The study area is the city of Zintan, in northwestern Libya, which has grown over the past

30 years. Its current population is roughly 30,000. Although the city is in part commercial, most

of the population engages in agriculture and primarily grows cereal crops (wheat and barley). The

demand of the growing city for agricultural products has increased, intensifying the use of fertilizers,

pesticides, and insecticides. Consequently, concentrations of potentially toxic elements (PTE) in

the soil have increased. To assess the soil quality (to provide a snapshot of the condition of the

soil), systematic sampling was undertaken across a grid of about 2 km  2 km. The main objective

was to determine the chemical and mineral composition of the area of interest, keeping in mind

the geological footprint of the terrain. The geologic framework itself is not conducive to elevated

concentrations of elements like U, Th, Mo, As, Hg, Pb, and Cr. Therefore, metal concentrations

greater than the amounts in the Earth’s crust are most likely of anthropogenic origin. A total of

143 samples were collected and chemical analyses were performed using a Thermo Fisher Scientific

Niton XL3t GOLDD+ XRF analyzer for the following elements: Mo, Zr, Sr, U, Rb, Th, Pb, Au, Se,

As, Hg, Zn, W, Cu, Ni, Co, Fe, Mn, Cr, V, Ti, Sc, Ca, K, S, Ba, Cs, Te, Sb, Sn, Cd, Pd, and Ag. This

paper provides examples of elevated concentrations, potentially harmful to the environment, such as

those of the following: sulfur of unknown origin (two to three times higher than the Earth’s crust

average); arsenic, given that there are no related natural phenomena (all the samples measured

displayed concentrations higher than those found in the Earth’s crust); mercury (concentrations much

higher than permissible levels); cesium (additional investigations required to determine the origin);

molybdenum; and uranium likely resulting from the use of superphosphates (concentrations nearly

always significantly higher than those in the Earth’s crust).

Small molecule, (2-(2-(2-nitrophenyl)diazenyl)malononitrile) (NPDAM), is synthesized and its chemical structure is characterized by different analyses. NPDAM powder is identified as polycrystalline monoclinic structure, whereas the thermally deposited films have nanostructure character with average particle size of 39 nm. NPDAM films are utilized for manufacturing hybrid solar cells in the structure of Au/NPDAM/p-Si/Al. The dark current-voltage (I-V) curves of the diode are measured in the temperature range 303-383 K and the thermionic emission theory is employed to extract the ideality factor, n, and potential barrier height, ∅ at forward applied voltages of V≤0.20 volt. The n value increases, whereas the ∅ value decreases with decreasing temperature. This behavior is analyzed in terms of the lateral inhomogeneous barrier following Gaussian distribution at the NPDAM/p-Si interface. Cheung and Cheung functions are used for extracting the values of series resistance, Rs, n and ∅. The behavior of these parameters as a function of temperature is discussed. At forward applied voltages 0.20<V≤2, the I-V relation reveals crossover from thermionic emission to square power law. This behavior is discussed by means of the space charge limited current. Under illumination, the device exhibits a response to light exposure with a photoelectrical conversion efficiency of 2.91 %.

Two pyrazolo[4,3-b] pyridine derivatives namely; 2,3-dihydro-6-(4-methoxyphenyl)-1-methyl-3-oxo-2-phenyl-1H-pyrazolo[4,3-b]pyridine-5-carbonitrile (L1) and 2,3-dihydro-6-(4-hydroxyphenyl)-1-methyl-3-oxo-2-phenyl-1H-pyrazolo[4,3-b]pyridine-5-carbonitrile (L2) were prepared. The thermal analysis showed that the L1 is stable up to 266 °C, whereas L2 is stable up to 376 °C. The L1 and L2 powders were found to have polycrystalline structure in which their lattice parameters and Miller indices were determined. Thin films of L1 and L2 were deposited by thermal evaporation technique. The absorption spectra of the films were measured, from which the optical band gap of L1 and L2 films was estimated as 2.72 and 2.83 eV, respectively. Two devices based on the films of both materials, independently, were deposited onto p-Si single crystal substrates, were fabricated and showed rectification behavior. The current

In this paper, of primary interest is to synthesis 8-(1H-indol-3-ylazo)-naphthalene-2-sulfonic acid (INSA) and to evaluate the main parameters of Au/INSA/n-Si/Al diode in dark and under illumination. Different techniques are used for interpreting the proposed INSA chemical structure. The dark current-voltage measurements were achieved in the temperature range of 293−413 K. It is noticed that INSA films modify the interfacial barrier height of classical Au/n-Si junction. At low applied voltages, the I–V relation shows exponential behavior. The values ideality factor, n, and the barrier height, φ, are improved by heating. The abnormal trend of n and φ is discussed, and a homogenous barrier height of 1.45 eV is evaluated. The series resistance is also calculated using Norde's function and it changes inversely with temperature. The space charge limited current ruled with exponential trap distribution dominates at relatively high potentials, trap concentration and carriers mobility are extracted. The reverse current of the diode has illumination intensity dependence with a good photosensitivity indicating that the device is promising for photodiode applications.

Global population is growing rapidly. As a result, increasingly large areas are being settled and

farmed. This devastates soils and causes pollution by heavy metals and other components. Heavy metals in

the environment originate from both natural and anthropogenic sources. Natural sources generally include

rock weathering and the propagation of heavy metals, such as Cr and Ni, from ultrabasic rocks. These are natural

processes that generally do not threaten human health. Anthropogenic sources include industry and inappropriate

disposal of waste in the environment. In such cases concentrations of heavy metals can be harmful

to people and other living beings. Al Zintan is a city located in northwestern Libya, on a plateau mainly built

up of Cretaceous sediments. Since the 1980’s, nomadic population has rapidly been settling this area. As a

result, a former part of the desert was transformed and is used for farming. Soil sampling at Al Zintan was

conducted in 2017, across a 2×2 km grid. A total of 143 samples were collected from depths of about 30 cm.

The samples weighed 2 to 2.5 kg and generally comprised sand with a clay component. A Niton Xl3t goldd+

instrument was used for chemical analyses, based on which GIS heavy-metal distribution maps were generated.

The distribution of Cr, Ni, Cu and Zn is discussed on the paper.