector and we give a new efficient derivation of Compton's scattering formula, and a simple formulation of Dirac's and Maxwell's equations. Based on the mathematical structure of the multivector, we produce a semi-classical model of massive particles, which can then be viewed as the origin of the Minkowski spacetime structure and thus a deeper explanation for relativistic effects. We also find a new perspective on the nature of time, which is now given a precise mathematical definition as the bivector of the plane.

- by Nicolangelo Iannella and +1
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- Engineering, Physics, Chemistry, Biology
- by Ed Rybicki
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- Chemistry, Electrophoresis, SDS PAGE, Polyacrylamide

Objective: To determine the conductivity of various acid and the dissociation constant, a K for acetic acid 1 Theory 1.1 Electrical conductivity in solutions An electric current in solution is the result of the net movement of free ions in a specific direction. The current may be determined by measuring the resistance R between two similar inert electrodes immersed in the solution, as in the figure below where the oval region represents the solution; A represents the electrode area and l is the normal distance between the electrode planes. In actual practice an A.C. current with a low frequency of the order of approximately 1000 Hertz is used (to prevent electrolysis) in the measurement, and the components representing the resistance R in the complex impedance Z for the circuit is determined. We will always refer to this component (the real portion of the complex impedance) for what follows. The resistance is also dependent on the frequency (Debye-Falkenhagen effect). The theory and measurement here concentrates on low frequency measurements where the Onsager equation is meaningful. The fully automated measuring apparatus has been configured for low frequency measurement in accordance with the theory of electrolytes.

- by Collins Madu
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- Chemistry

An efficient and new but non-intrusive method to detect the fluctuation in gear load may be the motor current signature analysis (MCSA). In this paper, a multi-stage transmission gearbox (with and without defects) has been studied in order to replace the conventional vibration monitoring by MCSA. It has been observed through FFT analysis that low frequencies of the vibration signatures have sidebands across line frequency of the motor current whereas high frequencies of vibration signature are difficult to be detected. Hence, discrete wavelet transform (DWT) is suggested to decompose the current signal, and FFT analysis is carried out with the decomposed current signal to trace the sidebands of the high frequencies of vibration

- by Naiphinich Kotchabhakdi
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- Chemistry, Medicine, Cats, Cerebellum
- by Alison Abbott
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- Psychology, Chemistry, Arts, Multidisciplinary

Laboratory Information System (LIS) streamlines workflow in the laboratory and eliminates time-consuming paperwork. The business today is getting increasingly pressured to be more productive and efficient with less traditional resources. If we look at a typical production process, for instance, the level of automation and optimization that has permeated into the production floor is quite astounding. Many industries have had a tremendous impact in bringing to the market the automation and optimization solutions to streamline -the production floor. The other ends of the spectrum are the back-office transaction oriented processes like Inventory Management, Materials Management, Financials and so on, Therefore a lab’s ability to process data quickly and its ability to disseminate that information efficiently throughout the plant is vital for the success of the production process. Laboratory Information Management System (LIMS) can help in managing the information flow within the lab and can be the modus operandi of connecting the lab with the rest of the organization. For instance, imagine all the information that is generated in a lab.

ABSTRACT
This work was carried out to investigate the chemical/mineral composition of the water extract of zobo (Hibiscus sabdariffa) drink using the modern atomic absorption spectrophotometer. Zobo drink is a popular drink in the Nigeria, especially in the northern part of Nigeria. The result of the analysis indicated that the drink is high in vital mineral nutrients required for the healthy growth by humans and for the proper metabolic processes to be adequately maintained. Zobo drink is high, as indicated in the result, in iron – a major component of the human haemoglobin, when compared with other leaf like the popular vegetable leaf known as awa (Piper methysticum).

- by Okafor Osita
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- Biochemistry, Chemistry, Conservation Biology, Molecular Biology
- by Ping Furlan
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- Chemistry, Chemical Education, Illustrations, Education
- by Antony J Williams
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- Chemistry, Chemistry Databases, Public domain databases

I. STRUCTURE DU CHEVEU
II. PRODUITS D’HYGIENE CAPILLAIRE : LES SHAMPOOINGS
1. Composition et propriétés des molécules de base
2. Propriétés et résultats attendus
III. PRODUITS DE MODIFICATION DE LA FORME
1. Produits de modification temporaire
1.1. Extension du cheveu mouillé et séchage sous tension
1.2. Produits de maintien de la coiffure
1.2.1. Formulation des laques et des gels
1.2.2. Ingrédients et fonctions d’une laque
2. Produits de modification durable de la forme
2.1. Produits de permanente
2.1.1. Principe de la permanente
2.1.2. Les principes actifs utilisés en permanente
2.1.2.1. Les produits réducteurs
2.1.2.2. Les produits fixateurs
2.1.3. Les oxydoréductions de la permanente
2.1.4. Formulation d’un produit de permanente
2.2. Produits de défrisage
2.2.1. Principe du défrisage
2.2.2. Principaux composants et leurs fonctions
2.2.2.1. Défrisants thiolés
2.2.2.2. Défrisants alcalins

- by stefanie wang
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- Environmental Engineering, Chemical Engineering, Materials Science, Chemistry

Metallurgical Factors Affecting Corrosion in Petroleum and Chemical Industries
Abstract:
Humans have most likely been trying to understand and control corrosion for as long as
they have been using metal objects. With a few exceptions, metals are unstable in ordinary
aqueous environments. Certain environments offer opportunities for these metals to
combine chemically with elements to form compounds and return to their lower energy
levels. Corrosion is the primary means by which metals deteriorate. Most metals corrode on
contact with water (and moisture in the air), acids, bases, salts, oils, aggressive metal
polishes, and other solid and liquid chemicals. Metals will also corrode when exposed to
gaseous materials like acid vapors, formaldehyde gas, ammonia gas, and sulfur containing
gases. The production of oil and gas, its transportation and refining, and its subsequent use
as fuel and raw materials for chemicals constitute a complex and demanding process.
Various problems are encountered in this process, and corrosion is the major one. Since
metals are the principal material suffering corrosive deterioration, it is important to develop
a background in the principles of metallurgy to fully understand corrosion. The control of
corrosion through the use of coatings, metallurgy, nonmetallic materials for constructions
cathodic protection and other methods has evolved into a science in its own right and has
created industries devoted solely to corrosion control. Metallurgical factors that affect
corrosion are chemical composition, material structure, grain boundaries, alloying elements,
mechanical properties, heat treatment, surface coating, welding and manufacturing
conditions. Understanding these factors are of great importance to decrease and control
corrosion problem in many industrial applications.

- by Professor Dr. Loutfy H . Madkour
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- Chemistry, Corrosion Science

The end of the Early Bronze Age, in other words the EBA III, is one of the significant turning points in the cultural history of the Anatolian Peninsula. Metal objects that indicate social class differences, advancements in architecture, and finds that point to connections with distant regions all demonstrate that a political structure began to emerge in Anatolia during this period. Parallel to these developments, especially with the increase in interregional relations, the use of new vessels indicates a novelty in eating and drinking habits. Tankards, bell-shaped cups and depas amphikypellon stand out within this group and are referred to as the new drinking vessels. In addition to these, it is noteworthy that beakers or goblets, and also container amphorae started to become widespread. All these types are considered to be associated with new drinking habits, and the new drink type is suggested to be wine. However, the suggestions proposed regarding the use of these vessels are not supported by any archaeometric studies until now. In this study, we share results from total lipid extraction analyses (TLE) performed by gas chromatography-mass spectrometry (GC-MS) on a group of depa vessels from the archaeological site of Küllüoba located in Eskişehir, Turkey, and re-evaluate at the possible purposes of these vessels. Biomolecules such as fatty acids, salicylic acids, organic acids, hydrocarbons, n-alkanes, and herbal steroids identified as a result of these analyzes provided the first direct evidence of the use of fermented products such as wine and herbal analgesics in Early Bronze Age Anatolia. Additionally, we present the first archaeological data of the period and the region regarding the use of salicylic acid.

- by Murat Türkteki
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- Archaeology, Prehistoric Archaeology, Chemistry, Anatolian Archaeology
- by Cady Lancaster
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- Earth Sciences, Chemistry, Mass Spectrometry, Flavonoids
- by JuanC. Thompson
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- Chemistry, Organic Chemistry

The aim of this work was to determine physicochemical parameters of winter savory (Satureja montana L.) honey produced in the Adriatic part of Croatia. Honey samples were collected from several production seasons and following physicochemical parameters were determined: water content, electrical conductivity, pH value, free acidity, sugar content, diastase activity and HMF content. The results of electrical conductivity (0.155 - 0.456 mS/cm), free acidity (16.1 - 35.8 mEq/kg) and diastase activity (16.3 - 45.8) varied in a wide range. Fructose/glucose and glucose/water ratios indicate moderate crystallisation rate of the honey.

- by Ljiljana Primorac
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- Chemistry

Denila, Richard V.
This study investigated the relationship of high school chemistry students’ motivation to learn and attitude towards chemistry with their chemistry academic achievement. This study was conducted at Norala National High School, Division of South Cotabato, for the school year 2009-2010.
The study made use of the correlation method with the questionnaires in Likert scale to gather the data. The instruments used were: Motivation questionnaire to learn (as adopted and modified by Ortiz, 1997) for determining the students’ motivation to learn chemistry; the Attitude Towards Science Scale (ATSS) by Wilkinson, 1979, as adopted by Alava, 2004 for determining the students’ attitude towards chemistry; and the Achievement Test in Chemistry for ascertaining the academic achievement of the third year chemistry students. The statistical tools used in the study were frequency count, percentage, the mean, standard deviation, and Pearson product-moment correlation (r) at 0.05 confidence level.
Findings showed that the third year students are motivated in achievement, in affiliation, in competence, and in maintenance to learn chemistry. Study show that they have the desire to learn the concepts and skills in chemistry. Collectively, the third year high school students’ have favorable attitude towards chemistry. The academic performance level of the of the third year students in high school chemistry is satisfactory. This indicates that the students are moderately competent in the knowledge and skills in chemistry. There is a statistically significant relationship between the third year students’ motivation to learn chemistry and their attitude towards chemistry. A statistically significant relationship exists between the third year students’ motivation to learn chemistry and their academic achievement in chemistry. Statistically there is a significant relationship between the third year students’ attitude towards chemistry and their academic achievement in chemistry.

- by Richard V Denila
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- Chemical Engineering, Chemistry, Organic Chemistry
- by Jolanta Gurtat
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- Chemistry, Collagen Cross-linking, Applications, Polyamines