Impact of strengthening fluids on roughness of 3D printed models

For some applications, 3D printed parts usually do not have satisfactory mechanical properties, so to broaden their usage, additive technologies should be combined with the well-known metallurgical processes, such as investment and others casting techniques. 3D printing developers persistently introduce new base materials and strengthening fluids which may cause different surface roughness. Therefore, in this paper, the authors have tested the roughness of 3D printed samples strengthened with common, but also with alternative fluids. Measurements proved that fluids do have significant influence on the roughness

Istraživanje i procjena zaostalih naprezanja u plinski naštrcanim NiCrBSi slojevima

For thermally sprayed coatings, beside good wear and corrosion resistance there is also a need for a good coating/substrate adhesion, reduced porosity and reduced level of residual stresses. Residual stresses that occur in the substrate/coating system are very significant because their relaxation can cause different coating failures. In this paper, different approaches to investigation of residual stresses in thermally sprayed coatings, have been presented. An analytical model (authors Tsui and Clyne) was used to estimate the distribution of residual stresses in flame sprayed and fused NiCrBSi coatings. These data can be used as input data for the numerical model.Za toplinski naštrcane slojeve, uz dobru otpornost slojeva na trošenje i koroziju, postoje i zahtjevi za dobrom prionjivosti sloja na podlogu,smanjenom poroznosti i smanjenom razinom zaostalih naprezanja. Zaostala naprezanja koja se pojavljuju u sustavu podloga/naštrcani sloj, osobito su važna, jer se njihovom relaksacijom mogu pojaviti razna oštećenja sloja. U ovome radu prikazani su pristupi istraživanju zaostalih naprezanja u toplinski naštrcanim slojevima, te je na osnovi analitičkog modela (autori Tsui i Clyne) procijenjena raspodjela zaostalih naprezanja za NiCrBSi slojeve nanesene postupkom plinskog naštrcavanja praha s utaljivanjem. Ovi podaci mogu se koristiti kao ulazni podaci za numerički model

Extraction of Inorganic Ions with Organic Solvents. I. Continuous Extraction of Uranyl Nitrate with Tetrahydrosylvane and Tetrahydropyrane

The extraction of uranyl nitrate with tetrahydrosylvane and tetrahydropyrane was imvestigated and compared with that of ethylacetate and diethylether. The effect of ammonium nitrate and nitric acid was shown and the influence of sulfate, chloride, and phosphate anions as well as calcium nitrate and ferric nitrate was examined

The Relationship Between Occlusion and Temporomadibular Disorders

Etiologija temporomandibularnih poremećaja i može bitini utjecaj nisu potpuno razjašnjeni. Svrha istraživanja bila je utvrditi utjecaj okluzijskih odnosa na funkciju stomatognatoga sustava. Ispitivana skupina sastojala se je od 96 ispitanika u dobi od 24-52 godine (x = 35,03 ± 6,92). Kliničkim pregledom utvrđen je broj zuba, broj zuba u okluziji, okluzijska koncepcija (okluzija vođena očnjakom, grupna funkcija i bilateralno uravnotežena okluzija). Izjereni su iznosi okomitog preklopa i vodoravnog pregriza. RKP položaj određen je chin-point tehnikom i fiksiran Luciajigom. Klizanje iz RKP u IKP položaj izmjereno je u anteroposteriornom, okomitom i postraničnome smjeru. Mjerenja maksimalnih kretnji izvršena su s pomoću precizne pomične mjerke. Registrirana je možebitna pojava zvuka i boli. Izvršena je palpacija temporomandibularnih zglobova, žvačnih i vratnih mišića. Izračunani su Helkimov okuzijski, anamnestiči i klinički disfunkcijski indeks (indeks mandibularne pokretljivosti, indeks funkcije temporomandibularnoga zgloba, indeks bolnosti mandibularnih kretnji te indeks mišićne i zglobne boli). 3,21% ispitanika bilo je bez okluzijskih poremećaja (Oi0), 52,32% imalo je umjerene okluzijske poremećaje (OiI), a 38,56% imalo je ozbiljne okluzijske poremećaje (OiII). U usporedbi s anamnestičkim i kliničkim disfunkcijskim indeksom Pearson ?2 test pokazuje da ozbiljni okluzijski poremećaji nisu povezani sa ozbiljnim disfunkcijskim poremećajima. Razlika među skupinama nije statistički znatna (p > 0,05). Rezultati ovoga istraživanja upućuju na zaključak da okluzija nema utjecaja na nastanak i tijek TMD-a.The etiology of temporomandibular disorders and the role of occlusion, has still not been entirely clarified. The objective of this investigation was to determine the effect of occlusal relationship on the function of the stomatognathic system. A group of subjects, aged from 24-52 years (x = 35.03 ± 6.92) was examined. The number of teeth, the number of teeth in occlusion, type of occlusion (canine guided occlusion, group function and balanced occlusion) was determined by clinical examination. Overbite and overjet were measured. RCP position was determined by chinpoint technique and fixing by Lucia-jig. The sliding from RCP to IKP position was determined in the anteroposterior, vertical and lateral direction. A precise calliper was used to measure maximal jaw movement. Pain and sounds were registred. Temporomandibular joints, masticatory and neck muscles were palpated. Helkimo Occlusal, Anamnestic and Clinical Dysfunction Indexes (Index of mandibular movement, index of TMJ function, Index of painful mandibular movements, index of muscular and TMJ pain) were calculated. 3.21% of the subjects were without occlusal disorders (Oi0), 58.32% had moderate occlusal problems (OiI) and 38.56% had severe occlusal problems (OiII). When compared to Anamnestic and Clinical Dysfunction Index the Pearson ?2 test analysis shows that severe occlusal problems are not correlated to severe dysfunction. The difference between the groups is not statistically significant (p > 0.05). The results of this study suggest that occlusion does not have an influence on the occurrence of TMD

The Influence of Bruxism on Mandibular Movement

Etiologija temporomandibularnih poremećaja (TMD) još je uvijek nerazješnjena. Mogući utjecaj bruksizma predmet je mnogih rasprava. Svrha ovog istraživanja bila je odrediti učinak bruksizma na funkciju stomatognatoga sustava. Ispitivana se skupina sastojala od 46 bruksista u dobi od 24-52 godine (x = 35,03 ± 6,92). Kontrolnu skupinu tvorilo je 50 nebruksista u dobi od 25-51 (x = 37,24 ± 6,37). Dijagnoza bruksizma postavljena je anamnestičkim upitnikom i kliničkim pregledom. Za mjerenje kretnje čeljusti uporabljena je precizna klizna mjerka. Mjereno je maksimalno otvaranje, desna i lijeva maksimalna laterotruzijska kretnja, te maksimalna protruzijska kretnja. U skupini bruksista srednja vrijednost maksimalnog otvaranja bila je 48,51 ± 5,01 mm, a u skupini nebruksista 49,76 ± 6,92 mm. Srednja vrijednost maksimalne desne laterotruzijske kretnje u skupini bruksista iznosila je 10,04 ± 2,51 mm, a kontrolna skupina imala je srednju vrijednost 10,31 ± 2,47 mm. Maksimalna lijeva aterotruzijska kretnja u bruksista iznosila je 9,74 ± 2,50 mm, a vrijednost kontrolne skupine bila je 10,33 ± 2,30 mm. Maksimalna protruzijska kretnja kod bruksista iznosila je 9,53 ± 1,97 mm, a u kontrolnoj skupini 10,81 ± 2,29 mm. Pearson ?2 test pokazao je statistički znatnu razliku između ispitivanih skupina (p < 0,05) jedino u varijabli maksimalne protruzijske kretnje (t = 2,93, p = 0,0004). Rezultati ovog istraživanja upućuju na zaključak da bruksizam može imati samo ograničeni utjecaj na pokretljivost čeljusti.The aetiology of temporomandibular disorders (TMD) remains controversial. The role of bruxism is still under discussion. The objective of this investigation was to determine the effect of bruxism on the function of the stomatognatic system. A group of 46 bruxers, aged from 24-52 years (x = 35.03 ± 6.92) was examined. The control group consisted of 50 nonbruxers aged from 25-51 years (x = 37.24 ± 6.37) bruxism was assessed by a questionaire and clinical examination. A precise calliper was used to measure jaw movement. Maximal opening, right and left aterotrusion, and maximal protrusion were measured. The mean value of maximal opening in the bruxers group was 48.51 ± 5.01 mm, and in the nonbruxers group 49.76 ± 6.92 mm. Ther mean value of maximal right laterotrusion in the bruxers group was 10.04 ± 2.51 mm, and of left laterotrusion 9.74 ± 2.50 mm compared to the nonbruxers group where the mean value of right laterotrusion was 10.31 ± 2.47 mm, and left laterotrusion 10.33 ± 2.30 mm. The mean value of maximal protrusion in the bruxers group was 9.53 ± 1.97 mm, while in the nonbruxers group it was 10.81 ± 2.29 mm. Pearson ?2 test analysis shows statisticaly significant difference (p < 0.05) between the groups only in relation to the maximal protrusion (t = 2.93, p = 0.0004). The results of this study suggest that bruxism may only have a limited influence on mandibular mobility

Effect of Disorder and Notches on Crack Roughness

We analyze the effect of disorder and notches on crack roughness in two dimensions. Our simulation results based on large system sizes and extensive statistical sampling indicate that the crack surface exhibits a universal local roughness of $\zeta_{loc} = 0.71$ and is independent of the initial notch size and disorder in breaking thresholds. The global roughness exponent scales as $\zeta = 0.87$ and is also independent of material disorder. Furthermore, we note that the statistical distribution of crack profile height fluctuations is also independent of material disorder and is described by a Gaussian distribution, albeit deviations are observed in the tails.Comment: 6 pages, 6 figure

MENTAL DISORDERS AS INFLUENCING FACTORS FOR DISCORDANCES IN THE SIGNS AND SYMPTOMS OF DRY EYE DISEASE

Dry eye disease (DED) is a multifactorial disease of the tear film and ocular surface representing one of the most common problems in ophthalmological practice. Characteristic symptoms of DED include gritty, sandy foreign body sensation as well as he symptoms of dry eye are the main features of this disease, however, the symptoms do not always coincide with the signs and the results of diagnostic tests and the cause of this discordance in perception is still unclear. Numerous studies have been conducted in order to determine the cause of these discrepancies. Mental health disorders may be one of considerable contributing factors for dry eye symptoms and undiagnosed mental health conditions can be an influencing element for unexplained levels of DED symptoms. Depression, anxiety, stress, hypochondriasis, neuroticism, sleep and mood disorders may be associated with the exacerbation of symptoms to degrees that are not consistent with the objective signs related to tear dysfunction as well as changes in the anterior surface of the eye. Thus, a detailed medical history, thorough ophthalmological examination and referral to a psychologist or psychiatrist may be essential in the treatment of patients whose symptoms do not correlate with objective evidence of DE

Prevalence of Self-Reported Symptoms of TMD in a Population of Rijeka, Croatia

Svrha ovog istraživanja bila je ispitati prevalenciju simptoma TMD u stanovništvu Rijeke. Istraživanje je provedeno na uzorku 408 odraslih osoba starih od 18-84 godine, podijeljenih po dobi i spolu. Postojanje TMD simptoma dobili smo upotrebom kliničko- anamnestičkih upitnika koji se sastojao od 11 pitanja tipičnih za TMD simptomatologiju. Okluzalne parametre dobili smo raščlambom RCP, ICP prednjega vođenja i lateralnih kretnji. Kliničke znakove TMD dobili smo palpacijom mišića žvakača i TMJ. Anamnezom smo došli do podatka da je 16 % ispitanika izjavilo kako ima noćni bruksizam, a 33 % dnevni. 26 % ispitanika osjetilo je škljocanje u zglobu. 37 % pacijenata ima uz bruksizam i glavobolju, 35 % ima bolan vrat i ramena, a 33 % ima škljocanje u TMZ. U skupini pacijenata bez bruksizma 41 % ima glavobolju, 29 % bolni vrat i 24 % ima škljocanje. Možemo zaključiti da postoji veza između pojave noćnog bruksizma i bolnosti mišića vrata i ramena te škljocanje TMZ.The aim of this study was to evaluate the prevalence of temporomandibular disorder (TMD) symptoms in a population of Rijeka, Croatia. The study was performed on a sample of 408 adult subjects, aged 18-84 years divided into three groups by age and gender. The presence and severity of TMD was determined by using a self reported anamnestic questionnaire comprised of 11 questions regarding common TMD symptoms. Occlusal evaluation included analyses of RCP, ICP, anterolateral guidance, and nonworking side contacts during mandibular movements. Palpation of the muscles and TMJ was performed to detect clinical signs of TMD. A total of 16 % of the examinees had self-reported nocturnal bruxism and 33 % had daily bruxism. 26 % of the examinees experienced TMJ clicking. 28 % of the examinees experienced tension type headache, more than once a month. 37 % of the patients with bruxism had headaches, 35 % had painful necks and shoulders, and 33 % experienced TMJ clicking. Of those who did not suffer from bruxism, 41 % had headaches, 29 % had painful neck and sholders and 24% had TMJ clicking. It appears that sleep bruxism is related with the presence of painful neck and sholders and TMJ clicking