ARHITEKTONSKE SLOŽENOSTI I MORFOLOŠKE VARIJACIJE SEDIMENTNIH VALOVA PLIO-PLEISTOCENSKIH KANALA U DELTI INDA

The architecture of the turbidity current sediment waves exhibits intricate morphologies and patterns on the Indus Fan channel levee backslope. The sediment waves are present on the channel levee of Plio-Pleistocene age and are absent in the deeper sections of the study area. The architecture of channel levee backslope on the Indus Fan is poorly understood. We used seismic interpretation techniques and modelling by utilizing high-resolution seismic data to approach this problem. The morphological variations in wavelength, crest dimensions and potential wave formation patterns suggest the autogenic and allogenic processes associated with wave development. Wavelengths reach up to 1473 m with an average of 486.84 m and the height of the levee ranges between 10 m and 60 m (average 30 m). The angle of the channel levee and dimension of the sediment wave here are independent of each other. Low angle levees have accommodated high dimension sediment waves and vice versa at multiple points downslope. Characteristically, the waves have formed on the outer levee (usually left) of the channels marked by steep margins suggesting that flow overspill caused the development of the waves. Generally, the younger sediment waves followed the patterns of older sediment waves, but the varying trends are often observed in the study area. The patterns of the sediment waves towards the younger sections of the levee indicate the modified and varying architectural style of growth. Sediment waves are generated by downslope turbidity currents. However, the deformation features have also possibly triggered the development of sediment waves.Arhitektura sedimentnih valova nastalih uslijed turbiditnih struja pokazuje zamršenu morfologiju i obrasce unutar kanala i njihovih rubova u prostoru deltne lepeze Inda. Tragovi taloženja energijom valova prisutni su u plio-pleistocenskim kanalima i oko njih, no izostaju u dubljim dijelovima istraživanoga područja. Arhitektura rubova kanala u delti Inda do sada nije bila detaljno opisana. U istraživanju ovoga problema korištene su seizmičke metode i modeliranje podataka visoke razlučivosti. Morfološke varijacije u duljinama valova, dimenzijama kresta i potencijalnim obrascima stvaranja valova upućuju na autogene i alogene procese povezane s razvojem valova. Dujine valova dosežu do 1473 m s prosjekom od 486,84 m, a visina se kreće između 10 m i 60 m (prosječno 30 m). Kut rubova kanala i dimenzija vala u ovome slučaju bili su neovisni jedno o drugome. Mali kut omogućio je na nekoliko točaka u nižim dijelovima akomodiranje valova velikih dimenzija i obrnuto. Karakteristični valovi nastajali su na vanjskome dijelu nasipa kanala (obično lijevome) sa strmim rubovima, što upućuje na to da je njihovo prelijevanje utjecalo na energiju. Općenito, mlađi valni sedimenti slijedili su obrasce starijih, ali se ponekad može uočiti i promjena trenda. Obrasci valnih taložina u mlađim naslagama rubova upućuju na promjenu, pa i inverziju oblika. Općenito su valni sedimenti posljedica aktivnosti turbiditnih struja u podnožju rubova kanala, a i njihov nastanak vrlo je usko povezan s deformacijskim strukturama

MODELIRANJE TRANSPORTA OTOPINE U NISKOPROPUSNOME, HOMOGENOME I ZASIĆENOME TLU

Fickian and non-Fickian behaviors were often detected for contaminant transport activity owed to the preferential flow and heterogeneity of soil media. Therefore, using diverse methods to measure such composite solute transport in soil media has become an important research topic for solute transport modeling in soil media. In this article, the continuous-time random walk (CTRW) model was applied to illustrate the relative concentration of transport in low-permeability homogeneous and saturated soil media. The solute transport development was also demonstrated with the convection-dispersion equation (CDE) and Two Region Model (TRM) for comparison. CXTFIT 2.1 software was used for CDE and TRM, and CTRW Matlab Toolbox v.3.1 for the CTRW simulation of the breakthrough curve. It was found that higher values of determination coefficient (R2) and lower values of root mean square error (RMSE) concerning the best fits of CDE, TRM, and CTRW. It was found that in the comparison of CDE, TRM, and CTRW, we tend to use CTRW to describe the transport behavior well because there are prevailing Fickian and non-Fickian transport. The CTRW gives better fitting results to the breakthrough curves (BTCs) when β has an increasing pattern towards 2.00. In this study, the variation of parameters in three methods was investigated and results showed that the CTRW modeling approach is more effective to determine non-reactive contaminants concentration in low-permeability soil media at small depths.Fickovo i nefickovo ponašanje često se opaža kod prijenosa gdje postoji preferencijski tok i heterogenost tla (medija) kroz koji se događa protok. Stoga je uporaba različitih metoda mjerenja prijenosa otopina u takvim medijima važno područje istraživanja. Ovdje je prikazan model kontinuiranoga i vremenski slučajnoga gibanja (engl. skr. CTRW) kako bi se opisala relativna koncentracija tijekom prijenosa kroz niskopropustan, homogen i zasićen medij. To je demonstrirano konvekcijsko-disperzijskom jednadžbom (engl. skr. CDE) te dvočlanim modelom (engl. skr. TRM) i njihovom usporedbom. Programskim paketom CXTFIT 2.1 opisani su CDE i TRM, a paketom CTRW Matlab Toolbox v.3.1 model CTRW. Uočeno je kako veće vrijednosti koeficijenta determinacije (R2) te manje srednje kvadratne pogrješke (engl. skr. RMSE) najbolje opisuju podudaranje između CDE-a, TRM-a i CTRW-a. Usporedbom tih triju vrijednosti odabran je CTRW za opis ponašanja prijenosa, kako Fickova, tako i nefickova. CTRW se bolje podudara s krivuljama protoka (engl. skr. BTC), gdje β raste prema vrijednosti 2. Istražena je i promjena parametara u svim trima metodama, što je ponovno istaknulo CTRW kao najprimjereniji model u određivanju koncentracije nereaktivnih čestica u slabopropusnome tlu na malim dubinama

KARAKTERIZACIJA VODONOSNIKA I FIZIČKO-KEMIJSKA ANALIZA PODRUČJA DERA GHAZI KHAN, PUNJAB, PAKISTAN

The study area is located in the arid section of Punjab province, Pakistan. The accessibility of freshwater is the main problem in this area. The area is mainly flat and alluvial deposits are present down to 800 m. The groundwater is not fit for drinking because of its salinity. Hence, it is essential to mark the transition between fresh water and saltwater. Resistivity models were used to locate freshwater areas. The saltwater areas are between 10 and 30 m deep. Salt flats and clayrich deposits are visible on resistivity maps and were identified by low resistance values. After linking resistivity data and maps, it is determined that the south portion of the area has a freshwater aquifer, especially at a depth of 200 m. At this depth, the quality of water is very good, regardless of its mild salinity in some areas. The margin between salty and freshwater is set to no degree. This is dependent upon the recharge and usage of an aquifer. Groundwater pollution poses a severe threat to the city’s residents. Results from the physio-chemical analysis of the water samples confirm the presence of arsenic in excessive amounts in water samples and are outside the limits set by the WHO and NDWQS. Just two out of 10 samples are within the limits for safe drinking water. The results of this research are valued for groundwater management and the installation of tubular wells in freshwater areas for households and irrigation purposes.Istraživano područje smješteno je u pustinjskome dijelu provincije Punjab u Pakistanu, obilježenome nedostatkom pitke vode. Područje je najvećim dijelom zaravnjeno i prekriveno aluvijem koji mjestimice može dosegnuti i 800 m debljine. Podzemna voda nije pogodna za piće zbog slanosti. Stoga je iznimno važno prepoznati prijelaznu zonu između slatke i slane vode. Za lociranje slatkovodnih područja korišteni su modeli otpornosti. Područja slane vode duboka su između 10 i 30 m. Taložine soli i gline opažaju se na kartama otpornosti niskim vrijednostima otpora. Uočeno je kako se na jugu područja javljaju vodonosnici slatke vode, čak na dubini od 200 m, s vrlo dobrom kvalitetom vode, uz rijetku pojavu bočatosti. Granicu između slatke i slane vode nije moguće jednoznačno odrediti, a ovisi o dotoku i uporabi vodonosnika. Njihovo zagađenje može biti ozbiljan problem, poglavito za gradska područja. Rezultati fizičko-kemijske analize pokazali su nazočnost prevelikih količina arsena, tj. u granicama iznad dopuštenih klasifikacijama WHO-a i NDWQS-a. Od 10 samo su 2 uzorka bila u granicama koje određuju pitku vodu. Rezultati su vrijedan doprinos za gospodarenje tom podzemnom vodom te projektiranje bušotina kojima bi se pitka/slatka voda dovodila kućanstvima ili koristila za navodnjavanje

Carrier Transport Enhancement in Conjugated Polymers through Interfacial Self-Assembly of Solution-State Aggregates

We demonstrate that local and long-range orders of poly­(3-hexylthiophene) (P3HT) semicrystalline films can be synergistically improved by combining chemical functionalization of the substrate with solution-state disentanglement and preaggregation of P3HT in a θ solvent, leading to a very significant enhancement of the field effect carrier mobility. The preaggregation and surface functionalization effects combine to enhance the carrier mobility nearly 100-fold as compared with standard film preparation by spin-coating, and nearly 10-fold increase over the benefits of preaggregation alone. In situ quartz crystal microbalance with dissipation (QCM-D) experiments reveal enhanced deposition of preaggregates on surfaces modified with an alkyl-terminated self-assembled monolayer (SAM) in comparison to unaggregated polymer chains in the same conditions. Additional measurements reveal the combined preaggregation and surface functionalization significantly enhances local order of the conjugated polymer through planarization and extension of the conjugated backbone of the polymer which clearly translate to significant improvements of carrier transport at the semiconductor–dielectric interface in organic thin film transistors. This study points to opportunities in combining complementary routes, such as well-known preaggregation with substrate chemical functionalization, to enhance the polymer self-assembly and improve its interfacial order with benefits for transport properties

Solvent Vapor Annealing in the Molecular Regime Drastically Improves Carrier Transport in Small-Molecule Thin-Film Transistors

We demonstrate a new way to investigate and control the solvent vapor annealing of solution-cast organic semiconductor thin films. Solvent vapor annealing of spin-cast films of 6,13-bis­(triisopropylsilylethynyl) pentacene (TIPS-Pn) is investigated in situ using quartz crystal microbalance with dissipation (QCM-D) capability, allowing us to monitor both solvent mass uptake and changes in the mechanical rigidity of the film. Using time-resolved grazing incidence wide angle X-ray scattering (GIWAXS) and complementary static atomic force microscopy (AFM), we demonstrate that solvent vapor annealing in the molecular regime can cause significant performance improvements in organic thin film transistors (OTFTs), whereas allowing the solvent to percolate and form a liquid phase results in catastrophic reorganization and dewetting of the film, making the process counterproductive. Using these lessons we devise processing conditions which prevent percolation of the adsorbed solvent vapor molecules for extended periods, thus extending the benefits of solvent vapor annealing and improving carrier mobility by nearly two orders of magnitude. Ultimately, it is demonstrated that QCM-D is a very powerful sensor of the state of the adsorbed solvent as well as the thin film, thus making it suitable for process development as well as in-line process monitoring both in laboratory and in future manufacturing settings